Glossary of Terms

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AAQG: Arizona Ambient Air Quality Guidelines

A.A.C: Stands for Arizona Administrative Code. A.A.C are the official rules of the state of Arizona are published. Rules are adopted by state agencies, boards or commissions, with specific rulemaking authority from the State Legislature.

AAR: Arizona Administrative Register

Absorption: The passage of one substance into or through another.

Absorption (of light): A process by which light is taken-up by another material. Examples include soot consisting of tiny black particles, which absorb all visible light; and nitrogen dioxide, a pollutant mostly from diesel and gasoline engines, that absorbs blue light resulting in air with a brown tint.

Acid: A substance that has a pH of less than 7 (7 = neutral) which can lower the pH value of water or soils to be harmful to growth of crops.

Acre-foot (AF): A quantity or volume of water covering one acre to a depth of one foot; equal to 43,560 cubic feet or 325,851 gallons.

Activated Carbon: Adsorptive particles or granules of carbon usually obtained by heating carbon (such as wood). These particles or granules have a high capacity to selectively remove certain trace and soluble materials, including many contaminants, from water.

Active Management Area (AMA): The five areas in the state – Prescott, Phoenix, Pinal, Tucson and Santa Cruz – where the 1980 Arizona Groundwater Code, administered by the Arizona Department of Water Resources, recognized the need to aggressively manage finite groundwater resources.

Acute: Occurring over a short period of time; used to describe brief exposures and effects which appear promptly after exposure.

Acute Exposure: A single exposure to a toxic substance which may result in severe biological harm or death.  Acute exposures are usually characterized as lasting no longer than a day, as compared to longer, continuing exposure over a period of time.

Acute Toxicity: The ability of a substance to cause poisonous effects resulting in severe biological harm or death soon after a single exposure or dose. Also, any severe poisonous effect resulting from a single short-term exposure to a toxic substance.

Adsorbent: The material (activated carbon) that is responsible for removing the undesirable substance in the adsorption process.

Adsorption: The adhesion (or sticking) of molecules of gas, liquid, or dissolved solids to a surface.

Advection: The horizontal transfer of heat or matter in the atmosphere.

Adverse Health Effect: Any effect resulting in a change in body function or cell structure that might lead to disease or health problems.

Aeration: The process of adding air to water. Air can be added to water by either passing air through water or passing water through air.

Aerobic: Requires air or oxygen to function.

Aeration: The process of adding air to water. Air can be added to water by either passing air through water or passing water through air.

Air Binding: A situation where air enters the filter media. Air is harmful to both the filtration and backwash processes. Air can prevent the passage of water during the filtration process and can cause the loss of filter media during the backwash process.

Air Gap: An open vertical drop, or vertical empty space, that separates a drinking (potable) water supply to be protected from another water system in a water treatment plant or other location. This open gap prevents the contamination of drinking water by backsiphonage or backflow because there is no way raw water or any other water can reach the drinking water.

Air Quality Division (AQD) of ADEQ: Core responsibilities include collecting and analyzing quality assured and precise ambient air monitoring data; preparing pollution forecasts to help people limit their exposure to air pollution and air pollution sources; conducting and collaborating on research and analyses to evaluate pollution sources and their impacts on public health and welfare; investigating complaints and violations of, and achieving compliance with, Arizona's air pollution laws; issuing permits to industries and other facilities, and for open burning activities that protect public health and welfare; operating and maintaining accurate, convenient, and affordable vehicle emissions inspections programs; and developing air quality plans and rules through partnerships, collaboration and public involvement.

Air Quality Index (AQI): An index for reporting daily air quality. It determines how clean or polluted air is and what associated health effects might be of concern. The AQI focuses on health effects you may experience within a few hours or days after breathing polluted air. EPA calculates the AQI for five major air pollutants regulated by the Clean Air Act: ground-level ozone, particle pollution (also known as particulate matter), carbon monoxide, sulfur dioxide, and nitrogen dioxide. For each pollutant, EPA has established national air quality standards to protect public health. Ground-level ozone and airborne particles are the two pollutants that pose the greatest threat to human health in this country.

Air Quality Standards: The level of pollutants prescribed by regulations that are not to be exceeded during a given time in a defined area.

Air Sparging: An in-situ treatment technology that uses injected air to help remove harmful vapors from polluted soil and groundwater below the water table by injecting air directly into the saturated subsurface to encourage the solvents and gasoline to evaporate faster, which makes them easier to remove with a vacuum.

Air Stripping: A treatment system that removes or “strips” VOCs from contaminated groundwater or surface water as air is forced through the water, causing the compounds to evaporate. Often the compounds are then captured using air filters.

Airshed: A geographical area where local topography and meteorology limit the dispersion of pollutants away from the area.

Alluvial: Relating to mud and/or sand deposited by flowing water. Alluvial deposits may occur after a heavy rain storm.

Ambient Air: Outside air in the environment.

Ambient Temperature: Temperature of the surrounding air (or other medium).

Anaerobic: To function without air or oxygen.

Anhydrous: Free from water.

Aquifer: An underground rock formation composed of such materials as sand, soil, or gravel, that can store groundwater and supply it to wells and springs. In aquifers, groundwater occurs in sufficient quantities to be used for drinking water, irrigation, and other purposes.

Aquifer Protection Permit (APP): The Arizona APP program was the first comprehensive groundwater protection program in the nation when it was adopted in 1987.Under the program, all groundwater is protected for drinking water use and discharges cannot cause an exceedance of a drinking water standard in groundwater.

Aquifer Water Quality Standard (AWQS): State of Arizona maximum levels for contaminants which apply to groundwater in aquifers designated for drinking water use. For example, the AWQS for tetrachloroethene (PCE) is 5 micrograms per liter (g/L).

Aquitard: A geologic formation (usually a layer of material such as clay) that creates an underground barrier to the flow of groundwater.

Area A: In accordance with Arizona Revised Statutes §49-541 , the part of the greater Phoenix Metropolitan area where specific pollution control programs are in place for ozone, carbon monoxide, and particulate matter. Includes parts of Yavapai and Pinal County.

Arizona Department of Environmental Quality (ADEQ): Executive agency of Arizona state government mandated to enforce and administer the state’s environmental laws and regulations. ADEQ has three divisions – air quality, water quality and waste programs.

Arizona Department of Health Services (ADHS): Promotes and protects the health of Arizona's children and adults. Its mission is to set the standard for personal and community health through direct care, science, public policy, and leadership. ADEQ determines, through sampling, the quantity of contaminants and ADHS determines health effects of the contaminants.

Arizona Department of Water Resources (ADWR): Mission is to ensure a long-term, sufficient, and secure water supply for Arizona by promoting, allocating, and comprehensively managing in an environmentally and economically sound manner the rights and interests of the state’s surface water resources for the citizens of Arizona. ADWR oversees water quantity issues in the state and ADEQ oversees water quality issues.

Arizona Municipal Water Users Association (AMWUA): Non-profit corporation -- composed of mayors and council members representing Avondale, Chandler, Gilbert, Glendale, Goodyear, Mesa, Peoria, Phoenix, Scottsdale and Tempe -- which protects assured, safe and sustainable water supplies.

Arizona Pollution Discharge Elimination System (AZPDES): In Arizona, the point source discharge permitting program established less than 18 A.A.C. 9, Article 9.

Arizona Radiation Regulatory Agency (ARRA): Responsible for the conduct of a statewide radiological health and safety program and for the enforcement of state rules and regulations for the control of ionizing and non-ionizing radiation.

Arizona Revised Statutes (A.R.S.§): State laws adopted by the Arizona State Legislature.

Arizona Superfund Response Action Contract (ASRAC): Implements requirements of the WQARF program and the State's Superfund long-term contracting strategy. Established working relationships between ADEQ and contractors aimed at minimizing administrative costs and maximize project work.

Arizona-Mexico Commission (AMC): Mission is to improve the economic prosperity and quality of life for all Arizonans through strong, public/private collaborations in advocacy, trade, networking and information. It is chaired by the governor of Arizona and has several cross-border committees, including an environment and water committee.

Artesian: Groundwater held under pressure in porous rock or soil confined by impermeable geologic formations which rises to the land surface when tapped by a well.

Artificial Recharge: Water put back into groundwater storage from surface water through man-made means.

Asbestos: Any of several minerals (like chrysotile) used commonly in the past as a building material for fireproof insulation. Asbestos can cause serious diseases of the lungs when people breathe its dust. The material readily separates into long flexible fibers that cause asbestosis and have been implicated as causes of certain cancers.

Asbestos Hazard Emergency Response Act (AHERA): A 1986 law that requires local educational agencies to inspect their school buildings for asbestos-containing building material, prepare asbestos management plans and perform asbestos response actions to prevent or reduce asbestos hazards.

Assimilative Capacity: The difference between the baseline water quality concentration for a pollutant and the most stringent applicable water quality criterion for that pollutant.

Auto Shredder Fluff: The non-metallic waste product that results from the reclamation process of recyclable ferrous and non-ferrous metals. The primary source of recyclable materials comes from automobiles, truck, buses and common household appliances such as washers, dryers and refrigerators.

Available Expansion: The vertical distance from the sand surface to the underside of a trough in a sand filter. This distance is also called Freeboard.

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Back Pressure: A pressure that can cause water to backflow into the water supply when a user’s water system is at a higher pressure than the public water system.

Backflow: A reverse flow condition, created by a difference in water pressures, which causes water to flow back into the distribution pipes of a potable water supply from any source or sources other than an intended source.

Bailer: A pipe with a valve at the lower end that is used to remove slurry from the bottom or side of a well as it is being driled, or to collect groundwater samples from wells or open boreholes.

Baseline Risk Assesment: An assessment conducted before cleanup activities begin at a site to identify and evaluate the threat to human health and the environment. After remediation has been completed, the information obtained during a baseline risk assessment can be used to determine whether the cleanup levels were reached.

Bedrock: The consolidated rock that underlies the soil; it can be permeable or non-permeable.

