Subpart L -- National Oil and Hazardous Substances
Pollution Contingency Plan; Lender Liability Under CERCLA
Sec.
300.1100 Security interest exemption.
300.1105 Involuntary acquisition of property by the government.

40 CFR §300.1100

A person who maintains indicia of ownership primarily to protect a interest in a vessel or facility, and who does not participate in the management of the vessel or facility, is not an "owner or operator'' of such vessel or facility under CERCLA section 107(a)(1) or section 107(a)(2). The plaintiff bears the burden of establishing that the defendant is liable as an owner or operator.

(a) Indicia of ownership as used in section 101(20)(A) of CERCLA means evidence of a security interest, evidence of an interest in a security interest, or evidence of an interest in real or personal property securing a loan or other obligation, including any legal or equitable title to real or personal property acquired incident to foreclosure and its equivalents. Evidence of such interests include, but are not limited to, mortgages, deeds of trust, liens, surety bonds and guarantees of obligations, title held pursuant to a lease financing transaction in which the lessor does not select initially the leased property (hereinafter "lease financing transaction''), legal or equitable title obtained pursuant to foreclosure, and their equivalents. Evidence of such interests also include assignments, pledges, or other rights to or other forms of encumbrance against property that are held primarily to protect a security interest. A person is not required to hold title or a security interest in order to maintain indicia of ownership.

(1) A holder is a person who maintains indicia of ownership (as defined in 40 CFR 300.1100(a)) primarily to protect a security interest (as defined in 40 CFR 300.1100(b)(1)). A holder includes the initial holder (such as a loan originator), any subsequent holder (such as a successor-in-interest or subsequent purchaser of the security interest on the secondary market), a guarantor of an obligation, surety, or any other person who holds ownership indicia primarily to protect a security interest, or a receiver or other person who acts on behalf or for the benefit of a holder.

(2) A borrower, debtor, or obligor is a person whose vessel or facility is encumbered by a security interest. These terms are used interchangeably.

(b) Primarily to protect a security interest for the purposes of section 101(20)(A) of CERCLA means that the holder's indicia of ownership are held primarily for the purpose of securing payment or performance of an obligation.

(1) Security interest as used in section 101(20)(A) of CERCLA means an interest in a vessel or facility created or established for the purpose of securing a loan or other obligation. Security interests include, but are not limited to, mortgages, deeds of trusts, liens, and title pursuant to lease financing transactions. Security interests may also arise from transactions such as sale and leasebacks, conditional sales, installment sales, trust receipt transactions, certain assignments, factoring agreements, accounts receivable financing arrangements, and consignments, if the transaction creates or establishes an interest in a vessel or facility for the purpose of securing a loan or other obligation.

(2) Primarily to protect a security interest does not include indicia of ownership held primarily for investment purposes, nor ownership indicia held primarily for purposes other than as protection for a security interest. A holder may have other, secondary reasons for maintaining indicia of ownership, but the primary reason why any ownership indicia are held must be as protection for a security interest.

(c) Participation in Management Defined. The term participating in the management of a vessel or facility means that the holder is engaging in acts of facility or vessel management, as defined herein.

(1) Actions That Are Participation in Management. Participation in the management of a facility means, for the purpose of section 101(20)(A), actual participation in the management or operational affairs of the vessel or facility by the holder, and does not include the mere capacity to influence, or ability to influence, or the unexercised right to control facility operations. A holder is participating in management, while the borrower is still in possession of the vessel or facility encumbered by the security interest, only if the holder either:

(i) Exercises decisionmaking control over the borrower's environmental compliance, such that the holder has undertaken responsiblity for the borrower's hazardous substance handling or disposal practices; or

(ii) Exercises control at a level comparable to that of a manager of the borrower's enterprise, such that the holder has assumed or manifested responsibility for the overall management of the enterprise encompassing the day-to-day decisionmaking of the enterprise with the respect to:

(A) Environmental compliance or

(B) All, or substantially all, of the operational (as opposed to financial or administrative) aspects of the enterprise other than environmental compliance. Operational aspects of the enterprise include functions such as that of facility or plant manager, operations manager, chief operating officer, or chief executive officer.

Financial or administrative aspects include functions such as that of credit manager, accounts payable/receivable manager, personnel manager, controller, chief financial officer, or similar functions.

(2) Actions That Are Not Participation in Management -- (i) Actions at the Inception of the Loan or Other Transaction. No act or omission prior to the time that indicia of ownership are held primarily to protect a security interest constitutes evidence of participation in management within the meaning of section 101(20)(A). A prospective holder who undertakes or requires an environmental inspection of the vessel or facility in which indicia of ownership are to be held, or requires a prospective borrower to clean up a vessel or facility or to comply or come into compliance (whether prior or subsequent to the time that indicia of ownership are held primarily to protect a security interest) with any applicable law or regulation, is not by such action considered to be participating in the vessel or facility's management. Neither the statute nor this regulation requires a holder to conduct or require an inspection to qualify for the exemption, and the liability of a holder cannot be based on or affected by the holder not conducting or not requiring an inspection.

(ii) Policing and Workout. Actions that are consistent with holding ownership indicia primarily to protect a security interest do not constitute participation in management for purposes of section 101(20)(A) of CERCLA. The authority for the holder to take such actions may, but need not, be contained in contractual or other documents specifying requirements for financial, environmental, and other warranties, covenants, conditions, representations or promises from the borrower. Loan policing and workout activities cover and include all activities up to foreclosure and its equivalents, as provided in 40 CFR 300.1100(d)(1).

(A) Policing the Security Interest or Loan. A holder who engages in policing activities prior to foreclosure will remain within the exemption provided that the holder does not by such actions participate in the management of the vessel or facility as provided in 40 CFR 300.1100(c)(1). Such actions include, but are not limited to, requiring the borrower to clean up the vessel or facility during the term of the security interest; requiring the borrower to comply or come into compliance with applicable federal, state, and local environmental and other laws, rules and regulations during the term of the security interest; securing or exercising authority to monitor or inspect the vessel or facility (including on-site inspections) in which indicia of ownership are maintained, or the borrower's business or financial condition during the term of the security interest; or taking other actions to adequately police the loan or security interest (such as requiring a borrower to comply with any warranties, covenants, conditions, representations or promises from the borrower).

(B) Work Out. A holder who engages in work out activities prior to foreclosure and its equivalents will remain within the exemption provided that the holder does not by such action participate in the management of the vessel or facility as provided in 40 CFR §300.1100(c)(1). For purposes of this rule, "work out'' refers to those actions by which a holder, at any time prior to foreclosure and its equivalents, seeks to prevent, cure, or mitigate a default by the borrower or obligor; or to preserve, or prevent the diminution of, the value of the security. Work out activities include, but are not limited to, restructuring or renegotiating the terms of the security interest; requiring payment of additional rent or interest; exercising forbearance; requiring or exercising rights pursuant to an assignment of accounts or other amounts owing to an obligor; requiring or exercising rights pursuant to an escrow agreement pertaining to amounts owing to an obligor; providing specific or general financial or other advice, suggestions, counseling, or guidance; and exercising any right or remedy the holder is entitled to by law or under any warranties, covenants, conditions, representations or promises from the borrower.

(iii) Actions Taken Under CERCLA section 107(d)(1). Notwithstanding 40 CFR 300.1100(c)(1), a holder does not participate in the management of a vessel or facility by taking any response action under section 107(d)(1) of CERCLA or under the direction of an on-scene coordinator.

(d) Foreclosure on Property and Post-Foreclosure Activities. -- (1) Foreclosure. Indicia of ownership that are held primarily to protect a security interest include legal or equitable title acquired through or incident to foreclosure and its equivalents. For purposes of this Subpart, the term "foreclosure and its equivalents'' includes purchase at foreclosure sale; acquisition or assignment of title in lieu of foreclosure; termination of a lease or other repossession; acquisition of a right to title or possession; an agreement in satisfaction of the obligation; or any other formal or informal manner (whether pursuant to law or under warranties, covenants, conditions, representations or promises from the borrower) by which the holder acquires title to or possession of the secured property. The indicia of ownership held after foreclosure continue to be maintained primarily as protection for a security interest provided that the holder undertakes to sell, re-lease property held pursuant to a lease financing transaction (whether by a new lease financing transaction or substitution of the lessee), or otherwise divest itself of the property in a reasonably expeditious manner, using whatever commercially reasonable means are relevant or appropriate with respect to the vessel of facility, taking all facts and circumstances into consideration, and provided that the holder did not participate in management (as defined in 40 CFR §300.1100(c)) prior to foreclosure and its equivalents. For purposes of establishing that a holder is seeking to sell, re-lease property held pursuant to a lease financing transaction (whether by a new lease financing transaction or substitution of the lessee), or divest a vessel or facility in a reasonably expeditious manner, the holder may use whatever commercially reasonable means as are relevant or appropriate with respect to the vessel or facility, or may employ the means specified in 40 CFR §300.1100(d)(2)(i). A holder that outbids, rejects or fails to act upon a written bona fide, firm offer of fair consideration for the property, as provided in 40 CFR §300.1100(d)(ii), is not considered to hold indicia of ownership primarily to protect a security interest.

(2) Holding Foreclosed Property for Disposition and Liquidation. A holder, who did not participate in management prior to foreclosure and its equivalents, may sell, re-lease property held pursuant to a lease financing transaction (whether by a new lease financing transaction or substitution of the lessee), liquidate, maintain business activities, wind up operations, undertake any response action under section 107(d)(1) of CERCLA or under the direction of an on-scene coordinator, and take measures to preserve, protect or prepare the secured asset prior to sale or other disposition. The holder may conduct these activities without voiding the exemption, subject to the requirements of 40 CFR §300.1100(d)(1) and §300.1100(d)(2).

(i) A holder establishes that the ownership indicia maintained following foreclosure and its equivalents continue to be held primarily to protect a security interest by, within twelve months following foreclosure, listing the vessel or facility with a broker, dealer, or agent who deals with the type of property in question, or by advertising the vessel or facility as being for sale or disposition on at least a monthly basis in either a real estate publication or a trade or other publication suitable for the vessel or facility in question, or a newspaper of general circulation (defined as one with a circulation over 10,000, or one suitable under any applicable federal, state, or local rules of court for publication required by court order or rules of civil procedure) covering the area where the property is located. For purposes of this provision, the twelve-month period begins to run from the time that the holder acquires marketable title, that the holder, after the expiration of any redemption or other waiting period provided by law, was acting diligently to acquire marketable title. If the holder fails to act diligently to acquire marketable title, the twelve-month period begins to run on the date of foreclosure and its equivalents.

(ii) A holder that outbids, rejects, or fails to act upon an offer of fair consideration for the vessel or facility establishes that the ownership indicia in the secured property are not held primarily to protect the security interest, unless the holder is required, in order to avoid liability under federal or state law, to make a higher bid, to obtain a higher offer, or to seek or obtain an offer in a different manner.

(A) Fair consideration, in the case of a holder maintaining indicia of ownership primarily to protect a senior security interest in the vessel or facility, is the value of the security interest as defined in this section. The value of the security interest is calculated as an amount equal to or in excess of the sum of the outstanding principal (or comparable amount in the case of a lease that constitutes a security interest) owed to the holder immediately preceding the acquisition of full title (or possession in the case of property subject to a lease financing transaction) pursuant to foreclosure and its equivalents, plus any unpaid interest, rent or penalties (whether arising before or after foreclosure and its equivalents), plus all reasonable and necessary costs, fees, or other charges incurred by the holder incident to work out, foreclosure and its equivalents, retention, maintaining the business activities of the enterprise, preserving, protecting and preparing the vessel or facility prior to sale, re-lease of property held pursuant to a lease financing transaction (whether by a new lease financing transaction or substitution of the lessee) or other disposition, plus response costs incurred under section 107(d)(1) of CERCLA or at the direction of an on-scene coordinator; less any amounts received by the holder in connection with any partial disposition of the property, net revenues received as a result of maintaining the business activities of the enterprise, and any amounts paid by the borrower subsequent to the acquisition of full title (or possession in the case property subject to a lease financing transaction) pursuant to foreclosure and its equivalents. In the case of a holder maintaining indicia of ownership primarily to protect a junior security interest, fair consideration is the value of all outstanding higher priority security interests plus the value of the security interest held by the junior holder, each calculated as set forth in the preceding sentence.

(B) Outbids, rejects, or fails to act upon an offer of fair consideration means that the holder outbids, rejects or fails to act upon within 90 days of receipt of a written, bona fide, firm offer of fair consideration for the property received at any time after six months following foreclosure and its equivalents. A "written, bona fide, firm offer'' means a legally enforceable, commercially reasonable, cash offer solely for the foreclosed vessel or facility, including all material terms of the transaction, from a ready, willing, and able purchaser who demonstrates to the holder's satisfaction the ability to perform. For purposes of this provision, the six-month period begins to run from the time that the holder acquires a marketable title, provided that the holder, after the expiration of any redemption or other waiting period provided by law, was acting diligently to acquire marketable title. If the holder fails to act diligently to acquire marketable title, the six-month period begins to run on the date of foreclosure and its equivalents.

(3) Holder's Basis of CERCLA Liability Independent of Status as Owner or Operator. (i) Provided that the holder did not participate in management prior to foreclosure and its equivalents and the holder complies with the requirements of 40 CFR §300.1100(d)(1)-(d)(2), during the period following foreclosure and its equivalents a holder in possession of a vessel or facility can incur liability CERCLA in connection with its activities at such foreclosed vessel or facility only by arranging for disposal or treatment of a hazardous substance, as provided by CERCLA section 107(a)(3), or by accepting for transportation and disposing of hazaradous substances at a facility selected by the holder, as provided by CERCLA section 107(a)(4).

(ii) Following foreclosure and its equivalents, a foreclosing holder that directs or undertakes activities under CERCLA section 107(d)(1) or at the direction of an on-scene coordinator at the foreclosed vessel or facility does not incur liability for such activities.

RETURN TO THE TOP


§300.1105

(a) Governmental ownership or control of property by involuntary acquisitions or involuntary transfers within the meaning of CERCLA section 101(20)(D) or section 101(35)(A)(ii) includes, but is not limited to:

(1) Acquisitions by or transfers to the government in its capacity as a sovereign, including transfers or acquisitions pursuant to abandonment proceedings, or as the result of tax delinquency, or escheat, or other circumstances in which the government involuntarily obtains ownership or control of property by virture of its function as sovereign;

(2) Acquisitions by or transfers to a government entity or its agent (including governmental lending and credit institutions, loan guarantors, loan insurers, and financial regulatory entities which acquire security interests or properties of failed private lending or depository institutions) acting as a conservator or receiver pursuant to a clear and direct statutory mandate or regulatory authority;

(3) Acquisitions or transfers of assets through foreclosure and its equivalents (as defined in 40 CFR §300.1100(d)(1)) or other means by a federal, state, or local government entity in the course of administering a governmental loan or loan guarantee or loan insurance program; and

(4) Acquisitions by or transfers to a government entity pursuant to seizure or forfeiture authority.

(b) Nothing in this section or in CERCLA section 101(20)(D) or section 101(35)(A)(ii) affects the applicability of 40 CFR §300.1100 to any security interest, property, or asset acquired pursuant to an involuntary acquisition or transfer, as described in this section.

Concentration corresponding to Food and Drug Administration Action Level (FDAAL) for fish or shellfish.

Screening concentration for cancer corresponding to that concentration that corresponds to the 10^6 individual cancer risk for oral exposures.

Screening concentration for noncancer toxicological responses corresponding to the Reference Dose (RfD) for oral exposures.

4.1.3.3.1 Food chain individual. Evaluate the food chain individual factor based on the fisheries (or portions of fisheries) within the target distance limit for the watershed. Assign this factor a value as follows:

If any fishery (or portion of a fishery) is subject to Level I concentrations, assign a value of 50.

If not, but if any fishery (or portion of a fishery) is subject to Level II concentrations, assign a value of 45.

If not, but if there is an observed release of a hazardous substance having a bioaccumulation potential factor value of 500 or greater to surface water in the watershed and there is a fishery (or portion of a fishery) present anywhere within the target distance limit, assign a value of 20.

If there is no observed release to surface water in the watershed or there is no observed release of a hazardous substance having a bioaccumulation potential factor value of 500 or greater, but there is a fishery (or portion of a fishery) present anywhere within the target distance limit, assign a value as follows:

-Using Table 4-13, determine the highest dilution weight (that is, lowest amount of dilution) applicable to the fisheries (or portions of fisheries) within the target distance limit. Multiply this dilution weight by 20 and round to the nearest integer.

-Assign this calculated value as the factor value.

If there are no fisheries (or portions of fisheries) within the target distance limit of the watershed, assign a value of 0.

Enter the value assigned in Table 4-1.

4.1.3.3.2 Population. Evaluate the population factor for the watershed based on three factors: Level I concentrations, Level II concentrations, and potential human food chain contamination. Determine which factor applies for a fishery (or portion of a fishery) as specified in section 4.1.3.3.

4.1.3.3.2.1 Level I concentrations. Determine those fisheries (or portions of fisheries) within the watershed that are subject to Level I concentrations.

Estimate the human food chain population value for each fishery (or portion of a fishery) as follows:

Estimate human food chain production for the fishery based on the estimated annual production (in pounds) of human food chain organisms (for example, fish, shellfish) for that fishery, except: if the fishery is closed and a hazardous substance for which the fishery has been closed has been documented in an observed release to the fishery from a source at the site, use the estimated annual production the period prior to closure of the fishery or use the estimated annual production from comparable fisheries that are not closed.

Assign the fishery a value for human food chain population from Table 4-18, based on the estimated human food production for the fishery.

Set boundaries between fisheries at those points where human food chain production changes or where the surface water dilution weight changes.

Sum the human food chain population value for each fishery (and portion of a fishery). Multiply this sum by 10. If the product is less than 1, do not round it to the nearest integer; if 1 or more, round to the nearest integer. Assign the resulting value as the Level I concentrations factor value. Enter this value in Table 4-1.

4.1.3.3.2.2 Level II concentrations. Determine those fisheries (or portions of fisheries) within the watershed that are subject to Level II concentrations. Do not include any fisheries (or portions of fisheries) already counted under the Level I concentrations factor.

Assign each fishery (or portion of a fishery) a value for human food chain population from Table 4-18, based on the estimated human food production for the fishery. Estimate the human food chain production for the fishery as specified in section 4.1.3.3.2.1.

Sum the human food chain population value for each fishery (and portion of a fishery). If this sum is less than 1, do not round it to the nearest integer; if 1 or more, round to the nearest integer. Assign the resulting value as the Level II concentrations factor value. Enter this value in Table 4-1.

Table 4-18 -- Human Food Chain Population Values
TABLE/GRAPH OMITTED

4.1.3.3.2.3 Potential human food chain contamination. Determine those fisheries (or portions of fisheries) within the watershed that are subject to potential human food chain contamination. Do not include those fisheries (or portion of fisheries) already counted under the Level I or Level II concentrations factors.

Calculate the value for the potential human food chain contamination factor (PF) for the watershed as follows:

TABLE/GRAPH OMITTED

where:

Pi=Human food chain population value for fishery i.

Di=Dilution weight from Table 4-13 for fishery i.

n=Number of fisheries subject to potential human food chain contamination.

In calculating PF:

Estimate the human food chain population value (Pi) for a fishery (or portion of a fishery) as specified in section 4.1.3.3.2.1.

Assign the fishery (or portion of a fishery) a dilution weight as indicated in Table 4-13 (section 4.1.2.3.1), except: do not assign a dilution weight of 0.5 for a "3-mile mixing zone in quiet flowing river''; instead assign a dilution weight based on the average annual flow.

If PF is less than 1, do not round it to the nearest integer; if PF is 1 or more, round to the nearest integer. Enter the value assigned in Table 4-1.

