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
RCRA Administrative Action Tracking System.
Radiation Advisory Committee.
Reasonably Available Control Measures.
Reasonably Available Control Technology.
Radiation Absorbed Dose.
a unit of measurement of any kind of radiation absorbed by humans.
in a furnace, the transfer of heat by energy waves, much like other forms of electromagnetic waves (e.g., light and radio waves). The emission of particles of rays by the nucleus of an atom.
regulations that govern exposure to permissible concentration of and transportation of radioactive materials.
substances that emit rays either naturally or as a result of scientific manipulation.
substances that emit radiation.
the study of the principles, mechanisms, and effects of radiation on living things.
the study of the effects of radiation on plants and animals in natural communities.
radio frequency radiation
(See non ionizing radiation).
radioactive forms of chemical compounds; such as cobalt-60, used in the treatment of diseases.
radioactive element characterized according to its atomic mass and atomic number which can be man-made or naturally occurring. Radioisotopes can have a long life as soil or water pollutants, and are believed to have potentially mutagenic effects on the human body.
radius of vulnerable zone
the maximum distance from the point of release of a hazardous substance in which the airborne concentration could reach the level of concern under specified weather conditions.
a colorless naturally occurring, radioactive, inert gaseous element formed by radioactive decay of radium atoms in soil or rocks.
radon decay products
a term used to refer collectively to the immediate products of the radon decay chain. These include Po-218, Pb-214, Bi-214, and Po-214, which have an average combined half of about 30 minutes.
debris that accumulates at an oil-water interface.
Real-Time Air-Quality Simulation Model.
Regional Air Monitoring System.
the successive changes in heat content and temperature as water is converted to steam, expands through a prime mover, condenses, and returns to the boiler.
Radon Action Plan.
Remedial Action Plan.
Response Action Plan.
Regional Air Pollution Study.
Routine Analytical Services.
a machine that grinds waste into a manageable material and helps prevent odor.
Radiological Assistance Team.
Relative Accuracy Test.
untreated waste water.
untreated surface or groundwater.
Regional Contingency Plan.
Resource Conservation and Recovery Act (1976, 1984); regulates management and disposal of hazardous wastes currently generated, treated, stored, disposed or distributed.
RCRA Hazardous Waste
a material designated by RCRA as hazardous waste and assigned a number to be used in record keeping and reporting compliance (e.g., D003, F001, U169).
RCRA Subpart O
regulates operations and emissions of hazardous waste incinerators.
RCRA Information System.
Resource Conservation and Recovery Information System.
remedial design; detailed plans for cleanup of a Superfund site.
Research and Development.
Research, Demonstration and Development.
Research, Development, Testing & Evaluation.
Regional Decision Units.
the expression of the exchange of ions brought about by differences, affinities, concentrations, temperature, flow, and other influences.
a chemical substance or mixture that vigorously polymerizes, decomposes, condenses, or becomes self-reactive due to shock, pressure, or temperature. Includes materials or mixtures that fall within any of these categories: (1) explosive material -- a substance or mixture that causes sudden, almost instantaneous release of pressure, gas, and heat when subjected to sudden adverse conditions; (2) organic peroxide -- an organic compound that contains the bivalent -O-O- structure, which can be considered a structural derivative of hydrogen peroxide, in which one or both of the hydrogen atoms has been replaced by an organic radical; (3) pressure-generating material -- a substance or mixture that may spontaneously polymerize with an increase in pressure unless protected by the addition of an inhibitor or by refrigeration or other thermal control; decompose to release gas in its container; (4) water-reactive material -- a substance or mixture that reacts with water to release heat or a flammable, toxic gas.
describes a substance's tendency to undergo chemical reaction either by itself or with other materials with the release of energy. Undesirable effects such as pressure buildup; temperature increase; or formation of noxious, toxic, or corrosive byproducts may occur because of the substance's reactivity to heating, burning, direct contact with other materials, or other conditions in use or in storage. A solid waste that exhibits a "characteristic of reactivity", as defined by RCRA, may be regulated (by the EPA) as a hazardous waste and assigned the number D003.
substance used in a chemical reaction to produce another substance or to detect its composition.
