A B C D E F G H I J K L M
N O P Q R S T U V W X Y Z
tachycardia
excessively rapid heartbeat, with a pulse rate above 100.
tachypnea
increased rate of respiration.
Tag Closed Cup
See TCC or TCT.
Tag Open Cup
See TOC.
Tag Open Tester
an open-tank tester for liquids with low flash points. See TCC or TCT.
tailings
residue of raw materials or waste separated out during the processing of crops or mineral ores.
TAL
Target Analyte List.
TALMS
Turnable Atomic Line Molecular Spectroscopy.
TAMS
Toxic Air Monitoring System.
tank
a stationary device, designed to contain an accumulation of hazardous waste, which is constructed primarily of non- earthen materials (e.g., wood, concrete, steel, plastic) that provide structural support.
TAP
Technical Assistance Program.
target compound list
developed by EPA for Superfund site sample analyses. The TCL is a list of analytes (34 volatile organic chemicals, 65 semi-volatile organic chemicals, 19 pesticides, 7 polychlorinated biphenyls, 23 metals, and total cyanide) for which every Superfund sample must be analyzed using the RAS of the EPA Contract Laboratory Program.
target organ effects
chemically caused effects from exposure to a material on specifically listed organs and systems such as the liver, kidneys, nervous system, lungs, skin, and eyes.
TAT
Technical Assistance Team.
TBT Paints (Trybutilin)
(See: organotins).
TC
Target Concentration.
TC
Technical Center.
TC
Toxic Concentration.
TC
Toxicity Characteristic.
TCC or TCT
Tag (Tagliabue) closed cup or Tag closed tester. One of several types of apparatus for determining flash points. The Tag closed tester, per ASTM D56-79, is intended for testing liquids with a viscosity of less than 45 SUS at 100 degrees F (38 degrees C) and a flash point below 200 degrees F (93.4 degrees C). Liquids should not have suspended solids or form surface films.
TCDD
Dioxin (Tetrachlorodibenzo-p-dioxin).
TCDF
Tetrachlorodibenzofurans.
TCL
Target Compound List.
TCLo
Toxic concentration low. The lowest concentration of a substance in air to which humans or animals have been exposed for any given period of time that has produced any toxic effect in humans or produced a tumorigenic or reproductive effect in animals or humans.
TCLP
Toxicity Characteristic Leaching Procedure.
TCLP
Toxic Concentration Leaching Procedure; required test under RCRA to determine toxicity and mobility characteristics of hazardous wastes.
TCM
Transportation Control Measure.
TCP
Transportation Control Plan.
TCP
Trichloropropane.
TCRI
Toxic Chemical Release Inventory.
TDS
(abbr.) total dissolved solids. TDS= TS-TSS.
TEAM
Total Exposure Assessment Model.
technology-based standards
effluent limitations applicable to direct and indirect sources which are developed on a category-by- category basis using statutory factors, not including water-quality effects.
TEG
Tetraethylene Glycol.
TEGD
Technical Enforcement Guidance Document.
TEM
Transmission Electron Microscopy.
temp
Temperature
TER, Teratogen
substance that causes malformation or serious deviation from normal development of embryos and fetuses.
teratogenic
substances that are suspected of causing malformations or serious deviations from the normal type, which can't be inherited, in or on animal embryos or fetuses.
terracing
dikes build along the contour of agricultural land to hold runoff and sediment, thus reducing erosion.
tertiary treatment
advanced cleaning of waste water that goes beyond the secondary or biological stage. It removes nutrients such as phosphorus and nitrogen and most suspended solids.
TES
Technical Enforcement Support.
TEXIN
Texas Intersection Air Quality Model.
TFX
toxic effects. Used to introduce the principal organ system affected as reported or its pathology. See RTECS.