4.1.3.3.2.4 Calculation of population factor value. Sum the values for the Level I concentrations, Level II concentrations, and potential human food chain contamination factors for the watershed. Do not round this sum to the nearest integer. Assign it as the population factor value for the watershed. Enter this value in Table 4-1.

4.1.3.3.3 Calculation of human food chain threat-targets factor category value. Sum the food chain individual and population factor values for the watershed. Do not round this sum to the nearest integer. Assign it as the human food chain threat-targets factor category value for the watershed. Enter this value in Table 4-1.

4.1.3.4 Calculation of human food chain threat score for a watershed. Multiply the human food chain threat factor category values for likelihood of release, waste characteristics, and targets for the watershed, and round the product to the nearest integer. Then divide by 82,500. Assign the resulting value, subject to a maximum of 100, as the human food chain threat score for the watershed. Enter this score in Table 4-1.

4.1.4 Environmental threat. Evaluate the environmental threat for the watershed based on three factor categories: likelihood of release, waste characteristics, and targets.

4.1.4.1 Environmental threat-likelihood of release. Assign the same likelihood of release factor category value for the environmental threat for the watershed as would be assigned in section 4.1.2.1.3 for the drinking water threat. Enter this value in Table 4-1.

4.1.4.2 Environmental threat-waste characteristics. Evaluate the waste characteristics factor category for each watershed based on two factors: ecosystem toxicity/persistence/bioaccumulation and hazardous waste quantity.

4.1.4.2.1 Ecosystem toxicity/persistence/bioaccumulation. Evaluate all those hazardous substances eligible to be evaluated for toxicity/persistence in the drinking water threat for the watershed (see

section 4.1.2.2).

4.1.4.2.1.1 Ecosystem toxicity. Assign an ecosystem toxicity factor value from Table 4-19 to each hazardous substance on the basis of the following data hierarchy:

EPA chronic Ambient Water Quality Criterion (AWQC) for the substance.

EPA chronic Ambient Aquatic Life Advisory Concentrations (AALAC) for the substance.

EPA acute AWQC for the substance.

EPA acute AALAC for the substance.

Lowest LC50 value for the substance.

In assigning the ecosystem toxicity factor value to the hazardous substance:

If either an EPA chronic AWQC or AALAC is available for the hazardous substance, use it to assign the ecosystem toxicity factor value. Use the chronic AWQC in preference to the chronic AALAC when both are available.

If neither is available, use the EPA acute AWQC or AALAC to assign the ecosystem toxicity factor value. Use the acute AWQC in preference to the acute AALAC.

If none of the chronic and acute AWQCs and AALACs is available, use the lowest LC50 value to assign the ecosystem toxicity factor value.

If an LC50 value is also not available, assign an ecosystem toxicity factor value of 0 to the hazardous substance and use other hazardous substances for which data are available in evaluating the pathway.

If an ecosystem toxicity factor value of 0 is assigned to all hazardous substances eligible to be evaluated for the watershed (that is, insufficient data are available for evaluating all the substances), use a default value of 100 as the ecosystem toxicity factor value for all these hazardous substances.

With regard to the AWQC, AALAC, or LC50 selected for assigning the ecosystem toxicity factor value to the hazardous substance:

If values for the selected AWQC, AALAC, or LC50 are available for both fresh water and marine water for the hazardous substance, use the value that corresponds to the type of water body (that is, fresh water or salt water) in which the sensitive environments are located to assign the ecosystem toxicity factor value to the hazardous substance.

If, however, some of the sensitive environments being evaluated are in fresh water and some are in salt water, or if any are in brackish water, use the value (fresh water or marine) that yields the higher factor value to assign the ecosystem toxicity factor value to the hazardous substance.

If a value for the selected AWQC, AALAC, or LC50 is available for either fresh water or marine water, but not for both, use the available one to assign an ecosystem toxicity factor value to the hazardous substance.

If an EPA chronic AWQCa or AALACb is available, assign a value as follows:c

TABLE/GRAPH OMITTED

TABLE/GRAPH OMITTED

TABLE/GRAPH OMITTED

4.1.4.2.1.2 Persistence. Assign a persistence factor value to each hazardous substance as specified in section 4.1.2.2.1.2, except: use the predominant water category (that is lakes; or rivers, oceans, coastal tidal waters, or Great Lakes) between the probable point of entry and the nearest sensitive environment (not the nearest drinking water or resources intake) along the hazardous substance migration path for the watershed to determine which portion of Table 4-10 to use. Determine the predominant water category based on distance as specified in section 4.1.2.2.1.2. For contaminated sediments with no identified source, use the point where measurement begins rather than the probable point of entry.

4.1.4.2.1.3 Ecosystem bioaccumulation potential. Assign an ecosystem bioaccumulation potential factor value to each hazardous substance in the same manner specified for the bioaccumulation potential factor in section 4.1.3.2.1.3, except:

Use BCF data for all aquatic organisms, not just for aquatic human food chain organisms.

Use the BCF data that corresponds to the type of water body (that is, fresh water or salt water) in which the sensitive environments (not fisheries) are located.

4.1.4.2.1.4 Calculation of ecosystem toxicity/persistence/bioaccumulation factor value. Assign each hazardous substance an ecosystem toxicity/persistence factor value from Table 4-20, based on the values assigned to the hazardous substance for the ecosystem toxicity and persistence factors. Then assign each hazardous substance an ecosystem toxicity/persistence/bioaccumulation factor value from Table 4-21, based on the values assigned for the ecosystem toxicity/persistence and ecosystem bioaccumulation potential factors. Select the hazardous substance with the highest ecosystem toxicity/persistence/bioaccumulation factor value for the watershed and use it to assign the value to this factor. Enter this value in Table 4-1.

Table 4-20 -- Ecosystem Toxicity/Persistence Factor Values
TABLE/GRAPH OMITTED

Table 4-21 -- Ecosystem Toxicity/Persistence/Bioaccumulation Factor Values

TABLE/GRAPH OMITTED

4.1.4.2.2 Hazardous waste quantity. Assign the same factor value for hazardous waste quantity for the watershed as would be assigned in section 4.1.2.2.2 for the drinking water threat. Enter this value in Table 4-1.

4.1.4.2.3 Calculation of environmental threat-waste characteristics factor category value. For the hazardous substance selected for the watershed in section 4.1.4.2.1.4, use its ecosystem toxicity/persistence factor value and ecosystem bioaccumulation potential factor value as follows to assign a value to the waste characteristics factor category. First, multiply the ecosystem toxicity/persistence factor value and the hazardous waste quantity factor value for the watershed, subject to a maximum product of 1 108. Then multiply this product by the ecosystem bioaccumulation potential factor value for this hazardous substance, subject to a maximum product of 1 1012. Based on this second product, assign a value from Table 2-7 (section 2.4.3.1) to the environmental threat-waste characteristics factor category for the watershed. Enter this value in Table 4-1.

Concentration corresponding to EPA Ambient Water Quality Criteria (AWQC) for protection of aquatic life (fresh water or marine).

Concentration corresponding to EPA Ambient Aquatic Life Advisory (AALAC).

Select the appropriate AWQC and AALAC as follows:

-Use chronic value, if available; otherwise use acute value.

-If the sensitive environment being evaluated is in fresh water, use fresh water value, except: if no fresh water value is available, use marine value if available.

-If the sensitive environment being evaluated is in salt water, use marine value, except: if no marine value is available, use fresh water value if available.

-If the sensitive environment being evaluated is in both fresh water and salt water, or is in brackish water, use lower of fresh water or marine values.

Table 4-23 -- Sensitive Environments Rating Values
TABLE/GRAPH OMITTED

Table 4-24 -- Wetlands Rating Values for Surface Water Migration Pathway
TABLE/GRAPH OMITTED

4.1.4.3 Environmental threat-targets. Evaluate the environmental threat-targets factor category for a watershed using one factor: sensitive environments.

4.1.4.3.1 Sensitive environments. Evaluate sensitive environments along the hazardous substance migration path for the watershed based on three factors: Level I concentrations, Level II concentrations, and potential contamination.

Determine which factor applies to each sensitive environment as specified in section 4.1.2.3, except: use ecological-based benchmarks (Table 4-22) rather than health-based benchmarks (Table 3-10) in determining the level of contamination from samples. In determining the level of actual contamination, use a point of direct observation anywhere within the sensitive environment or samples (that is, surface water, benthic, or sediment samples) taken anywhere within or beyond the sensitive environment (or anywhere adjacent to or beyond the sensitive environment if it is contiguous to the migration path).

4.1.4.3.1.1 Level I concentrations. Assign value(s) from Table 4-23 to each sensitive environment subject to Level I concentrations.

For those sensitive environments that are wetlands, assign an additional value from Table 4-24. In assigning a value from Table 4-24, include only those portions of wetlands located along the hazardous substance migration path in the area of Level I concentrations. If a wetland is located partially along the area of Level I concentrations and partially along the area of Level II concentrations and/or potential contamination, then solely for purposes of Table 4-24, count the portion(s) along the areas of Level II concentrations or potential contamination under the Level II concentrations factor (section 4.1.4.3.1.2) or potential contamination factor (section 4.1.4.3.1.3), as appropriate.

Estimate the total length of wetlands along the hazardous substance migration path (that is, wetland frontage) in the area of Level I concentrations and assign a value from Table 4-24 based on this total length. Estimate this length as follows:

For an isolated wetland or for a wetland where the probable point of entry to surface water is in the wetland, use the perimeter of that portion of the wetland subject to Level I concentrations as the length.

For rivers, use the length of the wetlands contiguous to the in-water segment of the hazardous substance migration path (that is, wetland frontage).

For lakes, oceans, coastal tidal waters, and Great Lakes, use the length of the wetlands along the shoreline within the target distance limit (that is, wetland frontage along the shoreline).

Calculate the Level I concentrations factor value (SH) for the watershed as follows:

TABLE/GRAPH OMITTED

where:

WH=Value assigned from Table 4-24 to wetlands along the area of Level I concentrations.

Si=Value(s) assigned from Table 4-23 to sensitive environment i.

n=Number of sensitive environments from Table 4-23 subject to Level I concentrations.

Enter the value assigned in Table 4-1.

4.1.4.3.1.2 Level II concentrations. Assign value(s) from Table 4-23 to each sensitive environment subject to Level II concentrations. Do not include sensitive environments already counted for Table 4-23 under the Level I concentrations factor for this watershed.

For those sensitive environments that are wetlands, assign an additional value from Table 4-24. In assigning a value from Table 4-24, include only those portions of wetlands located along the hazardous substance migration path in the area of Level II concentrations, as specified in section 4.1.4.3.1.1.

Estimate the total length of wetlands along the hazardous substance migration path (that is, wetland frontage) in the area of Level II concentrations and assign a value from Table 4-24 based on this total length. Estimate this length as specified in section 4.1.4.3.1.1, except: for an isolated wetland or for a wetland where the probable point of entry to surface water is in the wetland, use the perimeter of that portion of the wetland subject to Level II (not Level I) concentrations as the length.

Calculate the Level II concentrations value (SL) for the watershed as follows:

TABLE/GRAPH OMITTED

where:

WL=Value assigned from Table 4-24 to wetlands along the area of Level II concentrations.

Si=Value(s) assigned from Table 4-23 to sensitive environment i.

n=Number of sensitive environments from Table 4-23 subject to Level II concentrations.

Enter the value assigned in Table 4-1.

4.1.4.3.1.3 Potential contamination. Assign value(s) from Table 4-23 to each sensitive environment subject to potential contamination. Do not include sensitive environments already counted for Table 4-23 under the Level I or Level II concentrations factors.

For each type of surface water body in Table 4-13 (section 4.1.2.3.1), sum the value(s) assigned from Table 4-23 to the sensitive environments along that type of surface water body, except: do not use the surface water body type "3-mile mixing zone in quiet flowing river.'' If a sensitive environment is along two or more types of surface water bodies (for example, Wildlife Refuge contiguous to both a moderate stream and a large river), assign the sensitive environment only to that surface water body type having the highest dilution weight value from Table 4-13.

For those sensitive environments that are wetlands, assign an additional value from Table 4-24. In assigning a value from Table 4-24, include only those portions of wetlands located along the hazardous substance migration path in the area of potential contamination, as specified in section 4.1.4.3.1.1. Aggregate these wetlands by type of surface water body, except: do not use the surface water body type "3-mile mixing zone in quiet flowing river.'' Treat the wetlands aggregated within each type of surface water body as separate sensitive environments solely for purposes of applying Table 4-24. Estimate the total length of the wetlands within each surface water body type as specified in section 4.1.4.3.1.1, except: for an isolated wetland or for a wetland where the probable point of entry to surface water is in the wetland, use the perimeter of that portion of the wetland subject to potential contamination (or the portion of that perimeter that is within the target distance limit) as the length. Assign a separate value from Table 4-24 for each type of surface water body in the watershed.

Calculate the potential contamination factor value (SP) for the watershed as follows:

TABLE/GRAPH OMITTED

where:

n

Sj = S Sij

i=1

Sij=Value(s) assigned from Table 4-23 to sensitive environment i in surface water body type j.

n=Number of sensitive environments from Table 4-23 subject to potential contamination.

Wj=Value assigned from Table 4-24 for wetlands along the area of potential contamination in surface water body type j.

Dj=Dilution weight from Table 4-13 for surface water body type j.

m=Number of different surface water body types from Table 4-13 in the watershed.

If SP is less than 1, do not round it to the nearest integer; if SP is 1 or more, round to the nearest integer. Enter this value for the potential contamination factor in Table 4-1.

4.1.4.3.1.4 Calculation of environmental threat-targets factor category value. Sum the values for the Level I concentrations, Level II concentrations, and potential contamination factors for the watershed. Do not round this sum to the nearest integer. Assign this sum as the environmental threat-targets factor category value for the watershed. Enter this value in Table 4-1.

4.1.4.4 Calculation of environmental threat score for a watershed. Multiply the environmental threat factor category values for likelihood of release, waste characteristics, and targets for the watershed, and round the product to the nearest integer. Then divide by 82,500. Assign the resulting value, subject to a maximum of 60, as the environmental threat score for the watershed. Enter this score in Table 4-1.

4.1.5 Calculation of overland/flood migration component score for a watershed. Sum the scores for the three threats for the watershed (that is, drinking water, human food chain, and environmental threats). Assign the resulting score, subject to a maximum value of 100, as the surface water overland/flood migration component score for the watershed. Enter this score in Table 4-1.

4.1.6 Calculation of overland/flood migration component score. Select the highest surface water overland/flood migration component score from the watersheds evaluated. Assign this score as the surface water overland/flood migration component score for the site, subject to a maximum score of 100. Enter this score in Table 4-1.

4.2 Ground water to surface water migration component. Use the ground water to surface water migration component to evaluate surface water threats that result from migration of hazardous substances from a source at the site to surface water via ground water. Evaluate three types of threats for this component: drinking water threat, human food chain threat, and environmental threat.

4.2.1 General considerations.

4.2.1.1 Eligible surface waters. Calculate ground water to surface water migration component scores only for surface waters (see section 4.0.2) for which all the following conditions are met:

A portion of the surface water is within 1 mile of one or more sources at the site having a containment factor value greater than 0 (see section 4.2.2.1.2).

No aquifer discontinuity is established between the source and the portion of the surface water within 1 mile of the source (see section 3.0.1.2.2). However, if hazardous substances have migrated across an apparent discontinuity within this 1 mile distance, do not consider a discontinuity present in scoring the site.

The top of the uppermost aquifer is at or above the bottom of the surface water.

Do not evaluate this component for sites consisting solely of contaminated sediments with no identified source.

4.2.1.2 Definition of hazardous substance migration path for ground water to surface water migration component. The hazardous substance migration path includes both the ground water segment and the surface water in-water segment that hazardous substances would take as they migrate away from sources at the site:

Restrict the ground water segment to migration via the uppermost between a source and the surface water.

Begin the surface water in-water segment at the probable point of entry from the uppermost aquifer to the surface water. Identify the probable point of entry as that point of the surface water that yields the shortest straight-line distance, within the aquifer boundary (see section 3.0.1.2), from the sources at the site with a containment factor value greater than 0 to the surface water.

-For rivers, continue the in-water segment in the direction of flow (including any tidal flows) for the distance established by the target distance limit (see section 4.2.1.4).

-For lakes, oceans, coastal tidal waters, or Great Lakes, do not consider flow direction. Instead apply the target distance limit as an arc.

-If the in-water segment includes both rivers and lakes (or oceans, coastal tidal waters, or Great Lakes), apply the target distance limit to their combined in-water segments.

Consider a site to be in two or more watersheds for this component if two or more hazardous substance migration paths from the sources at the site do not reach a common point within the target distance limit. If the site is in more than one watershed, define a separate hazardous substance migration path for each watershed. Evaluate the ground water to surface water migration component for each watershed separately as specified in section 4.2.1.5.

4.2.1.3 Observed release of a specific hazardous substance to surface water in-water segment. Section 4.2.2.1.1 specifies the criteria for assigning values to the observed release factor for the ground water to surface water migration component. With regard to an individual hazardous substance, consider an observed release of that hazardous substance to be established for the surface water in-water segment of the ground water to surface water migration component only when the hazardous substance meets the criteria both for an observed release both to ground water (see section 4.2.2.1.1) and for an observed release by chemical analysis to surface water (see section 4.1.2.1.1).

If the hazardous substance meets the section 4.1.2.1.1 criteria for an observed release by chemical analysis to surface water but does not also meet the criteria for an observed release to ground water, do not use any samples of that hazardous substance from the surface water in-water segment in evaluating the factors of this component (for example, do not use the hazardous substance in establishing targets subject to actual contamination or in determining the level of actual contamination for a target).

4.2.1.4 Target distance limit. Determine the target distance limit for each watershed as specified in section 4.1.1.2, except: do not extend the target distance limit to a sample location beyond 15 miles unless at least one hazardous substance in a sample from that location meets the criteria in section 4.2.1.3 for an observed release to the surface water in-water segment.

Determine the targets eligible to be evaluated for each watershed and establish whether these targets are subject to actual or potential contamination as specified in section 4.1.1.2, except: do not establish actual contamination based on a sample location unless at least one hazardous substance in a sample from that location meets the criteria in section 4.2.1.3 for an observed release to the surface water in-water segment.

4.2.1.5 Evaluation of ground water to surface water migration component. Evaluate the drinking water threat, human food chain threat, and environmental threat for each watershed for this component based on three factor categories: likelihood of release, waste characteristics, and targets. Figure 4-2 indicates the factors included within each factor category for each type of threat.


Determine the ground water to surface water migration component score (Sgs) for a watershed in terms of the factor category values as follows:

TABLE/GRAPH OMITTED

where:

LRi=Likelihood of release factor category value for threat i (that is, drinking water, human food chain, or environmental threat).

WCi=Waste characteristics factor category value for threat i.

Ti=Targets factor category value for threat i.

SF=Scaling factor.

Table 4-25 outlines the specific calculation procedure.

If the site is in only one watershed, assign the ground water to surface water migration component score for that watershed as the ground water to surface water migration component score for the site.

If the site is in more than one watershed:

Calculate a separate ground water to surface water migration component score for each watershed, using likelihood of release, waste characteristics, and targets applicable to each watershed.

Select the highest ground water to surface water migration component score from the watersheds evaluated and assign it as the ground water to surface water migration component score for the site.

Table 4-25 -- Ground Water to Surface Water Migration Component Scoresheet
TABLE/GRAPH OMITTED

4.2.2 Drinking water threat. Evaluate the drinking water threat for each watershed based on three factor categories: likelihood of release, waste characteristics, and targets.

4.2.2.1 Drinking water threat-likelihood of release. Evaluate the likelihood of release factor category for each watershed in terms of an observed release factor or a potential to release factor.

