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Hazardous Waste Characteristics

EPA received many questions about hazardous waste test methods. The questions and responses for this category are listed below.

On this page:

What test methods are approved for determining if a liquid is ignitable? Where can someone find the ASTM standards?

A liquid is identified as an ignitable hazardous waste if it is a solid waste and a representative sample of the waste has the following properties: it is a liquid, other than an aqueous solution containing less than 24 percent alcohol by volume, and has a flash point less than 60° C (140° F), as determined by a Pensky-Martens Closed Cup Tester, using the test method specified in ASTM Standard D-93-79 or D-93-80 (incorporated by reference, see Section 260.11), or a Setaflash Closed Cup Tester, using the test method specified in ASTM Standard D-3278-78 (incorporated by reference, see Section 260.11), or as determined by an equivalent test method approved by the Administrator under procedures set forth in Section 260.20 and 260.21. The full citation for ASTM methods is incorporated by reference in the RCRA regulations.

There is also an explanation of the ignitability characteristic in Chapter 7 of SW-846, and SW-846 Methods. SW-846 Test Method 1010A and SW-846 Test Method 1020B also incorporate the ASTM methods by reference. While these methods have been revised, the regulated community must rely on the older standards specified in the regulation to determine whether or not a waste exhibits the characteristics of ignitability.

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Should a used oil marketer use SW-846 Method 1311 (TCLP) to determine whether used oil meets the specification levels for arsenic, cadmium, chromium and lead?

When determining the levels of arsenic, cadmium, chromium, and lead in used oil that will be burned for energy recovery, the TCLP is not the appropriate test. The TCLP was developed to simulate leaching in a landfill, addressing the degree of mobility of waste streams (61 FR 11798, 11809; March 29, 1990). This attribute of the used oil is irrelevant if the used oil will be burned for energy recovery rather than land disposed. Instead of a TCLP, a totals analysis should be performed on the used oil. Chapter Two of "Test Methods for Evaluating Solid Waste, Physical/Chemical Methods (SW-846)" offers guidance on selecting appropriate test methods for specific constituents in different matrices, such as used oil. For example, Table 2-39 of Chapter Two lists testing options for various metals, including arsenic, cadmium, chromium, and lead.

Other Category: Inorganic

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What waste analysis procedures must a generator follow if they are treating their hazardous waste to comply with the land disposal restrictions (LDR)?

The general requirements for generators treating in tanks, containers, and/or containment buildings to meet land disposal restrictions (LDR) treatment standards are included in 40 CFR §268.7(a)(5). These requirements must be documented in a Waste Analysis Plan (WAP), and are designed to ensure that the generator has sufficient knowledge of their wastes to manage them properly, including identifying:

  • Parameters to be analyzed
  • Sampling methods
  • Testing and analytical methods
  • Frequency for re-evaluating wastes; or frequency of spot checks.

The generator must obtain a detailed chemical and physical analysis of a representative sample of any waste that they generate, treat, store, or dispose. The WAP must contain all information necessary to treat the waste in accordance with the LDR requirements. It must be kept on-site and made available to inspectors when requested.

When wastes treated on-site are shipped off-site for disposal, the generator must comply with the notification and certification requirements of §267.8(a)(3) (for wastes which meet their treatment standards prior to shipment offsite). This notice must accompany the first shipment of waste to the disposal facility and be retained in the generator's files.

Detailed guidance regarding WAP development is available in the following documents:

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Does a waste derived from a hazardous waste listed solely for exhibiting a characteristic of ignitability, corrosivity, or reactivity remain hazardous when it no longer exhibits a characteristic?

Does a waste derived from a hazardous waste listed solely for exhibiting a characteristic of ignitability, corrosivity, and/or reactivity remain a hazardous waste when it no longer exhibits a hazardous waste characteristic?

A solid waste derived from a hazardous waste listed solely for exhibiting a characteristic of ignitability, corrosivity, and/or reactivity is not a hazardous waste when it no longer exhibits any characteristic of hazardous waste (40 CFR Section 261.3(g)(2)(ii)). However, a waste listed solely for exhibiting the characteristic of ignitability, corrosivity, and/or reactivity that exhibits the characteristic at the point of generation and subsequently loses the characteristic is still subject to the land disposal restrictions requirements in Part 268 (66 FR 27266; May 16, 2001).

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Are alcoholic beverages regulated as hazardous waste when they exhibit the characteristic of ignitability?

Aqueous solutions containing less than 24% alcohol by volume are excluded from the characteristic of ignitability (§261.21(a)(1)). EPA originally intended for the alcohol exclusion to exempt alcoholic beverages and some types of latex paints that exhibit low flash points due to the alcohol content, but do not sustain combustion because of the high water content (45 FR 33084, 33108; May 19, 1980). Nevertheless, the alcohol exclusion is not limited to alcoholic beverages or paints. The exclusion applies to all aqueous solutions containing less than 24% alcohol, even if additional non-alcoholic components are present. The term "alcohol" refers to any alcohol or combination of alcohols (55 FR 22520, 22543; June 1, l990). However, if the alcohol has been used for solvent properties and is one of the alcohols specified in EPA hazardous waste codes F001-F005, the waste must be evaluated to determine if it should be classified as an F-listed spent solvent waste.

Additional guidance on the alcohol exclusion is available in the following documents:

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Equation for the surface area of the stainless steel coupon in Section 4.5 of SW-846 Method 1110.

The equation for the surface area of the stainless steel coupon in Method 1110 is not clear to us. We have received widely differing answers from different laboratories for the analysis of the same waste and we believe it is because they calculated the area differently.

The apparent cause of the confusion is due, in part, to the age of Method 1110, for corrosivity towards steel. It was written at a time when word processing programs did not have the ability to display equations as clearly as they do at present. However, going back to first principles, the equation is used to determine the surface area of the coupon. The area of a circle is determined from the familiar product of the radius of the circle, squared, and the constant Pi. Since the radius (r) is half of the diameter (d) of the circle, the area can expressed in the three ways shown below.

Area (A) = π (r) 2 = π (d/2) 2 = π (d 2/4)

The total surface area of the coupon is the sum of the areas of the two faces of the coupon, plus the area around the outside edge, plus the area around the edge of the hole in the center of the coupon. Sec. 4.5 of Method 1110 contains an equation that illustrates adding these areas together to determine the total surface area.

Some laboratories are apparently misreading the equation in Sec. 4.5 of Method 1110 and placing the two diameters in the first term of the expression in the denominator of the equation, not the numerator. Using the mathematical rules for the order of precedence of the operations of addition, subtraction, multiplication, and division, the equation shown in the method is correct. However, it is shown below in a format that is less subject to misunderstanding:

Area (A) = [π (D2 - d2)]/2 + (t)(π)(D) + (t)(π)(d)

where:
t = thickness
D = diameter of the coupon
d = diameter of the mounting hole

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Is SW-846 Method 9045D (pH of solids) applicable to organic liquid waste matrices?