Regional Enforcement Activities Plan.
reasonably available control technology (RACT)
the lowest emissions limit that a particular source is capable of meeting by the application of control technology that is both reasonably available, as well as technologically and economically feasible.RACT is usually applied to existing sources in nonattainment areas and most cases is less stringent than new source performance standards.
any body of water where untreated wastes are dumped.
refers to a facility where registration, monitoring, and decontamination of evacuees takes place.
process by which water is added to the zone of saturation, as recharge of an aquifer.
a land area in which water reaches to the zone of saturation from surface infiltration, e.g., an area where rainwater soaks through the earth to reach an aquifer.
recombinant DNA (rDNA)
a new DNA that is formed by combining pieces of DNA from different organisms or cells.
a type of microorganism whose genetic makeup has been altered by deliberate introduction of new genetic elements. The offspring of these altered bacteria also contain these new genetic elements.
recommended maximum contaminant level (RMCL)
the maximum level of a contaminant in drinking water at which no known or anticipated adverse affect on human health would occur, and which includes an adequate margin of safety. Recommended levels are nonenforceable health goals. (See: maximum contaminant level).
an existing facility in which components are replaced to such an extent that the fixed capital cost of the new components exceed 50 percent of the capital cost that would be required to construct a comparable entirely new facility. New source performance standards may be applied to sources which are reconstructed after the proposal of the standard if it is technologically and economically feasible to meet the standard.
record of decision (ROD)
a public document that explains which cleanup alternative(s) will be used at National Priorities List sites where under CERCLA, Trust Funds pay for the cleanup.
refers to the efforts involved and resources dedicated to returning an affected area to its pre-emergency condition.
a furnace which burns black liquor from the kraft pulping process, to recover the cooking chemicals as smelt.
the process of minimizing the generation of waste by recovering usable products that might otherwise become waste.Examples are the recycling of aluminum cans, wastepaper, and bottles.
process wastewater or treatment facility effluent which is recirculated to the same process.
converting solid waste into new products by using the resources contained in discarded materials.
an EPA document that is undergoing final review before being submitted for final management decision.
the gangue from bauxite processing.
a term used to abbreviate a reduction-oxidation reaction.
reduction-oxidation potential measured against a standard electrode.
a proliferation of ocean plankton that may kill large numbers of fish. This natural phenomenon may be stimulated by the addition of nutrients.
in a reduction reaction (which always occurs simultaneously with an oxidation reaction), the reducing agent is the chemical or substance that (1) combines with oxygen or(2) loses electrons to the reaction. See Oxidation; Oxidizing Agent.
a chemical reaction in which an element or compound gains electrons, being reduced in positive valence.
the period of time immediately following the application of a pesticide during which unprotected workers should not enter a field.
refers to the return of evacuees to an affected area following a hazardous materials incident. Also may include the controlled reentry of emergency personnel during or towards the end of an incident for sampling or monitoring purposes.
Review of Environmental Effects of Pollutants.
reference dose (RfD)
Toxicity value used most often in evaluating noncarcinogenic effects resulting from exposures at Superfund sites.See specific entries for chronic RfDs, subchronic RfDs, and developmental RfDs.
an area designated for the protection of wild animals, within which hunting and fishing is either prohibited or strictly controlled.
see solid waste.
conversion of solid waste into useful products, e.g., composting organic wastes to make a soil conditioner.
a chemical used to restore the ion exchange resin back to its desired form.
the amount of regeneration used, usually in pounds of 100% form of the chemical.
a solution of a chemical compound used to restore the capacity of an ion exchange system. Sodium chloride brine is used as a regenerant for ion exchange water softeners, and acids and bases are used as regenerants for the cation and anion resins used in demineralization.
manipulation of individual cells or masses of cells to cause them to develop into whole plants.
in utility stations, a scheme for reducing heat losses to the main condenser in the cycle by using steam extracted from the turbine to heat feedwater. In engineering designs, the use of a heat exchanger to preheat the feed to a process by extracting heat from the product.
the highest ranking official in each of the ten EPA regions.