4.2.2.1.1 Observed release. Establish an observed release to the uppermost aquifer as specified in section 3.1.1. If an observed release can be established for the uppermost aquifer, assign an observed release factor value of 550 to that watershed, enter this value in Table 4-25, and proceed to section 4.2.2.1.3. If no observed release can be established, assign an observed release factor value of 0, enter this value in Table

4-25, and proceed to section 4.2.2.1.2.

4.2.2.1.2 Potential to release. Evaluate potential to release only if an observed release cannot be established for the uppermost aquifer. Calculate a potential to release value for the uppermost aquifer as specified in section 3.1.2 and sections 3.1.2.1 through 3.1.2.5. Assign the potential to release value for the uppermost aquifer as the potential to release factor value for the watershed. Enter this value in Table 4-25.

4.2.2.1.3 Calculation of drinking water threat-likelihood of release factor category value. If an observed release is established for the uppermost aquifer, assign the observed release factor value of 550 as the likelihood of release factor category value for the watershed. Otherwise, assign the potential to release factor value as the likelihood of release factor category value for the watershed. Enter the value assigned in Table 4-25.

4.2.2.2 Drinking water threat-waste characteristics. Evaluate the waste characteristics factor category for each watershed based on two factors: toxicity/mobility/persistence and hazardous waste quantity. Evaluate only those hazardous substances available to migrate from the sources at the site to the uppermost aquifer (see section 3.2). Such hazardous substances include:

Hazardous substances that meet the criteria for an observed release to ground water.

All hazardous substances associated with a source that has a ground water containment factor value greater than 0 (see sections 2.2.2, 2.2.3, and 3.1.2.1).

4.2.2.2.1 Toxicity/mobility/persistence. For each hazardous substance, assign a toxicity factor value, a mobility factor value, a persistence factor value, and a combined toxicity/mobility/persistence factor value as specified in sections 4.2.2.2.1.1 through 4.2.2.2.1.4.

4.2.2.2.1.1 Toxicity. Assign a toxicity factor value to each hazardous substance as specified in section 2.4.1.1.

4.2.2.2.1.2 Mobility. Assign a ground water mobility factor value to each hazardous substance as specified in section 3.2.1.2.

4.2.2.2.1.3 Persistence. Assign a surface water persistence factor value to each hazardous substance as specified in section 4.1.2.2.1.2.

4.2.2.2.1.4 Calculation of toxicity/mobility/persistence factor value. First, assign each hazardous substance a toxicity/mobility factor value from Table 3-9 (section 3.2.1.3), based on the values assigned to the hazardous substance for the toxicity and mobility factors. Then assign each hazardous substance a toxicity/mobility/persistence factor value from Table 4-26, based on the values assigned for the toxicity/mobility and persistence factors. Use the substance with the highest toxicity/mobility/ persistence factor value for the watershed to assign the value to this factor. Enter this value in Table 4-25.

4.2.2.2.2 Hazardous waste quantity. Assign the same factor value for hazardous waste quantity for the watershed as would be assigned for the uppermost aquifer in section 3.2.2. Enter this value in Table 4-25.

4.2.2.2.3 Calculation of drinking water threat-waste characteristics factor category value. Multiply the toxicity/mobility/persistence and hazardous waste quantity factor values for the watershed, subject to a maximum product of 1 108. Based on this product, assign a value from Table 2-7 (section 2.4.3.1) to the drinking water threat-waste characteristics factor category for the watershed. Enter this value in Table 4-25.

4.2.2.3 Drinking water threat-targets. Evaluate the targets factor category for each watershed based on three factors: nearest intake, population, and resources.

Table 4-26 -- Toxicity/Mobility/Persistence Factor Values
TABLE/GRAPH OMITTED

For the nearest intake and population factors, determine whether the target surface water intakes are subject to actual or potential contamination as specified in section 4.1.1.2, subject to the restrictions specified in sections 4.2.1.3 and 4.2.1.4.

When the intake is subject to actual contamination, evaluate it using Level I concentrations or Level II concentrations. Determine which level applies for the intake by comparing the exposure concentrations from a sample (or comparable samples) to health-based benchmarks as specified in section 4.1.2.3, except use only those samples from the surface water in-water segment and only those hazardous substances in such samples that meet the conditions in sections 4.2.1.3 and 4.2.1.4.

4.2.2.3.1 Nearest intake. Assign a value to the nearest intake factor as specified in section 4.1.2.3.1 with the following modification. For the intake being evaluated, multiply its dilution weight from Table 4-13 (section 4.1.2.3.1) by a value selected from Table 4-27. Use the resulting product, not the value from Table 4-13, as the dilution weight for the intake for the ground water to surface water component. Do not round this product to the nearest integer.

Select the value from Table 4-27 based on the angle Q, the angle defined by the sources at the site and either the two points at the intersection of the surface water body and the 1-mile distance ring of any two other points of the surface water body within the 1-mile distance ring, whichever results in the largest angle. (See Figure 4-3 for an example of how to determine Q.) If the surface water body does not extend to the 1-mile ring at one or both ends, define Q using the surface water endpoint(s) within the 1-mile ring or any two other points of the surface water body within the 1-mile distance ring, whichever results in the largest angle.

Table 4-27 -- Dilution Weight Adjustments
TABLE/GRAPH OMITTED


Table 4-28 -- Toxicity/Mobility/Persistence/Bioaccumulation Factor Values
TABLE/GRAPH OMITTED

4.2.2.3.2 Population. Evaluate the population factor for the watershed based on three factors: Level I concentrations, Level II concentrations, and potential contamination. Determine which factor applies to an intake as specified in section 4.2.2.3. Determine the population to be counted for that intake as specified in section 4.1.2.3.2, using the target distance limits in section 4.2.1.4 and the hazardous substance migration path in section 4.2.1.2.

4.2.2.3.2.1 Level I concentrations. Assign a value to this factor as specified in section 4.1.2.3.2.2.

4.2.2.3.2.2 Level II concentrations. Assign a value to this factor as specified in section 4.1.2.3.2.3.

4.2.2.3.2.3 Potential contamination. For each applicable type of surface water body in Table 4-14, determine the dilution-weighted population value as specified in section 4.1.2.3.2.4. Select the appropriate dilution weight adjustment value from Table 4-27 as specified in section 4.2.2.3.1.

Calculate the value for the potential contamination factor (PC) for the watershed as follows:

TABLE/GRAPH OMITTED

where:

A=Dilution weight adjustment value from Table 4-27.

Wi=Dilution-weighted population from Table 4-14 for surface water body type i.

n=Number of different surface water body types in the watershed.

If PC is less than 1, do not round it to the nearest integer; if PC is 1 or more, round to the nearest integer. Enter the value in Table 4-25.

4.2.2.3.2.4 Calculation of population factor value. Sum the factor values for Level I concentrations, Level II concentrations, and potential contamination. Do not round this sum to the nearest integer. Assign this sum as the population factor value for the watershed. Enter this value in Table 4-25.

4.2.2.3.3 Resources. Assign a value to the resources factor as specified in section 4.1.2.3.3.

4.2.2.3.4 Calculation of drinking water threat-targets factor category value. Sum the nearest intake, population, and resources factor values for the watershed. Do not round this sum to the nearest integer. Assign this sum as the drinking water threat-targets factor category value for the watershed. Enter this value in Table 4-25.

4.2.2.4 Calculation of drinking water threat score for a watershed. Multiply the drinking water threat factor category values for likelihood of release, waste characteristics, and targets for the watershed, and round the product to the nearest integer. Then divide by 82,500. Assign the resulting value, subject to a maximum of 100, as the drinking water threat score for the watershed. Enter this score in Table 4-25.

4.2.3 Human food chain threat. Evaluate the human food chain threat for a watershed based on three factor categories: likelihood of release, waste characteristics, and targets.

4.2.3.1 Human food chain threat-likelihood of release. Assign the same likelihood of release factor category value for the human food chain threat for the watershed as would be assigned in section 4.2.2.1.3 for the drinking water threat. Enter this value in Table 4-25.

4.2.3.2 Human food chain threat-waste characteristics. Evaluate the waste characteristics factor category for each watershed based on two factors: toxicity/mobility/persistence/bioaccumulation and hazardous waste quantity.

4.2.3.2.1 Toxicity/mobility/persistence/bioaccumulation. Evaluate all those hazardous substances eligible to be evaluated for toxicity/mobility/persistence in the drinking water threat for the watershed (see section 4.2.2.2.1).

4.2.3.2.1.1 Toxicity. Assign a toxicity factor value to each hazardous substance as specified in section 2.4.1.1.

4.2.3.2.1.2 Mobility. Assign a ground water mobility factor value to each hazardous substance as specified for the drinking water threat (see section 4.2.2.2.1.2).

4.2.3.2.1.3 Persistence. Assign a surface water persistence factor value to each hazardous substance as specified for the drinking water threat (see section 4.2.2.2.1.3), except: use the predominant water category (that is, lakes; or rivers, oceans, coastal tidal waters, or Great Lakes) between the probable point of entry and the nearest fishery (not the nearest drinking water or resources intake) along the hazardous substance migration path for the watershed to determine which portion of Table 4-10 to use. Determine the predominant water category based on distance as specified in section 4.1.2.2.1.2.

4.2.3.2.1.4 Bioaccumulation potential. Assign a bioaccumulation potential factor value to each hazardous substance as specified in section 4.1.3.2.1.3.

4.2.3.2.1.5 Calculation of toxicity/mobility/persistence/ bioaccumulation factor value. Assign each hazardous substance a toxicity/mobility factor value from Table 3-9 (section 3.2.1.3), based on the values assigned to the hazardous substance for the toxicity and mobility factors. Then assign each hazardous substance a toxicity/mobility/persistence factor value from Table 4-26, based on the values assigned for the toxicity/mobility and persistence factors. Then assign each hazardous substance a toxicity/mobility/persistence/ factor value from Table 4-28. Use the substance with the highest toxicity/mobility/persistence/bioaccumulation factor value for the watershed to assign the value to this factor for the watershed. Enter this value in Table 4-25.

4.2.3.2.2 Hazardous waste quantity. Assign the same factor value for hazardous waste quantity for the watershed as would be assigned in 4.2.2.2.2 for the drinking water threat. Enter this value in Table 4-25.

4.2.3.2.3 Calculation of human food chain threat-waste characteristics factor category value. For the hazardous substance selected for the watershed in section 4.2.3.2.1.5, use its toxicity/mobility/ persistence factor value and bioaccumulation potential factor value as follows to assign a value to the waste characteristics factor category. First, multiply the toxicity/mobility/persistence factor value and the hazardous waste quantity factor value for the watershed, subject to a maximum product of 1 108. Then multiply this product by the bioaccumulation potential factor value for this hazardous substance, subject to a maximum product of 1 1012. Based on this second product, assign a value from Table 2-7 (section 2.4.3.1) to the human food chain threat-waste characteristics factor category for the watershed. Enter this value in Table 4-25.

4.2.3.3 Human food chain threat-targets. Evaluate two target factors for the watershed: food chain individual and population.

For both factors, determine whether the target fisheries are subject to Level I concentrations, Level II concentrations, or potential human food chain contamination. Determine which applies to each fishery (or portion of a fishery) as specified in section 4.1.3.3, subject to the restrictions specified in sections 4.2.1.3 and 4.2.1.4.

4.2.3.3.1 Food chain individual. Assign a value to the food chain individual factor as specified in section 4.1.3.3.1 with the following modification. When a dilution weight is used, multiply the appropriate dilution weight from Table 4-13 by the adjustment value selected from Table 4-27, as specified in section 4.2.2.3.1. Use the resulting product, not the value from Table

4-13, as the dilution weight in assigning the factor value. Do not round this product to the nearest integer. Enter the value assigned in Table 4-25.

4.2.3.3.2 Population. Evaluate the population factor for the watershed based on three factors: Level I concentrations, Level II concentrations, and potential human food chain contamination. Determine which of these factors is to be applied to each fishery as specified in section 4.2.3.3.

4.2.3.3.2.1 Level I concentrations. Assign a value to this factor as specified in section 4.1.3.3.2.1. Enter this value in Table 4-25.

4.2.3.3.2.2 Level II concentrations. Assign a value to this factor as specified in section 4.1.3.3.2.2. Enter this value in Table 4-25.

4.2.3.3.2.3 Potential human food chain contamination. Assign a value to this factor as specified in section 4.1.3.3.2.3 with the following modification. For each fishery being evaluated, multiply the appropriate dilution weight for that fishery from Table 4-13 by the adjustment value selected from Table 4-27, as specified in section 4.2.2.3.1. Use the resulting product, not the value from Table

4-13, as the dilution weight for the fishery. Do not round this product to the nearest integer. Enter the value assigned in Table 4-25.

4.2.3.3.2.4 Calculation of population factor value. Sum the factor values for Level I concentrations, Level II concentrations, and potential human food chain contamination for the watershed. Do not round this sum to the nearest integer. Assign this sum as the population factor value for the watershed. Enter this value in Table 4-25.

4.2.3.3.3 Calculation of human food chain threat-targets factor category value. Sum the food chain individual and population factor values for the watershed. Do not round this sum to the nearest integer. Assign this sum as the human food chain threat-targets factor category value for the watershed. Enter this value in Table 4-25.

4.2.3.4 Calculation of human food chain threat score for a watershed. Multiply the human food chain threat factor category values for likelihood of release, waste characteristics, and targets for the watershed, and round the product to the nearest integer. Then divide by 82,500. Assign the resulting value, subject to a maximum of 100, as the human food chain threat score for the watershed. Enter this score in Table 4-25.

4.2.4 Environmental threat. Evaluate the environmental threat for the watershed based on three factor categories: likelihood of release, waste characteristics, and targets.

4.2.4.1 Environmental threat-likelihood of release. Assign the same likelihood of release factor category value for the environmental threat for the watershed as would be assigned in section 4.2.2.1.3 for the drinking water threat. Enter this value in Table 4-25.

4.2.4.2 Environmental threat-waste characteristics. Evaluate the waste characteristics factor category for each watershed based on two factors: ecosystem toxicity/mobility/persistence/bioaccumulation and hazardous waste quantity.

4.2.4.2.1 Ecosystem toxicity/mobility/persistence/bioaccumulation. Evaluate all those hazardous substances eligible to be evaluated for toxicity/mobility/persistence in the drinking water threat for the watershed (see section 4.2.2.2.1).

4.2.4.2.1.1 Ecosystem toxicity. Assign an ecosystem toxicity factor value to each hazardous substance as specified in section 4.1.4.2.1.1.

4.2.4.2.1.2 Mobility. Assign a ground water mobility factor value to each hazardous substance as specified in section 4.2.2.2.1.2 for the drinking water threat.

4.2.4.2.1.3 Persistence. Assign a surface water persistence factor value to each hazardous substance as specified in section 4.2.2.2.1.3 for the drinking water threat, except: use the predominant water category (that is, lakes; or rivers, oceans, coastal tidal waters, or Great Lakes) between the probable point of entry and the nearest sensitive environment (not the nearest drinking water or resources intake) along the hazardous substance migration path for the watershed to determine which portion of Table 4-10 to use. Determine the predominant water category based on distance as specified in section 4.1.2.2.1.2.

4.2.4.2.1.4 Ecosystem bioaccumulation potential. Assign an ecosystem bioaccumulation potential factor value to each hazardous substance as specified in section 4.1.4.2.1.3.

4.2.4.2.1.5 Calculation of ecosystem toxicity/mobility/persistence/ bioaccumulation factor value. Assign each hazardous substance an ecosystem toxicity/mobility factor value from Table 3-9 (section 3.2.1.3), based on the values assigned to the hazardous substance for the ecosystem toxicity and mobility factors. Then assign each hazardous substance an ecosystem toxicity/mobility/persistence factor value from Table 4-29, based on the values assigned for the ecosystem toxicity/mobility and persistence factors. Then assign each hazardous substance an ecosystem toxicity/mobility/
persistence/bioaccumulation factor value from Table 4-30, based on the values assigned for the ecosystem toxicity/mobility/persistence and ecosystem bioaccumulation potential factors. Select the substance with the highest ecosystem toxicity/mobility/
persistence/bioaccumulation factor value for the watershed and use it to assign the value to this factor for the watershed. Enter this value in Table 4-25.

Table 4-29 -- Ecosystem Toxicity/Mobility/Persistence Factor Values
TABLE/GRAPH OMITTED

Table 4-30 -- Ecosystem Toxicity/Mobility/Persistence/Bioaccumulation Factor Values
TABLE/GRAPH OMITTED

4.2.4.2.2 Hazardous waste quantity. Assign the same factor value for hazardous waste quantity for the watershed as would be assigned in section 4.2.2.2.2 for the drinking water threat. Enter this value in Table 4-25.

4.2.4.2.3 Calculation of environmental threat-waste characteristics factor category value. For the hazardous substance selected for the watershed in section 4.2.4.2.1.5, use its ecosystem toxicity/mobility/persistence factor value and ecosystem bioaccumulation potential factor value as follows to assign a value to the waste characteristics factor category. First, multiply the ecosystem toxicity/mobility/
persistence factor value and the hazardous waste quantity factor value for the watershed, subject to a maximum product of 1 108. Then multiply this product by the ecosystem bioaccumulation potential factor value for this hazardous substance, subject to a maximum product of 1 1012. Based on this product, assign a value from Table 2-7 (section 2.4.3.1) to the environmental threat-waste characteristics category for the watershed. Enter the value in Table 4-25.

4.2.4.3 Environmental threat-targets. Evaluate the environmental threat-targets factor category for a watershed using one factor: sensitive environments.

4.2.4.3.1 Sensitive environments. Evaluate sensitive environments for the watershed based on three factors: Level I concentrations, Level II concentrations, and potential contamination. Determine which applies to each sensitive environment as specified in section 4.1.4.3.1, except: use only those samples from the surface water in-water segment and only those hazardous substances in such samples that meet the conditions in sections 4.2.1.3 and 4.2.1.4.

4.2.4.3.1.1 Level I concentrations. Assign a value to this factor as specified in section 4.1.4.3.1.1. Enter this value in Table 4-25.

4.2.4.3.1.2 Level II concentrations. Assign a value to this factor as specified in section 4.1.4.3.1.2. Enter this value in Table 4-25.

4.2.4.3.1.3 Potential contamination. Assign a value to this factor as specified in section 4.1.4.3.1.3 with the following modification. Multiply the appropriate dilution weight from Table 4-13 for the sensitive environments in each type of surface water body by the adjustment value selected from Table 4-27, as specified in section 4.2.2.3.1. Use the resulting product, not the value from Table 4-13, as the dilution weight for the sensitive environments in that type of surface water body. Do not round this product to the nearest integer. Enter the value assigned in Table 4-25.

4.2.4.3.1.4 Calculation of environmental threat-targets factor category value. Sum the values for Level I concentrations, Level II concentrations, and potential contamination for the watershed. Do not round this sum to the nearest integer. Assign this sum as the environmental threat targets factor category value for the watershed. Enter this value in Table 4-25.

4.2.4.4 Calculation of environmental threat score for a watershed. Multiply the environmental threat factor category values for likelihood of release, waste characteristics, and targets for the watershed, and round the product to the nearest integer. Then divide by 82,500. Assign the resulting value, subject to a maximum of 60, as the environmental threat score for the watershed. Enter this score in Table 4-25.

4.2.5 Calculation of ground water to surface water migration component score for a watershed. Sum the scores for the three threats for the watershed (that is, drinking water, human food chain, and environmental threats). Assign the resulting score, subject to a maximum value of 100, as the ground water to surface water migration component score for the watershed. Enter this score in Table 4-25.

4.2.6 Calculation of ground water to surface water migration component score. Select the highest ground water to surface water migration component score from the watersheds evaluated. Assign this score as the ground water to surface water migration component score for the site, subject to a maximum score of 100. Enter this score in Table 4-25.