Section 1.1 of Method 9045D states that the pH of non-aqueous liquids can be determined by the procedure. Water should be added to the non-aqueous liquid and mixed, because pH cannot be determined without the presence of water. The non-aqueous liquid should be separated from the water [aqueous phase] and the water analyzed. The pH of the water is representative of the pH of the waste thereby, the waste is not directly measured. Liquid organic wastes, such as oily wastes, may damage the pH electrode if the electrode is exposed directly to the oil.

Note: This does not mean that you must use Method 9045D to evaluate non-aqueous liquids to see if they exhibit the RCRA characteristic of corrosivity (40 CFR §261.22).

First, the characteristic of corrosivity is limited to wastes that are aqueous with pH less than or equal to 2 or greater than or equal to 12.5 using Method 9040C; OR any liquid that corrodes steel at a rate greater than 6.35 mm per year using Method 1110A.

A clarification was written to explain “aqueous” as a waste that is amenable to pH measurement. It is accepted that this can include liquids, gels, and sols. The inclusion of Method 1110(A) in the regulation was discussed in the original background document. The intention was to regulate liquids that have pH between 2 and 4, but can corrode steal at a rate that can cause harm to humans and/or the environment in a relatively short period of time.

When a sample is so corrosive that it exceeds the capacity of the electrode and/or the meter (for both high and low pH), the analyst may want to include additional testing to support Method 9040C. Diluting the waste in water (similar to Method 9045D) and measuring the pH again can demonstrate that the original pH is much less than 2 or much greater than 12.5. Additionally, millivolt readings can be used to calculate pH values in support of Method 9040C.

Method 9045D may be used to evaluate pH properties of non-aqueous liquids, solids, and sludges, but not for the RCRA characteristic of corrosivity. Organic liquids may be diluted/extracted in water according to Method 9045D, and the pH of the aqueous phase can be measured. If the organic liquid (such as organic acids) contributes hydronium ions to the solution, the measured pH is reflective of the pH of the organic liquid. However, if the organic liquid (such as hexane) does not contribute hydronium ions, the pH being measured is that of the water that was used for the dilution/extraction. It should be noted that many organic liquids (even those miscible with water) may interfere with and/or damage pH electrodes.

Other Category: 9000 Series

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For SW-846 Method 1311, what are the holding times for the samples before leaching, the leachates before extraction, and the extracts before analysis?

A table in Sec. 8.5 of Method 1311 indicates:

Sample must undergo TCLP within the following time periods:

SAMPLE MAXIMUM HOLDING TIMES [DAYS]

  From:
Field
Collection:

To:
TCLP
Extraction		 From:
TCLP
Extraction

To:
Preparative
Extraction		 From:
Preparative
Extraction

To:
Determ.
Analysis		 Total Elapsed Time
Volatiles 14 NA 14 28
Semi-volatiles 14 7 40 61
Mercury 28 NA 28 56
Metals, except Mercury 180 NA 180 360

NA: Not Applicable

For the leachate that will be analyzed for organics (including volatiles, semivolatiles, and the herbicides), you have 14 days from the collection of the original sample until you have to start the leaching (extraction). For the metals, you have 180 days from collection until leaching, except for mercury, where leaching must start within 28 days.

The herbicides are grouped with the "semivolatiles" in Sec. 8.5 of the method, since both types of analytes are extracted with an organic solvent. The extractions of the semivolatiles and herbicides from the leachate must start within 7 days of the completion of the leaching procedure.

The determinative analyses for the semivolatiles and herbicides must be completed within 40 days of the completion of the solvent extractions. The determinative analyses for the volatiles must be completed within 14 days of the completion of the leaching procedure.

The determinative analyses for the metals must be completed within 180 days of the completion of the leaching procedure, except for mercury, where analyses must be completed within 28 days of the completion of the leaching procedure.

Other Category: Holding Time & Preservation

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What are the preservation requirements for the leachates in SW-846 Method 1311 (TCLP)?

As noted in Secs. 6.3 and 6.4 of Method 1311 (the Toxicity Characteristic Leaching Procedure), chemical preservatives shall not be added to samples before leaching. However, the samples may be refrigerated, unless refrigeration will result in irreversible physical changes to the waste.

According to Sec. 6.6, once leached, the portion of the leachate for the metals analyses must be acidified with nitric acid to a pH < 2, unless precipitation occurs, in which case, consult Sec. 7.2.14 of the method for instructions.

The portions of the leachate to be analyzed for the organics must be preserved as described in the individual determinative methods. For volatiles, there is generally no need for further acidification, since the leachate is already at a pH below 7, which should retard any biological activity in the leachate. The portions of the leachate for volatiles, semivolatiles, and herbicides analyses must be stored with minimal headspace at 4° C.

Other Category: Holding Time & Preservation

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Is it allowable to increase the strength of the acid solution in SW-846 Method 1311 and use the acid solution to test additional analytes?

We believe that the strength of the acid solution in Method 1311 should be increased in order to leach more of the contaminants from the sample. We also want to use it to test additional analytes. Are we allowed to do that?

The Toxicity Characteristic Leaching Procedure (TCLP), Method 1311, is a Method Defined Parameter, which means that the results depend entirely on how the test is conducted.

The test was designed to model a theoretical scenario in which a waste is mismanaged by placing it in an unlined landfill containing municipal solid waste. The acetic acid solution in Method 1311 is designed to simulate the result of rainwater infiltrating the landfill, reacting with the municipal solid waste, and then leaching through the waste being tested. The numerical limits for the RCRA toxicity characteristic (40 CFR §261.24) were derived using the same scenario and were set at levels that would prevent the groundwater under the landfill from posing a threat to human health and the environment.

As a result, the specific details of Method 1311 and the numerical limits for the toxicity characteristic itself are linked together. Increasing the acid strength of the leaching fluid to leach a larger amount of the contaminants changes the scenario that the test was designed to simulate. Therefore, one would have to consider changing the numerical limits for the constituents listed in the toxicity characteristic too. Similarly, if one adds constituents to the list of those to be tested, one would have to develop numerical limits for them using the same sort of model that EPA used for the toxicity characteristic.

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What is the definition of aqueous for the purposes of determining whether a waste is corrosive?

There is no regulatory definition of aqueous however, for purposes of the corrosivity characteristic an aqueous waste is defined as the waste for which pH is measurable. Furthermore, Method 9040C in Test Methods for the Evaluation of Solid Waste, Physical/Chemical Methods (SW-846) is the appropriate test method to determine the pH of a waste. This method is used to measure the pH of aqueous wastes and those wastes where the aqueous phase constitutes at least 20% of the total volume of the waste. Therefore, any waste to which this method is applicable must contain at least 20% free water by volume.

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How are representative sampling, confidence levels, and statistical analysis used to determine if a waste is hazardous?