THC
Total Hydrocarbons.
thermal pollution
discharge of heated water from industrial processes that can affect the life processes of aquatic plants and animals.
thermal treatment
the treatment of hazardous waste in a device which uses elevated temperatures as the primary means to change the chemical, physical, or biological character or composition of the hazardous waste. Incineration is an example of thermal treatment.
thermocline
the layer in a lake dividing the upper, current- mixed zone, from the cool lower stagnant zone.
THM
Trihalomethane.
threat of discharge or release
see definitions for discharge and release.
threat of release
see definition for release.
threshold dose
the minimum application of a given substance required to produce a measurable effect.
threshold limit value (TLV)
represents the air concentrations of chemical substances to which it is believed that workers may be daily exposed without adverse effect.
threshold planning quantity
a quantity designated for each chemical on the list of extremely hazardous substances that triggers notification by facilities to the state emergency response commission that such facilities are subject to emergency planning under SARA Title III.
threshold treatment
the control of scale or deposits by application of sub-stoichiometric dosage of treatment chemicals.
thickener
a device or system wherein the solid contents of slurries or suspensions are increased by gravity settling and mechanical separation of the phases, or by flotation and mechanical separation of the phases.
thickening
(sludge dewatering): thickening or concentration is the process of removing water from sludge after the initial separation of the sludge from wastewater. The basic objective of thickening is to reduce the volume of liquid sludge to be handled in subsequent sludge disposal processes.
THIO-RED
Polythiocarbonate - Organic - Chelate Breaker - Heavy Metal (ETUS).
THIO-D
Catalyzed Polythiocarbonate Precipitant - Chelate Breaker - Heavy Metal (ETUS).
THIO-T
Catalyzed Polythiocarbonate Precipitant - Chelate Breaker - Heavy Metal (ETUS).
THIORd 2
Specialty Polythiocarbonate Precipitant - Chelate Breaker - Heavy Metal (ETUS).
TI
Temporary Intermittent.
TI
Therapeutic Index.
TIBL
Thermal Internal Boundary Layer.
TIC
Technical Information Coordinator.
TIC
Tentatively Identified Compounds.
tidal marsh
low, flat marshlands traversed by interlaced channels and tidal sloughs and subject to tidal inundation, normally, the only vegetation present is salt-tolerant bushes and grasses.
TIM
Technical Information Manager.
time-line
refers to a chronology of exercise events. A time-line is compiled to provide a frame of reference for evaluating exercise performance and to evaluate time-sensitive actions (e.g., alert and notifications). Time-lines and evaluators' meetings are essential for determining the coordination between the various response organizations.
Time-Weighted Average
See TLV-TWA.
tinnitus
a ringing sound in the ears.
TIP
Total Ionization Probe.
TIP
Transportation Improvement Program.
TI/RE
Toxicity Investigation/Reduction Evaluation.
TISE
Take It Somewhere Else.
TITC
Toxic Substances Control Act Interagency Testing Committee.
titrate
to determine the amount of a substance in solution by adding a measured amount of another substance to produce a desired reaction or end point.
TLC
Total Lung Capacity.
TLm
median tolerance limit. Designates the concentration of a toxic material at which 50% of the test organisms, usually aquatic organisms, survive. TL90, for example, may be required by a conservation authority where pollution must be limited to protect the fish.
TLV
threshold limit value; term for standards set by the American Conference of Governmental Industrial Hygienists in 1968. A term used by ACGIH to express the airborne concentration of a material to which nearly all workers can be exposed day after day without adverse effects. "Workers" means health individuals. The young, old, ill, or naturally susceptible will have lower tolerances and need to take additional precautions. ACGIH expresses TLVs in three ways; TLV-TWA, the allowable time-weighted average concentration for a normal 8-hour workday or 40-hour week; TLV-STEL, the short-term exposure limit or maximum concentration for a continuous exposure period of 15 minutes (with a maximum of four such period per day, with at least 60 minutes between exposure periods, and provided that the daily TLV-TWA is not exceeded); ceiling (C) the concentration that should not be exceeded at any time.