4.3 Calculation of surface water migration pathway score. Determine the surface water migration pathway score as follows:

If only one of the two surface water migration components (overland/flood or ground water to surface water) is scored, assign the score of that component as the surface water migration pathway score.

If both components are scored, select the higher of the two component scores from sections 4.1.6 and 4.2.6. Assign that score as the surface water migration pathway score.

5.0 Soil Exposure Pathway

Evaluate the soil exposure pathway based on two threats: Resident threat and nearby population threat. Evaluate both threats based on three factor categories: Likelihood of exposure, waste characteristics, and targets. Figure 5-1 indicates the factors included within each factor category for each type of threat.

Determine the soil exposure pathway score (Ss)in terms of the factor category values as follows:

TABLE/GRAPH OMITTED

where:

LEi=Likelihood of exposure factor category value for threat i (that is, resident population threat or nearby population threat).

WCi=Waste characteristics factor category value for threat i.

Ti=Targets factor category value for threat i.

SF=Scaling factor.

Table 5-1 outlines the specific calculation procedure.


Table 5-1_Soil Exposure Pathway Scoresheet
TABLE/GRAPH OMITTED

5.0.1 General considerations. Evaluate the soil exposure pathway based on areas of observed contamination:

Consider observed contamination to be present at sampling locations where analytic evidence indicates that:

-A hazardous substance attributable to the site is present at a concentration significantly above background levels for the site (see Table 2-3 in section 2.3 for the criteria for determining analytical significance), and

-This hazardous substance, if not present at the surface, is covered by 2 feet or less of cover material (for example, soil).

Establish areas of observed contamination based on sampling locations at which there is observed contamination as follows:

-For all sources except contaminated soil, if observed contamination from the site is present at any sampling location within the source, consider that entire source to be an area of observed contamination.

-For contaminated soil, consider both the sampling location(s) with observed contamination from the site and the area lying between such locations to be an area of observed contamination, unless available information indicates otherwise.

If an area of observed contamination (or portion of such an area) is covered by a permanent, or otherwise maintained, essentially impenetrable material (for example, asphalt) that is not more than 2 feet thick, exclude that area (or portion of the area) in evaluating the soil exposure pathway.

For an area of observed contamination, consider only those hazardous substances that meet the criteria for observed contamination for that area to be associated with that area in evaluating the soil exposure pathway (see section 2.2.2).

If there is observed contamination, assign scores for the resident threat and the nearby population threat, as specified in sections 5.1 and 5.2. If there is no observed contamination, assign the soil exposure pathway a score of 0.

5.1 Resident Population Threat. Evaluate the resident population threat only if there is an area of observed contamination in one or more of the following locations:

Within the property boundary of a residence, school, or day care center and within 200 feet of the respective residence, school, or day care center, or

Within a workplace property boundary and within 200 feet of a workplace area, or

Within the boundaries of a resource specified in section 5.1.3.4, or

Within the boundaries of a terrestrial sensitive environment specified in section 5.1.3.5.

If not, assign the resident population threat a value of 0, enter this value in Table 5-1, and proceed to the nearby population threat (section 5.2).

5.1.1 Likelihood of exposure. Assign a value of 550 to the likelihood of exposure factor category for the resident population threat if there is an area of observed contamination in one or more locations listed in section 5.1. Enter this value in Table 5-1.

5.1.2 Waste characteristics. Evaluate waste characteristics based on two factors: toxicity and hazardous waste quantity. Evaluate only those hazardous substances that meet the criteria for observed contamination at the site (see section 5.0.1).

5.1.2.1 Toxicity. Assign a toxicity factor value to each hazardous substance as specified in section 2.4.1.1. Use the hazardous substance with the highest toxicity factor value to assign the value to the toxicity factor for the resident population threat. Enter this value in Table 5-1.

5.1.2.2 Hazardous waste quantity. Assign a hazardous waste quantity factor value as specified in section 2.4.2. In estimating the hazardous waste quantity, use Table 5-2 and:

Consider only the first 2 feet of depth of an area of observed contamination, except as specified for the volume measure.

Use the volume measure (see section 2.4.2.1.3) only for those types of areas of observed contamination listed in Tier C of Table 5-2. In evaluating the volume measure for these listed areas of observed contamination, use the full volume, not just the volume within the top 2 feet.

Use the area measure (see section 2.4.2.1.4), not the volume measure, for all other types of areas of observed contamination, even if their volume is known.

Enter the value assigned in Table 5-1.

Table 5-2 -- Hazardous Waste Quantity Evaluation Equations For Soil Exposure Pathway
TABLE/GRAPH OMITTED

5.1.2.3 Calculation of waste characteristics factor category value. Multiply the toxicity and hazardous waste quantity factor values, subject to a maximum product of 110. /8/ Based on this product, assign a value from Table 2-7 (section 2.4.3.1) to the waste characteristics factor category. Enter this value in Table 5-1.

5.1.3 Targets. Evaluate the targets factor category for the resident population threat based on five factors: resident individual, resident population, workers, resources, and terrestrial sensitive environments.

In evaluating the targets factor category for the resident population threat, count only the following as targets:

Resident individual -- a person living or attending school or day care on a property with an area of observed contamination and whose residence, school, or day care center, respectively, is on or within 200 feet of the area of observed contamination.

Worker -- a person working on a property with an area of observed contamination and whose workplace area is on or within 200 feet of the area of observed contamination.

Resources located on an area of observed contamination, as specified in section 5.1.

Terrestrial sensitive environments located on an area of observed contamination, as specified in section 5.1.

5.1.3.1 Resident individual. Evaluate this factor based on whether there is a resident individual, as specified in section 5.1.3, who is subject to Level I or Level II concentrations.

First, determine those areas of observed contamination subject to Level I concentrations and those subject to Level II concentrations as specified in sections 2.5.1 and 2.5.2. Use the health-based benchmarks from Table 5-3 in determining the level of contamination. Then assign a value to the resident individual factor as follows:

Assign a value of 50 if there is at least one resident individual for one or more areas subject to Level I concentrations.

Assign a value of 45 if there is no such resident individuals, but there is at least one resident individual for one or more areas subject to Level II concentrations.

Assign a value of 0 if there is no resident individual.

Enter the value assigned in Table 5-1.

5.1.3.2 Resident population. Evaluate resident population based on two factors: Level I concentrations and Level II concentrations. Determine which factor applies as specified in sections 2.5.1 and 2.5.2, using the health-based benchmarks from Table 5-3. Evaluate populations subject to Level I concentrations as specified in section 5.1.3.2.1 and populations subject to Level II concentrations as specified in section 5.1.3.2.2.

Screening concentration for cancer corresponding to that concentration that corresponds to the 10^6 individual cancer risk for oral exposures.

Screening concentration for noncancer toxicological responses corresponding to the Reference Dose (RfD) for oral exposures.

Count only those persons meeting the criteria for resident individual as specified in section 5.1.3. In estimating the number of people living on property with an area of observed contamination, when the estimate in based on the number of residences, multiply each residence by the average number of persons per residence for the county in which the residence is located.

5.1.3.2.1 Level I concentrations. Sum the number of resident individuals subject to Level I concentrations and multiply this sum by 10. Assign the resulting product as the value for this factor. Enter this value in Table 5-1.

5.1.3.2.2 Level II concentrations. Sum the number of resident individuals subject to Level II concentrations. Do not include those people already counted under the Level I concentrations factor. Assign this sum as the value for this factor. Enter this value in Table 5-1.

5.1.3.2.3 Calculation of resident population factor value. Sum the factor values for Level I concentrations and Level II concentrations. Assign this sum as the resident population factor value. Enter this value in Table 5-1.

5.1.3.3 Workers. Evaluate this factor based on the number of workers that meet the section 5.1.3 criteria. Assign a value for these workers using Table 5-4. Enter this value in Table 5-1.

Table 5-4 -- Factor Values for Workers
TABLE/GRAPH OMITTED

5.1.3.4 Resources. Evaluate the resources factor as follows:

Assign a value of 5 to the resources factor if one or more of the following is present on an area of observed contamination at the site:

-Commercial agriculture.

-Commercial silviculture.

-Commercial livestock production or commercial livestock grazing.

Assign a value of 0 if none of the above are present.

Enter the value assigned in Table 5-1.

5.1.3.5 Terrestrial sensitive environments. Assign value(s) from Table 5-5 to each terrestrial sensitive environment that meets the eligibility criteria of section 5.1.3.

Calculate a value (ES) for terrestrial sensitive environments as follows:

TABLE/GRAPH OMITTED

where:

Si=Value(s) assigned from Table 5-5 to terrestrial sensitive environment i.

n=Number of terrestrial sensitive environments meeting section 5.1.3 criteria.

Because the pathway score based solely on terrestrial sensitive environments is limited to a maximum of 60, determine the value for the terrestrial sensitive environments factor as follows:

Table 5-5 -- Terrestrial Sensitive Environments Rating Values
TABLE/GRAPH OMITTED

Multiply the values assigned to the resident population threat for likelihood of exposure (LE), waste characteristics (WC), and ES. Divide the product by 82,500.

-If the result is 60 or less, assign the value ES as the terrestrial sensitive environments factor value.

-If the result exceeds 60, calculate a value EC as follows:

TABLE/GRAPH OMITTED

Assign the value EC as the terrestrial sensitive environments factor value. Do not round this value to the nearest interger.

Enter the value assigned for the terrestrial sensitive environments factor in Table 5-1.

5.1.3.6 Calculation of resident population targets factor category value. Sum the values for the resident individual, resident population, workers, resources, and terrestrial sensitive environments factors. Do not round to the nearest integer. Assign this sum as the targets factor category value for the resident population threat. Enter this value in Table 5-1.

5.1.4 Calculation of resident population threat score. Multiply the values for likelihood of exposure, waste characteristics, and targets for the resident population threat, and round the product to the nearest integer. Assign this product as the resident population threat score. Enter this score in Table 5-1.

5.2 Nearby population threat. Include in the nearby population only those individuals who live or attend school within a 1-mile travel distance of an area of observed contamination at the site and who do not meet the criteria for resident individual as specified in section 5.1.3.

Do not consider areas of observed contamination that have an attractiveness/accessibility factor value of 0 (see section 5.2.1.1) in evaluating the nearby population threat.

5.2.1 Likelihood of exposure. Evaluate two factors for the likelihood of exposure factor category for the nearby population threat: attractiveness/accessibility and area of contamination.

5.2.1.1. Attractiveness/accessibility. Assign a value for attractiveness/accessibility from Table 5-6 to each area of observed contamination, excluding any land used for residences. Select the highest value assigned to the areas evaluated and use it as the value for the attractiveness/accessibility factor. Enter this value in Table 5-1.

5.2.1.2 Area of contamination. Evaluate area of contamination based on the total area of the areas of observed contamination at the site. Count only the area(s) that meet the criteria in section 5.0.1 and that receive an attractiveness/accessibility value greater than 0. Assign a value to this factor from Table 5-7. Enter this value in Table 5-1.

Table 5-6 -- Attractiveness/Accessibility Values
TABLE/GRAPH OMITTED

Table 5-7 -- Area of Contamination Factor Values
TABLE/GRAPH OMITTED

5.2.1.3 Likelihood of exposure factor category value. Assign a value from Table 5-8 to the likelihood of exposure factor category, based on the values assigned to the attractiveness/accessibility and area of contamination factors. Enter this value in Table 5-1.

Table 5-8 -- Nearby Population Likelihood of Exposure Factor Values
TABLE/GRAPH OMITTED

5.2.2 Waste characteristics. Evaluate waste characteristics based on two factors: toxicity and hazardous waste quantity. Evaluate only those hazardous substances that meet the criteria for observed contamination (see section 5.0.1) at areas that can be assigned an attractiveness/accessibility factor value greater than 0.

5.2.2.1 Toxicity. Assign a toxicity factor value as specified in section 2.4.1.1 to each hazardous substance meeting the criteria in section 5.2.2. Use the hazardous substance with the highest toxicity factor value to assign the value to the toxicity factor for the nearby population threat. Enter this value in Table 5-1.

5.2.2.2 Hazardous waste quantity. Assign a value to the hazardous waste quantity factor as specified in section 5.1.2.2, except: consider only those areas of observed contamination that can be assigned an attractiveness/accessibility factor value greater than 0. Enter the value assigned in Table 5-1.

5.2.2.3 Calculation of waste characteristics factor category value. Multiply the toxicity and hazardous waste quantity factor values, subject to a maximum product of 110. /8/ Based on this product, assign a value from Table 2-7 (section 2.4.3.1) to the waste characteristics factor category. Enter this value in Table 5-1.

5.2.3 Targets. Evaluate the targets factory category for the nearby population threat based on two factors: nearby individual and population within a 1-mile travel distance from the site.

5.2.3.1 Nearby individual. If one or more persons meet the section 5.1.3 criteria for a resident individual, assign this factor a value of 0. Enter this value in Table 5-1.

If no person meets the criteria for a resident individual, determine the shortest travel distance from the site to any residence or school. In determining the travel distance, measure the shortest overland distance an individual would travel from a residence or school to the nearest area of observed contamination for the site with an attractiveness/
accessibility factor value greater than 0. If there are no natural barriers to travel, measure the travel distance as the shortest straight-line distance from the residence or school to the area of observed contamination. If natural barriers exist (for example, a river), measure the travel distance as the shortest straight-line distance from the residence or school to the nearest crossing point and from there as the shortest straight-line distance to the area of observed contamination. Based on the shortest travel distance, assign a value from Table 5-9 to the nearest individual factor. Enter this value in Table 5-1.

Table 5-9 -- Nearby Individual Factor Values
TABLE/GRAPH OMITTED

5.2.3.2 Population within 1 mile. Determine the population within each travel distance category of Table 5-10. Count residents and students who attend school within this travel distance. Do not include those people already counted in the resident population threat. Determine travel distances as specified in section 5.2.3.1.

In estimating residential population, when the estimate is based on the number of residences, multiply each residence by the average number of persons per residence for the county in which the residence is located.

Based on the number of people included within a travel distance category, assign a distance-weighted population value for that travel distance from Table 5-10.

Calculate the value for the population within 1 mile factor (PN) as follows:

TABLE/GRAPH OMITTED

where:

Wi=Distance-weighted population value from Table 5-10 for travel distance category i.

If PN is less than 1, do not round it to the nearest integer; if PN is 1 or more, round to the nearest integer. Enter this value in Table 5-1.

5.2.3.3 Calculation of nearby population targets factor category value. Sum the values for the nearby individual factor and the population within 1 mile factor. Do not round this sum to the nearest integer. Assign this sum as the targets factor category value for the nearby population threat. Enter this value in Table 5-1.

Table 5-10 -- Distance-Weighted Population Values for Nearby Population Threata

TABLE/GRAPH OMITTED

5.2.4 Calculation of nearby population threat score. Multiply the values for likelihood of exposure, waste characteristics, and targets for the nearby population threat, and round the product to the nearest integer. Assign this product as the nearby population threat score. Enter this score in Table 5-1.

5.3 Calculation of soil exposure pathway score. Sum the resident population threat score and the nearby population threat score, and divide the sum by 82,500. Assign the resulting value, subject to a maximum of 100, as the soil exposure pathway score (Ss). Enter this score in Table 5-1.

6.0 Air Migration Pathway

Evaluate the air migration pathway based on three factor categories: likelihood of release, waste characteristics, and targets. Figure 6-1 indicates the factors included within each factor category.

Determine the air migration pathway score (Sa) in terms of the factor category values as follows:

TABLE/GRAPH OMITTED

where:

LR=Likelihood of release factor category value.

WC=Waste characteristics factor category value.

T=Targets factor category value.

SF=Scaling factor.

Table 6-1 outlines the specific calculation procedure.


Table 6-1 -- Air Migration Pathway Scoresheet

TABLE/GRAPH OMITTED

6.1 Likelihood of Release. Evaluate the likelihood of release factor category in terms of an observed release factor or a potential to release factor.

6.1.1 Observed release. Establish an observed release to the atmosphere by demonstrating that the site has released a hazardous substance to the atmosphere. Base this demonstration on either:

Direct observation -- a material (for example, particulate matter) that contains one or more hazardous substances has been seen entering the atmosphere directly. When evidence supports the inference of a release of a material that contains one or more hazardous substances by the site to the atmosphere, demonstrated adverse effects accumulated with that release may be used to establish an observed release.

Chemical analysis -- an analysis of air samples indicates that the concentration of ambient hazardous substance(s) has increased significantly above the background concentration for the site (see section 2.3). Some portion of the significant increase must be attributable to the site to establish the observed release.

If an observed release can be established, assign an observed release factor value of 550, enter this value in Table 6-1, and proceed to section 6.1.3. If an observed release cannot be established, assign an observed release factor value of 0, enter this value in Table 6-1, and proceed to section 6.1.2.

6.1.2 Potential to release. Evaluate potential to release only if an observed release cannot be established. Determine the potential to release factor value for the site by separately evaluating the gas potential to release and the particulate potential to release for each source at the site. Select the highest potential to release value (either gas or particulate) calculated for the sources evaluated and assign that value as the site potential to release factor value as specified below.

6.1.2.1 Gas potential to release. Evaluate gas potential to release for those sources that contain gaseous hazardous substances -- that is, those hazardous substances with a vapor pressure greater than or equal to 10^9 torr.

Evaluate gas potential to release for each source based on three factors: gas containment, gas source type, and gas migration potential. Calculate the gas potential to release value as illustrated in Table 6-2. Combine sources with similar characteristics into a single source in evaluating the gas potential to release factors.

Table 6-2 -- Gas Potential to Release Evaluation

TABLE/GRAPH OMITTED

6.1.2.1.1 Gas containment. Assign each source a value from Table 6-3 for gas containment. Use the lowest value from Table 6-3 that applies to the source, except: assign a value of 10 if there is evidence of biogas release or if there is an active fire within the source.

Table 6-3 -- Gas Containment Factor Values

TABLE/GRAPH OMITTED

6.1.2.1.2 Gas source type. Assign a value for gas source type to each source as follows:

Determine if the source meets the minimum size requirement based on the source hazardous waste quantity value (see section 2.4.2.1.5). If the source receives a source hazardous waste quantity value of 0.5 or more, consider the source to meet the minimum size requirement.

If the source meets the minimum size requirement, assign it a value from Table 6-4 for gas source type.

If the source does not meet the minimum size requirement, assign a value of 0 for gas source type.

If no source at the site meets the minimum size requirement, assign each source at the site a value from Table 6-4 for gas source type.

Table 6-4 -- Source Type Factor Values
TABLE/GRAPH OMITTED

6.1.2.1.3 Gas migration potential. Evaluate this factor for each source as follows:

Assign a value for gas migration potential to each of the gaseous hazardous substances associated with the source (see section 2.2.2) as follows:

- Assign values from Table 6-5 for vapor pressure and Henry's constant to each hazardous substance. If Henry's constant cannot be determined for a hazardous substance, assign that hazardous substance a value of 2 for the Henry's constant component.

- Sum the two values assigned to the hazardous substance.

- Based on this sum, assign the hazardous substance a value from Table 6-6 for gas migration potential.

Assign a value for gas migration potential to each source as follows:

- Select three hazardous substances associated with the source:

        - -If more than three gaseous hazardous substances can be associated with the source, select three that have the highest gas migration potential values.

        - -If fewer than three gaseous hazardous substances can be associated with a source, select all of them.

- Average the gas migration potential values assigned to the selected hazardous substances.

- Based on this average value, assign the source a gas migration potential value from Table 6-7.

Table 6-5 -- Values for Vapor Pressure and Henry's Constant

TABLE/GRAPH OMITTED

TABLE/GRAPH OMITTED

Table 6-6 -- Gas Migration Potential Values for a Hazardous Substance
TABLE/GRAPH OMITTED

Table 6-7 -- Gas Migration Potential Values for the Source
TABLE/GRAPH OMITTED

6.1.2.1.4 Calculation of gas potential to release value. Determine the gas potential to release value for each source as illustrated in Table 6-2. For each source, sum the gas source type factor value and gas migration potential factor value and multiply this sum by the gas containment factor value. Select the highest product calculated for the sources evaluated and assign it as the gas potential to release value for the site. Enter this value in Table 6-1.