A generator can either test his or her waste or apply knowledge of the waste to determine whether the waste is hazardous. If a generator decides to test the waste, testing should be done in accordance with the test methods set forth in 40 CFR Part 261, Subpart C.

For the purposes of Subpart C, a representative sample can be obtained using any of the specified methods in Part 261, Appendix I. A representative sample means a sample of a universe or whole (e.g., waste pile, lagoon, groundwater) which can be expected to exhibit the average properties of the universe or whole.

Sampling is the physical collection of a representative portion of the universe or whole of a waste or waste treatment residual. For a sample to provide meaningful data, it is imperative that it reflect the average properties of the universe from which it was obtained, that its physical and chemical integrity be maintained, and that it be analyzed within a dedicated quality assurance program. You can choose to use sampling methods specified in the regulations in 40 CFR Part 261, Appendix I, or you may choose to petition EPA for equivalency testing and analytical methods. In particular, SW-846 has been developed by EPA to assist the regulated community in meeting analytical responsibilities under the RCRA program. Refer to the following documents for planning and implementing your strategies for representative sampling, and setting confidence levels for statistical analysis of data to determine if a waste is hazardous. See RCRA Waste Sampling Draft Technical Guidance Documents (August 2002).

Also see ASTM Manual 42 - RCRA Waste Management: Planning, Implementation, and Assessment of Sampling ActivitiesExit

Other Category: Sampling

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What testing may be done to prove that a solid meets the characteristic of corrosivity?

There is no definition of a corrosive solid in the RCRA hazardous waste regulations.

The following guidance documents provide additional guidance on corrosive solids:

The following guidance documents provide additional guidance on the definition of aqueous in 40 CFR §261.22:

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What is the time limit for filtering the TCLP leachates after completing the tumbling?

There is no time limit specified in the TCLP method for the filtration of the leachate after tumbling. However, the lack of a specification should not be perceived as permission to delay filtration. The method assumes that the filtration will be conducted as soon as practical after the completion of the tumbling (e.g., within 2 hours). If you are running a number of samples, it may take only a short while to filter all of the leachates, but you should not delay this filtration any longer than necessary (e.g., do not wait a day, but start the filtrations as soon as the tumbling is complete and proceed through all of the samples). Additionally, for samples that are difficult to filter, the samples may be centrifuged and then the supernates can be quickly filtered.

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What is the effect on the TCLP results if we miss any of the holding times specified in the method?

What is the effect on the TCLP results if we miss any of the holding times specified in the method, or if we do not perform the procedure exactly as written?

The TCLP is a Method Defined Parameter and therefore it must be performed as written, which includes meeting all specifications for holding and tumbling times. The effect of failing to perform the method as written is that the results are not valid for the purposes of determining whether the waste is hazardous based on the toxicity characteristic.

However, if the holding times are not met and the results for the analyses are over the numerical limits in the toxicity characteristic (40 CFR §261.24), then the data can be used by the generator to demonstrate that the waste failed the toxicity characteristic and therefore must be managed as a hazardous waste.

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What is the current guidance regarding the reactivity characteristic in regards to cyanide and sulfide?

What is the current guidance regarding the reactivity characteristic? I heard that EPA had withdrawn the method for Reactive Cyanide and Reactive Sulfide as specified in Chapter 7 of SW-846. Is this true?

40 CFR §261.23 includes 8 different properties of a waste that is hazardous because of the characteristic of reactivity. A waste is a reactive hazardous waste if it exhibits one or more of those properties. The regulations do not require specific test methods for any of these properties. Therefore, generators must use waste knowledge to determine whether their waste exhibits the characteristic of reactivity.

According to property (5) under 261.23, a waste is hazardous if it is a cyanide- or sulfide-bearing waste which generates toxic gases or vapors at a quantity sufficient to present a health danger. In July 1985, EPA issued interim guidance describing certain threshold levels for cyanide- and sulfide-bearing wastes and laboratory methods for evaluating such wastes. In April 1998, EPA withdrew the July 1985 guidance in a memo from Bussard and Johnson to Love (RCRA Online #14177 (PDF) (10 pp, 561.3 K, About PDF). Therefore, EPA does not recommend use of the interim threshold levels or methods to determine if a waste is hazardous based on the characteristic of reactivity. The reactivity guidance threshold levels and laboratory methods were removed from SW-846 Chapter Seven in Update IIIB.

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What is a representative sample?

What is a representative sample? Where can I find guidance on representative sampling?

Representative sample means a sample of a universe or whole which can be expected to exhibit the average properties of the universe or whole. To be representative, a sample must be collected and handled by means that will preserve its original form and composition, as well as prevent contamination or changes in concentration of parameters to be analyzed.

Sites where the wastes are of large size or varied composition, including landfills and drum dumps, present severe difficulties to investigators attempting to collect representative samples to facilitate site cleanup.

"Characterizing Heterogeneous Wastes" summarizes the planning tools and sampling design strategies now in use, identifying the advantages and disadvantages of each. The discussion of the study planning process emphasizes the establishment of reasonable goals and the participation of the decision maker and the technical specialists.

"Samplers and Sampling Procedures for Hazardous Waste Streams" describes a variety of sampling devices designed to meet the needs of those who regulate and mange hazardous waste.

"RCRA Waste Sampling and Draft Technical Guidance", updates the information provided in Chapter Nine of SW-846. It provides many improvements and new features.

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What are the requirements for performing the method of standard addition when analyzing TCLP extracts by SW-846 Method 6010?

What are the requirements for performing the method of standard addition when analyzing TCLP extracts by Method 6010?

The criteria for the method of standard addition (MSA) are outlined in Sec. 8.4 of Method 1311. In general, when the recovery of the matrix spike is less than 50%, and the analyte of concern is within 20% of the regulatory concentration, the sample must be quantified by MSA. This requirement applies to all TCLP inorganic analytes and the methods used to determine those analytes, including the current version of ICP Method 6010. Generally, most samples will not have to be analyzed by MSA when using ICP, which is less susceptible to suppression than other techniques (e.g. graphite furnace atomic absorption) that were more commonly used when the TCLP method was published. However, the laboratory may choose to apply tighter criteria than those described in the method.

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What is meant by “a quantity sufficient to present a danger to human health or the environment” in 40 CFR 261.23 for the reactivity characteristic for cyanide or sulfide waste?

Is there any guidance that clarifies what is meant by “a quantity sufficient to present a danger to human health or the environment” from 40 CFR 261.23 discussing the characteristic of reactivity for cyanide or sulfide waste?

EPA received many comments regarding the proposed rule for the identification and listing of hazardous waste and the inclusion in the reactivity definition of "any cyanide or sulfide bearing waste which can generate toxic gases, vapors or fumes when exposed to mild acidic or basic conditions."

EPA clarified the language from the proposed rule by including only those cyanide or sulfide bearing wastes "which generate toxic gases, vapors and fumes in a quantity sufficient enough to present a danger to human health or the environment." EPA also specified that "mild acidic or basic conditions" refers to pH conditions between 2 and 12.5.

Although there are no known test methods for accurately measuring reactivity, the narrative statement clearly provides guidance on the description of the reactivity characteristic. In addition, most generators of reactive wastes are aware that their wastes possess this property and require special handling. This is because such wastes are dangerous to the generator's own operations and are rarely generated from unreactive feed stocks.

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How can a solid sample evaluated by TCLP have a concentration in terms of its volume in liters?

I sent a solid sample to the laboratory for TCLP and they sent back results in units of milligrams per liter (mg/L). How can a solid sample have a concentration in terms of its volume in liters?

The TCLP Method 1311 is a leaching procedure that is used to evaluate a sample to see if it exhibits the RCRA characteristic of toxicity, as defined in 40 CFR §261.24. As part of the TCLP process, the sample is leached with a specific acidic solution and the resulting liquid leachate is subsequently analyzed. Since the leachate is a liquid, the results from its analysis are reported in units of milligrams per liter, even though the original sample was a solid.

Because the regulatory limits used in the toxicity characteristic apply to the leachate, the units are also expressed in units of milligrams per liter (mg/L). As a result, you do not need to convert the units for these results and you can simply compare the results to the numerical limits for the toxicity characteristic shown in 40 CFR §261.24.

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How does a generator determine whether a waste contains a liquid for the purposes of testing for the ignitability and corrosivity characteristics?

The definitive procedure for determining whether a waste contains a liquid for the purposes of the ignitability and corrosivity characteristics is Method 1311, the pressure filtration technique. Method 9095B, the paint filter liquids test, may be utilized to demonstrate the “positive,” that is that a liquid exists for the purpose of testing for the corrosivity and ignitability characteristics; however, it is not adequate to demonstrate the “negative,” that is that a waste does not contain a liquid for the purpose of characteristic testing. This means that, if a generator obtains a free liquid phase using Method 9095B, then that liquid may be used for the purposes of determining ignitability and corrosivity. However; wastes that do not yield a free liquid phase using Method 9095B must be assessed for the presence of an ignitable or corrosive liquid using the pressure filtration technique specified in Method 1311 (60 FR 3089, 3092; January 13, 1995).

Methods 1311 and 9095B are available in SW-846 Online.

Additional guidance regarding the use of Methods 1311 and 9095B for determining the presence of a liquid phase in a waste is available in the following documents:

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How can I find a copy of the protocol for the TCLP test (Method 1311) in SW-846?

The Toxicity Characteristic Leaching Procedure (TCLP), which is used for determining whether a solid waste is a hazardous waste by exhibiting the characteristic of toxicity, is Method 1311. You can download a copy of Method 1311 from the EPA website.

SW-846 is also available on-line at no cost from the EPA Website.

Other Category: General

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Can totals analysis be used in lieu of the TCLP for determining the toxicity characteristic?

For purposes of RCRA regulations, a solid waste exhibits the characteristic of toxicity if by using the Toxicity Characteristic Leaching Procedure (TCLP), Test Method 1311, the extract from a representative sample of the waste contains any of the contaminants listed in Table 1 of Section 261.24 at a concentration equal to or greater than the respective value in the table.

The totals analysis can be useful in determining if the TCLP should be run to definitively characterize a waste. Section 1.2 of Method 1311 allows for a total analysis in lieu of the TCLP when the constituents of concern are absent from the waste, or if present, are at such low concentration that the appropriate regulatory level could not be exceeded. If a total analysis of the waste demonstrates that individual analytes are not present in the waste, or that they are present at such low concentrations that the appropriate regulatory levels could not possibly be exceeded, the TCLP need not be run.

Wastes that are either 100% solid or that contain both a liquid and a solid component require conversion of total waste analysis data to estimates of constituent concentrations in the TCLP extract, or maximum theoretical leachate concentrations. To evaluate the regulatory status of a 100% solid, a generator can simply divide each total constituent concentration by 20 and then compare the resulting maximum theoretical leachate concentration to the appropriate regulatory limit. If maximum theoretical leachate concentrations are less than the applicable limits under Section 261.24, the waste does not exhibit the toxicity characteristic (TC) and the TCLP need not be run. If the total waste analysis data yield a maximum theoretical leachate concentration that equals or exceeds the TC threshold, the data cannot be used to conclusively demonstrate that the waste does not exceed the TC. If the latter is true, the generator may have to conduct further testing to make a definitive TC determination.

For waste that has both solid and liquid components, an analyst can perform a compositional analysis of the waste instead of a full TCLP evaluation. A representative sample of the waste must be subjected to a preliminary percent solids determination as described in the TCLP. The liquid and solid portions of the sample are then analyzed for total constituent concentration. The following equation may be used to calculate the maximum theoretical leachable concentration:

[A x B] + [C x D]
___________________ = E
B + [20 (L/kg) x D]

Where:
A = Concentration of the analyte in liquid portion of the sample (mg/L)
B = Volume of the liquid portion of the sample (L).
C = Concentration of the analyte in solid portion of the sample (mg/kg)
D = Weight of the solid portion of the sample (kg)
E = Maximum theoretical concentration in leachate (mg/L)

If the maximum leachable concentration is below the regulatory concentration, the TCLP does not need to be performed.

A representative sample means a sample of a universe or whole (e.g., waste pile, lagoon, groundwater) which can be expected to exhibit the average properties of the universe or whole. Sampling is the physical collection of a representative portion of a universe or whole of a waste or waste treatment residual. To be representative, a sample must be collected and handled by means that will preserve its original physical form and composition, as well as prevent contamination or changes in concentration of the parameters to be analyzed. For a sample to provide meaningful data, it is imperative that it reflect the average properties of the universe or whole from which it was obtained, that its physical and chemical integrity be maintained, and that it be analyzed within a dedicated quality assurance program.

To illustrate, suppose a restaurant is demolished and several stainless steel containers are the only metal included among other debris consisting of concrete, brick, plaster and glass. A representative sample would include stainless steel, concrete, brick, wood, plaster, and glass in the same proportions as they are found in the restaurant debris.

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Are we required to prepare a duplicate TCLP sample that is tumbled at the same time as the original sample?

Method 1311 does not address the need for a duplicate sample. The need for a duplicate sample could be specified in a quality assurance project plan (QAPP) or sampling and analysis plan (SAP) for any given project, but it is not a required part of the method.

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What is the proper way to handle petroleum products (i.e., oils) for SW-846 Method 1311 (TCLP)?

What is the proper way to handle Petroleum Products (i.e., oils) for Method 1311 (TCLP)? We prefer to handle these as totals because we do not want to contaminate our ZHEs and pressure filtration apparatus with oil. However, we get some resistance from clients that feel we are not handling their samples by the regulatory procedure.

Waste oils need to be characterized if they will be disposed of instead of being recycled.