Benzene, Toluene, Ethylbenzene, Xylene (BTEX): The acronym used for compounds typically found in petroleum products such as gasoline and diesel fuel.

Berm: A raised linear bank separating two areas.

Beryllium: A metal hazardous to human health when inhaled as an airborne pollutant. It is discharged by machine shops, ceramic and propellant plants, and foundries.

Best Available Control Technology (BACT): An emission limitation, including a visible emissions standard, based on the maximum possible reduction of an air pollutant.

Best Management Practice (BMP): Methods that have been determined to be the most effective, practical means of preventing or reducing pollution from non-point sources.

Billet: A bar of steel or iron that is in an intermediate manufacturing stage.

Bioaccumulation: The retention and concentration of a substance by an organism.

Bioassay: A test which determines the effect of a chemical on a living organism.

Bioconcentration: The accumulation of a chemical in tissues of an organism (such as fish) to levels that are greater than the level in the medium (such as water) in which the organism resides.

Biological Degradation: A process by which micro-organisms break down waste materials. Nutrient additives may be introduced into a contaminated area (such as groundwater or soil) for the specific purpose of encouraging biodegradation.

Bioremediation: Refers to treatment processes that use microorganisms (usually naturally occuring) such as bacteria, yeast, or fungi to break down hazardous substances and pollutants. Bioremediation can be used to clean up contaminated soil and water.

Bioventing: An in-situ remediation technology that combines soil vapor extraction methods with bioremediation. It uses vapor extraction wells that induce air flow in the subsurface through air injection or through the use of a vacuum. Bioventing can be effective in remediating releases of petroleum products, such as gasoline, jet fuels, kerosene, and diesel fuel.

Blackwater: Water that contains animal, human, or food waste.

Blowing Dust: Dust picked up locally from the surface of the earth and blown about in clouds or sheets. Common during the North American Monsoon because of thunderstorm outflows like a dust storm or haboob during the summer or cold frontal passages.

Border 2020: Administered by the U.S. Environmental Protection Agency and its counterpart in Mexico, Border 2020 funds environmental and public health programs in the border region. It builds on the Border 2012 environmental program, emphasizing regional, bottom-up approaches for decision making, priority setting, and project implementation for nearly 12 million people living along the border.

Border Environment Cooperation Commission (BECC): Created by the governments of the United States and Mexico in conjunction with its sister organization, the North American Development Bank, to improve environmental conditions of the border region in order to advance the well-being of residents in both nations, primarily through environmental infrastructure projects.

Border Environmental Protection, Office of (OBEP): ADEQ office based in Tucson whose mission is to protect public health and the environment in Arizona border communities by facilitating efforts that address environmental problems with a transboundary link and enhancing collaboration with other border-focused programs.

Borehole or boring: A narrow shaft drilled in the ground, either vertically or horizontally, by means of a drilling rig.

Brackish: Mixed fresh and salt water.

British Thermal Unit (BTU): Unit of heat energy equal to the amount of heat required to raise the temperature of one pound of water by one degree Fahrenheit at sea level.

Brownfields: Abandoned, idled, or underused industrial and commercial facilities where expansion or redevelopment is complicated by real or perceived environmental contamination.

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Cadmium: A highly toxic soft, malleable, bluish white metal that accumulates in the environment, found primarily in zinc ores.

Cap: A layer of clay, or other impermeable material, installed over the top of a closed landfill to prevent entry of rainwater and minimize leachate.

Carbon Absorption Unit (CAU): A control device that uses activated carbon to absorb volatile organic compounds from a gas or liquid stream. (The VOCs are later recovered from the carbon.) It is commonly known as a granular activated carbon (GAC) unit.

Carbon monoxide: A colorless, odorless gas formed by incomplete combustion of carbon or a material relating to, containing or composed of carbon material.

Carcinogen: A substance or agent that may produce or increase the risk of cancer.

Catalytic converter: An air pollution abatement device that removes pollutants from motor vehicle exhaust, either by oxidizing them into carbon dioxide and water or reducing them to nitrogen.

Centers for Disease Control and Prevention (CDC): Federal agency based in Atlanta tasked with protecting the nation from health threats.

Central Arizona Project
An aerial photo of the Central Arizona Project

Central Arizona Project (CAP): A 336-mile-long system of aqueducts, tunnels, pumping plants and pipelines that divert water from the Colorado River from Lake Havasu near Parker into central and southern Arizona. The CAP is the largest and most expensive aqueduct system ever constructed in the United States and is designed to bring about 1.5 million acre-feet of Colorado River water per year to Maricopa, Pinal and Pima counties.

Channelization: Straightening and deepening streams so water will move faster, a marsh-drainage tactic that can interfere with waste assimilation capacity, disturb fish and wildlife habitats, and aggravate flooding.

Characteristic: With respect to hazardous waste, one of the following four categories: ignitability, corrosivity, reactivity, and toxicity.

Chemical Compound: A distinct and pure substance formed by the union or two or more elements in definite proportion by weight.

Children’s Environmental Health, Office of (CEH): ADEQ office that protects the health and environment of Arizona’s school children. Its major initiatives are the No Idling Initiative for Schools, in which bus engines are turned off while waiting for students to protect them from harmful fumes, and the Air Quality Flag Program, which uses colored flags to alert students, teachers and parents about risks of high-pollution days.

Chlorinated Hydrocarbons: Chemicals containing only chlorine, carbon, and hydrogen. These include a class of persistent insecticides that linger in the environment and accumulate in the food chain like DDT, aldrin and chlordane and industrial solvents like TCE.

Chlorinated Solvent: An organic solvent containing chlorine atoms. Chlorinated solvents are used in aerosol spray containers, highway paint, dry cleaning fluids and the electronics industry.

Chlorination: The application of chlorine to water, generally for the purpose of disinfection, but frequently for accomplishing other biological or chemical results (aiding coagulation and controlling tastes and odors).

Chlorinator: A device that adds chlorine, in gas or liquid form, to water or sewage to kill bacteria.

Chlorofluorocarbons (CFC): A family of inert, nontoxic, and easily liquefied chemicals used in refrigeration, air conditioning, packaging, insulation, or as solvents and aerosol propellants.

Chronic: Occurring over a long period of time, either continuously or intermittently; used to describe ongoing exposures and effects that develop only after a long exposure.

Chronic Exposure: A continuous or repeated exposure to a hazardous substance over a long period of time.

Circle of Influence: The circular outer edge of a depression produced in the water table by the pumping of water from a well.

Clay: A sediment of soft plastic consistency composed primarily of fine-grained particles less than 1/256 of a millimeter.

Clay Soil: A soil containing more than 40 percent clay, but less than 45 percent sand, and less than 40 percent silt.

Clean Air Act (CAA): Federal law designed to control air pollution on a national level. It requires the EPA to develop and enforce regulations to protect the public from airborne contaminants known to be hazardous to human health.

Clean Water Act (CWA): Primary federal law governing water pollution. Its objective is to restore and maintain the chemical, physical, and biological integrity of the nation's waters by preventing point and nonpoint pollution sources, providing assistance to publicly owned treatment works for the improvement of wastewater treatment, and maintaining the integrity of wetlands.

Cleanup: Actions taken which deal with a release or threat of a release of hazardous substances that could adversely affect public health and/or the environment. The word “cleanup” is sometimes used interchangeably with the terms remedial action, removal action, response action, remedy, remediation, or corrective action.

Clinical Studies: Studies of humans suffering from symptoms induced by chemical exposure.

Closed-Loop Recycling: Reclaiming or reusing wastewater for non-potable purposes in an enclosed process.

Coal Gasification: Conversion of coal to a gaseous product by one of several available technologies.

Code of Federal Regulations (CFR): Document that codifies all rules of the executive departments and agencies of the federal government.

Cold Front: The leading edge of a relatively cold air mass that moves so that the colder air replaces the warmer air. Cold frontal passages can result in wind-blown dust events, precipitation, and drop in temperatures.

Coliform: Microorganisms found in the intestinal tract of humans and animals. Their presence in water indicates fecal pollution and potentially adverse contamination by pathogens.

Comisión de Ecología y Desarrollo Sustentable (CEDES): State of Sonora Environment and Sustainable Development Commission. The environmental protection agency in the State of Sonora that also has flora and fauna regulatory authority. It is considered ADEQ’s counterpart agency but it has no regulatory authority regarding water quality.

Comisión Estatal del Agua (CEA): The State of Sonora Water Commission and counterpart to the Arizona Department of Water Resources.

Comisión Nacional del Agua (CONAGUA): Mexico’s national water commission. The commission has oversight authority nationwide.

Commingled Recyclables: Mixed recyclables that are collected together.

Community Advisory Board (CAB): A diverse group of community members interested in or affected by the presence of an EPA NPL site. The EPA forms a CAG for each NPL site where it is initiating a remedial investigation. The EPA seeks the CAG’s input in the decision-making process.  

Community Advisory Group (CAG): A diverse group of community members interested in or affected by the presence of an EPA NPL site. The EPA forms a CAG for each NPL site where it is initiating a remedial investigation. The EPA seeks the CAG’s input in the decision-making process.  

Community Involvement Area (CIA): The mailing area of residences and businesses used in the notification for public meetings and other written notices regarding a WQARF site.

Community Involvement Coordinator (CIC): The ADEQ employee responsible for ensuring that all statutes and rules related to the involvement of the public and public outreach at WQARF sites are upheld and complied with by ADEQ. CICs manage and coordinate the work of Community Advisory Boards for WQARF sites.

Community Involvement Plan (CIP): A document that identifies techniques used by ADEQ and EPA to communicate effectively with the public during the Superfund cleanup process at a specific site. This plan describes the site history, nature and history of community involvement, and concerns expressed during community interviews. In addition, the plan outlines methodologies and timing for continued interaction between the agencies and the public at the site.

Community Water System (CWS):A public water system which serves at least 15 service connections used by year-round residents or regularly serves at least 25 year-round residents.

Compact Fluorescent Lamp (CFL): Small fluorescent lamps used as more efficient alternatives to incandescent lighting.

Compliance Cycle: The nine- year calendar cycle during which public water systems must monitor. The cycle consists of three three-year compliance periods.

Compliance Monitoring: Collection and evaluation of data, including self-monitoring reports, and verification to show whether pollutant concentrations and loads contained in permitted discharges are in compliance with the limits and conditions specified in the permit.

Compliance Schedule: A negotiated agreement between a pollution source and a government agency that specifies dates and procedures by which a source will reduce emissions and, thereby, comply with a regulation.

Comprehensive Environmental Response, Compensation, and Liability Act (CERCLA): This federal law, also known as “Superfund,” was passed in 1980. It established a program to (1) identify sites where hazardous substances have been, or might be, released into the environment; (2) ensure that these sights are cleaned up by the responsible parties or the government; (3) evaluate damages to natural resources; and (4) create a claims procedure for parties who have cleaned up sites to recover their costs from a responsible party or parties.

Compressed Natural Gas (CNG): An alternative fuel for motor vehicles; considered one of the cleanest because of low hydrocarbon emissions and its vapors are relatively non-ozone producing.

Concentrated Animal Feeding Operation (CAFO): An animal feeding operation that confines animals for more than 45 days during a growing season in an area that does not produce vegetation and meets certain size thresholds.

Concentration: The relative amount of one material dispersed/distributed/dissolved in a larger amount of another material.

Conditionally Exempt Small Quantity Generator (CESQG): Someone that generates less than 220 pounds of hazardous waste, or less than 2.2 pounds of acutely hazardous waste, per calendar month.

Cone of Depression / Area of Influence:  The depression, roughly conical in shape, produced in an aquifer by pumping in a well. The radius of water affected around the well is called the area of influence. This area of influence varies, depending upon many factors such as the characteristics of the rock or soil formation (material) the water must travel through to get to the well.

Confined Aquifer: An aquifer bounded on the top by a relatively impermeable layer of material such as clay. Though the confining layer may hold water, it does not allow water to freely move through it.

Consent Order (CO): A legal document, approved by a judge, that formalizes an agreement reached between ADEQ and potentially responsible parties (PRPs) to clean up, cease or correct actions that are polluting the environment.

Containment: A remediation method that seals off all possible exposure pathways between a hazardous disposal site and the environment, which generally includes capping (putting an engineered soil cover over a contaminated area) and institutional controls like deed restrictions.

Contaminant: Any physical, chemical, biological or radiological substance or matter present in any media at concentrations that may result in adverse effects on air, water or soil. A harmful or hazardous matter introduced into the environment that is not normally found there, or not naturally occurring.

Contaminant Level: A contaminant level is a relative measure of how much of a contaminant is present. Contaminant levels are expressed in concentrations such as parts per million (ppm), parts per billion (ppb), milligrams per liter (mg/l), or micrograms per liter (μg/l).

Contaminants of Emerging Concern (CEC): Those chemicals in detergents, fragrances, prescription and nonprescription drugs, disinfectants, and pesticides that recently have been shown to occur widely in water resources and identified as being a potential environmental or public health risk, although adequate data do not yet exist to determine their risk.

Contamination: Any hazardous or regulated substance released into the environment.

Convection: Vertical transport of heat and moisture that can lead to an increase in cloud cover and precipitation. Commonly results in thunderstorm activity during the North American Monsoon.

Cost Recovery: A legal process where responsible parties can be required to pay back the state for money it spends on any investigative and/or cleanup actions.

Criteria (for Water): Elements of water quality standards that are expressed as pollutant concentrations, levels, or narrative statements representing water quality that supports a designated use.

Criteria Air Pollutant (CAP): The 1970 amendments to the Clean Air Act required EPA to set National Ambient Air Quality Standards for pollutants hazardous to human health -- ozone, carbon monoxide, total suspended particulates, sulfur dioxide, lead and nitrogen oxide. The term "criteria pollutants" derives from the requirement that EPA must describe the characteristics and potential health and welfare effects of these pollutants. It is on the basis of these criteria that standards are set or revised.

Criteria Flow Condition: The lowest flow over seven consecutive days that has a probability of occurring once in 10 years.

Crumb Rubber: Ground rubber fragments the size of sand or silt used in rubber or plastic products, or processed further into reclaimed rubber or asphalt products.

Cubic Feet Per Second (CFS): The flow rate or discharge equal to one cubic foot of water per second or about 7.5 gallons per second commonly used to indicate the rate of flow of a creek, river or flood, i.e., the volume of water that passes a given point in a given amount of time.

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Declaration of Environmental Use Restriction (DEUR): A restrictive covenant that runs with and burdens the land and requires maintenance of any institutional or engineering control. It must be approved and signed by ADEQ before it may be recorded with the county recorder’s office.

Delegation Agreement (DA): An agreement between ADEQ and a political subdivision that authorizes the political subdivision to exercise functions , powers or duties conferred on the delegating agency by a provision of law.

Desalinization: Removal of salt from saline water to provide fresh water (also desalination).

Destination Facility: Facility that treats, disposes of, or recycles a particular category of universal waste.

Dichloro-Diphenyl-Trichloroethane (DDT): The first chlorinated hydrocarbon insecticide chemical name. It has a half-life of 15 years and can collect in fatty tissues of certain animals. EPA banned registration and interstate sale of DDT for virtually all but emergency uses in 1972.

Dichloroethane (DCA): A colorless, oily liquid that is primarily used to make other chemicals, as a solvent, or degreaser.

Dichloroethylene (DCE): Used to make certain plastics, packaging materials, and flame retardant coatings. Typically, it is a degradation product of other chlorinated solvents.

Digester: In wastewater treatment, a closed tank; in solid-waste conversion, a unit in which bacterial action is induced and accelerated to break down organic matter and establish carbon to nitrogen ratio.

Disinfectant: A chemical or physical process that kills pathogenic organisms in water, air, or on surfaces. Chlorine is often used to disinfect effluent, water supplies, wells, and swimming pools.

Dispersion: Dilution over time of a pollutant concentration from its point source due to spreading out of the pollutant.

Dissolved Oxygen (DO): The oxygen freely available in water, vital to fish and other aquatic life and for the prevention of odors. DO levels are considered a most important indicator of a water body's ability to support desirable aquatic life.

Diurnal Winds: Local winds recurring on a daily basis along the axis of a valley, blowing upslope by day and downslope by night. They occur mostly in calm, clear weather.

Domestic Water Source (DWS): The use of a surface water as a source of potable water.

Downgradient: The direction that groundwater flows, similar to “downstream” for rivers. The direction of groundwater flow does not necessarily reflect the topography of the surface.

Drain Water: Water that enters a drain or channel.

Drawdown: The vertical distance the groundwater level is lowered due to the removal of water from an aquifer.

Drinking Water: Water safe enough to be consumed by humans or used with low risk of immediate or long-term harm. Also known as potable water.

Dross: A mass of solid impurities that is considered a waste product from molten metal.

Drywell: A bored, drilled, or driven shaft or hole, the depth of which is greater than its width, and which disposes of unwanted water, most commonly stormwater runoff, by dissipating it into the ground, where it infiltrates to groundwater.

Dust Control Action Forecast: An Arizona Department of Environmental Quality forecast which assesses the risk of exceeding the PM-10 federal health standard in Maricopa and Pinal counties.

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Early Response Action (ERA): Refers to a remedial action performed prior to the final remedy, and often prior to the remedial investigation. An ERA addresses current risks to public health, welfare, and the environment; protects or provides a supply of water; addresses sources of contamination; or controls or contains contamination where such actions are expected to reduce the scope or cost of the remedy needed at the site. It is also referred to as an interim remedial action.

Ecosystem: The interacting system of a biological community and its non-living environmental surroundings.

An example of effluent

Effluent: Treated or untreated wastewater that flows out of a treatment plant, sewer, or industrial outfall. Generally refers to wastes discharged into surface waters.

Effluent-Dependent Water (EDW): A surface water that consists of a point source discharge of wastewater. Without the point source discharge of wastewater, it would be an ephemeral water.

Electric arc shaft furnace: A cylindrical furnace lined with material capable of enduring high temperatures that produces molten steel by heating iron and steel scrap and other materials that are used as charge materials, using discharges of electricity from carbon-based conductors and direct-current electrical energy. This energy-efficient technology recovers the heat from the furnace off-gas by exhausting it through a shaft where the steel scrap is held prior to charging.

Electronic Waste (e-waste): Electronic products nearing the end of their useful life. Computers, televisions, VCRs, stereos, copiers, and fax machines are common electronic products. Many of these products can be reused, refurbished, or recycled.

Emergency Response: A remedial action taken in response to a situation that might cause serious harm to people or the environment if not addressed immediately. An example is removal of soil contaminated by lead in a residential area.

Emission: Pollution discharged into the atmosphere from smokestacks, other vents, and surface areas of commercial or industrial facilities; from residential chimneys; and from motor vehicle, locomotive, or aircraft exhausts.

Environment: Includes the air, water and land, and the relationship that exists between them and all living things, including plants, man and other animals.

Environmental Assessment (EA): An environmental analysis prepared pursuant to the National Environmental Policy Act to determine whether a federal action would significantly affect the environment and thus require a more detailed environmental impact statement.

Environmental Council of the States (ECOS): National non-profit, non-partisan association of state and territorial environmental agency leaders. The purpose of ECOS is to improve the capability of state environmental agencies and their leaders to protect and improve human health and the environment.

Environmental Impact Statement (EIS): A document required of federal agencies by the National Environmental Policy Act for major projects or legislative proposals significantly affecting the environment. A tool for decision making, it describes the positive and negative effects of the undertaking and cites alternative actions.

Environmental Justice (EJ): The fair treatment of people of all races, cultures, incomes, and educational levels with respect to the development and enforcement of environmental laws, regulations, and policies.

