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Glossary

A B C D E F G H I L M N O P Q R S T U V W Z

Test Methods for Evaluating Solid Waste, Physical/Chemical Methods (SW-846)
SW-846 refers to an EPA guidance and reference document, "Test Methods for Evaluating Solid Waste, Physical/Chemical Methods," which is intended to assist analytical chemists and other users in the RCRA and Superfund programs by suggesting procedures that analysts have found to be successful when applied to typical samples. The SW-846 methods are analytical and sampling methods that have been evaluated and approved for use in complying with RCRA regulations. The methods are not intended to be prescriptive, nor are all technologies or methods that may be used identified.

Tetrachloroethene
Tetrachloroethene is a nonflammable manufactured chemical widely used for dry cleaning fabrics and in metal degreasing operations. It also is used as a starting material (building block) for the production of other manufactured chemicals. Other names for tetrachloroethene include PERC, tetrachloroethylene, perchloroethylene, and PCE.

Thermal Desorption
Thermal desorption is an innovative treatment technology that heats soils contaminated with hazardous wastes to temperatures from 200 to 1,000ºF so that contaminants that have low boiling points will vaporize and separate from the soil. The vaporized contaminants then are collected for further treatment or destruction, typically by an air emission treatment system. The technology is most effective for treating VOCs; SVOCs; and other organic contaminants such as PCBs, PAHs, and pesticides. It is effective in separating organics from refining wastes, coal tar wastes, waste from wood treatment, and paint wastes. It also can separate solvents, pesticides, PCBs, dioxins, and fuel oils from contaminated soil.

See also:

Toluene
Toluene is a colorless liquid chemical with a sweet, strong odor. It is used as a solvent in aviation gasoline and in making other chemicals, perfumes, medicines, dyes, explosives, and detergents.

Total Petroleum Hydrocarbons (TPH)
TPH refers to a measure of concentration or mass of petroleum hydrocarbon constituents present in a given amount of air, soil, or water.

Toxic Substance
A toxic substance is a chemical or mixture that may present an unreasonable risk of injury to health or the environment.

Toxic Substances Control Act (TSCA)
TSCA was enacted in 1976 to test, regulate, and screen all chemicals produced or imported into the United States. TSCA requires that any chemical that reaches the consumer marketplace be tested for possible toxic effects prior to commercial manufacture. Any existing chemical that poses health and environmental hazards is tracked and reported under TSCA.

Toxicity
Toxicity is a quantification of the degree of danger posed by a substance to animal or plant life.

Triad Approach
The Triad approach is a three-pronged approach designed to encourage modernization of data collection, analysis, interpretation, and management in order to support cleanup decisions for hazardous waste sites. The three parts of the Triad approach include systematic planning, a dynamic work strategy, and use of real-time measurement tools to allow on-site analysis of samples. The Triad approach enables project managers to minimize uncertainty while expediting site cleanup and reducing project costs. Systematic planning is a common-sense approach used to ensure that the level of detail of project planning matches the intended use of the data being collected. The dynamic work strategy relies on real-time data to reach decision points. The logic for decision-making is identified, and responsibilities, authority, and lines of communication are established. Real-time measurement is made possible by use of on-site analytical tools and rapid sampling platforms, on-site interpretation and management of data, and supports on-site decision-making.

Trichloroethene (TCE)
TCE is a stable, low-boiling point, colorless liquid that is used as a solvent, as a metal degreasing agent, and in other industrial applications. TCE is also known as trichloroethylene.



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