TLV-Ceiling Limit
TLV-C. The ceiling exposure limit or the concentration that should not be exceeded even instantaneously.The ACGIH publishes a book annually that explains and lists TLVs in TLVs: Threshold Limit Values for Chemical Substances in the Work Environment Adopted by ACGIH. Copies are available from ACGIH (q.v).
TMA
(abbr.) total mineral acidity or anions.
TMI
Three Mile Island.
TOA
Trace Organic Analysis.
TOC
Tag open-cup test method.
TOC
(abbr.) total organic carbon.
TOC
Total Organic Compound.
tolerance
the ability of an organism to cope with changes in its environment. Also the safe level of any chemical applied to crops that will be used as food or feed.
tolerances
the permissible residue levels for pesticides in raw agricultural produce and processed foods. Whenever a pesticide is registered for use on a food or a feed crop, a tolerance (or exemption from the tolerance requirement) must be established. EPA establishes the tolerance levels, which are enforced by the Food and Drug Administration and the Department of Agriculture.
topography
the physical features of a surface area including relative elevations and the position of natural and manmade features.
total dissolved solids (TDS)
total amount of dissolved solid materials present in an aqueous solution.
total exposure point
a point of potential exposure to substances from more than one exposure.
total metal
sum of the metal content in both soluble and insoluble form.
total organic carbon (TOC)
a measure of the amount of carbon in a sample originating from organic matter only. The test is run by burning the sample and measuring the COà produced.
total solids
sum of dissolved and undissolved constituents in water or wastewater, usually stated in milligrams per liter.
total suspended solids (TSS)
solids found in wastewater or in the stream, which in most cases can be removed by filtration.The origin of suspended matter may be manmade or of natural sources, such as silt from erosion.
total volatile solids
volatile residue present in wastewater.
totally enclosed treatment facility
a facility for the treatment of hazardous waste which is directly connected to an industrial production process and which is constructed and operated in a manner which prevents the release of any hazardous waste or any constituent thereof into the environment during treatment. An example is a pipe in which waste acid is neutralized.
TOX
Tetradichloroxylene.
TOX
Total Organic Halogens.
toxic
harmful to living organisms.
toxic chemical
-OSHA A chemical that falls within any of the following categories:(1) A chemical that has a median lethal dose (LD50) or more than so milligrams per kilogram, but no more than 500 milligrams per kilogram of body weight, when administered orally to albino rats weighing between 200 and 300 grams each.(2) A chemical that has a median lethal dose (LD50) of more than 200 milligrams per kilogram, but no more than 1000 milligrams per kilogram of body weight, when administered by continuous contact for 24 hours (or less, if death occurs within 24 hours) with the bare skin of albino rabbits weighing between 2 and 3 kilograms each.(3) A chemical that has a median lethal concentration (LC50) in air of more than 200 parts per million (ppm), but no more than 2000 parts per million (ppm) of gas or vapor by volume, or more than 2 milligrams per liter, but no more than 20 milligrams per liter, of mist, fume, or dust, when administered by continuous inhalation for 1 hour (or less, if death occurs within 1 hours) to albino rats weighing between 200 and 300 grams each.-SARA A chemical so designated under Section 313 of SARA Title III. Its release into the environment must be reported annually to the EPA and to designated State officials. The presence of a toxic chemical in a mixture or trade name product must be notified to customers. This notification must be incorporated into or attached to the MSDS for that product.
toxic chemical release form
information form required to be submitted by facilities that manufacture, process, or use (in quantities above a specific amount) chemicals listed under SARA Title III.
toxic cloud
airborne mass of gases, vapors, fumes, or aerosols containing toxic materials.
toxic pollutants
materials contaminating the environment that cause death, disease, birth defects in organisms that ingest or absorb them. The quantities and length of exposure necessary to cause these effects can vary widely.
toxic substances
any chemical or material that (1) has evidence of an acute or chronic health hazard and (2) is listed in the NIOSH Registry of Toxic Effects of Chemical Substances (RTECS), provided that the substance causes harm at any dose level; causes cancer or reproductive effects in animals at any dose level; has a median lethal dose (LD50) of less than 500 mg per kg of body weight when administered orally to rats; has a median LD50 of less than 1000 mg per kg of body weight when administered by continuous contact to the bare skin of albino rabbits; or has a median lethal concentration (LC50) in air of less than 2000 ppm by volume of gas or vapor, or less than 20 mg per 1 of mist, fume, or dust when administered to albino rats.
