TCLP vs SPLP and the Proper Applications for Each

April 8, 2021

TCLP and SPLP are both procedures designed to simulate the natural leaching process that test extractants to determine the concentrations of target analytes. The similarities end regarding their respective applications.

TCLP simulates the natural leaching process that occurs to wastes in a landfill and is used make hazardous waste determinations based on whether the analytical results exceed Federal and State RCRA regulatory thresholds for certain metals and organic compounds.

SPLP simulates the natural leaching process that occurs to wastes on or in the ground as a result of precipitation and is used to determine the potential a material left on the ground has to impact groundwater (or surface water).

TCLP and SPLP Defined

First, TCLP is an abbreviation of Toxicity Characteristic Leaching Procedure and SPLP is an abbreviation of Synthetic Precipitation Leaching Procedure. Both procedures are laboratory tests used to analyze leachate. Leachate is defined in §260.10 of 40 CFR as follows:

“’Leachate’ means any liquid, including any suspended components in the liquid, that has percolated through or drained from hazardous waste.”

The analytical procedures, or Test Methods, for determining TCLP and SPLP are found in the USEPA publication, SW‐846, entitled Test Methods for Evaluating Solid Waste, Physical/Chemical Methods. This publication is the compendium of official test methods approved by the Agency. The Test Method to be used for TCLP determinations is Method 1311 and the Test Method for SPLP determinations is Method 1312.

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