Environmental Management System (EMS): Management of an organization's environmental programs in a comprehensive, systematic, planned and documented manner and maintaining policy for environmental protection.

Environmental Protection Agency (EPA): Agency of the federal government created in 1970 for the purpose of protecting human health and the environment by writing and enforcing regulations based on laws passed by Congress.

Environmental Sustainability: Maintenance of ecosystem components and functions for future generations.

Ephemeral Water: A surface water that has a channel that is at all times above the water table and flows only in direct response to precipitation.

Evaporation Ponds: Areas where sewage sludge is dumped and dried.

Exceedance (of pollution standard): Violation of the pollutant levels permitted by environmental protection standards.

Explanation of Significant Differences (ESD): A document issued by the EPA after adoption of the record of decision which explains differences in the remedial action that significantly change but do not fundamentally alter the remedy selected in the ROD with respect to scope, performance or cost.

Exposure Pathway: The route of contaminants from the source of contamination to potential contact with a medium (air, soil, surface water, or groundwater) that represents a potential threat to human health or the environment. Determining whether exposure pathways exist is an essential step in conducting a risk assessment.

Extinction (of light): The loss of light due to scattering and absorption as it passes through the atmosphere.

Extraction Well: A well specifically designed to withdraw groundwater or soil vapor for treatment.

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Facility: Usually includes a place, site, or area where a hazardous substance has been deposited, stored, disposed of, placed, or otherwise came to be located.

Feasibility Study (FS): A process to identify a reference remedy and alternative remedies that appear to be capable of achieving the remedial objectives for the site. It is often done as part of a two-phase investigation in conjunction with a remedial investigation (RI/FS).

Federal Implementation Plan: A federally implemented plan to achieve attainment of air quality standards, used when a state is unable to develop an adequate plan.

Federal Register (FR) : Official journal of the federal government that contains government agency rules, proposed rules and public notices.

Ferrous Metals: Magnetic metals derived from iron or steel. The products made from ferrous metals include appliances, furniture, containers, and packaging like steel drums and barrels. Recycled products include processing tin/steel cans, strapping, and metals from appliances into new products.

Filtration: A treatment process, under the control of qualified operators, for removing solid (particulate) matter from water by means of porous media such as sand or a man-made filter. Filtration also is often used to remove particles that contain pathogens.

Fish Consumption: The use of a surface water by humans for harvesting aquatic organisms for consumption. Harvestable aquatic organisms include fish, clams, turtles, crayfish, and frogs.

Fissure: A narrow crack or cleft, as in a rock face.

Five-Year Review: A periodic review of a Superfund/WQARF site conducted after a response action has been initiated; the purpose of a five-year review is to evaluate whether the response action remains protective of public health and the environment.

Floodplain: The flat or nearly flat land along a river or stream or in a tidal area that is covered by water during a flood.

Floodwater: The water that overflows because of a flood.

Fly Ash: Non-combustible residual particles expelled by flue gas.

Fractures: Cracks, faults, or breaks that occur in rock material.

Friable Asbestos Material (FAM): Any material that is more than one percent asbestos and that can be crumbled or reduced to powder by hand pressure.

Fugitive Emissions: Emissions not caught by a capture system.

Full-Body Contact (FBC): The use of a surface water for swimming or other recreational activity that causes the human body to come into direct contact with the water to the point of complete submergence. The activity is such that ingestion of the water is likely and sensitive body organs, such as the eyes, ears, or nose, may be exposed to direct contact with the water.

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Generator: Any person who produces hazardous waste or causes a hazardous waste to become subject to regulation.

Geographical Information System (GIS): A system designed to capture, store, manipulate, analyze, manage, and present all types of spatial or geographical data.

Geologic Formation: A body of rock strata (layers) that consists of a certain type or combination of types of rock with the same characteristics such as grain size, or mineral content, or mode of deposition. A formation is usually visually distinguishable from the rock above and below.

Global Positioning System (GPS): A space-based satellite navigation system that provides location and time information in all weather conditions, anywhere on or near the Earth where there is an unobstructed line of sight to four or more GPS satellites.

Good Neighbor Environmental Board (GNEB): Independent federal advisory committee with mission to advise U.S. government on good neighbor practices along the border with Mexico. Its recommendations are focused on environmental infrastructure needs within the U.S. states contiguous to Mexico.

Granular Activated Carbon (GAC): An effective absorbent primarily due to its extensive porosity and very large available surface area. By definition, granular activated carbon (as opposed to powdered activated carbon) is composed of particles with sizes greater than 0.8 mm, about the size of coarse sand. Activated carbon is manufactured from a variety of raw materials, including wood, coal, and coconut shells, making it plentiful, relatively inexpensive, and versatile.

Gray Water: Wastewater generated from kitchen sinks, washing machines, wash-hand basins, showers and baths, which can be recycled for landscape irrigation and constructed wetlands.

Green cleaning: Refers to the use of cleaning methods and products with environmentally friendly ingredients designed to preserve human health and environmental quality. Green cleaning techniques and products avoid the use of chemically reactive and toxic products which contain various toxic chemicals.

Greenhouse Gas (GHG): Any gas that absorbs infrared radiation in the atmosphere. Greenhouse gases include water vapor, carbon dioxide (CO2), methane (CH4), nitrous oxide (N2O), chlorofluorocarbons (CFCs), hydrochlorofluorocarbons (HCFCs), ozone (O3 ), hydrofluorocarbons (HFCs), perfluorocarbons (PFCs), and sulfur hexafluoride (SF6).

Greenwashing: A form of corporate misrepresentation where a company will present a green public image and publicize green initiatives that are false or misleading.

Groundwater: Water located beneath the ground surface in soil pore spaces and in the fractures of geologic formations. A formation of rock or soil is called an aquifer when it can yield a usable quantity of water.

Groundwater Basin: A groundwater reservoir defined by an overlaying land surface and the underlying aquifers that contain the stored groundwater. In some cases, the boundaries of successively deeper aquifers may differ and make it difficult to define the limits of the basin.

Groundwater Model: Refers to computer models of groundwater flow systems that are used by hydrogeologists to simulate and predict aquifer conditions. Models can be used to help summarize, interpret, and present available data; to evaluate such things as monitoring networks or alternate remedial measures; to compare and assess different hypothetical groundwater flow conditions; and to help with water management problems such as predicting changes to the water table due to human activities.

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Hardness (of water): The sum of the calcium and magnesium concentrations, expressed as calcium carbonate (CaCO3) in milligrams per liter. Excessive hardness results in excessive use of soaps and detergents and causes the deposition of scale in teapots, water heaters, etc.

Hazardous Air Pollutants (HAPs): Air pollutants which are not covered by ambient air quality standards but which, as defined in the Clean Air Act, may present a threat of adverse human health effects or adverse environmental effects. Such pollutants include asbestos, beryllium, mercury, benzene, coke oven emissions, radionuclides, and vinyl chloride.

Hazardous Substance: Any material that, because of its quantity, concentration, and physical or chemical characteristics, poses a significant present or potential hazard to human health and safety or to the environment.

Hazardous Waste (HW): By-products of society that can pose a substantial or potential hazard to human health or the environment when improperly managed. Hazardous waste possesses at least one of four characteristics -- ignitability, corrosivity, reactivity, or toxicity.

Hazardous Waste Operator Certification: The training process to meet guidelines produced and maintained by the Occupations Safety and Health Administration that regulates hazardous waste operations and emergency services.

Health Based Guidance Level (HBGL): Represents  human ingestion (drinking) levels that are unlikely to result in adverse health effects during long-term exposure. The HBGLs are recommended maximum levels and not legally enforceable. However, the HBGLs can be referred to when there are no regulatory levels specified by law or regulation.

Heat Island Effect: A "dome" of elevated temperatures over an urban area caused by structural and pavement heat fluxes, and pollutant emissions.

Heavy Metals: Refers to a group of toxic metals including arsenic, chromium, copper, lead, mercury, silver, and zinc. Heavy metals often are present at industrial sites where operations have included battery recycling and metal plating.

High Pollution Advistory (HPA): Issued when it is imminent or there is a high probability for a pollutant to exceed the federal health standard.

High Pollution Watch (HPW): Issued when there is the potential for a pollutant to exceed the federal health standard.

Holding Pond: A pond or reservoir, usually made of earth, built to store polluted runoff.

Household Hazardous Waste (HHW): Hazardous products used and disposed of by residential consumers. Those products include paints, stains, varnishes, solvents, pesticides, and other materials or products containing volatile chemicals that can catch fire, react or explode, or that are corrosive or toxic.

Human Health Risk Assessment: An evaluation of available data on existing or potential risks to human health posed by a contaminated site.

Hydraulics: TThe study of the behavior of fluids, static (not moving) and dynamic (moving).

Hydrogeology: TThe part of hydrology that deals with the distribution and movement of groundwater in the soil and rocks of the earth's crust, most commonly in aquifers.

Hydrology: TThe study of the movement, distribution, and quality of water throughout the earth.

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Indian Country: As defined in U. S. Code Title 18 §1151, Indian Country includes all land within the limits of any Indian reservation under the jurisdiction of the U. S. government, all dependent Indian communities within the borders of the U. S., and all Indian allotments to which the Indian titles have not been extinguished. The Arizona Department of Environmental Quality does not have discharge permitting authority in Indian Country, even on private fee lands. Operators in Indian Country must pursue permitting through U.S. EPA Region 9 or federally recognized tribes granted “treatment as state” status or primacy by U.S. EPA over specific environmental programs.

Information Repository: A collection of documents about a specific project. Information on certain WQARF and Superfund sites may be available at ADEQ offices and libraries throughout the state.

Impervious Surface: A surface which does not allow water or other liquids to pass through. Impervious surfaces greatly increase the volume and velocity of runoff and the amount of pollution and sediment that enters streams and lakes.

Infiltration: The flow of a fluid into a substance through pores or small openings.

Information Repository: A collection of documents about a specific project. Information on certain WQARF and Superfund sites may be available at ADEQ offices and libraries throughout the state.

