Frequent Questions

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

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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