It is absolutely acceptable to analyze the total fraction in oil samples to determine if they are hazardous. However, the results must be properly interpreted. For oil that passes through a filter as described in the method, the total concentrations must be compared DIRECTLY to the TCLP limits. For oil that does NOT pass through the filter, it is considered a solid and the total concentrations can be divided by 20 in order to compare to the TCLP limits.

Here is a more detailed description of the steps to follow:
First, determine if the waste passes through a filter according to Section 7.1.1 of EPA Method 1311. If the waste passes through the filter, treat the filtrate as the TCLP sample, perform all appropriate determinative methods directly on this sample (diluted as necessary for analysis), and compare the results (corrected for any dilution) directly to the TCLP limits given in Table 7‐1 of Chapter 7.

According to Section 7.1.2, if the percent solids are greater than 0.5% of the sample, the unfilterable portion is treated as a solid. Caution should be taken when attempting to dry waste samples that may be flammable. The unfilterable material can either be processed through TCLP as a solid or a total analysis can be performed on the material (i.e., divide the total result by 20 for comparison to TCLP limits). For details on how to convert total results to a number for comparison to TCLP limits, see the FAQ above on the use of totals analysis in lieu of the TCLP for  determining the toxicity characteristic.

If the totals results corrected as described in the link above are below the TCLP limits, the waste can be considered nonhazardous. If the corrected total results exceed the TCLP limits, the sample can be considered hazardous. In order to demonstrate that such a sample (where total results exceed TCLP limits) is NOT hazardous, it would need to be carried through the TCLP procedure as a solid to determine if the leachate yields results less than the TCLP limits.

Following is a web link to an older reference document titled, Technical Assistance Document for Complying with the TC Rule and Implementing the Toxicity Characteristic Leaching Procedure (TCLP) that is quite comprehensive.

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Are there SW‐846 methods and regulatory levels for determining if cyanide and sulfide are reactive?

Are there specific SW‐846 methods for Reactive Cyanide and Reactive Sulfide? Also, is there a reactivity characteristic regulatory level for cyanide and sulfide?

There are multiple SW-846 methods for determining various cyanide and sulfide species. However, there are no specific methods currently available for reactive cyanide and reactive sulfide for reactivity characteristic determination. Such guidance and methods used to exist, including regulatory thresholds, but the methods were removed from SW-846 in 1998 due to a variety of issues (e.g., the tests worked well with pure compounds, but failed with waste mixtures such that results were very unreliable). Please see Chapter 7 of SW-846 for further discussion of the issue.

You can also visit 40 CFR §261.23, which includes the 8 properties of waste that is hazardous due to the characteristic of reactivity. A waste is reactive hazardous waste if it exhibits one or more of these properties. The regulations do not require specific test methods for any of these properties, so generators must use their knowledge of the waste to make a determination. According to property (5) under 261.23, a waste is hazardous if it is a cyanide- or sulfide-bearing waste which generates toxic gases or vapors at a quantity sufficient to present a health danger.

In July 1985, EPA issued interim guidance describing certain threshold levels for cyanide- and sulfide-bearing wastes and laboratory methods for evaluating such wastes. In April 1998, EPA withdrew the July 1985 guidance. Therefore, EPA does not recommend use of the interim threshold levels of methods to determine if a waste is hazardous based on the characteristic of reactivity. EPA has removed the guidance threshold levels and the laboratory methods from Chapter Seven of SW-846. A copy of the EPA memorandum which withdrew the reactivity characteristic guidance can be found in the memorandum Withdrawal of Cyanide and Sulfide Reactivity Guidance (PDF)(10 pp, 561.3 K, About PDF).

The agency relies entirely on a descriptive definition of reactivity for cyanide and sulfide wastes, and depends on the generator's knowledge of their waste stream to classify it as a D003 waste, without the benefit of a characteristic test.

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Skipping sections 7.1.4 – 7.1.4.4 in SW-846 Method 1311 based on previous extraction fluid determinations.

Can sections 7.1.4 – 7.1.4.4 (determining the type of extraction fluid) in Method 1311 be skipped if you have significant data showing the extraction fluid always used has been number 1 or 2 for a certain waste stream? We have a waste stream that always requires extraction fluid number 2 and were wondering if sections 7.1.4 – 7.1.4.4 could be skipped based on the previous extraction fluid determinations?

Method 1311 is a Method Defined Parameter (MDP) and must be followed exactly as described. However, there are situations where it may be inappropriate or wasteful to perform parts of the procedure. What you describe might be one of those situations. The best thing to do is to contact the RCRA regulator for the applicable site and get their permission to not check which fluid to use based on the historical precedent for your waste stream.

Two factors might have to be considered. Is the waste stream liable to change such that the other fluid might have to be chosen occasionally? Secondly, when performing 7.1.4-7.1.4.4 on the waste in question, is the measured pH in the vicinity of the pH 5.0 decision point? If it is not close to the decision point and the waste stream is stable, the wrong extraction fluid could not be chosen and the regulator may agree to let you skip steps 7.1.4-7.1.4.4.

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What is the procedure when matrix interference effects cause elevated TCLP Lower Limit of Quantitation (LLOQ) that are above the TCLP regulatory limits?

What is the procedure when matrix interference effects cause elevated TCLP Lower Limit of Quantitation (LLOQ) that are above the TCLP regulatory limits?

For example, if you analyze a soil sample for TCLP SVOCs and you have a LLOQ for 2,4‐Dinitrotoluene (D030) of “<2.0 mg/L,” how is this handled if the TCLP regulatory limit for 2,4‐Dinitrotulene is 0.13 mg/L? Based on generator knowledge, you know that there should be no 2,4‐Dinitrotoluene at the site ‐ however you can’t disprove a negative since the LLOQ is higher than the TCLP regulatory limit for this constituent.

According to Table 7‐1 footnote (2) in Chapter Seven of SW‐846, Characteristics—Introduction and Regulatory Definitions, several contaminants, including 2,4‐dinitrotoluene, have quantitation limits greater than the calculated regulatory level. In such cases, the quantitation limit becomes the regulatory level.

However, for this to be valid, the laboratory should take every step possible to keep the reporting limit as low as possible (e.g., avoid unnecessarily high sample dilutions, use a clean‐up method, etc.).

For analytes not covered by the footnote, it is expected that the laboratory will use analytical procedures that achieve quantitation limits at or below the regulatory level.

Other Category: QA/QC

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Extraction fluids for SW-846 Method 1312 (SPLP) analyses of samples that may contain cyanide.

According to Method 1312, Section 5.4.3, extraction fluid #3 is used to determine cyanide. Also, Section 7.1.4.3 states for cyanide containing wastes and/or soils, extraction fluid #3 must be used because leaching of cyanide containing samples under acidic conditions may result in the formation of hydrogen cyanide gas. How is this to be interpreted when analyzing both cyanide and metals on an SPLP extraction? Is fluid #3 to be used for all SPLP analyses which may contain cyanide, or is one extraction done with fluid #3 for cyanide and another extraction with the appropriate fluid for metals?