Injection Well: A well in which fluids are injected rather than produced as when treated water is put back into the aquifer after contaminants have been removed.

Inorganic Compounds: Compounds that are considered to be of mineral as opposed to biological.

In-Situ: In its original place; unmoved unexcavated; remaining at the site or in the subsurface.

Institutional Controls (ICs):  Actions, such as legal controls that help minimize the potential for human exposure to contamination by ensuring appropriate land or resource use. ICs are meant to supplement engineering controls, and they are rarely the sole remedy at a site. ICs are commonly used when residual contamination remains onsite at a level that does not allow for unrestricted use and unlimited exposure after cleanup.

Integrated Pest Management: The coordinated use of pest and environmental information with available pest control methods to prevent unacceptable levels of pest damage by the most economical means and with the least possible hazard to people, property, and the environment.

Interim Remedial Actions (IRA): Minimum remedial actions taken to address the loss or reduction of available water from a well until a remedy is selected.

Intermittent Water: A stream or reach that flows continuously only at certain times of the year, as when it receives water from rainfall or snow melt.

International Boundary and Water Commission: Mission is to provide binational solutions to issues that arise during the application of United States - Mexico treaties regarding boundary demarcation, national ownership of waters, sanitation, water quality, and flood control in the border region. Also includes Mexican section. The U.S. section, located in El Paso, Texas, is administered by the Department of State; the Mexican section, located in Ciudad Juarez, Chihuahua, is known as Comisión Internacional de Límites y Aguas (CILA) and is administered by the Secretariat of Foreign Relations. The U.S. IBWC operates the Nogales International Wastewater Treatment Plant located in Rio Rico.

International Outfall Interceptor (IOI): A 30-inch pipe that serves Nogales, Arizona, and Nogales, Sonora, with wastewater collection. The IOI conveys wastewater from the border with Mexico over a distance of 10 miles to the Nogales International Wastewater Treatment Plant in Rio Rico, Arizona. The IOI runs both under and adjacent to the Nogales Wash.

Inversion: A departure from the usual decrease of temperature with altitude. Also, the layer through which this departure occurs (the "inversion layer"), or the lowest altitude at which the departure is found (the "base of the inversion"). Inversions, which are common in winter in the Phoenix area, can trap pollutants near the surface resulting in what is commonly known as the “brown cloud.”

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LaPaz Agreement: 1983 agreement between the U.S. and Mexico to cooperate for protection and improvement of the environment in the border area. The agreement defines the border as 62 miles (100 kilometers) north and south of the international border.

Ladle Metallurgical Furnace: A cylindrical furnace, which is lined with a material capable of enduring high temperatures, that is used for adjusting the chemical and mechanical properties of the molten steel produced in the electric arc shaft furnace.

Lamp: Also referred to as “universal waste lamp,” a lamp is defined as the bulb or tube portion of an electric lighting device.

Landfill: A location on land where wastes are placed for permanent disposal.

Landfill Gas: Refers to the carbon dioxide, methane, and other compounds produced during the decomposition of organic waste.

Large Quantity Generators (LQG): Facilities that generate more than 2,200 pounds of hazardous waste per calendar month, or more than 2.2 pounds of acutely hazardous waste per calendar month.

Leachate: Liquid that forms when water passes down through solid waste, carrying suspended particles and chemicals it picks up and dissolves along the way into the ground and groundwater below. For example, rain falling on a landfill and passing through the waste would appear as leachate below the waste.

Lead: A heavy metal that is hazardous to health if breathed or swallowed. Its use in gasoline, paints and plumbing compounds has been sharply restricted or eliminated by federal laws and regulations.

Leaking Underground Storage Tank (LUST): Petroleum releases from regulated underground storage tanks.

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Manifest (Hazardous Waste): The shipping document, originated and signed by a waste generator or his or her representative, that is required by state or federal environmental regulators.

Maricopa Association of Governments (MAG): Regional air quality planning agency and metropolitan planning organization for transportation for all jurisdictions in Maricopa County, including the Phoenix urbanized area and the contiguous urbanized area in Pinal County, including the Town of Florence and City of Maricopa.

Maximum Contaminant Level (MCL): A federally designated, enforceable drinking water standard set to ensure that water is safe for drinking and other uses. The MCL varies for each contaminant being analyzed.

Medical Waste Incinerator (MWI): Incineration equipment that burns wastes produced by hospitals, veterinary facilities, and medical research facilities. These wastes include both infectious medical wastes as well as non-infectious, general housekeeping wastes.

Methane: A colorless, non-poisonous, flammable gas created by microorganisms as they digest (anaerobic decomposition) organic compounds found in landfill wastes. Methane is found in nature as a gas and is the major component of the gas that provides energy for our homes.

Micrograms per Liter (μg/L) : A unit of measurement that expresses a concentration that is the mass (weight) of one material dissolved into a volume of another material. A microgram (μg) is a metric unit of mass which is equivalent to 0.0000000022 pounds. A liter is a metric unit of volume which is approximately equivalent to a quart. Also, 1 μg/L is equivalent to 1 part per billion (ppb).

Migration: The movement of a contaminant in the environment through soil, groundwater, surface water, air, etc.

Milligrams per Liter (mg/L): A unit of measurement that expresses a concentration that is the mass (weight) of one material dissolved into a volume of another material. A milligram is a metric unit of mass equal to 0.0000022 pounds or 1000 micrograms. A liter is a metric unit of volume approximately equivalent to 1 quart. Also, 1 mg/L is equivalent to 1 part per million (ppm).

Million Gallons per Day (MGD): A measure of water flow often used for indicating the treatment capacity of sewage treatment plants or production capacity of drinking water treatment plants. One MGD is equivalent to about 700 gallons per minute or 1.5 cubic feet per second.

Mixing Height: The height to which the lower atmosphere will undergo mechanical or turbulent mixing, producing a nearly uniform air mass.

Mixing Zone: an area or volume of a surface water that is contiguous to a point source discharge where dilution of the discharge takes place.

Monitored Natural Attenuation (MNA): Describes a range of physical and biological processes which, unaided by human intervention, reduce the concentration, toxicity, or mobility of chemical or radioactive contaminants. These processes take place whether or not other active cleanup measures are in place.

Monitoring Assistance Program (MAP): ADEQ program designed to lessen the monitoring and financial burdens on small public water systems in Arizona to ensure that all water served meets state and federal safe drinking water standards.

Monitoring Wells: Wells installed for the purpose of collecting samples such as groundwater and soil gas. Analytical results from samples are used to characterize the extent of contamination, the direction of groundwater flow, and the types and quantities of contaminants present in the groundwater.

Monsoon (North American): A seasonal change in prevailing winds accompanied by corresponding increase in precipitation. It describes the seasonal changes in atmospheric circulation and precipitation associated with the asymmetric heating of land and sea. Usually, the term monsoon is used to refer to the rainy phase of a seasonally changing pattern, although technically there is also a dry phase. It is formally defined as occurring from June 15 to September 30.

Multiple Use: Use of land for more than one purpose like grazing of livestock, watershed and wildlife protection, recreation, and timber production. Also applies to use of bodies of water for recreational purposes, fishing, and water supply.

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National Ambient Air Quality Standards (NAAQS): Federal standards for the minimum ambient air quality needed to protect public health and welfare.

National Emissions Standards for Hazardous Air Pollutants (NESHAP): Emissions standards set by EPA for an air pollutant not covered by NAAQS that may cause an increase in fatalities or in serious, irreversible, or incapacitating illness. Primary standards are designed to protect human health, secondary standards to protect public welfare like building facades, visibility, crops, and domestic animals.

National Environmental Policy Act of 1969: An act that established a U.S. national policy promoting the enhancement of the environment. NEPA's most significant accomplishment was setting up procedural requirements for all federal government agencies to prepare environmental assessments and environmental impact statements.

National Institute for Occupational Safety and Health (NIOSH): The federal agency responsible for conducting research and making recommendations for the prevention of work-related injury and illness. NIOSH is part of the Centers for Disease Control and Prevention.

National Pollution Discharge Elimination System (NPDES): Provision of the Clean Water Act which prohibits discharge of pollutants into waters of the United States unless a special permit is issued by EPA, a state, or, where delegated, a tribal government on an Indian reservation.

National Priorities List (NPL): EPA’s list of the most serious hazardous waste sites identified for possible long-term remedial response under the federal superfund (CERCLA).

National Response Center (NRC): The federal government's national communications center, which is staffed by U.S. Coast Guard officers and marine science technicians. The NRC is the sole federal point of contact for reporting all hazardous substances releases and oil spills.

National Response Team: Representatives of 13 federal agencies that, as a team, coordinate federal responses to nationally significant incidents of pollution -- an oil spill, a major chemical release, or a superfund response action -- and provide advice and technical assistance to the responding agency(ies) before and during a response action.

Navigable Waters: Traditionally, waters sufficiently deep and wide for navigation by all, or specified vessels. Such waters in the United States come under federal jurisdiction and are protected by certain provisions of the Clean Water Act.

New Source Performance Standards: Uniform national EPA air emission and water effluent standards which limit the amount of pollution allowed from new sources or from modified existing sources.

New Source Review: A Clean Air Act requirement that state implementation plans must include a permit review that applies to the construction and operation of new and modified stationary sources in nonattainment areas to ensure attainment of national ambient air quality standards.

Nitrate: A compound containing nitrogen and oxygen that exists in the atmosphere or as a dissolved gas in water and has harmful effects on humans and animals. Nitrates in water can cause severe illness in infants and domestic animals. A plant nutrient and inorganic fertilizer, nitrate is found in septic systems, animal feed lots, agricultural fertilizers, manure, industrial waste waters, and sanitary landfills.

Nitrogen oxides:Any inorganic compound containing both nitrogen and oxygen. These compounds act as precursors to other pollutants such as nitrate and ozone.