Toxic Substances Control Act
See TSCA.
toxicant
a chemical that controls pests by killing rather than repelling them.
toxicity
the degree of danger posed by a substance to animal or plant life.
toxicologist
A scientist specializing in the study of the adverse effects of chemicals in animals.
toxicology
the study of the nature, effects, and detection of poisons in living organisms. Also, substances that are otherwise harmless but prove toxic under particular conditions. The basic assumption of toxicology is that there is a relationship among the dose (amount), the concentration at the affected site, and the resulting effects.
TPCA
Toxic Pits Cleanup Act.
TPH
total petroleum hydrocarbon.
TPQ
threshold planning quantity. Per 40 CFR 302. The amount of material at a facility that requires emergency planning and notification per CERCLA.
TPSIS
Transportation Planning Support Information System.
TPY
Tons per Year.
TR-20
Activated Polymer Precipitant - Chelate Breaker - Heavy Metal (ETUS).
trade name
a name given to a product by the manufacturer or supplier. It is usually not the chemical name, and the same or similar products can be marketed under different trade names by different companies.
trade secret
Confidential information (formula, process, device, or compilation of data) that gives the owner an advantage over competitors. Manufacturers may choose to withhold data of a proprietary nature from an MSDS. Typically this would be the ingredients of a formulated product. OSHA permits this provided that (1) the trade secret claim can be substantiated, (2) the MSDS indicates that data is being withheld, and (3) the properties and health effects are included. State laws vary on this practice; some states require a trade secret registration number to be assigned to a material. There are procedures to obtain limited trade secret disclosure in emergency situations.
Traffic Controllers
refers to persons assigned to assist in facilitating traffic flow and to restrict access into potentially hazardous areas.
transient noncommunity system
these water systems typically serve travelers and others who are "passing through" or staying temporarily at locations such as highway rest stops, restaurants, and public parks. These systems serve at least 25 people a day for at least 60 days a year, but typically do not serve the same people each day.
TR-BB
Polythiocarbonate Blends Precipitant - Chelate Breaker - Heavy Metal (ETUS).
train
a single ion exchange system capable of producing the treated water desired, such as SAC + SBA, with multiple trains being duplicates of the single system.
transfer facility
any transportation related facility including loading docks, parking areas, storage areas and other similar areas where shipments of hazardous waste are held during the normal course of transportation.
transformation
the process of placing new genes into a host cell, thereby inducing the host cell to exhibit functions encoded by the DNA.
transpiration
the process by which water vapor is lost to the atmosphere from living plants. The term can also be applied to the quantity of water thus dissipated.
transporter
any person engaged in the off-site transportation of hazardous waste within the United States, by air, rail, highway, or water, if such transportation requires a manifest under 40 CFR Part 262.
trash-to energy plan
a plan for putting waste back to work by burning trash to produce energy.
TRC
Technical Review Committee.
TRD
Technical Review Document.
treatment
any method, technique or process, including neutralization, designed to change the physical, chemical, or biological character or composition of any hazardous waste so as to neutralize it, or render it non-hazardous or less hazardous, or to recover it, make it safer to transport, store or dispose of, or amenable for recovery, storage, or volume reduction.
treatment, storage, and disposal facility
site where a hazardous substance is treated, stored, or disposed. TSd facilities are regulated by EPA and states under RCRA.
treatment technique requirement
this requirement is set for contaminants that are difficult or costly to measure and is used instead of MCLs. Under this requirement, specific water treatment practices, such as filtration or corrosion control, may be required.
treatment technology
means any unit operation or series of unit operations that alters the composition of a hazardous substance or pollutant or contaminant through chemical, biological, or physical means so as to reduce toxicity, mobility, or volume of the contaminated materials being treated. Treatment technologies are an alternative to land disposal of hazardous wastes without treatment.