Section 5.4 of Method 1312 indicates that Extraction fluid #3 is to be used for cyanide and volatiles. Extraction fluid #1 and #2 are supposed to be used for other analytes: Extraction fluid #1 for sites east of the Mississippi River and #2 for sites west of the Mississippi River. Therefore, if metals and cyanide analyses are needed, two separate sample aliquots would be extracted with two different fluids.

Other Category: Inorganic

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Clarification on the selection of the extraction fluid for SW-846 Method 1312, SPLP.

We are looking for clarification on the selection of the extraction fluid for EPA Method 1312, SPLP. Written in the method is as follows:

Section 5.4.1 (Extraction fluid #1) The fluid is used to determine the leachability of soil from a site that is east of the Mississippi River, and the leachability of wastes and wastewaters.

Section 5.4.2 (Extraction fluid #2) The fluid is used to determine the leachability of soil from a site that is west of the Mississippi River. (Similar statements are made in section 7.1.4.)

1) Does the source (generation) location or disposal location determine whether or not the soil is east or west of the Mississippi River?

2) It appears that whether or not the sample is a waste (or wastewater) takes precedence over whether or not the waste (or wastewater) comes from east or west of the Mississippi River. Is this correct? (As an example, if the sample is a waste and comes from west of the Mississippi River, use fluid #1?) This seems to be confirmed in Section 2.2 “If the sample is a waste or wastewater, the extraction fluid employed is a pH 4.2 solution.”

3) What would the specific definition of a “waste” or “wastewater” be as used in the 1312 method (where this would take precedence over sample site for the selection of the extraction fluid)?

The purpose of SPLP is to determine the mobility of both organic and inorganic analytes from liquids, soils, and wastes, caused from the actions of precipitation. There is a very simplified assumption that precipitation east of the Mississippi is more acidic due to industrial activity and less buffering capacity of the soils there, versus west of the Mississippi. Therefore, the concern is leaching and mobilization of contaminants above the regulatory limits at the location of disposal where the contaminants would be released into the environment. Generally, the soil origin and potential disposal site would be exactly the same place or on the same side of the river, although there may be cases where this is not so (i.e., in states bordering the river).

On the second item, the fluid selection only applies if the sample is a soil. If it is a waste or solids from wastewater, the pH 4.2 fluid is used by default. No fluid is used if the sample has less than 0.5% solids, in which case the filtered liquid is considered the extract. (See section 2.1)

On the third item, there are many definitions as to what is a waste or wastewater. Rather than define those for the method, it is much simpler to just determine if the sample is a soil or not. If it is a soil, make the fluid selection. If it is not a soil, consider it a waste or wastewater and use the pH 4.2 fluid, except if the sample is <0.5% solids when no fluid is used.

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For SW-846 Methods 1311 and 1312, is it an acceptable alternative to use internal standards for all leachates?

Both Method 1311 and Method 1312 have language specifying the use of an internal calibration quantitation method for each metallic component if the spike recovery for the element is < 50% and the concentration of the contaminant falls in the range from 80 to 100% of the regulatory level. Both of these methods then specify that “the method of standard additions shall be employed as the internal calibration quantitation method for each metallic component.”

For Methods 1311 and 1312, is it an acceptable alternative to use internal standards for all leachates to meet the requirement of an internal calibration quantitation method rather than using methods of standard additions?

The purpose of the language in Section 8.4 of the methods is to remove the effects of matrix suppression that might cause a sample extract within 20% of the regulatory limit to appear to be below the regulatory limit. When 1311 and 1312 were written, atomic absorption techniques were most commonly used and could be strongly affected by matrix effects. Since you are free to choose the analytical method for TCLP and SPLP extracts, choosing an inductively coupled plasma (ICP) method, which is far less prone to matrix effects, will make the situation described in Section 8.4 of Methods 1311 and 1312 much less likely.

Use of dilution or internal standards, or both, increases the likelihood of a passing matrix spike recovery above 50%, removing the need for the method of standard additions (MSA). If dilution and internal standards do not work and spike recoveries are still below 50%, then MSA may be the only option left. This would be very unlikely if ICP analysis is used.

Internal standards are not mentioned anywhere in either Method 1311 or 1312. As mentioned in Section 8.4.1 of both methods, "The method of standard additions shall be employed as the internal calibration quantitation method for each metallic contaminant." Use of an analytical method that utilizes internal standards (whether ICP-MS or ICP‐AES) does not eliminate the need for MSA when spike recoveries are below 50%. Section 8.2.3 allows you to use "other internal calibration methods, modification of the analytical methods, or use of alternate analytical methods to accurately measure the analyte concentration in the [TCLP or 1312] extract when the recovery of the matrix spike is below the expected analytical method performance." "Accurately measure" in that statement means acceptable spike recovery.

Other Category: QA/QC

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Defining the TCLP extract for a volatile organic compound sample for SW-846 Method 1311.

Within EPA Method 1311, Section 2, Summary of Method, specifically Section 2.1 “for liquid wastes < 0.5% solids, the waste, after filtration through 0.6‐0.8 μm filter", is defined as the TCLP Extract. Would that be true for a VOC sample?

The method indicates that the percent solids be determined as described in Section 7.1 using the non‐ZHE filtration unit, and if the solids are less than 0.5%, section 7.1.2 directs the user to section 7.3 for volatile compounds.

Section 7.3.4 indicates that if the waste contains <0.5% solids, the liquid portion of the waste, after filtration, is defined as the TCLP extract. Although the method does not explicitly state this, it is presumed that liquid samples for volatiles would be filtered using the ZHE, and the filtrate would be collected for analysis.

However, it would be a more conservative, and therefore acceptable approach to analyze the liquid sample with less < 0.5% solids for VOCs without filtration. In this scenario, there is a possibility of getting a larger value without filtration that may cause a sample to be classified as hazardous when it is not technically hazardous (i.e., if it was carried through Method 1311 as written). This potential high bias is acceptable from a regulatory standpoint because the waste would be treated more carefully than if it was considered non‐hazardous.

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Is it permissible to use a reduced sample volume to perform the leachate extraction for SW-846 Method 1311 (TCLP)?

Is it permissible to use a reduced sample volume (e.g., 50g/1L extraction fluid vs. 100g/2L) to perform the leachate extraction as long as the 20:1 extraction fluid to dry weight ratio is maintained?

Since Method 1311 is a Method Defined Parameter (MDP) method, it is exempt from the flexibility clause that is in effect for most of the other SW-846 methods. As such, it must be followed prescriptively, especially in a regulatory situation.

There are multiple places within the method that call for a minimum of 100-gram samples. When the method indicates a 100-gram minimum is recommended, it means that a larger sample size may be needed with some types of wastes, especially if it is very heterogeneous. Concrete is a good example of heterogeneous waste. If more than the minimum of 100-grams is used, you must retain the 1:20 ratio of solids to fluid. The method warns samplers to make sure enough sample is provided for the correct weight of sample required, plus extra for the duplicates and the preliminary tests for particle sizing and fluid selection.

