Toxicity characteristic leaching procedure (TCLP) is a soil sample extraction method for chemical analysis employed as an analytical method to simulate leaching through a

landfill A landfill is a site for the disposal of waste materials. It is the oldest and most common form of waste disposal, although the systematic burial of waste with daily, intermediate and final covers only began in the 1940s. In the past, waste was ...

. The testing methodology is used to determine if a waste is characteristically hazardous, i.e., classified as one of the "D" listed wastes by the U.S. Environmental Protection Agency (EPA). The extract is analyzed for substances appropriate to the protocol.

Background

In the United States, the

Resource Conservation and Recovery Act The Resource Conservation and Recovery Act (RCRA), enacted in 1976, is the primary federal law in the United States governing the disposal of solid waste and hazardous waste.United States. Resource Conservation and Recovery Act. , , ''et seq., ...

(RCRA) of 1976 led to establishment of federal standards for the disposal of

solid waste Municipal solid waste (MSW), commonly known as trash or garbage in the United States and rubbish in Britain, is a waste type consisting of everyday items that are discarded by the public. "Garbage" can also refer specifically to food waste, ...

and

hazardous waste Hazardous waste is waste that must be handled properly to avoid damaging human health or the environment. Waste can be hazardous because it is Toxicity, toxic, Chemical reaction, reacts violently with other chemicals, or is Corrosion, corrosive, ...

. RCRA requires that

industrial waste Industrial waste is the waste produced by industrial activity which includes any material that is rendered useless during a manufacturing process such as that of factories, mills, and mining operations. Types of industrial waste include dirt and ...

s and other wastes must be characterized following testing protocols published by EPA. Part o
"Test Methods for Evaluating Solid Waste, Physical/Chemical Methods."
Document no. SW-846. TCLP is one of these tests.

Application of test

The Environmental Compliance Supervisor at a typical municipal

(as defined by RCRA Subtitle D) uses TCLP data 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 $50.00/ton to as much as $1200.00/ton. As extremely contaminated material is expensive to dispose of, grading is necessary to ensure safe disposal and to avoid paying for disposal of "clean fill." The TCLP procedure is generally useful for classifying waste material for disposal options. Spent abrasive or soil from a construction site usually needs to have a TCLP for lead done to determine where the waste goes next.

Procedure

TCLP comprises four fundamental procedures: * Sample preparation for leaching * Sample leaching * Preparation of leachate for analysis * Leachate analysis In the TCLP procedure the pH of the sample material is first established, and then leached with an

acetic acid Acetic acid , systematically named ethanoic acid , is an acidic, colourless liquid and organic compound with the chemical formula (also written as , , or ). Vinegar is at least 4% acetic acid by volume, making acetic acid the main compone ...

sodium hydroxide Sodium hydroxide, also known as lye and caustic soda, is an inorganic compound with the formula . It is a white solid ionic compound consisting of sodium cations and hydroxide anions . Sodium hydroxide is a highly corrosive base (chemistry), ...

solution at a 1:20 mix of sample to solvent. For example, a TCLP jug may contain 100g of sample and 2000 mL of solution. The leachate mixture is sealed in extraction vessel for general analytes, or possibly pressure sealed as in zero-headspace extractions (ZHE) for

volatile organic compound Volatile organic compounds (VOCs) are organic compounds that have a high vapor pressure at room temperature. They are common and exist in a variety of settings and products, not limited to Indoor mold, house mold, Upholstery, upholstered furnitur ...

s and tumbled for 18 hours to simulate an extended leaching time in the ground. It is then filtered so that only the solution (not the sample) remains and this is then analyzed.

References

* Davis, Sherry (2001)
"Regulated Metals: The Rule of 20."
Pollution Prevention Institute, Kansas State University. * Environment, Health and Safety Online

2008-03-07. {{Refend

External links

- EPA Environmental soil science Hazardous waste Landfill

Background

Application of test

Procedure

See also

References

External links