No Burn Day: Admonition to not burn wood issued by Maricopa County Air Quality Department when forecasted soot, dust or ozone conditions have led to issuance of a high pollution advisory or health watch by ADEQ.

Non-Attainment Area: Area that does not meet one or more of the National Ambient Air Quality Standards for the criteria pollutants designated in the Clean Air Act.

Non-Point Sources: Diffuse pollution sources (i.e. without a single point of origin or not introduced into a receiving stream from a specific outlet). The pollutants are generally carried off the land by storm water. Common non-point sources are agriculture, forestry, urban, mining, construction, dams, channels, land disposal, saltwater intrusion, and city streets.

North American Development Bank (NADB): Created with the Border Environment Cooperation Commission (BECC) as an interdependent institution, NADB concentrates on project financing and oversight for project implementation to preserve and enhance environmental conditions for people living along the U.S.-Mexico border.

Notice of Opportunity to Correct (NOC): An informal enforcement action taken by ADEQ which documents the factual nature of an environmental violation, the legal authority regarding compliance, a description of what constitutes compliance and how it is to be documented and a time frame in which ADEQ expects compliance to be achieved. NOCs are issued for violations considered to pose less environmental risk than NOV violations.

Notice of Violation (NOV): An informal enforcement action taken by ADEQ which documents the factual nature of an environmental violation, the legal authority regarding compliance, a description of what constitutes compliance and how it is to be documented and a time frame in which ADEQ expects compliance to be achieved. NOVs are issued for violations considered to pose higher environmental risk than NOC violations.

Noxious Gases: Poisonous gases that can harm people and the environment. Some gases have a strong smell, for example sulfur dioxide and methane, while others, such as carbon monoxide, do not have any smell at all.

Nuclear Regulatory Commission (NRC): The NRC was created as an independent agency by Congress in 1974 to ensure the safe use of radioactive materials for beneficial civilian purposes while protecting people and the environment. The NRC regulates commercial nuclear power plants like Palo Verde Nuclear Generating Station west of Phoenix.

Nutrient: Any substance assimilated by living things that promotes growth. The term is often applied to nitrogen and phosphorus in wastewater, where excessive amounts create algae growth and other problems, but is also applied to other essential and trace elements.

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Occupational Safety and Health Administration (OSHA): Created by Congress to assure safe and healthful working conditions for workers by setting and enforcing standards and by providing training, outreach, education and assistance.

On-Screen Coordinator: The predesignated EPA, Coast Guard, or Department of Defense official who coordinates and directs Superfund removal actions or Clean Water Act oil- or hazardous-spill response actions.

Opacity: The amount of light obscured by particulate pollution in the air; clear window glass has zero opacity, a brick wall is 100 percent opaque. Opacity is an indicator of changes in performance of particulate control systems.

Operable Unit: Term for each of a number of separate activities undertaken as part of a Superfund site cleanup.

Operation and Maintenance (O&M): 1. Activities conducted after a Superfund site action is completed to ensure that the action is effective;  2. Actions taken after construction to ensure that facilities constructed to treat wastewater will be properly operated and maintained to achieve normative efficiency levels and prescribed effluent limitations in an optimum manner; 3. On-going asbestos management plan in a school or other public building, including regular inspections, various methods of maintaining asbestos in place, and removal when necessary.

Operator Certificate: Certification of operators of community and nontransient noncommunity water systems, asbestos specialists, pesticide applicators, hazardous waste transporters, and other such specialists as required by the EPA or ADEQ implementing an EPA-approved program.

Organic Compounds: Carbon-based compounds (also containing oxygen, hydrogen, or nitrogen) most commonly associated with living organisms  like proteins, sugars and cellulose.

Organismo Operador de Agua Potable, Alcantarillado y Saneamiento (OOMAPAS): The authority for drinking water, sewerage and sanitation operations in Mexico. Entity responsible for operational aspects of drinking water and wastewater functions in Mexican municipal governments.

Osmosis: The passage of a liquid from a weak solution to a more concentrated solution across a semipermeable membrane that allows passage of the solvent (water) but not the dissolved solids.

Outfall: The place where effluent is discharged into receiving waters.

Outflow: The outward flow of air from a thunderstorm associated with gusty and erratic winds that can result in blowing dust. An outflow is most common during the North American Monsoon season.

Outstanding Arizona Water: A designated section of surface water by the ADEQ director that affords it the highest protection under the U.S. Clean Water Act.

Overdraft: A condition that occurs in a groundwater basin when pumping exceeds recharge over an extended period of time.

Oxidation: The chemical addition of oxygen to break down pollutants or organic waste; e.g., destruction of chemicals such as cyanides, phenols, and organic sulfur compounds in sewage by bacterial and chemical means.

Ozone: a nearly colorless gas, that appears blue at high concentrations. It is formed in the reaction between atomic oxygen and molecular oxygen. Ozone, produced by photochemical reactions (i.e., sunlight), is found at all altitudes in the atmosphere. Ozone is a strong disinfectant that is sometimes used in drinking water and sewage treatment.

Ozone Layer: The thin protective layer of gas 10 kilometers to 50 kilometers above the earth that acts as a filter for ultraviolet (UV) radiation from the sun. High UV levels can lead to skin cancer and cataracts and affect the growth of plants.

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Palo Verde Nuclear Generating Station
Palo Verde Nuclear Generating Station


Palo Verde Nuclear Generating Station: Nuclear power plant located near community of Tonopah west of Phoenix which is the largest power plant in the country for net generation. Palo Verde uses reclaimed water from local cities for condenser cooling water.

Partial-Body Contact: The recreational use of a surface water that may cause the human body to come into direct contact with the water, but normally not to the point of complete submergence (for example, wading or boating). The use is such that ingestion of the water is not likely and sensitive body organs, such as the eyes, ears, or nose, will not normally be exposed to direct contact with the water.

Particulate matter: Any finely divided airborne solid or liquid material with a diameter smaller than 100 micrometers while it is in the air. Examples of particulate matter include dust, smoke, soot, pollen and soil particles.

Particulate Matter (Inhalable): Any finely divided airborne solid or liquid material with a diameter smaller than 10 micrometers while it is in the air.

Particulate Matter-10 (PM10): Dust, particulate matter measuring 10 microns or less. A dust particle of 10 microns is one-seventh the width of a human hair.

Particulate Matter-2.5 (PM2.5): Particulate matter measuring 2.5 microns or less. A major pollutant source, it is generated by smoke from wildfires, prescribed burns and fireplace activity.

Parts Per Billion (ppb)/Parts Per MillionMillion (ppm): Units commonly used to express contamination ratios, as in establishing the maximum permissible amount of a contaminant in water, land, or air.

Unit1 ppm1 ppb
Length1 inch in 16 miles1 inch in 16,000 miles
Time1 minute in 2 years1 second in 32 years
Money1 cent in $10,000. cent in $10,000,000
Weight1 ounce in 31 tons of potato chips1 pinch of salt in 10 tons of potato chips
Area1 square foot in 23 acres1 square foot in 36 square miles

Pathogens: Microorganisms like bacteria, viruses, or parasites that can cause disease in humans, animals and plants.

Pathway: The means for a contaminant to enter the body or plant life. Examples are ingestion (eating or drinking), inhalation (breathing), or transdermal (absorption through the skin). If no pathway exists, then exposure to a contaminant is not possible.

Perched Aquifer: A relatively small, localized aquifer that lies above the regional aquifer and is underlain by a confining layer. Perched aquifers may be formed when the groundwater table drops and water is trapped above a confining layer. They are usually discontinuous and are not usually sources for drinking water.

Perchlorate: A manufactured salt that is found in rocket fuels, explosives, flares, fireworks, some bleach products, and some herbicides. Perchlorate can impair thyroid function.

Perchloroethene (also known as tetrachloroethylene) (PCE): Also called tetrachloroethene, PCE, or perc. It is a manufactured chemical widely used for dry cleaning and metal degreasing.

Percolation: The movement under the force of gravity of water downward and radially through subsurface soil layers to the water table. In septic tank installations, a percolation test is used to determine the size of trench needed for adequate disposal of wastewater.

Perennial Water: A surface water that flows continuously throughout the year.

Permeability: The degree to which groundwater can move freely through the rocks and soil of an aquifer, indicative of the degree to which pores and fractures in rocks are actually interconnected. A typical measure of permeability is the number of gallons of water that can move through a cross section of one square foot. 

Permit: An authorization, license, or equivalent control document issued by ADEQ to implement the requirements of an environmental regulation, usually to limit the amount of pollutants discharged into the environment. For example, a permit to operate a wastewater treatment plant.

Personal Protective Equipment (PPE): Equipment worn to minimize exposure to serious workplace injuries and illnesses. These injuries and illnesses may result from contact with chemical, radiological, physical, electrical, mechanical, or other workplace hazards.

Pesticides: Any substance or mixture of substances intended for preventing, destroying, repelling, or mitigating any pest, or intended for use as a plant regulator, defoliant, or desiccant.

pH: A measure of the acidity or basicity of an aqueous solution. Solutions with a pH less than 7 are said to be acidic and solutions with a pH greater than 7 are basic or alkaline.

Plume: A well-defined area of contamination in groundwater, soil or the air downstream from the source. 

Point Source: Refers to a specific, identifiable source from which waste or pollution is released into the environment.

Pollution Prevention (P2): A national policy created by the Pollution Prevention Act of 1990 to have pollution prevented or reduced at the source wherever possible and also expand the Toxics Release Inventory. The Pollution Prevention Act focused industry, government, and public attention on reducing the amount of pollution through cost-effective changes in production, operation, and raw materials use.

Polychlorinated Biphenyl (PCB): A group of toxic, persistent chemicals that once were used in high voltage electrical transformers because they conducted heat well while being fire resistant and good electrical insulators. These contaminants are typically generated from metal degreasing, printed circuit board cleaning, gasoline, and wood preserving processes.

Porosity: The ratio between openings (voids, pores) in rocks or soil to the total volume. It is a measure of the ability of soil/rock material to store water. The more openings, the more water that may be stored, and the more porous the soil/rock is.

