What is a TCLP (Toxicity Characteristic Leaching Procedure)?
TCLP is an SW-846 Method-Defined Parameter (Method 1311), meaning the specific laboratory procedure outlined in this method is required by RCRA regulations for hazardous waste determination (40 CFR 262.11). Every laboratory must complete the two-part analysis in order to comply with RCRA waste 40 CFR characterization requirements. Waste samples are placed in leaching fluid, and the vessel is tumbled for approximately 18 hours prior to the resulting leachate being analyzed for specific constituents.
A TCLP can be performed on liquid, solid, and multiphasic wastes. This procedure simulates landfill conditions to determine the mobility of contaminants in waste. The goal is to assess if these contaminants could leach into the environment, thus indicating whether the waste must be managed and disposed of as hazardous.
List of Analyses performed on TCLP Leachate
A “complete TCLP” refers to analyzing the leachate for all of the compounds found on Table 1 in 40 CFR 261.24. This table can be broken down into five sections and totals 39 constituents:
- Volatiles (Method 8260B)
- Semi-volatiles (Method 8270C/D)
- Pesticides (Method 8081 A/B)
- Herbicides (Method 8151A)
- Metals (Method 6010B/7470A)
When is TCLP analysis necessary?
TCLP is utilized to determine if a waste is hazardous and to determine the concentration of the hazardous constituent(s) for treatment and disposal options. TCLP analysis may be required for disposal at a Treatment, Storage, and Disposal Facility (TSDF), landfill, or for recycling specifications.
There are 8 metals and 31 organic chemicals that are regulated as characteristically toxic above a certain level as specified in 40 CFR 261.24. These comprise the waste codes D004- D043. For example, lead is D008, Benzene is D018, and Tetrachlororethylene (PCE) is D039.
It is the generator’s responsibility to classify their waste accurately and certify that it is hazardous or non-hazardous. Although generators may use generator knowledge to determine if their waste is hazardous, the classification must be accurate and TCLP testing is the best way to determine if hazardous constituents exceed regulatory thresholds.
What is the difference between total analysis and TCLP analysis?
The TCLP determines the mobility, or leachability, of analytes in a waste. This data allows us to know how much of an analyte would leach into the soil or groundwater after placement on the land. TCLP results are reported as mg/l.
Total analysis reports the total concentration of an analyte in the waste, and those analyses are reported in mg/kg. If the analysis of the total concentration demonstrates that an analyte is not present in the waste, or that they are present at a low enough concentration, a TCLP analysis is not necessary to confirm that the waste is non-hazardous (more on what a “low enough concentration” is below in the “Rule of 20” section).
When to analyze for totals vs. TCLP?
The decision to run totals or TCLP depends on budget, time allowance, and any clean-up testing requirements or analysis requirements from disposal facilities.
Totals provide more information on the exact levels of constituents in the material. Many disposal facilities require total results for certain parameters to ensure the material meets their acceptance criteria.
Totals are normally more cost-effective than TCLP testing. Therefore, if it is an option to have samples run for total analysis and have TCLP analysis “on hold” at the lab until the results are received to see if they meet regulatory requirements via the “rule of 20”; that can be a good option for waste characterization.
However, anytime TCLP results are being kept on hold at the lab, you need to be cognizant of hold times to ensure none of the samples expire while you are deliberating if they should be analyzed or not (inquire with the laboratory regarding hold times for your specific analysis).
If the generator only needs to know if material is hazardous or not, it is often simpler (albeit more expensive) to go straight to running a complete TCLP, especially if time is of the essence.
Rule of 20
If a total result (reported in mg/kg) is less than 20x the RCRA standard (in mg/l), TCLP is not required to determine if the waste is hazardous or not, it can be presumed to be non-hazardous. For example, the TCLP Extract Regulatory Action Level for chromium is 5 mg/L. Since 5 times 20 equals 100, if the total chromium result is less than 100 mg/kg, TCLP isn’t required. If a sample contains 30 mg/kg of chromium, even if all of the chromium was leached from the soil, the maximum concentration in the TCLP extract would be 1.5 mg/L (30 ÷ 20), which is below the regulatory requirement.
How do you conduct TCLP sampling and analysis?
Finding a Lab
Most states have their own laboratory accreditation. If you are reporting the results to a state agency or sampling for disposal at a certain facility, ensure that the laboratory you choose has any accreditation these agencies and companies require. At a minimum, the laboratory you choose should hold a state or national accreditation.
Also ensure they use EPA SW846 Methods, specifically Method 1311, because this is the only valid method under RCRA to determine if the material meets cleanup standards or is below characteristically hazardous waste thresholds.
Collecting the sample
If you contact the laboratory prior to sampling, they will be able to tell you the exact container type and size of the sample required to run the analysis you are requesting. They can also provide the glassware for collecting samples if that is desired.
TCLP samples are most commonly analyzed on composite samples. A composite sample is comprised of discrete samples, or grabs, from representative locations to form a waste characterization sample that represents an area. For example, if there is a 1,000 cubic yard stockpile of soil, collecting 5 discrete samples in various locations and depths of the pile and mixing them together would be considered a representative composite sample. The exception to this is volatiles which should almost always be performed on a grab sample. Laboratories can provide their customers with special collection vials for volatiles that preserve the constituents for transportation, as these constituents are easily lost in the mixing that takes place for compositing.
It is important to consider decontamination between samples and ensure your collection and mixing materials are not contaminated with any material that could skew the results. Each grab should be the same volume, so the composite is equal parts of each aliquot.
The minimum amount of sample required to run TCLP analysis is 110 grams. However, when analyzing for TCLP on composites, it is wise to keep extra of each discrete sample rather than mixing all of the grab samples into the composite. That way if the composite result comes up hazardous, you are able to have the laboratory run each individual sample to hopefully narrow down which grab sample was the elevated location WITHOUT another costly mobilization to the field to resample those locations.
Filling out a Chain of Custody (COC)
Each laboratory will have their own version of a COC that can be filled out by hand or electronically. Often it is helpful to fill out the existing information electronically and then fill in the sampling specific information in the field by hand as the samples are collected (for example date and time sampled).
The COC is a legal document that certifies when, where, and who collected a sample. The accuracy of sample dates, times, and names are crucial. The EPA methods have set hold times that the samples need to be analyzed during in order to consider the samples valid.
When filling out the COC you will need information such as the customer contact and billing location, the project and site name, name of the sampler, sample identification (name), date/time sampled, the matrix (soil, air, liquid, wastewater, etc.), number of containers, type of sample (composite or grab), and the analysis requested.
Hotspots
The EPA technical assistance document for TCLP notes that the RCRA definition of “average property” is very different than the mathematical definition of “average”. For example, since the TCLP extract regulatory action level is 5 mg/l for Lead, if there is one sample that is 8 mg/l and another sample 0 mg/l, we cannot compute the numerical average as 4 mg/l and say the waste is not hazardous. Known or discovered hotspots of elevated contamination must be sampled separately and delineated to separate them from the non-hazardous material. Or if there is no way to define a clean endpoint to the hazardous material, the entire waste must be sent as hazardous.
How do you interpret TCLP results?
A waste is considered hazardous, specifically characteristically toxic (D004-D043), if a representative sample of the waste contains any of the contaminants listed in table 1 of 40 CFR 261.24 at or above the limits. It is vital to ensure that you are comparing the Method 1311 TCLP results in mg/l to the Table 1 standards, not the total result in mg/kg.
If you have any questions on sampling or waste characterization under RCRA, please consider reaching out to our team of experts for assistance at 800.229.6655:
