40 CFR PART 268 -- LAND DISPOSAL RESTRICTIONS
Appendix IX to Part 268 --
Extraction Procedure (EP) Toxicity Test Method and Structural
Integrity Test (SW-846, Method 1310A) (con't.)
7.0 Procedure
7.1 If the waste does not contain any free liquid, go to Step
7.9. If the sample is liquid or multiphase, continue as follows.
Weigh filter membrane and prefilter to 0.01 g. Handle membrane
and prefilters with blunt curved-tip forceps or vacuum tweezers,
or by applying suction with a pipet.
7.2 Assemble filter holder, membranes, and prefilters following
the manufacturer's instructions. Place the 0.45- m membrane on
the support screen and add prefilters in ascending order of pore
size. Do not prewet filter membrane.
7.3 Weigh out a representative subsample of the waste (100 g
minimum).
7.4 Allow slurries to stand, to permit the solid phase to settle.
Wastes that settle slowly may be centrifuged prior to filtration.
7.5 Wet the filter with a small portion of the liquid phase from
the waste or from the extraction mixture. Transfer the remaining
material to the filter holder and apply vacuum or gentle pressure
(10-15 psi) until all liquid passes through the filter. Stop
filtration when air or pressurizing gas moves through the
membrane. If this point is not reached under vacuum or gentle
pressure, slowly increase the pressure in 10-psi increments to 75
psi. Halt filtration when liquid flow stops. This liquid will
constitute part or all of the extract (refer to Step 7.16). The
liquid should be refrigerated until time of analysis.
Note: Oil samples or samples containing oil are treated in
exactly the same way as any other sample. The liquid portion of
the sample is filtered and treated as part of the EP extract. If
the liquid portion of the sample will not pass through the filter
(usually the case with heavy oils or greases), it should be
carried through the EP extraction as a solid.
7.6 Remove the solid phase and filter media and, while not
allowing them to dry, weigh to
0.01 g. The wet weight of the residue is determined by
calculating the weight difference between the weight of the
filters (Step 7.1) and the weight of the solid phase and the
filter media.
7.7 The waste will be handled differently from this point on,
depending on whether it contains more or less than 0.5% solids.
If the sample appears to have <0.5% solids, determine the
percent solids exactly (see Note below) by the following
procedure:
7.7.1 Dry the filter and residue at 80 C until two successive
weighings yield the same value.
7.7.2 Calculate the percent solids, using the following equation:
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Note: This procedure is used only to determine whether the solid
must be extracted or whether it can be discarded unextracted. It
is not used in calculating the amount of water or acid to use in
the extraction step. Do not extract solid material that has been
dried at 80 C. A new sample will have to be used for extraction
if a percent solids determination is performed.
7.8 If the solid constitutes <0.5% of the waste, discard the
solid and proceed immediately to Step 7.17, treating the liquid
phase as the
7.9 The solid material obtained from Step 7.5 and all materials
that do not contain free liquids shall be evaluated for particle
size. If the solid material has a surface area per g of material
3.1 cm /2/
or passes through a 9.5-mm (0.375-in.) standard sieve, the
operator shall proceed to Step 7.11. If the surface area is
smaller or the particle size larger than specified above, the
solid material shall be prepared for extraction by crushing,
cutting, or grinding the material so that it passes through a
9.5-mm (0.375-in.) sieve or, if the material is in a single
piece, by subjecting the material to the "Structural
Integrity Procedure'' described in Step 7.10.
7.10 Structural Integrity Procedure (SIP).
7.10.1 Cut a 3.3-cm diameter by 7.1-cm long cylinder from the
waste material. If the waste has been treated using a fixation
process, the waste may be cast in the form of a cylinder and
allowed to cure for 30 days prior to testing.
7.10.2 Place waste into sample holder and assemble the tester.
Raise the hammer to its maximum height and drop. Repeat 14
additional times.
7.10.3 Remove solid material from tester and scrape off any
particles adhering to sample holder. Weigh the waste to the
nearest 0.01 g and transfer it to the extractor.
7.11 If the sample contains 0.5% solids, use the wet weight of
the solid phase (obtained in Step 7.6) to calculate the amount of
liquid and acid to employ for extraction by using the following
equation:
W=Wf^Wt
where:
W=Wet weight in g of solid to be charged to extractor.
Wf=Wet weight in g of filtered solids and filter media.
Wt=Weight in g of tared filters.
If the waste does not contain any free liquids, 100 g of the
material will be subjected to the extraction procedure.
7.12 Place the appropriate amount of material (refer to Step
7.11) into the extractor and add 16 times its weight with water.
7.13 After the solid material and water are placed in the
extractor, the operator shall begin agitation and measure the pH
of the solution in the extractor. If the pH is 5.0, the pH of the
solution shall be decreased to 5.0 0.2 by slowly adding 0.5N
acetic acid. If the pH is 5.0, no acetic acid should be added.
The pH of the solution shall be monitored, as described below,
during the course of extraction, and, if the pH rises above 5.2,
0.5N acetic acid shall be added to bring the pH down to 5.0 0.2.