6.1.2.2 Particulate potential to release. Evaluate particulate potential to release for those sources that contain particulate hazardous substances -- that is, those hazardous substances with a vapor pressure less than or equal to 10^1 torr.

Evaluate particulate potential to release for each source based on factors: particulate containment, particulate source type, and particulate migration potential. Calculate the particulate potential to release value as illustrated in Table 6-8. Combine sources with similar characteristics into a single source in evaluating the particulate potential to release factors.

6.1.2.2.1 Particulate containment. Assign each source a value from Table 6-9 for particulate containment. Use the lowest value from Table 6-9 that applies to the source.

6.1.2.2.2 Particulate source type. Assign a value for particulate source type to each source in the same manner as specified for gas sources in section 6.1.2.1.2.

6.1.2.2.3 Particulate migration potential. Based on the site location, assign a value from Figure 6-2 for particulate migration potential. Assign this same value to each source at the site.

Table 6-8 -- Particulate Potential to Release Evaluation
TABLE/GRAPH OMITTED

Table 6-9 -- Particulate Containment Factor Values
TABLE/GRAPH OMITTED

Figure 6-2 -- Particulate Migration Potential Factor Values -- Concluded
TABLE/GRAPH OMITTED

For site locations not on Figure 6-2, and for site locations near the boundary points on Figure 6-2, assign a value as follows. First, calculate a Thornthwaite P-E index using the following equation:

TABLE/GRAPH OMITTED

where:

PE=Thornthwaite P-E index.

Pi=Mean monthly precipitation for month i, in inches.

Ti=Mean monthly temperature for month i, in degrees Fahrenheit; for any month having a mean monthly temperature less than 28.4 F, use 28.4 F.

Based on the calculated Thornthwaite P-E index, assign a source particulate migration potential value to the site from Table 6-10. Assign this same value to each source at the site.

Table 6-10 -- Particulate Migration Potential Values
TABLE/GRAPH OMITTED

6.1.2.2.4 Calculation of particulate potential to release value. Determine the particulate potential to release value for each source as illustrated in Table 6-8. For each source, sum its particulate source type factor value and particulate migration potential factor value and multiply this sum by its particulate containment factor value. Select the highest product calculated for the sources evaluated and assign it as the particulate potential to release value for the site. Enter the value in Table 6-1.

6.1.2.3 Calculation of potential to release factor value for the site. Select the higher of the gas potential to release value assigned in section 6.1.2.1.4 and the particulate potential to release assigned in section 6.1.2.2.4. Assign the value selected as the site potential to release factor value. Enter this value in Table 6-1.

6.1.3 Calculation of likelihood of release factor category value. If an observed release is established, assign the observed release factor value of 550 as the likelihood of release factor category value. Otherwise, assign the site potential to release factor value as the likelihood of release factor category value. Enter the value in Table 6-1.

6.2 Waste characteristics. Evaluate the waste characteristics factor category based on two factors: toxicity/mobility and hazardous waste quantity. Evaluate only those hazardous substances available to migrate from the sources at the site to the atmosphere. Such hazardous substances include:

Hazardous substances that meet the criteria for an observed release to the atmosphere.

All gaseous hazardous substances associated with a source that has a gas containment factor value greater than 0 (see section 2.2.2, 2.2.3, and 6.1.2.1.1).

All particulate hazardous substances associated with a source that has a particulate containment factor value greater than 0 (see section 2.2.2, 2.2.3, and 6.1.2.2.1).

6.2.1 Toxicity/mobility. For each hazardous substance, assign a toxicity factor value, a mobility factor value, and a combined toxicity/mobility factor value as specified below. Select the toxicity/mobility factor value for the air migration pathway as specified in section 6.2.1.3.

6.2.1.1 Toxicity. Assign a toxicity factor value to each hazardous substance as specified in section 2.4.1.1.

6.2.1.2 Mobility. Assign a mobility factor value to each hazardous substance as follows:

Gaseous hazardous substance.

- Assign a mobility factor value of 1 to each gaseous hazardous substance that meets the criteria for an observed release to the atmosphere.

- Assign a mobility factor value from Table 6-11, based on vapor pressure, to each gaseous hazardous substance that does not meet the criteria for an observed release.

Particulate hazardous substance.

- Assign a mobility factor value of 0.02 to each particulate hazardous substance that meets the criteria for an observed release to the atmosphere.

- Assign a mobility factor value from Figure 6-3, based on the site's location, to each particulate hazardous substance that does not meet the criteria for an observed release. (Assign all such particulate hazardous substances this same value.)

- For site locations not on Figure 6-3 and for site locations near the boundary points on Figure 6-3, assign a mobility factor value to each particulate hazardous substance that does not meet the criteria for an observed release as follows:

- Calculate a value M:

M=0.0182 (U /3/ /(PE) /2/ )

where:

U=Mean average annual wind speed (meters per second).

PE=Thornthwaite P-E index from section 6.1.2.2.3.

- Based on the value M, assign a mobility factor value from Table 6-12 to each particulate hazardous substance.

Gaseous and particulate hazardous substances.

- For a hazardous substance potentially present in both gaseous and particulate forms, select the higher of the factor values for gas mobility and particulate mobility for that substance and assign that value as the mobility factor value for the hazardous substance.

6.2.1.3 Calculation of toxicity/mobility factor value. Assign each hazardous substance a toxicity/mobility factor value from Table 6-13, based on the values assigned to the hazardous substance for the toxicity and mobility factors. Use the hazardous substance with the highest toxicity/mobility factor value to assign the value to the toxicity/mobility factor for the air migration pathway. Enter this value in Table 6-1.

Table 6-11 -- Gas Mobility Factor Values
TABLE/GRAPH OMITTED

Figure 6-3 -- Particulate Mobility Factor Values -- Concluded
TABLE/GRAPH OMITTED

Table 6-12 -- Particulate Mobility Factor Values
TABLE/GRAPH OMITTED

Table 6-13 -- Toxicity/Mobility Factor Values
TABLE/GRAPH OMITTED

6.2.2 Hazardous waste quantity. Assign a hazardous waste quantity factor value for the air migration pathway as specified in section 2.4.2. Enter this value in Table 6-1.

6.2.3 Calculation of waste characteristics factor category value. Multiply the toxicity/mobility factor value and the hazardous waste quantity factor value, subject to a maximum product of 108. Based on this product, assign a value from Table 2-7 (section 2.4.3.1) to the waste characteristics factor category. Enter this value in Table 6-1.

6.3 Targets.

Evaluate the targets factor category based on four factors: nearest individual, population, resources, and sensitive environments. Include only those targets (for example, individuals, sensitive environments) located within the 4-mile target distance limit, except: if an observed release is established beyond the 4-mile target distance limit, include those additional targets that are specified below in this section and in section 6.3.4.

Evaluate the nearest individual and population factors based on whether the target populations are subject to Level I concentrations, Level II concentrations, or potential contamination. Determine which applies to a target population as follows.

If no samples meet the criteria for an observed release to air and if there is no observed release by direct observation, consider the entire population within the 4-mile target distance limit to be subject to potential contamination.

If one or more samples meet the criteria for an observed release to air or if there is an observed release by direct observation, evaluate the population as follows:

Determine the most distant sample location that meets the criteria for Level I concentrations as specified in sections 2.5.1 and 2.5.2 and the most distant location (that is, sample location or direct observation location) that meets the criteria for Level II concentrations. Use the health-based benchmarks from Table 6-14 in determining the level of contamination for sample locations. If the most distant Level II location is closer to a source than the most distant Level I sample location, do not consider the Level II location.

Determine the single most distant location (sample location or direct observation location) that meets the criteria for Level I or Level II concentrations.

If this single most distant location is within the 4-mile target distance limit, identify the distance categories from Table 6-15 in which the selected Level I concentrations sample and Level II concentrations sample (or direct observation location) are located:

- Consider the target population anywhere within this furthest Level I distance category, or anywhere within a distance category closer to a source at the site, as subject to Level I concentrations.

- Consider the target population located beyond any Level I distance categories, up to and including the population anywhere within the furthest Level II distance category, as subject to Level II concentrations.

- Consider the remainder of the target population within the 4-mile target distance limit as subject to potential contamination.

If the single most distant location is beyond the 4-mile target distance limit, identify the distance at which the selected Level I concentrations sample and Level II concentrations sample (or direct observation location) are located:

- If the Level I sample location is within the 4-mile target distance limit, identify the target population subject to Level I concentrations as specified above.

- If the Level I sample location is beyond the 4-mile target distance limit, consider the target population located anywhere within a distance from the sources at the site equal to the distance to this sample location to be subject to Level I concentrations and include them in the evaluation.

- Consider the target population located beyond the Level I target population, but located anywhere within a distance from the sources at site equal to the distance to the selected Level II location, to be subject to Level II concentrations and include them in the evaluation.

- Do not include any target population as subject to potential contamination.

Table 6-14 -- Health-Based Benchmarks for Hazardous Substances in Air
TABLE/GRAPH OMITTED

Table 6-15 -- Air Migration Pathway Distance Weights TABLE/GRAPH OMITTED

6.3.1 Nearest individual. Assign the nearest individual factor a value as follows:

If one or more residences or regularly occupied buildings or areas is subject to Level I concentrations as specified in section 6.3, assign a value of 50.

If not, but if one or more a residences or regularly occupied buildings or areas is subject to Level II concentrations, assign a value of 45.

If none of the residences and regularly occupied buildings and areas is subject to Level I or Level II concentrations, assign a value to this factor based on the shortest distance to any residence or regularly occupied building or area, as measured from any source at the site with an air migration containment factor value greater than 0. Based on this shortest distance, assign a value from Table 6-16 to the nearest individual factor.

Enter the value assigned in Table 6-1.

Table 6-16 -- Nearest Individual Factor Values
TABLE/GRAPH OMITTED

6.3.2 Population. In evaluating the population factor, count residents, students, and workers regularly present within the target distance limit. Do not count transient populations such as customers and travelers passing through the area.

In estimating residential population, when the estimate is based on the number of residences, multiply each residence by the average number of persons per residence for the county in which the residence is located.

6.3.2.1 Level of contamination. Evaluate the population factor based on three factors: Level I concentrations, Level II concentrations, and potential contamination.

Evaluate the population subject to Level I concentrations (see section 6.3) as specified in section 6.3.2.2, the population subject to Level II concentrations as specified in section 6.3.2.3, and the population subject to potential contamination as specified in section 6.3.2.4.

For the potential contamination factor, use population ranges in evaluating the factor as specified in section 6.3.2.4. For the Level I and Level II concentrations factors, use the population estimate, not population ranges, in evaluating both factors.

6.3.2.2 Level I concentrations. Sum the number of people subject to Level I concentrations. Multiply this sum by 10. Assign the product as the value for this factor. Enter this value in Table 6-1.

6.3.2.3 Level II concentrations. Sum the number of people subject to Level II concentrations. Do not include those people already counted under the Level I concentrations factor. Assign this sum as the value for this factor. Enter this value in Table 6-1.

6.3.2.4 Potential contamination. Determine the number of people within each distance category of the target distance limit (see Table 6-15) who are subject to potential contamination. Do not include those people already counted under the Level I and Level II concentrations factors.

Based on the number of people present within a distance category, assign a distance-weighted population value for that distance category from Table 6-17. (Note that the distance-weighted population values in Table 6-17 incorporate the distance weights from Table 6-15. Do not multiply the values from Table 6-17 by these distance weights.)

Calculate the potential contamination factor value (PI) as follows:
TABLE/GRAPH OMITTED

where:

Wi=Distance-weighted population from Table 6-17 for distance category i.

n=Number of distance categories.

If PI is less than 1, do not round it to the nearest integer; if PI is 1 or more, round to the nearest integer. Enter this value in Table 6-1.

6.3.2.5 Calculation of population factor value. Sum the factor values for Level I concentrations, Level II concentrations, and potential contamination. Do not round this sum to the nearest integer. Assign this sum as the population factor value. Enter this value in Table 6-1.

Table 6-17 -- Distance-Weighted Population Values For Potential Contamination Factor for Air Pathway
TABLE/GRAPH OMITTED

6.3.3 Resources. Evaluate the resources factor as follows:

Assign a value of 5 if one or more of the following resources are present within one-half mile of a source at the site having an air migration containment factor value greater than 0:

- Commercial agriculture.

- Commercial silviculture.

- Major or designated recreation area.

Assign a value of 0 if none of these resources is present.

Enter the value assigned in Table 6-1.

    6.3.4 Sensitive environments. Evaluate sensitive environments based on two factors: actual contamination and potential contamination. Determine which factor applies as follows.

If no samples meet the criteria for an observed release to air and if there is no observed release by direct observation, consider all sensitive environments located, partially or wholly, within the target distance limit to be subject to potential contamination.

If one or more samples meet the criteria for an observed release to air or if there is an observed release by direct observation, determine the most distant location (that is, sample location or direct observation location) that meets the criteria for an observed release:

If the most distant location meeting the criteria for an observed release is within the 4-mile target distance limit, identify the distance category from Table 6-15 in which it is located:

- Consider sensitive environments located, partially or wholly, anywhere within this distance category or anywhere within a distance category closer to a source at the site as subject to actual contamination.

- Consider all other sensitive environments located, partially or wholly, within the target distance limit as subject to potential contamination.

If the most distant location meeting the criteria for an observed release is beyond the 4-mile target distance limit, identify the distance at which it is located:

- Consider sensitive environments located, partially or wholly, anywhere within a distance from the sources at the site equal to the distance to this location to be subject to actual contamination and include all such sensitive environments in the evaluation.

- Do not include any sensitive environments as subject to potential contamination.

6.3.4.1 Actual contamination. Determine those sensitive environments subject to actual contamination (i.e., those located partially or wholly within a distance category subject to actual contamination). Assign value(s) from Table 4-23 (section 4.1.4.3.1.1) to each sensitive environment subject to actual contamination.

For those sensitive environments that are wetlands, assign an additional value from Table 6-18. In assigning a value from Table 6-18, include only those portions of wetlands located within distance categories subject to actual contamination. If a wetland is located partially in a distance category subject to actual contamination and partially in one subject to potential contamination, then solely for purposes of Table 6-18, count the portion in the distance category subject to potential contamination under the potential contamination factor in section 6.3.4.2. Determine the total acreage of wetlands within those distance categories subject to actual contamination and assign a value from Table 6-18 based on this total acreage.

Calculate the actual contamination factor value (EA) as follows:

TABLE/GRAPH OMITTED

where:

WA=Value assigned from Table 6-18 for wetlands in distance categories subject to actual contamination.

Si=Value(s) assigned from Table 4-23 to sensitive environment i.

n=Number of sensitive environments subject to actual contamination.

Enter the value assigned in Table 6-1.

Table 6-18 -- Wetlands Rating Values for Air Migration Pathwaya
TABLE/GRAPH OMITTED

6.3.4.2 Potential contamination. Determine those sensitive environments located, partially or wholly, within the target distance limit that are subject to potential contamination. Assign value(s) from Table 4-23 to each sensitive environment subject to potential contamination. Do not include those sensitive environments already counted for Table 4-23 under the actual contamination factor.

For each distance category subject to potential contamination, sum the value(s) assigned from Table 4-23 to the sensitive environments in that distance category. If a sensitive environment is located in more than one distance category, assign the sensitive environment only to that distance category having the highest distance weighting value from Table 6-15.

For those sensitive environments that are wetlands, assign an additional value from Table 6-18. In assigning a value from Table 6-18, include only those portions of wetlands located within distance categories subject to potential contamination, as specified in section Treat the wetlands in each separate distance category as separate sensitive environments solely for purposes of applying Table 6-18. Determine the total acreage of wetlands within each of these distance categories and assign a separate value from Table 6-18 for each distance category.

Calculate the potential contamination factor value (EP) as follows:

TABLE/GRAPH OMITTED

TABLE/GRAPH OMITTED

Sij=Value(s) assigned from Table 4-23 to sensitive environment in distance category j.

n=Number of sensitive environments subject to potential contamination.

Wj=Value assigned from Table 6-18 for wetland area in distance category j.

Dj=Distance weight from Table 6-15 for distance category j.

m=Number of distance categories subject to potential contamination.

If EP is less than 1, do not round it to the nearest integer; if EP is 1 or more, round to the nearest integer. Enter the value assigned in Table 6-1.

6.3.4.3 Calculation of sensitive environments factor value. Sum the factor values for actual contamination and potential contamination. Do not round this sum, designated as EB, to the nearest integer.

Because the pathway score based solely on sensitive environments is limited to a maximum of 60, use the value EB to determine the value for the sensitive environments factor as follows:

Multiply the values assigned to likelihood of release (LR), waste characteristics (WC), and EB. Divide the product by 82,500.

- If the result is 60 or less, assign the value EB as the sensitive environments factor value.

- If the result exceeds 60, calculate a value EC as follows:

TABLE/GRAPH OMITTED

Assign the value EC as the sensitive environments factor value. Do not round this value to the nearest integer.

Enter the value assigned for the sensitive environments factor in Table 6-1.

6.3.5 Calculation of targets factor category value. Sum the nearest individual, population, resources, and sensitive environments factor values. Do not round this sum to the nearest integer. Assign this sum as the targets factor category value. Enter this value in Table 6-1.

6.4 Calculation of air migration pathway score. Multiply the values for likelihood of release, waste characteristics, and targets, and round the product to the nearest integer. Then divide by 82,500. Assign the resulting value, subject to a maximum value of 100, as the air migration pathway score (Sa). Enter this score in Table 6-1.

7.0 Sites Containing Radioactive Substances.

In general, radioactive substances are hazardous substances under CERCLA and should be considered in HRS scoring. Releases of certain radioactive substances are, however, excluded from the definition of "release'' in section 101(22) of CERCLA, as amended, and should not be considered in HRS scoring.

Evaluate sites containing radioactive substances using the instructions specified in sections 2 through 6, supplemented by the instructions in this section. Those factors denoted with a "yes'' in Table 7-1 are evaluated differently for sites containing radioactive substances than for sites containing only nonradioactive hazardous substances, while those denoted with a "no'' are not evaluated differently and are not addressed in this section.

Table 7-1 -- HRS Factors Evaluated Differently for Radionuclides
TABLE/GRAPH OMITTED

In general, sites containing mixed radioactive and other hazardous substances involve more evaluation than sites containing only radionuclides. For sites containing mixed radioactive and other hazardous substances, HRS factors are evaluated based on considerations of both the radioactive substances and the other hazardous substances in order to derive a single set of factor values for each factor category in each of the four pathways. Thus, the HRS score for these sites reflects the combined potential hazards posed by both the radioactive and other hazardous substances.

Section 7 is organized by factor category, similar to sections 3 through 6. Pathway-specific differences in evaluation criteria are specified under each factor category, as appropriate. These differences apply largely to the soil exposure pathway and to sites containing mixed radioactive and other hazardous substances. All evaluation criteria specified in sections 2 through 6 must be met, except where modified in section 7.

7.1 Likelihood of release/likelihood of exposure. Evaluate likelihood of release for the three migration pathways and likelihood of exposure for the soil exposure pathway as specified in sections 2 through 6, except: establish an observed release and observed contamination as specified in section 7.1.1. When an observed release cannot be established for a migration pathway, evaluate potential to release as specified in section 7.1.2. When observed contamination cannot be established, do not evaluate the soil exposure pathway.