Portable Particulate Monitor (PPM): A network of monitors across Arizona operated by ADEQ that record hourly average concentrations of Particulate Matter-2.5. The monitors can be deployed to measure PM-2.5 levels generated by wildfires and prescribed burns.

Potable: Water of sufficient quality to serve as drinking water.

Potentially Responsible Party (PRP): A party (individual, corporation) identified by state or federal authorities as potentially liable for cleanup costs at a contaminated site.

Preliminary Investigation: Refers to the process of collecting and reviewing available information about a known or suspected hazardous waste site or release.

Prevention of significant deterioration (PSD): A construction air pollution permitting program designed to ensure air quality does not degrade beyond the national ambient air quality standard levels or beyond specified incremental amounts above a baseline level. It also ensures that the best available control technology is applied to major stationary sources and major modifications for regulated pollutants, and consideration of soils, vegetation and visibility in the permitting process.

Primary Treatment: The removal of particulate materials from domestic wastewater, usually done by allowing the solid materials to settle as a result of gravity.

Procuraduría Ambiental del Estado de Sonora (PROAES): State of Sonora Attorney General for the Environment. A separate agency in Sonora that conducts inspections and enforcement actions applied to air and waste regulatory requirements.

Procuraduría Federal de Protección al Ambiente (PROFEPA): Attorney General for Environmental Protection. A federal agency in Mexico that is responsible for inspections, compliance, and enforcement actions for environmental and natural resources protection.

Production Well: A well specifically designed to pump groundwater for domestic or municipal use (to differentiate from a monitoring well).

Proposed Remedial Action Plan (PRAP): A document which reviews the cleanup alternatives presented in the site feasibility study and identifies ADEQ’s preferred alternative. Selection of a preferred alternative is not a closed-end commitment to use that alternative; rather, it is a way for the agency to indicate, based on experience and expertise, which alternative is the most likely course of action. ADEQ must actively solicit public review of and comment on all the alternatives under consideration.

Public Comment Period: A period during which the public can formally review and comment on various documents and ADEQ actions.

Public Water System (PWS): Refers to water systems which provide water to at least 15 service connections used by year-round residents or which provide water to at least 25 year-round residents, thus falling under the drinking water safety requirements of the federal Safe Drinking Water Act.

Pump and Treat: A common method for cleaning up groundwater using pumps to bring polluted groundwater to the surface where it can be treated by various methods.

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Radioactive Waste: Any waste that emits energy as rays, waves, streams or energetic particles. Radioactive materials are often mixed with hazardous waste from nuclear reactors, research institutions, or hospitals.

Radionuclide: Radioactive particle, man-made (anthropogenic) or natural, with a distinct atomic weight number. Radionuclides can have a long life as a soil or water pollutant.

Radon: A common radioactive gas emitted from ordinary soils and rock. Radon has no smell, taste or color and can seep into homes, building up to dangerous levels if there is not enough ventilation. Exposure to high levels of radon gas over a long period of time increases the risk of developing lung cancer.

Reasonably Available Control Technology (RACT): Control technology that is reasonably available, and both technologically and economically feasible. Usually applied to existing sources in nonattainment areas; in most cases is less stringent than new source performance standards.

Recharge: The process by which water is added to a zone of saturation, usually by percolation from the soil surface, like the recharge to an aquifer.

Reclaimed Water: Former wastewater that is treated to remove solids and impurities in compliance with standards in regulation, which may then be used for agriculture, landscape irrigation, recharge of groundwater aquifers, and power generation supplies, industrial and other uses.

Record of Decision (ROD): A legal document that announces and explains the cleanup methods ADEQ will use at a Superfund/WQARF site. The ROD is based on information and technical analysis generated during the remedial investigation and feasibility study, and in consideration of comments received during the public comment record for the proposed remedial action plan.

Recycling: The process by which salvaged materials become usable products. Specifically, the reuse of specific consumer or industrial items in order to conserve scarce materials, reduce pollution and littering and generally improve the condition of the environment.

Release: A release occurs when a hazardous substance goes from a controlled condition (for example, inside a truck, barrel, storage tank, or landfill) to an uncontrolled condition in the air, water, or land.

Remedial Action: Any action taken to investigate, monitor, assess and evaluate the release or threat of release of hazardous substances or contaminants to the environment. It may also refer to the actual “cleanup” of the environment by various removal, treatment, monitored remediation, or corrective actions. The term cleanup is sometimes used interchangeably with the terms remedial action, removal action, response action, remedy, remediation, or corrective action.

Remedial Investigation (RI): Establishes the nature and extent of the contamination and the sources; identifies current and potential impacts to public health, welfare, and the environment; identifies current and reasonable foreseeable uses of land and waters of the state; and obtains and evaluates any information necessary for identification and comparison of alternative remedial actions.

Remedial Objective (RO): Established remedial goals for the current and reasonably foreseeable uses of lands and waters of the state that have been or are threatened to be affected by a release of hazardous substance..

Remediation: Cleanup or other methods used to remove or contain a toxic spill or hazardous materials.

Removal Action: An immediate, short-term cleanup action to address a release or threatened release of hazardous substances. This action is initiated to reduce or eliminate an immediate threat to public health and/or the environment.

Renewable Energy: Electricity supplied from renewable energy sources, such as wind and solar power, geothermal, hydropower, and various forms of biomass. These energy sources are considered renewable sources because they are continuously replenished on the earth.

Reportable Quantity: Quantity of a hazardous substance that triggers reports under CERCLA. If a substance exceeds its RQ, the release must be reported to the National Response Center, the SERC, and community emergency coordinators for areas likely to be affected.

Resource Conservation and Recovery Act (RCRA): The primary federal act that manages and controls the formation, storage, release, and permitting of hazardous substances and wastes. Primarily applied to the industrial and manufacturing sectors.

Responsible Party (RP): A party (individual, corporation) identified by state or federal authorities as liable for cleanup costs at a contaminated site.

Responsiveness Summary: A summary of oral and written comments (and ADEQ responses to those comments) received during the public comment period.

Retention Pond: Temporary containment for a material in an area where it can be treated for proper disposal.

Reverse Osmosis: A treatment process used in drinking water systems by adding pressure to force water through a semi-permeable membrane. Reverse osmosis removes salinity and most drinking water contaminants and produces a waste stream of highly saline water. Also used in wastewater treatment.

Riffle Habitat: A stream segment where moderate water velocity and substrate roughness produce moderately turbulent conditions that break the surface tension of the water and may produce breaking wavelets that turn the surface water into white water.

Rip Rap: A layer of man-made hard, durable material for bank protection and stabilization usually consisting of rock or stone.

Riparian Habitat: Areas adjacent to rivers and streams with a differing density, diversity, and productivity of plant and animal species relative to nearby uplands.

Risk Assessment: A scientific evaluation of the probability of harm resulting from exposure to a hazardous substances. The contaminant exposure pathways examined are inhalation (breathing the contaminant), ingestion (drinking/eating contaminant), and dermal (skin having contact with contaminant).

Run Habitat: A stream segment where there is moderate water velocity that does not break the surface tension of the water and does not produce breaking wavelets that turn the surface water into white water. Back to the top of the page


Safe Drinking Water Act (SDWA): Main federal law that ensures the quality of the country's drinking water. Under SDWA, the EPA sets standards for drinking water quality and oversees the states, localities, and water suppliers who implement those standards.

Scattering (of light): An interaction of a light wave with an object like tiny particles of dust or soot, that cause the light to be redirected.

Scrubber: An air pollution device that uses a spray of water or reactant or a dry process to trap pollutants in emissions.

Secondary Treatment: A wastewater treatment process used to convert dissolved or suspended materials into a form more readily separated from the water being treated.

Secretaria de Medio Ambiente y Recursos Naturales (SEMARNAT): Secretariat of the Environment and Natural Resources. Mexico’s environmental and natural resources protection agency. It is considered the counterpart to the U.S. EPA.

Sediment: Topsoil, sand, and minerals washed from the land into water, usually after rain or snow melt.

Self-Monitoring Report Form (SMRF): Forms filled out to fulfill specific monitoring and reporting requirements as set forth by the facility's aquifer protection permit or reuse permit.

Semi Volatile Organic Compound (SVOC): Organic compounds that volatilize slowly at standard temperature (20 degrees C and 1 atm pressure).

Septic System: An on-site system designed to treat and dispose of domestic sewage. A typical septic system consists of a tank that receives waste from a residence or business and a system of trenches or beds in the soil for disposal of the liquid effluent that remains after decomposition of the solids by bacteria in the tank. The sludge remaining in the septic tank must be pumped out periodically.

Septic Tank: An underground storage tank and treatment device for wastes from homes not connected to a sewer line. Waste goes directly from the home to the tank. The septic tank is a component of the septic system.

Sewage Treatment Plants: A plant used for treatment of domestic sewage. Often used synonymously with wastewater treatment plant.

Medical Sharps
Medical Sharps

Sharps: Hypodermic needles, syringes (with or without the attached needle), Pasteur pipettes, scalpel blades, blood vials, needles with attached tubing, and culture dishes used in animal or human patient care or treatment, or in medical, research or industrial laboratories. Also included are other types of broken or unbroken glassware that were in contact with infectious agents, such as used slides and cover slips, and unused hypodermic and suture needles, syringes, and scalpel blades.

Significant Noncompliance: Violations by point source dischargers of sufficient magnitude or duration to be a regulatory priority.

Sludge: A semi-solid residue from any of a number of air or water treatment processes. Sludge can be a hazardous waste.

Slurry: A watery mixture of insoluble matter resulting from some pollution control techniques.

Small Quantity Generators: A generator who generates less than 2,200 pounds of hazardous waste in a calendar month.

Smelter: A facility that melts or fuses ore, often with an accompanying chemical change, to separate its metal content. Emissions cause pollution. "Smelting" is the process involved.

Smoke: Particles suspended in air after incomplete combustion.