If you are doing organic volatiles you must use the zero-headspace extractor (ZHE) and the minimum sample size is reduced to 25 g due to the 0.5-L volume limitation of the ZHE device. For all other extractions not done in a ZHE, the minimum is 100 g. If you use less than 100 g, even if you use the correct solid:fluid ratio, the results will not be valid.

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What is the correct procedure to meet the ambient temperature requirement for SW-846 Method 1311 (TCLP)?

Method 1311 Section 7.2.11 says: Ambient temperature (i.e., temperature of room in which extraction takes place) shall be maintained at 23 ± 2° C during the extraction period.

Does this mean we have to continuously monitor and record the temperature throughout the 18 hours, or is recording at the beginning and end sufficient? What is the correct procedure to meet the temperature requirement?

Extraction temperature is one of the more critical parameters in TCLP, so some form of control is necessary. As you pointed out, the method only states the temperature shall be maintained at 23 plus or minus 2° C. It does not specify how to monitor the temperature, or that continuous monitoring of the temperature is needed. It then becomes a matter of how well the extraction temperature is documented within allowable limits to the satisfaction of the auditor or regulator. A given auditor or regulator may be satisfied with the laboratory just recording a starting temperature. Another may want to see a starting and ending temperature. Another may want to see a starting, middle, and end temperature. For example, it may happen that extractions run overnight and room heating or cooling is reduced during off hours to save energy. In that case you may drop below or go above the approved temperature range during the night. In such cases, it may be necessary to record temperatures during the night to document that stayed within range. In such cases, an auditor may be satisfied that the temperature at the beginning and end was recorded, and that it is documented the room is on a thermostat control with set points to heat if temperature goes below 70 and cool if above 77 degrees F. Still another auditor may want to see continuous temperature monitoring. That is the most conservative approach and should satisfy all auditors or regulators, including NELAC auditors for laboratory certification.

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Does a lab have to check the pH of the extraction fluid daily for SW-846 Method 1311 (TCLP)?

Method 1311, Section 5.7.2 (note), states, “The pH should be checked prior to use to ensure that these fluids are made up accurately”. With using “should be”, not "must" or "shall", does a lab have to check the pH of the extraction fluid daily?

In this situation, checking the pH after the fluid is prepared, but before it is used, is mandatory. The pH is a critical parameter and must be controlled and monitored.

The note in 5.7.2 does not state that the pH of the extraction fluid should be checked daily. However, it would be a good practice to check the pH on the day of use, especially since it is very simple and quick to do.

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Particle size reduction during the determination of the appropriate extraction fluid in Section 7.1.4.1 of SW-846 Method 1311 (TCLP).

I was hoping you could please provide some guidance on Section 7.1.4.1 of the EPA 1311 TCLP method. Specifically, the requirement for particle size reduction (< 1 mm) used during the determination of the appropriate extraction fluid. We are unclear as to the best way to approach the < 1 mm particle size reduction for samples such as rags, cloth, etc. Is the intent that particle size reduction is necessary for these types of samples, and if so, do you have any recommendations on how this can be done? For the < 9.5 mm particle size reduction for the extraction, there is information about not requiring particle size reduction where the surface area per gram of material is equal to or greater than 3.1 cm2 (section 7.1.3). Even though the surface area comment is not included for the < 1 mm particle size reduction (section 7.1.4.1), is the intent the same (i.e., particle size reduction to < 1 mm is not required where the surface area per gram of material is equal to or greater than 3.1 cm2, such as for cloth, paper, etc.)?

Because of the difficulty in reducing the particle size to less than 9.5 mm for samples like cloth, paper and rags, the surface area criteria is used instead of particle size criteria for the extraction procedure. It would be even harder to reduce the particle size for those types of samples to less than the 1 mm called for in the extraction fluid determination procedure. Therefore, the surface area criteria would also apply for the procedure to determine which extraction fluid to use. As you mentioned, the intent is the same.

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If sufficient solid volume remains from the solids determination in SW-846 Method 1311, Section 7.1.1.7, can it be used for extraction starting at Section 7.2.10?

Please clarify that if sufficient solid volume remains from the % solids determination in Method 1311, Section 7.1.1.7, to support analysis, it can be used for extraction starting at Section 7.2.10, even if below the recommended 100-gram sample size.

The 100-gram minimum applies to the unfiltered sample, not the solid remaining after filtration (unless its 100% solid). Section 7.2.1 states that if the sample is 100% solid, a minimum of 100 grams should be carried through the procedure starting at Section 7.2.9.

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Range of pH allowed during preparation of leachate fluids for SW-846 Method 1311 (TCLP).

The sections of Method 1311 (TCLP) that deals with the preparation of Leachate fluids 1 and 2 states that if the fluids do not fall between a certain pH range, they must be remade.

Why can't a few drops of the individual reagent (i.e. sodium hydroxide solution or acetic acid solution) be used to adjust the pH of the extraction fluid, instead of having to discard the bulk solution and start again?

Since Method 1311 is a Method Defined Parameter (MDP) method, it is exempt from the flexibility clause that is in effect for most of the other SW‐846 methods. As such, it must be followed prescriptively, especially in a regulatory situation. Getting the exact pH with buffered solutions that are used in TCLP depends on using the right amount and concentration of the reagents. The range of pH allowed is fairly easy to accommodate using regular laboratory glassware and equipment to measure volumes and prepare reagents. Some laboratories measure everything out by weight (accounting for the density) to get more accuracy, which is also allowed.

Technically, the nature of the fluid is changed by pH adjustments. As more acid or base is added to get the pH within range, the buffering capacity of the fluid is changed. Glacial acetic acid is pure, so diluting it with the right amount of water to prepare fluid #2 is straightforward. Fluid #1 requires the use of 1N NaOH, which can be prepared improperly. If prepared from NaOH pellets, which are hygroscopic, significant amounts of water can be absorbed if the pellets are old or exposed to the atmosphere for any length of time. Consequently, you may not have 1N NaOH, and using the prescribed volumes in the method will give you a pH that is too low. If the NaOH concentration is verified after making it from scratch or 1N NaOH is purchased, the prescribed amount of NaOH and glacial acetic acid per liter will give the right pH, within the allowed window. We have also seen situations where the fluids were prepared correctly, but the pH probe was calibrated improperly. Adjusting the pH to the supposed "proper" pH in that case, would have led to improper fluid.

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Acceptable extraction container construction for SW-846 Methods 1311 (TCLP) and 1312 (SPLP).

Both Methods 1311 (TCLP) and 1312 (SPLP) contain the following passage for acceptable extraction container construction.

“It is recommended that borosilicate glass bottles be used instead of other types of glass, especially when inorganics are of concern.”

If another container type was used, but the blanks are acceptable, what would the concerns be?