However, in no event shall the aggregate amount of acid added to
the solution exceed 4 mL of acid per g of solid. The mixture
shall be agitated for 24 hours and maintained at 20-40 C (68-104
F) during this time. It is recommended that the operator monitor
and adjust the pH during the course of the extraction with a
device such as the Type 45-A pH Controller, manufactured by
Chemtrix, Inc., Hillsboro, Oregon 97123, or its equivalent, in
conjunction with a metering pump and reservoir of 0.5N acetic
acid. If such a system is not available, the following manual
procedure shall be employed.
Note: Do not add acetic acid too quickly. Lowering the pH to
below the target concentration of 5.0 could affect the metal
concentrations in the leachate.
7.13.1 A pH meter shall be calibrated in accordance with the
manufacturer's specifications.
7.13.2 The pH of the solution shall be checked and, if necessary,
0.5N acetic acid shall be manually added to the extractor until
the pH reaches 5.0
0.2. The pH of the solution shall be adjusted at 15-, 30-, and
60-minute intervals, moving to the next longer interval if the pH
does not have to be adjusted more than 0.5 pH units.
7.13.3 The adjustment procedure shall be continued for at least 6
hours.
7.13.4 If, at the end of the 24-hour extraction period, the pH of
the solution is not below 5.2 and the maximum amount of acid (4
mL per g of solids) has not been added, the pH shall be adjusted
to 5.0
0.2 and the extraction continued for an additional 4 hours,
during which the pH shall be adjusted at 1-hour intervals.
7.14 At the end of the extraction period, water shall be added to
the extractor in an amount determined by the following equation:
V=(20)(W)^16(W)^A
Where:
V=mL water to be added.
W=Weight in g of solid charged to extractor.
A=mL of 0.5N acetic acid added during extraction.
7.15 The material in the extractor shall be separated into its
component liquid and solid phases in the following manner:
7.15.1 Allow slurries to stand to permit the solid phase to
settle (wastes that are slow to settle may be centrifuged prior
to filtration) and set up the filter apparatus (refer to Steps
4.3 and 4.4).
7.15.2 Wet the filter with a small portion of the liquid phase
from the waste or from the extracted mixture. Transfer the
remaining material to the filter holder and apply vacuum or
gentle pressure (10-15 psi) until all liquid passes through the
filter. Stop filtration when air or pressurized gas moves through
the membrane. If this point is not reached under vacuum or gentle
pressure, slowly increase the pressure in 10-psi increments to 75
psi. Halt filtration when liquid flow stops.
7.16 The liquids resulting from Steps 7.5 and 7.15 shall be
combined. This combined liquid (or waste itself, if it has <
0.5% solids, as noted in Step 7.8) is the extract and shall be
analyzed for the presence of any of the contaminants specified in
40 CFR §261.24 using the analytical procedures as designated in
Step 7.17.
7.17 The extract is then prepared and analyzed using the
appropriate analytical methods described in Chapters Three and
Four of this manual.
Note: If the EP extract includes two phases, concentration of
contaminants is determined by using a simple weighted average.
For example: An EP extract contains 50 mL of oil and 1,000 mL of
an aqueous phase. Contaminant concentrations are determined for
each phase. The final contamination concentration is taken to be:
TABLE/GRAPH OMITTED
Note: In cases where a contaminant was not detected, use the MDL
in the calculation. For example, if the MDL in the oily phase is
100 mg/L and 1 mg/L in the aqueous phase, the reporting limit
would be 6 mg/L (rounded to the nearest mg). If the regulatory
threshold is 5 mg/L, the waste may be EP toxic and results of the
analysis are inconclusive.
7.18 The extract concentrations are compared with the maximum
contamination limits listed in 40 CFR §261.24. If the extract
concentrations are greater than or equal to the respective
values, the waste then is considered to exhibit the
characteristic of Extraction Procedure Toxicity.
8.0 Quality Control
8.1 Refer to Chapter One for specific quality control procedures.
9.0 Method Performance
9.1 The data tabulated in Table 3 were obtained from records of
state and contractor laboratories and are intended to show the
precision of the entire method (1301 plus analysis method).
10.0 References
1. Rohrbough, W.G.; et al. Reagent Chemicals, American Chemical
Society Specifications, 7th ed.; American Chemical Society:
Washington, DC 1986.
2. 1985 Annual Book of ASTM Standards, Vol. 11.01; "Standard
Specification for Reagent Water''; ASTM: Philadelphia, PA, 1985;
D1193-77.
3. Gaskill, A., Compilation and Evaluation of RCRA Method
Performance Data, Work Assignment No. 2, EPA Contract No.
68-01-7075, September 1986.
Table 1. -- EPA-Approved Filter Holders
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Table 2. -- EPA-Approved Filtration Media
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Table 3. -- Precisions of Extraction-Analysis Procedures for
Several Elements
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(56 FR 3920, Jan. 31, 1991)