TRI
Toxic Release Inventory; annual report on chemical releases regulated industries must file with EPA under SARA Title III.
Triage
is the process of sorting or selection of patients to determine priority of care to be rendered to each.
Trichloroethylene (TCE)
a stable, low boiling colorless liquid, toxic by inhalation. TCE is used as a solvent, metal degreasing agent, and in other industrial applications.
trickling filter
a biological treatment device; wastewater is trickled over a bed of stones covered with bacterial growth, the bacteria break down the organic wastes in the sewage and produce cleaner water.
triholomethane (THM)
one of a family or organic compounds, named as derivatives of methane. THM's are generally the by-product from chlorination of drinking water that contains organic material.
TRIP
Toxic Release Inventory Program.
troposphere
the portion of the atmosphere between seven and ten miles from the Earth's surface, where clouds form.
Trust Fund (CERCLA)
a fund set up under the Comprehensive Environmental Response, Compensation and Liability Act (CERCLA) to help pay for cleanup of hazardous waste sites and for legal action to force those responsible for the sites to clean them up.
Trustee
means an official of a federal natural resources management agency designated in subpart G of the NCP or a designated state official or Indian tribe who may pursue claims for damages under section 107(f) of CERCLA.
TRX
Polythiocarbonate Blends Precipitant - Chelate Breaker - Heavy Metal (ETUS).
TS
Toxic Substances.
TSA
Technical Systems Audit.
TSCA
Toxic Substances Control Act. Public Law PL 94-469. Found in 40 CFR 700-799. EPA has jurisdiction. Effective January 1, 1977.Controls the exposure to and use of raw industrial chemicals not subject to other laws. Chemicals are to be evaluated prior to use and can be controlled based on risk. The act provides for a listing of all chemicals that are to be evaluated prior to manufacture or use in the US. (Call the EPA, Industry Assistance Office, (202) 554-1404).
TSCATS
TSCA Test Submissions Database.
TSCP
Toxic Substances Control Program.
TSD
Technical Support Document.
TSD
acronym for treatment, storage, or disposal facility.
TSDF
treatment, storage or disposal facility; hazardous waste facility regulated under RCRA.
TSI
Thermal System Insulation.
TSM
Transportation System Management.
TSP
Total Suspended Particulates.
TSS
(abbr.) total suspended solids. TSS= TS-TDS.
TTFA
Target Transformation Factor Analysis.
TTHM
Total Trihalomethane.
TTLC
Total Threshold Limit Concentration.
TTO
Total Toxic Organics.
TTU
Transportable Treatment Unit.
tuberculation
a corrosion process that produces hard mounds of corrosion products on the metal surface, increasing friction and reducing flow in a water distribution system.
tundra
a type of ecosystem dominated by lichens, mosses, grasses, and woody plants. Tundra is found at high latitudes (arctic tundra) and high altitudes (alpine tundra). Arctic tundra is underlain by permafrost and is usually very wet.(See: wetlands).
turbidimeter
an instrument for measurement of turbidity in which a standard suspension is usually used for reference.
turbidity
1. a condition in water or wastewater caused by the presence of suspended matter resulting in the scattering and adsorption of light rays; 2. a measure of fine suspended matter in liquids; 3. an analytical quantity usually reported in arbitrary turbidity units determined by measurements of light diffraction.
turnover
the mixing of lower and upper layers in a lake in spring and fall caused by temperature and density equalization.
TVA
Tennessee Valley Authority.
TWA
Time-weighted average. See TLV-TWA.
TWC
Texas Water Commission.
TX
(abbr.) total solids, TS= TDS+TSS.
TXDS
Qualifying toxic dose.