The recommendation for borosilicate glass in Methods 1311 and 1312 is based on potential leaching of inorganic species from other types of glass. Borosilicate glass causes fewer problems. Keep in mind that this is only a recommendation and use of borosilicate glass is not mandatory. If other types of glass bottles are providing acceptable blanks for the parameters being monitored, then they are acceptable to use. However, extra diligence is needed regarding blanks when using non-borosilicate glass bottles.

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What are the requirements for documenting the tumbling rate for TCLP extractions?

What are the recommendations or requirements for documenting the tumbling rate for TCLP extractions (e.g., on a daily basis, annual basis, etc.)? We know the equipment is typically within range since they are simple motors and if there are problems they seem to be very apparent (not rotate at all).

The rotation speed of the tumbling apparatus must be within specifications of 28-32 rotations per minute. At a minimum, this should be checked at the start of the extraction and recorded with every batch as you would record the temperature and rotation time. Depending on the apparatus type, you may want to record the rpm at the end of rotation as well to assure the apparatus was stable. This check can be done in 30 seconds looking for 14-16 rotations.

Many tumblers have safety features built in like a friction clutch that allows slippage, should an arm, leg, or loose clothing get caught during rotation. Those clutches can become loose over time and rotations may be slower or stop, even though the motor is turning normally. Rotations should be checked under full load as the extra weight may cause slippage, whereas an empty tumbler may rotate acceptably. Friction clutches can also loosen when the motor is shut off and the rotator is moved by hand to a position that allows loading the vessels. Motors can also wear out and bearings or gear boxes can become dry, causing slower rotation speeds. If the tumbler was purchased, check with the manufacturer's documentation for proper operation and maintenance.

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What is an appropriate SW-846 method to use for reactive sulfide?

What is an appropriate method to use for reactive sulfide? The method that was described in Chapter 7 of SW-846 (7.3.4.2) no longer exists.

Reactive sulfide, formerly described in SW‐846 Section 7.3.4.2, referred to those sulfide species that could form hydrogen sulfide gas under mildly acidic conditions. In July 1985, EPA issued interim guidance describing certain threshold levels for cyanide‐ and sulfide‐bearing wastes and laboratory methods for evaluating such wastes. In April 1998, EPA withdrew the July 1985 guidance. Therefore, EPA does not recommend use of the interim threshold levels or methods to determine if a waste is hazardous based on the characteristic of reactivity. Sections 7.3.3 and 7.3.4 were amended by the Methods Innovation Rule (SW‐846 Final Update IIIB) published in the Federal Register, June 14, 2005 (Volume 70, Number 113), to withdraw specific reference to methodologies and threshold concentration levels.

However, the reactivity characteristic for waste must still be evaluated; 40 CFR §261.23 includes 8 different properties of a waste that would trigger the designation as “hazardous” based on the characteristic of reactivity. A waste is a reactive hazardous waste if it exhibits one or more of those properties. The regulations do not require specific test methods for any of these properties. Therefore, generators must use waste knowledge to determine if their waste exhibits the characteristic of reactivity. According to property (5) under §261.23, a waste is hazardous if it is a cyanide‐ or sulfide‐bearing waste which generates toxic gases or vapors at a quantity sufficient to present a health danger. It is the responsibility of the generator and their analytical laboratory to evaluate the waste for the reactivity characteristic, as EPA no longer specifies a procedure for this evaluation.

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How are the cyanide and sulfide reactivity characteristics determined?

These parameters are no longer determined analytically. With the promulgation of the Methods Innovation Rule on June 19, 2005, SW-846 was amended to withdraw references to required methods for testing of reactive sulfide and cyanide, and also withdrew the threshold levels for conditional delisting of RCRA Facilities. Please also see the 1998 memorandum regarding this issue, "Withdrawal of Cyanide and Sulfide Reactivity Guidance "(PDF)(10 pp, 561.3 K, About PDF).

Waste generators continue to have the obligation to determine whether their waste is RCRA hazardous under 261.23(a)(5) and 262.11, as well as other parts of the regulations. One must use the regulatory narrative for the determination of reactive cyanide and sulfide. The 1998 memo provides some guidance to waste generators, and there is a more specific Land Disposal Restriction (LDR) treatment standard for wastes that are hazardous under this provision (see 40 CFR §268.40).

There are a number of sources for more general guidance on making a "knowledge-based" hazardous waste determination under 40 CFR §262.11.

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Can you provide more definitive guidance regarding the interpretation of “as soon as possible” in SW-846 Methods 9040 and 9045?

Methods 9040 and 9045 for pH both say that samples should be analyzed as soon as possible. 40 CFR 136 Table II defines the maximum holding time for Hydrogen ion (pH) as 15 minutes.

Can you provide more definitive guidance regarding the interpretation of “as soon as possible”?

Methods 9045D and 9040C can be done in the field, but often field conditions cannot be controlled and may be unfavorable for accurate analyses. The methods are generally meant to be used in a laboratory setting under controlled conditions.

Because of potential changes from microbial activity, or shifts in chemical equilibrium, sample pH should be taken as soon as possible upon receipt at the laboratory. It is expected pH of collected samples would be analyzed within a few hours of laboratory receipt, and not the next day. The method is written to be followed sequentially with no undue delay between steps, except for the one hour settling time for soils in Section 7.2.2 or 15 minutes settling time for wastes in Section 7.3.2 of 9045D. Also, keep in mind that Methods 9045D and 9040C are Method Defined Parameter (MDP) methods that must be followed exactly as written with no modifications.

The holding time of "Analyze as soon as possible" is not clearly defined for SW-846, but is only recommended as a qualitative goal. In 2007, the definition for “immediately” was established as 15 minutes for the NPDES Program (40 CFR 136, Table II), however, that does not apply to the RCRA program and SW-846. Even though SW-846 Method 9040C (and Method 9045D) are MDP methods and must be followed prescriptively, Section 6.0 of Method 9040C on holding time is not prescriptive. The method authors recognized changes in pH begin as soon as a sample is put into a container and specified that samples should be analyzed as soon as possible. If they meant to analyze by an exact time, the method authors would have put that time into the method. Instead, they left it up to the user to do what is feasible as soon as possible. SW-846 also makes a distinction between "must" or "shall" language that is mandatory, as opposed to guidance language like "should" or "may". Note that Section 6.0 of Method 9040C uses the word "should".

The actual holding time for pH analysis should be specified in the quality assurance plan under which the sample was collected and agreed‐upon by all stakeholders involved, including those who have to measure the pH (be it in the laboratory or in the field). In the laboratory, we recommend performing the analysis within a few hours of receipt, and not the next day.

Other Categories: 9000 Series, Holding Time & Preservation

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If a client asks for Ignitability on a solid matrix sample, is it normally considered acceptable to analyze by the 1020B method, or should 1030 be used?

For determination of the ignitability characteristic in solid wastes, SW‐846 Method 1030 should be followed. Method 1020 is only applicable to liquid wastes.

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