Regional Response Team (RRT)
representatives of federal, local, and state agencies who may assist in coordination of activities at the request of the On-Scene Coordinator before and during a Superfund response action.
any manufacturer or formulator who obtains registration for a pesticide active ingredient or product.
published reviews of all the data available on pesticide active ingredients.
formal listing with EPA of a new pesticide before it can be sold or distributed in intra- or inter-state commerce.The product must be registered under the Federal Insecticide, Fungicide, and Rodenticide Act. EPA is responsible for registration (pre-market licensing) of pesticides on the basis of data demonstrating that they will not cause unreasonable adverse effects on human health or the environment when used according to approved label directions.
See CAS number.
means (a) any substance defined in section 101(14) of the Comprehensive Environmental Response, Compensation and Liability Act (CERCLA) of 1980 (but not including any substance regulated as a hazardous waste under subtitle C), and (b) petroleum, including crude oil or any fraction thereof that is liquid at standard conditions of temperature and pressure (60 degrees Fahrenheit and 14.7 pounds per square inch absolute). The term "regulated substance" includes but is not limited to petroleum and petroleum-based substances comprised of a complex blend of hydrocarbons derived from crude oil though processes of separation, conversion, upgrading, and finishing, such as motor fuels, jet fuels, distillate fuel oils, residual fuel oils, lubricants, petroleum solvents, and used oils.
the legal mechanism that spells out how a statute's broad policy directives are to be carried out. Regulations are published in the Federal Register and then codified in the Code of Federal Regulations.
a heat exchanger located in a furnace to increase the temperature of steam extracted from a turbine for reinjection.
The NIOSH REL (Recommended Exposure Limit) is the highest allowable airborne concentration that is not expected to injure a worker. It may be expressed as a ceiling limit or as a time- weighted average (TWA), usually for 10-hour work shifts.
any occurrence in which a regulated substance is emitted into air, soil or water. As defined by section 101(22) of CERCLA, means any spilling, leaking, pumping, pouring, emitting, emptying, discharging, injecting, escaping, leaching, dumping, or disposing into the environment (including the abandonment or discarding of barrels, containers, and other closed receptacles containing any hazardous substance or pollutant or contaminant), but excludes: Any release which results in exposure to persons solely within a workplace, with respect to a claim which such persons may assert against the employer of such persons; emissions from the engine exhaust of a motor vehicle, rolling stock, aircraft, vessel, or pipeline pumping station engine; release of source, byproduct, or special nuclear material from a nuclear incident, as those terms are defined in the Atomic Energy Act of 1954, if such release is subject to requirements with respect to financial protection established by the Nuclear Regulatory Commission under section 170 of such Act, or, for the purposes of section 104 of CERCLA or any other response action, any release of source, byproduct, or special nuclear material from any processing site designated under section 102(a)(1) or 302(a) of the Uranium Mill Tailings Radiation Control Act of 1978; and the normal application of fertilizer. For purposes of the NCP, release also means threat of release.
means any spilling, leaking, emitting, discharging, escaping, leaching or disposing from an UST into ground water, surface water or subsurface soils.
means determining whether a release of a regulated substance has occurred from the UST system into the environment or into the interstitial space between the UST system and its secondary barrier or secondary containment around it.
relevant and appropriate requirements
means those cleanup standards, standards of control, and other substantive requirements, criteria, or limitations promulgated under federal environmental or state environmental or facility siting laws that, while not "applicable" to a hazardous substance, pollutant, contaminant, remedial action, location, or other circumstance at a CERCLA site, address problems or situations sufficiently similar to those encountered at the CERCLA site that their use is well suited to the particular site. Only those state standards that are identified in a timely manner and are more stringent than federal requirements may be relevant and appropriate.
a measurement of radiation by biological effect on human tissue. (Acronym for Roentgen equivalent man.)
remedial action (RA)
the actual construction or implementation phase of a Superfund site cleanup that follows remedial design.
(RD) a phase of remedial action that follows the remedial investigation/feasibility study and includes development of engineering drawings and specifications for a site cleanup.