7.1.1 Observed release/observed contamination. For radioactive substances, establish an observed release for each migration pathway by demonstrating that the site has released a radioactive substance to the pathway (or watershed or aquifer, as appropriate); establish observed contamination for the soil exposure pathway as indicated below. Base these demonstrations on one or more of the following, as appropriate to the pathway being evaluated:

Direct observation:

- For each migration pathway, a material that contains one or more radionuclides has been seen entering the atmosphere, surface water, or water, as appropriate, or is known to have entered ground water or surface water through direct deposition, or

- For the surface water migration pathway, a source area containing radioactive substances has been flooded at a time that radioactive substances were present and one or more radioactive substances were in contact with the flood waters.

Analysis of radionuclide concentrations in samples appropriate to the pathway (that is, ground water, soil, air, surface water, benthic, or sediment samples):

- For radionuclides that occur naturally and for radionuclides that are ubiquitous in the environment:

    - - Measured concentration (in units of activity, for example, pCi per kilogram (pCi/kg), pCi per liter (pCi/1), pCi per cubic meter (pCi/m3)) of a given radionuclide in the sample are at a level that:

        - - - Equals or exceeds a value 2 standard deviations above the mean site-specific background concentration for that radionuclide in that type of sample, or

        - - - Exceeds the upper-limit value of the range of regional background concentration values for that specific radionuclide in that type of sample.

    - - Some portion of the increase must be attributable to the site to establish the observed release (or observed contamination), and

    - - For the soil exposure pathway only, the radionuclide must also be present at the surface or covered by 2 feet or less of cover material (for example, soil) to establish observed contamination.

- For man-made radionuclides without ubiquitous background concentrations in the environment:

    - - Measured concentration (in units of activity) of a given radionuclide in a sample equals or exceeds the sample quantitation limit for that specific radionuclide in that type of media and is attributable to the site.

    - - However, if the radionuclide concentration equals or exceeds its sample quantitation limit, but its release can also be attributed to one or more neighboring sites, then the measured concentration of that radionuclide must also equal or exceed a value either 2 standard deviations above the mean concentration of that radionuclide contributed by those neighboring sites or 3 times its background concentration, whichever is lower.

    - - If the sample quantitation limit cannot be established:

        - - - If the sample analysis was performed under the EPA Contract Laboratory Program, use the EPA contract-required quantitation limit (CRQL) in place of the sample quantitation limit in establishing an observed release (or observed contamination).

        - - - If the sample analysis is not performed under the EPA Contract Labatory Program, use the detection limit in place of the sample quantitation limit.

    - - For the soil exposure pathway only, the radionuclide must also be present at the surface or covered by 2 feet or less of cover material (for example, soil) to establish observed contamination.

Gamma radiation measurements (applies only to observed contamination for the soil exposure pathway):

- The gamma radiation exposure rate, as measured in microroentgens per hour (mR/hr) using a survey instrument held 1 meter above the ground surface (or 1 meter away from an aboveground source), equals or exceeds 2 times the site-specific background gamma radiation exposure rate.

- Some portion of the increase must be attributable to the site to establish observed contamination. The gamma-emitting radionuclides do not have to be within 2 feet of the surface of the source.

For the three migration pathways, if an observed release can be established for the pathway (or aquifer or watershed, as appropriate), the pathway (or aquifer or watershed) an observed release factor value of 550 and proceed to section 7.2. If an observed release cannot be established, assign an observed release factor value of 0 and proceed to section 7.1.2.

For the soil exposure pathway, if observed contamination can be established, assign the likelihood of exposure factor for resident population a value of 550 if there is an area of observed contamination in one or more locations listed in section 5.1; evaluate the likelihood of exposure factor for nearby population as specified in section 5.2.1; and proceed to section 7.2. If observed contamination cannot be established, do not evaluate the soil exposure pathway.

At sites containing mixed radioactive and other hazardous substances, evaluate observed release (or observed contamination) separately for radionuclides as described in this section and for other hazardous substances as described in sections 2 through 6.

For the three migration pathways, if an observed release can be established based on either radionuclides or other hazardous substances, or both, assign the pathway (or aquifer or watershed) an observed release factor value of 550 and proceed to section 7.2. If an observed release cannot be established based on either radionuclides or other hazardous substances, assign an observed release factor value of 0 and proceed to section 7.1.2.

For the soil exposure pathway, if observed contamination can be established based on either radionuclides or other hazardous substances, or both, assign the likelihood of exposure factor for resident population a value of 550 if there is an area of observed contamination in one or more locations listed in section 5.1; evaluate the likelihood of exposure factor for nearby population as specified in section 5.2.1; and proceed to section 7.2. If observed contamination cannot be established based on either radionuclides or other hazardous substances, do not evaluate the soil exposure pathway.

7.1.2 Potential to release. For the three migration pathways, evaluate potential to release for sites containing radionuclides in the same manner as specified for sites containing other hazardous substances. Base the evaluation on the physical and chemical properties of the radionuclides, not on their level of radioactivity.

For sites containing mixed radioactive and other hazardous substances, evaluate potential to release considering radionuclides and other hazardous substances together. Evaluate potential to release for each migration pathway as specified in sections 3, 4, or 6, as appropriate.

7.2 Waste characteristics. For radioactive substances, evaluate the human toxicity factor, the ecosystem toxicity factor, the surface water persistence factor, and the hazardous waste quantity factor as specified in the following sections. Evaluate all other waste characteristic factors as specified in sections 2 through 6.

7.2.1 Human toxicity. For radioactive substances, evaluate the human toxicity factor as specified below, not as specified in section 2.4.1.1.

Assign human toxicity factor values to those radionuclides available to the pathway based on quantitative dose-response parameters for cancer risks as follows:

Evaluate radionuclides only on the basis of carcinogenicity and assign all radionuclides to weight-of-evidence category A.

Assign a human toxicity factor value from Table 7-2 to each radionuclide based on its slope factor (also referred to as cancer potency factor).

- For each radionuclide, use the higher of the slope factors for inhalation and ingestion to assign the factor value.

- If only one slope factor is available for the radionuclide, use it to assign the toxicity factor value.

- If no slope factor is available for the radionuclide, assign that radionuclide a toxicity factor value of 0 and use other radionuclides for which a slope factor is available to evaluate the pathway.

If all radionuclides available to a particular pathway are assigned a human toxicity factor value of 0 (that is, no slope factor is available for all the radionuclides), use a default human toxicity factor value of 1,000 as the human toxicity factor value for all radionuclides available to the pathway.

At sites containing mixed radioactive and other hazardous substances, evaluate the toxicity factor separately for the radioactive and other hazardous substances and assign each a separate toxicity factor value. This applies regardless of whether the radioactive and other hazardous substances are physically separated, combined chemically, or simply mixed together. Assign toxicity factor values to the radionuclides as specified above and to the other hazardous substances as specified in section 2.4.1.1.

At sites containing mixed radioactive and other hazardous substances, if all radionuclides available to a particular pathway are assigned a human toxicity factor value of 0, use a default human toxicity factor value of 1,000 for all those radionuclides even if nonradioactive hazardous substances available to the pathway are assigned human toxicity factor values greater than 0. Similarly, if all nonradioactive hazardous substances available to the pathway are assigned a human toxicity factor value of 0, use a default human toxicity factor value of 100 for all these nonradioactive hazardous substances even if radionuclides available to the pathway are assigned human toxicity factor values greater than 0.

7.2.2 Ecosystem toxicity. For the surface water environmental threat (see sections 4.1.4 and 4.2.4). assign an ecosystem toxicity factor value to radionuclides (alone or combined chemically or mixed with other hazardous substances) using the same slope factors and procedures specified for the human toxicity factor in section 7.2.1, except: use a default of 100, not 1,000, if all radionuclides eligible to be evaluated for ecosystem toxicity receive an ecosystem toxicity factor value of 0.

Table 7-2 -- Toxicity Factor Values for Radionuclides
TABLE/GRAPH OMITTED

At sites containing mixed radioactive and other hazardous substances, evaluate the ecosystem toxicity factor separately for the radioactive and other hazardous substances and assign each a separate ecosystem toxicity factor value. This applies regardless of whether the radioactive and other hazardous substances are physically separated, combined chemically, or simply mixed together. Assign ecosystem toxicity factor values to the radionuclides as specified above and to the other hazardous substances as specified in sections 4.1.4.2.1.1 and 4.2.4.2.1.1. If all radionuclides available to a particular pathway are assigned an ecosystem toxicity factor value of 0, use a default ecosystem toxicity factor value of 100 for all these radionuclides even if nonradioactive hazardous substances available to the pathway are assigned ecosystem toxicity factor values greater than 0. Similarly, if all nonradioactive hazardous substances available to the pathway are assigned an ecosystem toxicity factor value of 0, use a default ecosystem toxicity factor value of 100 for all these nonradioactive hazardous substances even if radionuclides available to the pathway are assigned ecosystem toxicity factor values greater than 0.

7.2.3 Persistence. For radionuclides, evaluate the surface water persistence factor based solely on half-life; do not include sorption to sediments in the evaluation as is done for nonradioactive hazardous substances. Assign a persistence factor value from Table 4-10 (section 4.1.2.2.1.2) to each radionuclide based on half-life (t1/2) calculated as follows:

TABLE/GRAPH OMITTED

where:

r=Radioactive half-life.

v=Volatilization half-life.

If the volatilization half-life cannot be estimated for a radionuclide from available data, delete it from the equation. Select the portion of Table 4-10 to use in assigning the persistence factor value as specified in section 4.1.2.2.1.2.

At sites containing mixed radioactive and other hazardous substances, evaluate the persistence factor separately for each radionuclide and for each nonradioactive hazardous substance, even if the available data indicate that they are combined chemically. Assign a persistence factor value to each radionuclide as specified in this section and to each nonradioactive hazardous substance as specified in section 4.1.2.2.1.2. When combined chemically, assign a single persistence factor value based on the higher of the two values assigned (individually) to the radioactive and nonradioactive components.

7.2.4 Selection of substance potentially posing greatest hazard. For each migration pathway (threat, aquifer, or watershed, as appropriate), select the radioactive substance or nonradioactive hazardous substance that potentially poses the greatest hazard based on its toxicity factor value, combined with the applicable mobility, persistence, and/or bioaccumulation (or ecosystem bioaccumulation) potential factor values. Combine these factor values as specified in sections 2, 3, 4, and 6. For the soil exposure pathway, base the selection on the toxicity factor alone (see sections 2 and 5).

7.2.5 Hazardous waste quantity. To calculate the hazardous waste quantity factor value for sites containing radioactive substances, evaluate source hazardous waste quantity (see section 2.4.2.1) using only the following two measures in the following hierarchy (these measures are consistent with Tiers A and B for nonradioactive hazardous substances in sections 2.4.2.1.1 and 2.4.2.1.2):

fRadionuclide constituent quantity (Tier A).

fRadionuclide wastestream quantity (Tier B).

7.2.5.1 Source hazardous waste quantity for radionuclides. For each migration pathway, assign a source hazardous waste quantity value to each source having a containment factor value greater than 0 for the pathway being evaluated. For the soil exposure pathway, assign a source hazardous waste quantity value to each area of observed contamination, as applicable to the threat being evaluated. Allocate hazardous substances and hazardous wastestreams to specific sources (or areas of observed contamination) as specified in section 2.4.2.

7.2.5.1.1 Radionuclide constituent quantity (Tier A). Evaluate radionuclide constituent quantity for each source (or area of observed contamination) based on the activity content of the radionuclides allocated to the source (or area of observed contamination) as follows:

Estimate the net activity content (in curies) for the source (or area of observed contamination) based on:

- Manifests, or

- Either of the following equations, as applicable:

TABLE/GRAPH OMITTED

where:

N=Estimated net activity content (in curies) for the source (or area of observed contamination).

V=Total volume of material (in cubic yards) in a source (or area of observed contamination) containing radionuclides.

ACi=Activity concentration above the respective background concentration (in pCi/g) for each radionuclide i allocated to the source (or area of observed contamination).

n=Number of radionuclides allocated to the source (or area of observed contamination) above the respective background concentrations.

or

TABLE/GRAPH OMITTED

where:

N=Estimated net activity content (in curies) for the source (or area of observed contamination).

V=Total volume of material (in gallons) in a source (or area of observed contamination) containing radionuclides.

ACi=Activity concentration above the respective background concentration (in pCi/1) for each radionuclide i allocated to the source (or area of observed contamination).

n=Number of radionuclides allocated to the source (or area of observed contamination) above the respective background concentrations.

    - - Estimate volume for the source (or volume for the area of observed contamination) based on records or measurements.

    - - For the soil exposure pathway, in estimating the volume for areas of observed contamination, do not include more than the first 2 feet of depth, except: for those types of areas of observed contamination listed in Tier C of Table 5-2 (section 5.1.2.2).

Include the entire depth, not just that within 2 feet of the surface.

Convert from curies of radionuclides to equivalent pounds of nonradioactive hazardous substances by multiplying the activity estimate for the source (or area of observed contamination) by 1,000.

Assign this resulting product as the radionuclide constituent quantity value for the source (or area of observed contamination).

If the radionuclide constituent quantity for the source (or area of observed contamination) is adequately determined (that is, the total activity of all radionuclides in the source and releases from the source (or in the area of observed contamination) is known or is estimated with reasonable confidence), do not evaluate the radionuclide wastestream quantity measure in section 7.2.5.1.2. Instead, assign radionuclide wastestream quantity a value of 0 and proceed to section 7.2.5.1.3. If the radionuclide constituent quantity is not adequately determined, assign the source (or area of observed contamination) a value for radionuclide constituent quantity based on the available data and proceed to section 7.2.5.1.2.

7.2.5.1.2 Radionuclide wastestream quantity (Tier B). Evaluate radionuclide wastestream quantity for the source (or area of observed contamination) based on the activity content of radionuclide wastestreams allocated to the source (or area of observed contamination) as follows:

Estimate the total volume (in cubic yards or in gallons) of wastestreams containing radionuclides allocated to the source (or area of observed contamination).

Divide the volume in cubic yards by 0.55 (or the volume in gallons by 110) to convert to the activity content expressed in terms of equivalent pounds of nonradioactive hazardous substances.

Assign the resulting value as the radionuclide wastestream quantity value for the source (or area of observed contamination).

7.2.5.1.3 Calculation of source hazardous waste quantity value for radionuclides. Select the higher of the values assigned to the source (or area of observed contamination) for radionuclide constituent quantity and radionuclide wastestream quantity. Assign this value as the source hazardous waste quantity value for the source (or area of observed contamination). Do not round to the nearest integer.

7.2.5.2 Calculation of hazardous waste quantity factor value for radionuclides. Sum the source hazardous waste quantity values assigned to all sources (or areas of observed contamination) for the pathway being evaluated and round this sum to the nearest integer, except: if the sum is greater than 0, but less than 1, round it to 1. Based on this value, select a hazardous waste quantity factor value for this pathway from Table 2-6 (section 2.4.2.2).

For a migration pathway, if the radionuclide constituent quantity is adequately determined (see section 7.2.5.1.1) for all sources (or all portions of sources and releases remaining after a removal action), assign the value from Table 2-6 as the hazardous waste quantity factor value for the pathway. If the radionuclide constituent quantity is not adequately determined for one or more sources (or one or more portions of sources or releases remaining after a removal action), assign a factor value as follows:

If any target for that migration pathway is subject to Level I or Level II concentrations (see section 7.3), assign either the value from Table 2-6 or a value of 100, whichever is greater, as the hazardous waste quantity factor value for that pathway.

If none of the targets for that pathway is subject to Level I or Level II concentrations, assign a factor value as follows:

- If there has been no removal action, assign either the value from Table 2-6 or a value of 10, whichever is greater, as the hazardous waste quantity factor value for that pathway.

- If there has been a removal action:

    - - Determine values from Table 2-6 with and without consideration of the removal action.

    - - If the value that would be assigned from Table 2-6 without consideration of the removal action would be 100 or greater, assign either the value from Table 2-6 with consideration of the removal action or a value of 100, whichever is greater, as the hazardous waste quantity factor value for the pathway.

    - - If the value that would be assigned from Table 2-6 without consideration of the removal action would be less than 100, assign a value of 10 as the hazardous waste quantity factor value for the pathway.

For the soil exposure pathway, if the radionuclide constituent quantity is adequately determined for all areas of observed contamination, assign the value from Table 2-6 as the hazardous waste quantity factor value. If the radionuclide constituent quantity is not adequately determined for one or more areas of observed contamination, assign either the value from Table 2-6 or a value of 10, whichever is greater, as the hazardous waste quantity factor value.

7.2.5.3 Calculation of hazardous waste quantity factor value for sites containing mixed radioactive and other hazardous substances. For each source (or area of observed contamination) containing mixed radioactive and other hazardous substances, calculate two source hazardous waste quantity values -- one based on radionuclides as specified in sections 7.2.5.1 through 7.2.5.1.3 and the other based on the nonradioactive hazardous substances as specified in sections 2.4.2.1 through 2.4.2.1.5 (that is, determine each value as if the other type of substance was not present). Sum the two values to determine a combined source hazardous waste quantity value for the source (or area of observed contamination). Do not round this value to the nearest integer.

Use this combined source hazardous waste quantity value to calculate the hazardous waste quantity factor value for the pathway as specified in section 2.4.2.2, except: if either the hazardous constituent quantity or the radionuclide constituent quantity, or both, are not adequately determined for one or more sources (or one or more portions of sources or releases remaining after a removal action) or for one or more areas of observed contamination, as applicable, assign the value from Table 2-6 or the default value applicable for the pathway, whichever is greater, as the hazardous waste quantity factor value for the pathway.

7.3 Targets. For radioactive substances, evaluate the targets factor category as specified in section 2.5 and sections 3 through 6, except: establish Level I and Level II concentrations at sampling locations as specified in sections 7.3.1 and 7.3.2.

For all pathways (and threats), use the same target distance limits for sites containing radioactive substances as is specified in sections 3 through 6 for sites containing nonradioactive hazardous substances. At sites containing mixed radioactive and other hazardous include all sources (or areas of observed contamination) at the site in identifying the applicable targets for the pathway.

7.3.1 Level of contamination at a sampling location. Determine whether Level I or Level II concentrations apply at a sampling location (and thus to the associated targets) as follows:

Select the benchmarks from section 7.3.2 applicable to the pathway (or threat) being evaluated.

Compare the concentrations of radionuclides in the sample (or comparable samples) to their benchmark concentrations for the pathway (or threat) as specified in section 7.3.2. Treat comparable samples as specified in section 2.5.1.

Determine which level applies based on this comparison.

If none of the radionuclides eligible to be evaluated for the sampling location have an applicable benchmark, assign Level II to the actual contamination at that sampling location for the pathway (or threat).

In making the comparison, consider only those samples, and only those radionuclides in the sample, that meet the criteria for an observed release (or observed contamination) for the pathway, except: tissue samples from aquatic human food chain organisms may also be used for the human food chain threat of the surface water pathway as specified in sections 4.1.3.3 and 4.2.3.3.

7.3.2 Comparison to benchmarks. Use the following media specific benchmarks (expressed in activity units, for example, pCi/l for water, pCi/kg for soil and for aquatic human food chain organisms, and pCi/m3 for air) for making the comparisons for the indicated pathway (or threat):

Maximum Contaminant Levels (MCLs) -- ground water migration pathway and drinking water threat in surface water migration pathway.

Uranium Mill Tailings Radiation Control Act (UMTRCA) standards -- soil exposure pathway only.

Screening concentration for cancer corresponding to that concentration that corresponds to the 10-6 individual cancer risk for inhalation exposures (air migration pathway) or for oral exposures (ground water migration pathway; drinking water or human food chain threats in surface water migration pathway; and soil exposure pathway).

- For the soil exposure pathway, include two screening concentrations for cancer -- one for ingestion of surface materials and one for external radiation exposures from gamma-emitting radionuclides in surface materials.

