TOXICITY CHARACTERISTIC LEACHING PROCEDURE (TCLP)

M. Sc. Environmental Engineering Firat University - Elazig - Turkey

Prepared by Shaimaa F. Alsadawee

Content 1- introduction 2- Meaning of Toxicity

3- Factors influencing toxicity

4- the concept of TCLP 5- Why we using TCLP analysis?

6- TCLP Process

7- Application of TCLP test

8- Conclusion

Introduction -Many products are classified as hazardous waste when they are

disposed at the end of their useful life. These products contain materials that are corrosive, flammable, reactive or toxic.

-the EPA developed a protocol known as the Toxicity Characteristic Leaching Procedure (TCLP) to determine the potential of specific wastes to leach dangerous concentrations of toxic chemicals into groundwater.

- TCLP estimate how much of toxic contents would be released into landfill leaching under ordinary conditions.

Meaning of the toxicity

Toxicity is the degree of a toxin or dose of the substance can damage the environment and organisms and its substructure. it could be any substance that can result in a detrimental effect when the concentration is increase

Factors influencing toxicity

- pathway of administration -the time of exposure -the number of exposures -the physical form of the toxin (solid, liquid, gas),

Toxicity characteristic leaching procedure concept

Background

In1976 the United States, led to establishment of federal standards for the disposal of solid waste and hazardous waste. They requires that industrial wastes and other wastes must be characterized by following testing protocols while TCLP is one of these tests. Then in 1986 EPA developed the TCLP rule and promulgated as a part of the land disposal restriction.

What is TCLP? (TCLP) is a soil sample extraction method for chemical

analysis employed as an analytical method to simulate leaching through a landfill. it designed to determine the mobility of both organic and inorganic compounds present in liquid, solid as well as multiphase samples waste. The extract is analyzed for substances .

Why we using TCLP analysis?

Since direct disposal of contaminated soil to landfill is not allowed and it must be qualified the Landfill Disposal Criteria prior to disposal. TCLP is one of approved method used to assess the soil contamination concentration. If any TCLP test results of the sample exceed the disposal criteria, the contaminated soil must first be pre-treated or stabilized before disposal.

TCLP Process

The TCLP analysis begins by determining the amount of solids in the sample. If the sample is a liquid waste that contains less than 0.5% dry solid material, the sample itself is defined as TCLP extract.

The liquid portion of the sample is separated from the solid phase and stored for later analysis. The remaining solid phase sample will undergo treatment in order to make sure every particle is <10 mm. After that, an appropriate extraction fluid, which is determined by the pH testing procedures is used for TCLP extraction.

The sample is then extracted with an amount of fluid equal to 20 times more then the solid phase for 16-20 hours on an agitation tumbler. After extraction, the TCLP extract is separated from the solid phase by filtering . Finally, the TCLP extract is combined with any liquid from the initial separation and the sample is analysis of TCLP metals by using Inductively coupled plasma mass spectrometry ICPMS .

At a typical municipal landfill TCLP data is used to determine whether a waste may be accepted into the facility. If TCLP analytical results are below the TCLP D-list maximum contamination levels (MCLs) the waste can be accepted. If they are above these levels the waste must be taken to a hazardous waste disposal facility and the cost of disposal may increase from about.

  -If an analysis of any one of the liquid fractions of the TCLP extract indicates that a regulated compound is present at such high concentrations that, even after accounting for dilution from the other fractions of the extract, the concentration would be above the regulatory level for that compound, then the waste is hazardous and it is not necessary to analyze the remaining fractions of the extract.

-If a total analysis of the waste demonstrates that individual analyte's are not present in the waste, or that they are present but at such low concentrations that the appropriate regulatory levels could not

possibly be exceeded, the TCLP need not be run . 

Application of TCLP test

-The TCLP procedure is generally useful for classifying waste material for disposal options.

-Spent abrasive or soil from a construction site usually need to have a TCLP for lead done to determine where the waste goes next.