(RI) an in-depth study designed to gather the data necessary to determine the nature and extent of contamination at a Superfund site; establish criteria for cleaning up the site; identify preliminary alternatives for remedial actions; support the technical and cost analyses of the alternatives. Their remedial investigation is usually done with the feasibility study. Together, they are usually referred to as the "RI/FS".
remedial project manager (RPM)
the EPA or state official responsible for overseeing remedial action at a site.
a long-term action that stops or substantially reduces a release or threat of a release of hazardous substances that is serious but not an immediate threat to public health.
remedy or remedial action
(RA) means those actions consistent with permanent remedy taken instead of, or in addition to, removal action in the event of a release or threatened release of a hazardous substance into the environment, to prevent or minimize the release of hazardous substances so that they do not migrate to cause substantial danger to present or future public health or welfare or the environment. The term includes, but is not limited to, such actions at the location of the release as storage, confinement, perimeter protection using dikes, trenches, or ditches, clay cover, neutralization, cleanup of released hazardous substances and associated contaminated materials, recycling or reuse, diversion, destruction, segregation of reactive wastes, dredging or excavations, repair or replacement of leaking containers, collection of leachate and runoff, on-site treatment or incineration, provision of alternative water supplies, any monitoring reasonably required to assure that such actions protect the public health and welfare and the environment and, where appropriate, post-removal site control activities. The term includes the costs of permanent relocation of residents and businesses and community facilities (including the cost of providing "alternative land of equivalent value" to an Indian tribe pursuant to CERCLA section 126(b)) where EPA determines that, alone or in combination with other measures, such relocation is more cost- effective than, and environmentally preferable to, the transportation, storage, treatment, destruction, or secure disposition off-site of such hazardous substances, or may otherwise be necessary to protect the public health or welfare; the term includes off-site transport and off-site storage, treatment, destruction, or secure disposition of hazardous substances and associated contaminated materials. For the purpose of the NCP, the term also includes enforcement activities related thereto.
Remedial/Field Investigation Team.
short-term immediate actions taken to address releases of hazardous substances that require expedited response. (See: cleanup).
remove or removal
as defined by section 311(a)(8) of the CWA, refers to removal of oil or hazardous substances from the water and shorelines or the taking of such other actions as may be necessary to minimize or mitigate damage to the public health or welfare or to the environment. As defined by section 101(23) of CERCLA, remove or removal means the cleanup or removal of released hazardous substances from the environment; such actions as may be necessary taken in the event of the threat of release of hazardous substances into the environment; such actions as may be necessary to monitor, assess, and evaluate the release or threat of release of hazardous substances; the disposal of removed material; or the taking of such other actions as may be necessary to prevent, minimize, or mitigate damage to the public health or welfare or to the environment, which may otherwise result from a release or threat of release. The term includes, in addition, without being limited to, security fencing or other measures to limit access, provision of alternative water supplies, temporary evacuation and housing of threatened individuals not otherwise provided for, action taken under section 104(b) of CERCLA, post- removal site control, where appropriate, and any emergency assistance which may be provided under the Disaster Relief Act of 1974. For the purpose of the NCP, the term also includes enforcement activities related thereto.
RCRA Enforcement Management System.
Reasonable Efforts Program.
a measurement of radiation by energy development in human tissue. (Acronym for Roentgen equivalent physical.)
means to restore a tank or UST system component that has caused a release of product from the UST system into the environment or into the interstitial space between the UST system and its secondary barrier or secondary containment around it.
reportable quantity (RQ)
the quantity of a hazardous substance that triggers reports under CERCLA. If a substance is released in amounts exceeding its RQ, the release must be reported to the National Response Center, the SERC, and community emergency coordinators for areas likely to be affected.
a sample of a universe or whole (e.g., waste pile, lagoon, ground water, or waste stream) which can be expected to exhibit the average properties of the universe or whole.
reproductive health hazard/toxin
any agent that has a harmful effect on the adult male or female reproductive system or the developing fetus or child. Such hazards affect people in several ways, including loss of sexual drive, mental disorders, impotence, infertility, sterility, mutagenic effects on germ cells, teratogenic effects on the fetus, and transplacental carcinogenesis.