Select the benchmark(s) applicable to the pathway (or threat) being evaluated. Compare the concentration of each radionuclide from the sampling location to its benchmark concentration(s) for that pathway (or threat). Use only those samples and only those radionuclides in the sample that meet the criteria for an observed release (or observed contamination) for the pathway, except: tissue samples from aquatic human food chain organisms may be used as specified in sections 4.1.3.3 and 4.2.3.3. If the concentration of any radionuclide from any sample equals or exceeds its benchmark concentration, consider the sampling location to be subject to Level I concentrations for that pathway (or threat). If more than one benchmark applies to the radionuclide, assign Level I if the radionuclide concentration equals or exceeds the lowest applicable benchmark concentration. In addition, for the soil exposure pathway, assign Level I concentrations at the sampling location if measured gamma radiation exposure rates equal or exceed 2 times the background level (see section 7.1.1).

If no radionuclide individually equals or exceeds its benchmark concentration, but more than one radionuclide either meets the criteria for an observed release (or observed contamination) for the sample or is eligible to be evaluated for a tissue sample (see sections 4.1.3.3 and 4.2.3.3), calculate a value for index I for these as specified in section 2.5.2. If I equals or exceeds 1, assign Level I to the sampling location. If I is less than 1, assign Level II.

At sites containing mixed radioactive and other hazardous substances, establish the level of contamination for each sampling location considering radioactive substances and nonradioactive hazardous substances separately. Compare the concentration of each radionuclide and each nonradioactive hazardous substance from the sampling location to its respective benchmark concentration(s). Use only those samples and only those substances in the sample that meet the criteria for an observed release (or observed contamination) for the pathway except: tissue samples from aquatic human food chain organisms may be used as specified in sections 4.1.3.3 and 4.2.3.3. If the concentration of one or more applicable radionuclides or other hazardous substances from any sample equals or exceeds its benchmark concentration, consider the sampling location to be subject to Level I If more than one benchmark applies to a radionuclide or other hazardous substance, assign Level I if the concentration of the radionuclide or other hazardous substance equals or exceeds its lowest applicable benchmark concentration.

If no radionuclide or other hazardous substance individually exceed a benchmark concentration, but more than one radionuclide or other hazardous substance either meets the criteria for an observed release (or observed contamination) for the sample or is eligible to be evaluated for a tissue sample, calculate an index I for both types of substances as specified in section 2.5.2. Sum the index I values for the two types of substances. If the value, individually or combined, equals or exceeds 1, assign Level I to the sample location. If it is less than 1, calculate an index J for the nonradioactive hazardous substances as specified in section 2.5.2. If J equals or exceeds 1, assign Level I to the sampling location. If J is less than 1, assign Level II.

(55 FR 51583, Dec. 14, 1990)

Oil Containment Cylinder. Use a 16-gauge stainless steel containment cylinder 7.5 inches (190 mm) in diameter and 9 inches (229 mm) long to contain the oil while the oil contacts the dispersant. Suspend the cylinder vertically in the center of the test tank with its midpoint 16 inches (406 mm) above the base of the tank. The design should be such that the cylinder can be removed from the tank in less than 10 seconds.

Hosing System. Provide a pressurized hosing system suitable for delivering synthetic seawater to the oil/dispersant mixture in the test tank. A suggested hosing system is shown in Figure 2. Deliver hosing water through a hose with a 1/2-inch (12.7 mm) inside diameter, which is connected to a shut-off nozzle with a discharge tip approximately with a 3/16-inch (4.8-mm) inside diameter (Akron Brass Company, Style 111 shutoff valve with Style 558, 3/16-inch tip, or equivalent).

    ILLUSTRATION OMITTED


The hosing system must be adjusted to deliver 15.1 0.8 liters/min at 140 kPa (4.0 0.2 gpm at 20 psig). Measure the flow by hosing synthetic seawater at 23 1 C into a calibrated container for the predetermined time. Set the proper flow rate by adjusting the pressure in the pressurized tank or a suitable valve in the hose line. The delivery pressure should be determined by means of a pressure gauge in the line immediately before the nozzle.

Corrosion buildup within the nozzle may change hosing pressure and alter test results. To prevent this, remove and flush the nozzle with water at the end of each day's tests.

Spectrophotometer. Use a spectrophotometer suitable for measurement at 620 nanometers to determine photochemically the oil concentration of the oil/chloroform mixture. A Bausch and Lomb Spectronic 20 spectrophotometer (or equivalent) is acceptable for this purpose.

Filter Paper. Use a filter paper suitable for filtering the oil/chloroform extract. Whatman No. 1 filter paper (or equivalent) is acceptable for this purpose.

Glassware. Glassware should consist of 5-. 10-, 25-, 100-, and 500-ml graduated cylinders; two 1,000-ml separatory funnels with Teflon stopcocks; 10-, 100-, and 1,000-ml volumetric flasks and two 250-ml Erlenmeyer flasks.

2.3 Reagents. Synthetic Seawater. Prepare a batch of concentrated synthetic seawater using the components listed in Table 1, which are added to 379 liters (100 gal) of tap water having a hardness less than 50 mg/liter.

Table 1 -- Synthetic Seawater (Effectiveness Test)
TABLE/GRAPH OMITTED

Chloroform Reagent Grade.

Sodium Sulfate, Anhydrous Reagent Grade.

Oils. Test the dispersant with 100 ml of No. 6 fuel oil that has the characteristics given in Table 2.

Table 2 -- Test Oil Characteristics: No. 6 Fuel Oil
TABLE/GRAPH OMITTED

2.4 Pretest Preparation. Calibration of Spectrophotometer. Prepare a stock solution by adding 3.50 g of the test oil to a 1,000-ml volumetric flask. Dissolve the oil in about 900 ml of chloroform, then dilute to the mark with choloroform. The resulting concentration of test oil is 3,500 mg/liter.

Prepare standard solutions of No. 6 fuel oil by pipetting 5, 10, 25, and 50 ml of the test oil stock solution into 10-ml volumetric flasks. Dilute each flask to the mark with chloroform. The concentration of test oil in each flask is given in Table 3:

Table 3 -- Preparation of Standards for Calibration
TABLE/GRAPH OMITTED

Determine the absorbance of the stock solution and the diluted aliquots at a wavelength of 620 nanometers. If a Bausch and Lomb Spectronic 20 spectrophotometer is used, the 1/2-inch (12.7-mm) cell is recommended. Plot the calibration curve for the test oil as mg/liter of test oil versus absorbance.

Measurement of Specific Gravity of the Test Oils and Dispersant. Equilibrate samples of the test oil and dispersant at 23 1 C.

Weigh two dry 10-ml volumetric flasks on a balance capable of weighing to 1 mg or better. Add enough test oil to one flask and enough dispersant to the second flask to fill them to the mark. Reweigh each flask. The density of the oil and dispersant is:

TABLE/GRAPH OMITTED

2.5 Dispersant Effectiveness Test Procedure. The dispersant effectiveness test procedures are as follows in steps 1-16:

1. Add 38 1 liters (10 0.25 gal) of the seawater concentrate to the test tank. Dilute the concentrate to a depth of 16 0.25 inches (410 5 mm) with hot and cold water in the proper amounts to bring the temperature of the diluted seawater to 23 1 C. Adjust the pH of the seawater to 8.0 0.1 with concentrated HC1 or NaOH. The salinity of the water should be 25.00 0.15 parts per thousand (ppt).

2. Insert the oil containment cylinder into the test tank. Position the cylinder in the center of the tank with its midpoint 16 0.25 inches (410 5 mm) above the base of the tank.

3. Select one of the following graduated cylinders, a 5-, 10-, or 25-ml graduated cylinder, as appropriate for addition of the dispersant and a 100-ml graduated cylinder for addition of the test oil.

4. Fill the 100-ml graduated cylinder with 100 ml of the test oil. Drain the Cylinder for 3.0 minutes. Weigh the drained cylinder and record the weight. Calculate the weight of 100 ml of test oil (weight (g) = density (g/ml) volume (ml)) and add this amount of test oil to the drained cylinder. Record the weight of the cylinder and oil.

Note: The precision of the effectiveness test is increased substantially if exactly the same weight of test oil or dispersant is added for each test. The purpose of Step 4 is to determine the amount of test oil or dispersant that will be left in the graduated cylinder after the addition.

5. Slowly and gently add the 100 ml of the test oil from the graduated cylinder directly onto the water surface within the center of the oil containment cylinder. Move the graduated cylinder in a circular motion to distribute the oil uniformly over the surface. Be careful that oil is not lost below the containment cylinder and that oil does not splash, drip onto, or contact the containment cylinder wall above the waterline during application.

Allow the oil to drain from the graduated cylinder for 3.0 minutes.

Weigh the drained graduated cylinder. Calculate the weight of oil actually added to the test tank. Check the weight to be sure that 100.0 0.5 ml of test oil was added to the test tank.

6. Fill either the 5-, 10-, or 25-ml graduated cylinder with 3, 10, or 25 ml of dispersant, respectively. Drain it for 3.0 minutes and weigh the drained cylinder. Calculate the weight of 3, 10, or 25 ml of dispersant required (weight (g) = density (g/ml)

volume (ml)) and add this amount of dispersant to the drained cylinder. Record the of the cylinder and dispersant.

7. From the graduated cylinder gently add the dispersant at 23 1 C onto the oil surface within the containment cylinder. Move the graduated cylinder in a circular motion to distribute the dispersant uniformly over the surface. Carefully apply the dispersant onto the oil surface only and not through the oil surface or onto the containment cylinder walls. Allow the dispersant to drain from the graduated cylinder for 3.0 minutes.

Weigh the drained graduated cylinder. Calculate the weight of dispersant added to the test tank. Check the weight to be sure that the correct volume of dispersant, 3 percent, was added to the test tank.

8. Activate the hosing system, adjust nozzle pressure to 140 kPa, and apply a stream of synthetic seawater at 23 1 C to the oil/dispersant mixture within the containment cylinder. Immediately lift the cylinder all the way out above the water surface, and simultaneously hose off any oil adhering to the cylinder's inner surface. Remove the cylinder completely and continue to hose and agitate the oil/dispersant mixture for a total hosing period of 1.0 minute. The flow rate of hosing nozzle must be 15.1 0.8 liters/min at 140 kPa (4.0 0.2 gpm at 20 psig).

Note: (1) Removing the containment cylinder must take no longer than 10 seconds. (2) To hose the oil/dispersant mixture, hold the discharge tip of the nozzle approximately level with the top edge of the test tank and pointed vertically downward. Move the nozzle rapidly in a random manner from side to side, backwards and forwards, and around the inner wall of the tank, as necessary, to facilitate continuous hosing and agitation of the entire oil/dispersant surface.

9. Immediately after hosing, start the recirculation pump and continue recirculation for 2.0 hours.

10. After 10.0 minutes of recirculation, withdraw a 500-ml sample into a 500-ml graduated cylinder and discard. Immediately collect another 500-ml sample for determining "initial dispersion.''

11. After 2.0 hours of recirculation, withdraw a 500-ml sample into a 500-ml graduated cylinder and discard. Immediately collect another 500-ml sample for determining "final dispersion.''

12. Transfer the 500-ml sample to a 1,000-ml separatory funnel. Add 25 ml of chloroform to the separatory funnel, stopper the funnel, and shake vigorously for 50 strokes. After shaking, place the funnel in a rack, vent, and allow a setting time of 2 to 3 minutes.

After the settling period, lift the funnel from the rack and gently invert it several times. While holding the funnel, allow the contents to settle and then gently swirl with a circular motion to afford additional settling of the oil/chloroform mixture. Transfer the oil/chloroform mixture to a 250-ml Erlenmeyer flask that contains anhydrous Na2SO4 for drying the extract.

Repeat the extractions using a total of at least three 25-ml portions of chloroform.

After the oil extraction is complete, filter the combined extracts from the Erlenmeyer flask through dry filter paper into an appropriate volumetric flask (100 ml, 250 ml, or 500 ml depending on the amount of chloroform used to complete the extraction).

Rinse the Na2SO4 and filter paper with small portions of chloroform to remove entrained oil. After removing, fill the volumetric flask to the mark with chloroform, invert and thoroughly mix contents.

13. Spectrophotometrically determine the absorbance of the extract using the identical wavelength and cell used to calibrate the spectrophotometer. From the calibration curve, determine the concentration of oil in the chloroform.

Compute the concentration of oil in the sample as follows:

TABLE/GRAPH OMITTED

where:

Cdo is the concentration of dispersed oil in the sample and C1 is the measured concentration of oil in the chloroform extract.

Note that the standard sample volume is 500 ml and the volume of chloroform used should also be expressed in ml.

Repeat steps 1 through 13 at least three times for each of the three required volumes of dispersant.

2.6 Blank Correction Determination.

14. Clean the test tank and prepare the synthetic seawater at 23 1 C as described in Step 1. Do not install the containment cylinder and do not use any test oil. Add 25 ml of the dispersant to the tank as described in Steps 6 and 7 and continue the test procedure as described in Steps 8 through 12.

15. Spectrophotometrically determine the absorbance of the extract using the identical wavelength and cell used to calibrate the spectrophotometer. From the calibration curve, determine the corresponding concentration of oil in the chloroform. Compute the dispersant blank correction for 25 ml of dispersant as follows:

TABLE/GRAPH OMITTED

where:

D is the blank correction for 25 ml of dispersant, and C2 is the measured concentration of oil in the chloroform extract.

Note that the standard sample volume is 500 ml and the volume of chloroform used should also be expressed in ml.

The Dispersant Blank Correction (DBC) for other volumes of dispersant used in a test may then be computed as:

TABLE/GRAPH OMITTED

16. Clean the test tank and prepare the synthetic seawater at 23 1 C as described in Step 1. Do not install the containment cylinder. Prepare 100 ml of test oil as described in Steps 4 and 5, and add it to the test tank. Continue the test procedure as described in Steps 8 through 13. The Oil Blank Correction (OBC) is:

TABLE/GRAPH OMITTED

2.7 Calculations. The concentrations of test oil equivalent to 100 percent dispersion is:

TABLE/GRAPH OMITTED

The weight of the test oil should be expressed in milligrams, so that resulting C100 will be in mg/liter.

The percent of oil dispersed is then:

Percent dispersed =

TABLE/GRAPH OMITTED

2.8 Report of the Effectiveness Test Results. Based on 100 ml of oil, determine the percent dispersion of the test oil caused by 3, 10, and 25 ml of dispersant: (a) after 10 minutes recirculation ("initial dispersion'') and (b) after 2 hours recirculation ("final dispersion'').

Determine the mean of at least three replicate tests for each of the three dispersant dosages. If the percent dispersion value found (after the 10-minute recirculation period only) for any of the three replicate tests varies from the mean value by more than 8 percent, discard that result and run another replicate.

For each test oil, using percent dispersion as the ordinate and dispersant dosage (ml) as the abscissa, plot two curves on one chart, one for "initial dispersion'' and the other for "final dispersion.'' Draw the graphs by plotting mean percent dispersion values for each of the dispersant dosages of 3, 10, and 25 ml and connecting the corresponding data points for each sampling time (10 minutes or 2 hours) with straight lines. From the "initial dispersion'' graph, determine the dispersant dosage (ml) causing 50 percent dispersion. From the "final dispersion'' graph, determine the dispersant dosage (ml) causing 25 percent dispersion.

Report the data in the format given in Table 4.

Table 4_Required Dispersant Effectiveness Tests Results

TABLE/GRAPH OMITTED

TABLE/GRAPH OMITTED

2.9 Comments on Revisions to Dispersant Effectiveness Tests. The comments discussed here refer only to these revisions to the dispersant effectiveness test described by McCarthy et al. (1).

Addition to Test Oil and Dispersant. Rewick et al. (2), (3), found that the method described in the revised method for adding the same amount of test oil and dispersant significantly improved the precision of the test. The percent standard deviation of the initial and final amount of oil dispersed was determined for dispersant C, E, and F using the method described in McCarthy et al. (1). The data for dispersants A, B, and D were obtained using the weighing method for the oil and dispersant described in the revised procedure. The average percent standard deviation was reduced from 41.6 percent to 4.9 percent for No. 6 fuel oil. Additional testing of dispersants on EPA's NCP Product Schedule recently has been initiated to determine the precision of the Revised Standard Dispersant Effectiveness Test Procedures.

Inclusion of the Oil Blank. Rewick et al. (2) found that the optical density of the oil blank was significantly higher than the dispersant blank. Including an oil blank increased the accuracy of the test because it corrects for the light absorption of the water-soluble components of the fuel (amount of test oil dispersed into the water column in the absence of a dispersant is low).

Dispersant-to-Oil Ratio. The maximum effectiveness of many dispersants occurs at dispersant-to-oil (D/O) ratios of less than 0.10 or 0.25 (10 or 25 ml dispersant) (see Figure 1, Rewick et al. (3)). Furthermore, the manufacturer's recommended application rates are usually less than D/O=0.10, and the actual application rates in a real spill may be less than a D/O=0.10 specifically when applied by aircraft. Therefore, the revised method specifies testing the dispersants at D/O=0.03, 0.10, and 0.25.

3.0 Revised Standard Dispersant Toxicity Test

3.1 Summary of Method. The standard toxicity test for dispersants involves exposing two species (Fundulus heteroclitus and Artemia salina) to five concentrations of the test dispersant and No. 2 fuel oil alone and in a 1:10 mixture of dispersant to oil. To aid in comparing results from assays performed by different workers, reference toxicity tests are conducted using dodecyl sodium sulfate as a reference toxicant. The test length is 96 hours for Fundulus and 48 hours for Artemia. LC50s are calculated based on mortality date at the end of the exposure period (for method of calculation, see section 3.6 of this appendix).

3.2 Selection and Preparation of test Materials. Test Organisms. Fundulus heteroclitus. Obtain test fish from a single source for each series of toxicity tests. Report any known unusual condition to which were exposed before use (e.g., pesticides or chemotherapeutic agents); avoid if possible. Use small fish 2.5 to 3.8 cm (1 to 1.5 inches) in length and weighing about 1 gram. The longest individual fish should be no more than 1.5 times the length of the smallest.

Acclimate test fish to a temperature of 20 1 C, a pH of 8.0 0.2, and 20 2ppt salinity for 10 to 14 days before using them for the toxicity tests. Eliminate groups of fish having more than 20 percent mortality during the first 48 hours, and more than five percent thereafter. During acclimation, feed all species a balanced diet. Dry, pelleted, commercially available fishfood containing 30 percent to 45 percent protein is satisfactory. The pellets should be easily consumable by the test fish. Feed the fish twice daily to satiation, but not for 24 hours before or during the bioassay test. Use only those organisms that feed actively and appear to be healthy. Discard any fish injured or dropped while handling.

Artemia Salina. To ensure uniformity of Artemia (brine shrimp), use eggs from the San Francisco Bay area. Since the eggs of Artemia may be kept disiccated for long periods in a viable state, required numbers of the organism can be secured at any time for use in the bioassay tests through the use of proper hatching procedures.

A rectangular tray (plastic, glass, or enamel) having 200 square inches of bottom surface is suitable for hatching Artemia eggs. Divide this tray into two parts by a partition that extends from the top down to about 1.9 to 1.3 cm (0.75 to 0.5 inch) from the bottom. This partition may be of any opaque, biologically inert material (a pasteboard strip, sealed with paraffin wrapping, is satisfactory). Raise one end of the tray about 1.27 cm (0.5 inch) and add 3 liters of the synthetic seawater formulation (see Table 5).

Table 5 -- Synthetic Seawater [Toxicity test)
TABLE/GRAPH OMITTED

Spread 0.5 gram of Artemia eggs in the shallow end of the tray. Cover this end of the tray with a piece of cardboard to keep the eggs in darkness until hatching is complete. About 20 hours after the eggs direct a narrow beam of light across the uncovered portion of the tray. Since brine shrimp are phototactic, they will swim beneath the partition into the illuminated end of the chamber and congregate in the beam of light. The Artemia concentrated in the beam of light can be easily collected with the use of a collecting pipette or siphon connected to a 30-cm (12-inch) rubber tube and mouthpiece. Transfer them to a beaker containing a small amount of the artificial seawater.

An alternative method for hatching Artemia eggs is to use a separator funnel. A small air line is placed in the bottom of the funnel and air is bubbled at a rate sufficient to keep the eggs from settling to the bottom. After the eggs hatch, the air line is removed and the newly hatched nauplii will settle to the bottom of the funnel where they can be drawn off without disturbing the empty egg cases, which will have floated to the surface.

Preparation of Experimental Water. Because large quantities of dilution water will be used in these tests, formulate the experimental water in large batches to ensure uniformity and constant conditions for the various tests. To prevent contamination, prepare and store the experimental water in inert containers of suitable size.

Synthetic Seawater Formation. To prepare standard seawater, mix technical-grade salts with 900 liters of distilled or demineralized water in the order and quantities listed in Table 5. These ingredients must be added in the order listed and each ingredient must be dissolved before another is added. Stir constantly after each addition during preparation until dissolution is complete.

Add distilled or demineralized water to make up to 1,000 liters. The pH should now be 8.0 0.2. To attain the desired salinity of 20 1 ppt, dilute again with distilled or demineralized water at time of use.

3.3 Sampling and Storage of Test Materials. Toxicity tests are performed with No. 2 fuel oil having the characteristics defined in Table 6. Store oil used in toxicity tests in sealed containers to prevent the loss of volatiles and other changes. For ease in handling and use, it is recommended that 1,000-ml glass containers be used. To ensure comparable results in the bioassay tests, use oils packaged and sealed at the source. Dispose of unused oil in each open container on completion of dosing to prevent its use at a later date when it may have lost some of its volatile components. Run all tests in a bioassay series with oil from the same container and with organisms from the same group collected or secured from the same source.

Table 6 -- Test Oil Characteristics: No. 2 Fuel Oil

TABLE/GRAPH OMITTED

3.4 General Test Conditions and Procedures for Toxicity Tests. Temperature. For these toxicity tests, use test solutions with temperatures of 20 1 C.

Dissolved Oxygen and Aeration. Fundulus. Because oils and dispersants contain toxic, volatile materials, and because the toxicity of some water-soluble fractions of oil and degradation products are changed by oxidation, special care must be used in the oxygenation of test solutions. A 2 liter volume of solution is used for the Fundulus test. Initiate aeration to provide dissolved oxygen (DO)) and mixing after the fish are added. The DO content of test solutions must not drop below 4 ppm. Aerate at a rate of 100, 15 bubbles per minute supplied from a 1-ml serological pipette. At this rate and with the proper weight of fish, DO concentration should remain slightly above 4 ppm over a 96-hour period. Take DO measurements daily.

Artemia. Achieve sufficient DO by ensuring the surface area to volume ratio of the test solution exposed is large enough. Oxygen content should remain high throughout the test because of the small quantity of test substances added and the low oxygen demand of organisms in each dish.

Controls. With each fish or Artemia test or each series of simultaneous tests of different solutions, perform a concurrent control test in exactly the same manner as the other tests and under the conditions prescribed or selected for those tests. Use the diluent water alone as the medium in which the controls are held. There must be no more than 10 percent mortality among the controls during the course of any valid test.

Reference Toxicant. To aid in comparing results from tests performed by different workers and to detect changes in the condition of the test organisms that might lead to different results, perform reference toxicity tests with reagent grade dodecyl sodium sulfate (DSS) in addition to the usual control tests. Prepare a stock solution of DSS immediately before use by adding 1 gram of DSS per 500 ml of test water solution. Use exploratory tests before the full scale tests are begun to determine the amount of reference standard to be used in each of the five different concentrations.

Number of Organisms. For the toxicity test procedures using Fundulus, place two fish in each jar. For the toxicity tests using Artemia, place 20 larvae in each container.

Transfer of Organisms. Transfer Fundulus from the acclimatizing aquaria to the test containers only with small-mesh dip nets of soft material, and do not rest the net on any dry surface. Do not hold fish out of the water longer than necessary. Discard any specimen accidentally dropped or otherwise mishandled during transfer.

Artemia can be conveniently handled and transferred with a small pipette connected to a 30-cm (12-inch) length of rubber tubing and mouthpiece or with a Pasteur pipette equipped with a small rubber squeeze bulb. To have the necessary Artemia ready for the study, transfer 20 Artemia apiece into small beakers containing 20 ml of artificial seawater. Hold these batches of Artemia until they are 24 hours old; at that time, place them in the respective series of test concentrations set up for the toxicity test.

To avoid large fluctuations in the metabolic rate of organisms and the fouling of test solutions with metabolic waste products and uneaten food, do not feed organisms during tests.

Test Duration and Observations. Fish. Observe the number of dead fish in each test container and record at the end of each 24-hour period. Fish are considered dead upon cessation of respiratory and all other overt movements, whether spontaneous or in response to mild mechanical prodding. Remove dead fish as soon as observed.

Also note and report when the behavior of test fish deviates from that of control fish. Such behavioral changes would include variations in opercular movement, coloration, body orientation, movement, depth in container, schooling tendencies, and others. Abnormal behavior of the test organisms (especially during the first 24 hours) is a desirable parameter to monitor in a toxicity test because changes in behavior and appearance may precede mortality. Toxicants can reduce an organism's ability to survive natural stresses. In these cases, the mortality is not directly attributed to the toxicant, but most certainly is an indirect effect. Reports on behavioral changes during a toxicity test can give insight into the nonacute effects of the tested material.

At the end of the 96-hour period, terminate the fish tests and determine the LC50 values.

Artemia. Terminate the Artemia test after 48 hours of incubation. To count the dead animals accurately and with relative ease, place the test dishes on a black surface and hold a narrow beam of light parallel to the bottom of the dish. Most of the dead Artemia will be on the bottom of the test dish and can be readily seen against the black background. Also search the top of the liquid for Artemia trapped there by surface tension. Exercise caution when determining death of the animals. Occasionally, an animal appears dead, but closer observation shows slight movement of an appendage or a periodic spasm of its entire body. For this test, animals exhibiting any movement when touched with a needle are considered alive. Account for all test animals to ensure accuracy since some Artemia may disintegrate. Consider individuals not accounted for as dead.

At the end of 48 hours of exposure, terminate the Artemia assay and determine the LC50 values.

Physical and Chemical Determinations. Fundulus. Determine the temperature, DO, and pH of the test solutions before the fish are added and at 24-, 72-, and 96-hour exposure intervals. It is necessary to take measurements from only one of the replicates of each of the toxicant series.

Artemia. Determine the temperature, DO, and pH of the test solutions before the nauplii are added and at the 48-hour exposure interval. Measure DO and pH in only one of the replicates of each of the toxicant series.

Testing Laboratory. An ordinary heated or air-conditioned laboratory room with thermostatic controls suitable for maintaining the prescribed test temperatures generally will suffice to conduct the toxicity tests. Where ambient temperatures cannot be controlled to 20 1 C, use water baths with the necessary temperature controls.

Test Containers. For fish tests, use 4-liter glass jars measuring approximately 22.5 cm in height, 15 cm in diameter and 11 cm in diameter at the mouth. The jars are to have screw top lids, lined with Teflon. In conducting the test, add to each of the jars 2 liters of the synthetic seawater formulation aerated to saturation with DO. To add the 2 liters easily and accurately, use a 2-liter-capacity, automatic dispensing pipette (Figure 3).

ILLUSTRATION OMITTED


For the Artemia tests, use Carolina culture dishes (or their equivalent) having dimensions approximately 8.9 cm by 3.8 cm (3.5 by 1.5 inches).

Process all required glassware before each test. Immerse in normal hexane for 10 minutes. Follow this with a thorough rinse with hot tap water, three hot detergent scrubs, an additional hot tap-water rinse, and three rinses with distilled water. Oven or air dry the glassware in a reasonably dust-free atmosphere.

3.5 Preparation of Test Concentrations. Fundulus. Place the test jars containing 2 liters of synthetic seawater on a reciprocal shaker. The shaker platform should be adapted to hold firmly six of the toxicity test jars. Add the desired amount of the petroleum product under test directly to each test jar. Dispense the appropriate amount of toxicant into the jars with a pipette. Tightly cap the test jars and shake for 5 minutes at approximately 315 to 333 2-cm (0.75-inch) strokes per minute in a reciprocal shaker or at approximately 150 to 160 rpm on orbital shakers. At the completion of shaking, remove the jars from the shaker to a constant-temperature water bath or room, remove the lids, take water quality measurements, add two test fish, and initiate aeration.

Artemia. To prepare test solutions for dispersants and oil/dispersant mixtures, blend or mix the test solutions with an electric blender having: speeds of 10,000 rpm or less, a stainless-steel cutting assembly and a 1-liter borosilicate jar. To minimize foaming, blend at speeds below 10,000 rpm.

For the dispersant test solution, add 550 ml of the synthetic seawater to the jar, then with the use of a gas-tight calibrated glass syringe with a Teflon-tipped plunger, add 0.55 ml of the dispersant and mix for 5 seconds.

For the oil test solution, add 550 ml of the synthetic seawater to the jar, then with the use of a gas-tight calibrated glass syringe equipped with a Teflon-tipped plunger, add 0.55 ml of the oil and mix for 5 seconds.

For the oil/dispersant mixture, add 550 ml of the synthetic seawater to the mixing jar. While the blender is in operation, add 0.5 ml of the oil under study with the use of calibrated syringe with Teflon-tipped plunger and then 0.05 ml of the dispersant as indicated above. Blend for 5 seconds after addition of dispersant. These additions provide test solutions of the dispersant, oil, and the oil/dispersant mixture at concentrations of 1,000 ppm.

Immediately after the test solutions are prepared, draw up the necessary amount of test solution with a gas-tight Teflon-tipped glass syringe of appropriate size and dispense into each of the five containers in each series. If the series of five concentrations to be tested are 10, 18 32, 56, and 100 ppm, the amount of the test solution in the order of the concentrations listed above would be as follows: 1.0, 1.8, 3.2, 5.6, and 10.0 ml.

Each time a syringe is to be filled for dispensing to the series of test containers, start the mixer and withdraw the desired amount in the appropriate syringe while the mixer is in operation. Turn off immediately after the sample is taken to limit the loss of volatiles.

Use exploratory tests before the full-scale test is set up to determine the concentration of toxicant to be used in each of the five concentrations. After adding the required amounts of liquid, bring the volume in each of the test containers up to 80 ml with the artificial seawater. To ensure keeping each of the series separate, designate on the lid of each container the date, the material under test, and its concentration.

When the desired concentrations are prepared, gently release into each dish the 20 test Artemia (previously transferred into 20 ml of medium). This provides a volume of 100 ml in each test chamber. A pair of standard cover glass forceps with flat, bent ends is an ideal tool for handling and tipping the small beaker without risk of contaminating the medium.

After adding the test animals, incubate the test dishes at 20 1 C for 48 hours. Recommended lighting is 2,000 lumens/m2 (200 ft-c) of diffused, constant, fluorescent illumination coming from beneath the culture dishes during incubation. Because Artemia are phototactic, bottom lighting should keep them from direct contact with the oil that sometimes layers on top.

Wash the blender thoroughly after use and repeat the above procedures for each series of tests. Wash the blender as follows: rinse with normal hexane, pour a strong solution of laboratory detergent into the blender to cover the blades, fill the container to about half of its volume with hot tap water, operate the blender for about 30 seconds at high speed, remove and rinse twice with hot tap water, mixing each rinse for 5 seconds at high speed, and then rinse twice with distilled water, mixing each rinse for 5 seconds at high speed.

3.6 Calculating and Reporting. At the end of the test period, the toxicity tests are terminated and the LC50 values are determined.

Calculations. The LC50 is the concentration lethal to 50 percent of the test population. It can be calculated as an interpolated value based on percentages of organisms surviving at two or more concentrations, at which less than half and more than half survived. The LC50 can be estimated with the aid of computer programs or graphic techniques (log paper). The 95 percent confidence intervals for the LC50 estimate should also be determined.

Reporting. The test dispersant and oil and their source and storage are described in the toxicity test report. Note any observed changes in the experimental water or the test solutions. Also include the species of fish used; the sources, size, and condition of the fish; data of any known treatment of the fish for disease or infestation with parasites before their use; and any observations on the fish behavior at regular intervals during tests. In addition to the calculated LC50 values, other data necessary for interpretation (e.g., DO, pH, other physical parameters, and the percent survival at the end of each day of exposure at each concentration of toxicant) should be reported.

3.7 Summary of Procedures.

Fundulus:

1. Prepare adequate stocks of the appropriate standard dilution water.

2. Add 2 liters of the standard dilution water to the 4-liter test jars. Each test consists of 5 replicates of each of 5 concentrations of the test material, a control series of 5 dishes, and a standard reference series of 5 different concentrations for a total of 35 dishes. Simultaneous performance of toxicity tests on the oil, dispersant, and oil/dispersant mixture requires a total of 105 dishes.

3. Add the determined amount (quarter points on the log scale) of test material to the appropriate jars. Preliminary tests will be necessary to define the range of definitive test concentrations.

4. Cap the jars tightly with the Teflon-lined screw caps and shake for 5 minutes at 315 to 333 2-cm (0.75-inch) strokes per minute on a reciprocal shaker.

5. Remove the jars from the shaker, take water quality data, and add two acclimated fish per jar.

6. Aerate with 100 15 bubbles per minute through a 1-ml serological pipette.

7. Observe and record mortalities, water quality, and behavioral changes each 24 hours.

8. After 96 hours, terminate the test, and calculate LC50 values and corresponding confidence limits.

Artemia:

1. Initiate the procedure for hatching the Artemia in sufficient time (approximately 48 hours) before the toxicity test is to be conducted so that 24-hour-old larvae are available.

2. With the use of a small pipette, transfer 20 Artemia into small beakers, each containing 20 ml of the proper synthetic seawater.

3. To prepare the test stock dispersant and oil solutions, add 550 ml of the artificial seawater to the prescribed blender jar. By means of a gas-tight glass syringe with a Teflon-tipped plunger, add 0.55 ml of the dispersant (or oil) and mix at 10,000 rpm for 5 seconds. To prepare the test stock oil/dispersant mixture, add 550 ml of the standard seawater to the blender jar. While the blender is in operation (10,000 rpm), add 0.5 ml of the oil, then 0.05 ml of the dispersant with the use of a calibrated syringe with a Telfon-tipped plunger. Blend for 5 seconds after adding the dispersant. One ml of these stock solutions added to the 100 ml of standard seawater in the test containers yields a concentration of 10 ppm dispersant, oil, or oil/dispersant combination (the test will be in a ratio of 1 part dispersant to 10 parts of oil).

4. Each test consists of 5 replications of each of 5 concentrations of the material under study, a control series of 5 dishes, and a standard reference series of 5 different concentrations, a total of 35 dishes. Simultaneous performance of toxicity tests on the oil, dispersant, and oil/dispersant mixture requires a total of 105 dishes. Immediately after preparing the test solution of the dispersant or oil/dispersant solution, and using an appropriately sized syringe, draw up the necessary amount of test solution and dispense into each of the five containers in each series.

Each time a syringe is to be filled for dispensing to the series of test containers, start the mixer and withdraw the desired amount in the appropriate syringe while the mixer is in operation. Turn mixer off immediately after the sample is taken to limit the loss of volatiles. After adding the required amount of the test oil/dispersant or dispersant mixture, bring the volume of liquid in each of the test containers up to 80 ml with the artificial seawater.

When the desired concentrations have been prepared, gently release into each dish the 20 nauplii previously transferred into 20 ml of medium. This provides a volume of 100 ml in each test chamber. Use a pair of standard cover glass forceps for handling and tipping the small beaker.

5. Wash the blender as prescribed for each series of tests.

6. Incubate the test dishes at 20 1 C for 48 hours with the prescribed lighting.

7. Terminate the experiment after 48 hours, observe and record the mortalities, and determine the LC50s and corresponding confidence limits.

4.0 Summary Technical Product Test Data Format

The purpose of this format is to summarize in a standard and convenient presentation the technical product test data required by the U.S. Environmental Protection Agency (EPA) before a product may be added to EPA's NCP Product Schedule, that may be used in carrying out the National Oil and Hazardous Substances Pollution Contingency Plan. This format, however, is not to preclude the submission of all the laboratory data used to develop the data summarized in this format. Sufficient data should be presented on both the effectiveness and toxicity tests to enable EPA to evaluate the adequacy of the summarized data.

A summary of the technical product test data should be submitted in the following format. The numbered headings should be used in all submissions. The subheadings indicate the kinds of information to be supplied. The listed subheadings, however, are not exhaustive; additional relevant information should be reported where necessary. As noted some subheadings may apply only to particular types of agents.

I. Name, Brand, or Trademark:

II. Name, Address, and Telephone Number of Manufacturer:

III. Name, Address, and Telephone Numbers of Primary Distributors:

IV. Special Handling and Worker Precautions for Storage and Field Application

1. Flammability.

2. Ventilation.

3. Skin and eye contact; protective clothing; treatment in case of contact.

4. Maximum and minimum storage temperatures; optimum storage temperature range; temperatures of phase separations and chemical changes.

V. Shelf Life.

VI. Recommended Application Procedure.

1. Application method.

2. Concentration, application rate (e.g., gallons of dispersant per ton of oil).

3. Conditions for use: water salinity, water temperature, types and ages of pollutants.

VII(a). Toxicity (Dispersants and Surface Collecting Agents):

TABLE/GRAPH OMITTED

VII(b). Effective (Dispersants):

Standard Effectiveness Test With No. 6 Fuel Oil
TABLE/GRAPH OMITTED

Dosage causing 50 percent dispersion (from initial dispersion graph) is ---- ml.

Dosage causing 25 percent dispersion (from initial dispersion graph) is ---- ml.

VIII. Microbiological Analysis (Biological Additives).

IX. Physical Properties of Dispersant/Surface Collecting

Agent:

1. Flash Point: ( F).

2. Pour Point: ( F).

3. Viscosity: XXX at XXX F (centistokes).

4. Specific Gravity: XXX at XXX F.

5. pH: (10 percent solution if hydrocarbon based).

6. Surface Active Agents (Dispersants). /1/

/1/
If the submitter claims that the information presented under this subheading is confidential, this information should be submitted on a separate sheet of paper clearly labeled according to the subheading and entitled "Confidential Information.''

7. Solvents (Dispersants). /1/

8. Additives (Dispersants).

9. Solubility (Surface Collecting Agents).

X. Analysis for Heavy Metals and Chlorinated Hydrocarbons (Dispersants and Surface Collecting Agents):

TABLE/GRAPH OMITTED

References

(1) L.T. McCarthy, Jr., I. Wilder, and J.S. Dorrler. Standard Dispersant Effectiveness and Toxicity Tests. EPA Report EPA-R2-73-201 (May 1973).

(2) R.T. Rewick, H.C. Bailey, and J.H. Smith. Evaluation of Oil Spill Dispersant Testing Requirements, draft report submitted in partial fulfillment of EPA Contract No. 68-03-2621. U.S. Environmental Protection Agency, Oil and Hazardous Materials Spills Branch, Edison, New Jersey (September 1982).

(3) R.T. Rewick, K.A. Sabo, J. Gates, J.H. Smith, and L.T. McCarthy, Jr. "An Evaluation of Oil Spill Dispersant Testing Requirements.'' Proceedings, 1981 Oil Spill Conference, Publication No. 4334. American Petroleum Institute, 1220 L Street, NW., Washington, DC 20005 (1981).

(49 FR 29199, July 18, 1984, as amended at 55 FR 8864, Mar. 8, 1990)

RETURN TO THE TOP

Return to 40 CFR 300 - Main Menu