Regional Emissions Projection System.
the reevaluation and relicensing of existing pesticides originally registered prior to current scientific and regulatory standards. EPA re-registers pesticides through its Registration Standards Program.
any holding area, natural or artificial, used to store, regulate, or control water.
is a tank located on property used primarily for dwelling purposes.
amount of a pollutant remaining in the environment after a natural or technological process has taken place, e.g., the sludge remaining after initial wastewater treatment, or particulates remaining in air after the air passes through a scrubbing or process.
residual disinfectant concentration
("C" in CT calculations) means the concentration of disinfectant measured in mg/l in a representative sample of water.
-DOT Residue refers to the material remaining in a packaging, including a tank car, after its contents have been unloaded to the maximum extent practicable and before the packaging is either refilled or cleaned of hazardous material and purged to remove any hazardous vapors.
synthetic organic ion exchange material, such as the high capacity cation exchange resin widely used in water softeners.
for plants and animals, the ability to withstand poor environmental conditions and/or attacks by chemicals or disease. The ability may be inborn or developed.
the breaking of an emulsion into its individual components.
a person, thing, or action needed for living or to improve the quality of life.
reduction of the amounts of solid waste that are generated, reduction of overall resource consumption, and utilization of recovered resources.
Resource Conservation and Recovery Act
the process of obtaining matter or energy from materials formerly discarded e.g. solid waste, wood chips.
Pertaining to respiration, including inspiration and expiration, diffusion of gases (oxygen and carbon dioxide) from alveoli to the blood and their transport from the body cells. 
respond or response
as defined by section 101(25) of CERCLA, means remove, removal, remedy, or remedial action, including enforcement activities related thereto.
a CERCLA-authorized action involving either a short-term removal action or a long-term removal response that may include but is not limited to: removing hazardous materials from a site to an EPA-approved hazardous waste facility for treatment, containment, or destruction; containing the waste safely on-site; destroying or testing the waste on-site; and identifying and removing the source of ground-water contamination and halting further migration of contaminants. (See: cleanup).
refers to any organization performing emergency operations in response to exercise scenario.
any of a variety of devices that limit the inhalation of toxic materials. They range from disposable dust masks to self-contained breathing apparatus. All have specific uses and limitations. Their use is covered by OSHA, 29CFR1910.134. See SCBA, Chemical Cartridge Respirator.
the breathing system, including the lungs and air passages (trachea or windpipe, larynx, mouth, and nose), as well as the associated system of nerves and circulatory supply.
measures taken to return a site to pre-violation conditions.
when a pesticide is registered, some or all of its uses may be classified (under FIFRA regulations) for restricted use if the pesticide requires special handling because of its toxicity. Restricted-use pesticides may be applied only by trained, certified applicators or those under their direct supervision.
refers to an area to which authorized personnel may enter, but for which protective measures are mandatory to minimize exposure to hazardous materials; also known as "hot zone".
enzymes that recognize certain specific regions of a long DNA molecule and then cut the DNA into smaller pieces.
volume of the vessel divided by the flowrate through the vessel.
process wastewater or treatment facility effluent which is further used in a different manufacturing process.
the echoes of a sound that persist in an enclosed space after the sound source has stopped.
a process that reverses (by the application of pressure) the flow of water in the natural process of osmosis so that it passes from the more concentrated to the more dilute solution.
the return of molecularly dehydrated phosphate (poly- phosphate) to its hydrated origin (orthophosphate).
Regulatory Flexibility Act.
RCRA Facility Assessment.
Reference Dose Values.
Developmental Reference Dose.
RCRA Facility Investigation.
Remedial Facility Investigation.
Reasonable Further Progress.
Request for Proposal.
Restricted Hazardous Waste.
Regulatory Impact Analysis.
Regulatory Impact Assessment.
Ribonucleic Acid (RNA)
a molecule that carries the genetic message from DNA to a cell's protein producing mechanisms; similar to, but chemically different from, DNA.
Radon Information Center.
Remedial Investigation and Feasibility Study; EPA investigation at a Superfund site to assess contamination and environmental problems, and evaluate cleanup alternatives.
Regulatory Interpretation Memorandum.
Regulatory Identifier Number.
a series of shaded illustrations used to measure the opacity of air pollution emissions. The chart ranges from light grey (number 1) through black (number 5) and is used to set and enforce emission standards.
a method of comparing the opacity of a stack plume to an arbitrary set of standard disks of increasing degrees of discoloration.
RCRA Implementation Plan.
areas adjacent to rivers and streams that have a high density, diversity,and productivity of plant and animal species relative to nearby uplands.
entitlement of a land owner to the water on or bordering his property, including the right to prevent diversion or misuse of it upstream.
Regulatory Information Service Center.
the qualitative and quantitative evaluation performed in an effort to define the risk posed to human health and/or the environment by the presence or potential presence and/or use of specific pollutants.
the exchange of information about health or environmental risks between risk assessors, risk managers, the general public, news media, interest groups, etc.
the process of evaluating alternative regulatory and non regulatory responses to risk and selecting among them.The selection process necessarily requires the consideration of legal, economic and social factors.
the land area drained by a river and its tributaries.
Recommended Maximum Contaminant Levels.
Reasonable Maximum Exposure.
Risk Management Plan.
Risk Management and Prevention Program.
Record of Communication.
record of decision; EPA's statement of remedy for a Superfund site cleanup.
a chemical or agent used to destroy rats or other rodent pests, or to prevent them from damaging food, crops, etc.
Reactive Organic Gases.
Regional Oxidant Model.
Rough Order Magnitude.
Recycled Oxide Media Extraction, a proprietary process for the extraction of metals from geological brine.
Regional Oversight Policy.
Record of Procurement Action.
those species not prized for game purposes or for eating; gar, suckers, etc. Most are more tolerant of changing environmental conditions than game species.
refers to a method of public alert and notification in which the alert signals and notifications are disseminated via equipment and staff which move through populated areas.
routes of entry
to do bodily damage, a material must contact the body. The method of bodily contact is called the route of entry.The routes of entry are (1) absorption (eye or skin contact);(2) ingestion; and (3) inhalation.
routes of exposure
The means by which material may gain access to the body, for example, breathing, eating or through the skin or eyes.
routine analytical services
the set of Contract Laboratory Program (CLP) analytical protocols that are used to analyze most Superfund site samples. These protocols are provided in the EPA Statements of Work for the CLP and must be followed by every CLP laboratory.
Rebuttable Presumption Against Registration.
Remedial Project Manager.
Responsible Property Transfer Act.
Reportable quantity.-CERCLA The quantity of a substance designated under CERCLA as hazardous the release of which requires notification to the National Response Center.(800) 424-8802. (9) -DOT Reportable quantity means the quantity specified for a substance in the Appendix to the Hazardous Materials Table.-SARA Reportable quantity means the quantity specified in Title III, section 304, which requires specific reporting.
Regional Response Center .
Risk Reduction Engineering Laboratory.
Regional Response Plan.
Regional Response Team
Requisite Remedial Technology.
Resist Stripper Treat-Semi - Printed Circuit Chemicals (ETUS).
Resist Stripper Treat-Aqueous - Printed Circuit Chemicals (ETUS).
Research and Special Programs Administration of DOT; encompasses several offices emphasizing safety regulation, emergency preparedness, and research and development associated with transportation of hazardous materials.
Resolution Trust Corporation.
Reasonable Transportation Control Measure.
Registry of Toxic Effects of Chemical Substances, published by NIOSH. Presents basic toxicity data on thousands of materials.Its objective is to identify "all known toxic substances" and to reference the original studies.
solid waste, excluding food waste and ashes, from homes, institutions, and workplaces.
water from rain, snow melt, or irrigation that flows over the ground surface and returns to streams. It can collect pollutants from air or land and carry them to the receiving waters.
Reid Vapor Pressure.
Residential Wood Combustion.
Regional Water Quality Control Board ( California ).