Solid Waste: Non-liquid, non-soluble materials ranging from municipal garbage to industrial wastes that contain complex and sometimes hazardous substances. Solid wastes also include sewage sludge, agricultural refuse, demolition wastes, and mining residues.

Soot: Carbon dust formed by incomplete combustion.

Special Waste: Items such as household hazardous waste, bulky wastes (refrigerators, pieces of furniture, etc.) tires, and used oil.

Stagnation: A high-pressure region causing subsidence and light winds that tends to trap pollutants near the ground where concentrations can become elevated.

Stakeholder: Any organization, governmental entity, or individual that has a stake in or may be impacted by a given approach to environmental regulation, pollution prevention, energy conservation, etc.

State Assurance Fund: An assurance account established by the Arizona legislature to assist eligible Underground Storage Tank (UST) owners, operators and others in meeting the potentially high costs of leaking UST investigations and cleanups.

State Implementation Plan (SIP): EPA-approved state plans for the establishment, regulation and enforcement of air pollution standards.

Stationary Source: A fixed-site producer of pollution, mainly power plants and other facilities using industrial combustion processes.

Stromwater: Water that originates during rainfall events and snow or ice melt and runs off into water courses, lakes and other water bodies and sewers.

Sulfur dioxide: A colorless, very irritating gas or liquid.

Sump: A pit or tank that catches liquid runoff for drainage or disposal.

Superfund: The program operated under the legislative authority of CERCLA and SARA that funds and carries out EPA solid waste emergency and long-term removal and remedial activities. These activities include establishing the National Priorities List, investigating sites for inclusion on the list, determining their priority, and conducting and/or supervising cleanup and other remedial actions.

Surface Water: Water that is present on the ground or in a stream, river, lake, wetland or ocean.

Surface Water Quality Standards: One of the cornerstones of the Clean Water Act, the standards that define the water quality goals for Arizona streams and lakes. They provide the basis for controlling discharges of pollutants to surface waters.

Sustainability: Human practices that do not result in the permanent damage, alteration or depletion of the environment, ecosystems, species or natural resources.

Synthetic Organic Chemical (SOC): Man-made (anthropogenic) organic chemicals. Some SOCs are volatile; others tend to stay dissolved in water instead of evaporating.

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Tail Water: The runoff of irrigation water from the lower end of an irrigated field.

Tailings: Residue of raw material or waste separated out during the processing of crops or mineral ores.

Tertiary Treatment: Advanced cleaning of wastewater that goes beyond the secondary or biological stage, removing nutrients such as phosphorus, nitrogen and suspended solids.

Tetrachloroethylene (PCE): A toxic chlorocarbon, widely known as "perc," which forms a colorless liquid widely used for dry cleaning of fabrics. 

Threshold: The dose or exposure level below which a significant adverse effect is not expected.

Total Dissolved Solids (TDS): The total amount of mobile charged ions, including minerals, salts or metals dissolved in a given volume of water.

Total Maximum Daily Load (TMDL): A calculation of the maximum amount of a pollutant that a water body can receive and still meet water quality standards, and an allocation of that load among the various sources of that pollutant.

Total Nitrogen: The sum of the concentrations of all nitrogen forms in water, including ammonia (NH3), ammonium ion (NH4+), nitrite (NO2), and nitrate (NO3), and dissolved and particulate organic nitrogen expressed as elemental nitrogen.

Total Petroleum Hydrocarbons (TPH): Measure of the concentration or mass of petroleum hydrocarbon constituents present in a given amount of soil or water.

Total Suspended Solids (TSS): A measure of the suspended solids in wastewater, effluent, or water bodies, determined by tests for total suspended non-filterable solids.

Toxic Substances Control Act: National law, administered by the EPA, that assesses and regulates new commercial chemicals before their entrance into the market, regulates existing chemicals that pose an unreasonable risk to health or to the environment.

Toxicity: The degree to which a substance or mixture of substances can harm humans or animals.

Toxics Release Inventory (TRI): EPA program that tracks the management of toxic chemicals that may pose a threat to human health and the environment.

Toxin: A poisonous substance that can either be natural (produced by plants, animals or bacteria) or manufactured.

Transfer Facilities: Any transportation-related facility such as loading docks, parking areas, storage areas, or other similar areas where shipments of hazardous waste are temporarily held during the normal course of transportation.

Transport (air pollution): The horizontal or vertical displacement of a pollutant from its emission source that can be carried through the atmosphere over some distance.

Transport Winds: A measure of the average rate of the horizontal movement of air within the mixing layer.

Treated Wastewater: Wastewater that has been subjected to one or more physical, chemical, and biological processes to reduce its potential of being health hazard.

Treatment, Storage, or Disposal Facility (TSDF): Site where a hazardous substance is treated, stored, or disposed of. TSD facilities are regulated by ADEQ under RCRA.

Trichloroethylene (TCE): A stable, low boiling-point colorless liquid that is toxic if inhaled. Used as a solvent or metal degreasing agent and in other industrial applications.

Turbidity: A cloudy condition in water due to suspended silt or organic matter. The degree of turbidity is measured with a turbidometer.

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Underground Injection Control (UIC): The program under the Safe Drinking Water Act that regulates the use of wells to pump fluids into the ground.

Underground Storage Tank (UST): A tank located at least partially underground and designed to hold gasoline or other petroleum products or chemicals.

Universal Waste: Any of the following hazardous wastes (batteries, pesticides, mercury-containing equipment and lamps) that are managed under the universal waste requirements of 40 CFR part 273.

Used Oil: Spent motor oil from passenger cars and trucks collected at specified locations for recycling.

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Vadose Zone: The zone between land surface and the water table within which the moisture content is less than saturation (except in the capillary fringe) and pressure is less than atmospheric. Soil pore space also typically contains air or other gases. The capillary fringe is included in the vadose zone.

Vapor: The gas given off by substances that are solids or liquids at ordinary atmospheric pressure and temperatures.

Vapor Intrusion: Vapor-phase migration of volatile organic compounds or volatile inorganic compounds into occupied buildings from underlying contaminated groundwater or soil.

Vector: Any agent (person, animal or microorganism) that carries and transmits an infectious pathogen into another living organism.

Vehicle Emissions Inspection Program: A mandatory vehicle emissions testing and repair program administered by ADEQ in metropolitan Phoenix and Tucson to reduce vehicle emissions and improve air quality.

Ventilation: The potential of the atmosphere to disperse airborne pollutants, such as smoke from a prescribed fire. It is based on both the transport winds and the mixing height.

Visibility: A measure of how far and how well an observer can see through the atmosphere.

Volatile: Any substance that evaporates readily.

Volatile Organic Compound (VOC): Any compound of carbon, excluding carbon monoxide, carbon dioxide, carbonic acid, metallic carbides or carbonates, and ammonium carbonate, that participate in reactions of radiant energy, especially light, in the atmosphere.

Voluntary Environmental Stewardship Program: An ADEQ program that provides recognition and incentives for organizations that have a good history of environmental compliance and endeavor to go above and beyond environmental law requirements. The VESP program was established by state of Arizona House Bill 2799 in 2012 and consists of platinum, gold, silver and bronze levels of recognition.

Voluntary Remediation Program: An ADEQ program through which property owners, prospective purchasers and other interested parties can investigate or clean up a contaminated site with a single point of contact at the agency. The agency reviews the work and provides a closure document for successful site remediation that is accepted by all relevant ADEQ programs.

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Waste Programs Division (WPD) of ADEQ: Protects and enhances public health and the environment of Arizona by reducing the risk associated with waste management, contaminated sites and regulated substances. Core responsibilities include assuring the proper handling, storage, treatment and disposal of wastes, and proper operation and maintenance of underground storage tanks; investigating complaints and violations of Arizona's solid waste, hazardous waste and underground storage tank laws; investigating, managing and remediating soil and groundwater that are contaminated with regulated and hazardous substances; promoting pollution prevention and recycling; reviewing and approving construction plans for landfills and special waste facilities; and administering payments from the State Assurance Fund for reimbursement of eligible costs associated with removal and remediation of leaking underground storage tanks.

Wastewater: The spent or used water from a home, community, farm, or industry that contains dissolved or suspended matter.

Wastewater Treatment Plant: A facility containing a series of tanks, screens, filters, and other processes by which pollutants are removed from water. Most treatments include chlorination to attain safe drinking water standards.

Water Body: Any significant accumulation of water.

Water Infrastructure Finance Authority of Airzona (WIFA): An independent agency of the state of Arizona authorized to finance the construction, rehabilitation and/or improvement of drinking water, wastewater, wastewater reclamation, and other water quality facilities and projects.

Water Quality Assurance Revolving Fund (WQARF): Created by the Environmental Quality Act of 1986 to support hazardous substance cleanup efforts in Arizona.

Water Quality Division (WQD) of ADEQ: Protects and enhances public health and the environment of Arizona by ensuring safe drinking water and reducing the impact of pollutants discharged to surface and groundwater. Core responsibilities include ensuring that public water systems deliver safe drinking water; identifying water pollution problems and establishing standards to address them; investigating complaints and violations of Arizona's water quality laws, rules and permits; issuing permits to protect waters from point sources of pollution; managing the quality of water resources through partnerships within the natural boundaries of the state's watersheds; monitoring and assessing the quality of surface and groundwater throughout the state; and regulating the discharge and treatment of wastewater.

Water Quality Standards: ADEQ-adopted and EPA-approved ambient standards for water bodies. The standards prescribe the use of the water body and establish the water quality criteria that must be met to protect designated uses.

Watershed: The land area that drains into a stream; the watershed for a major river may encompass a number of smaller watersheds that ultimately combine at a common point.

Water Regional Air Partnership: Voluntary partnership of states, tribes, federal land managers, local air agencies and the EPA whose purpose is to understand current and evolving regional air quality issues in the West.

Western States Air Resources Council (WESTAR): Formed to serve as a forum to discuss western regional air quality issues of common concern and share resources for the common benefit of the 15 member states, including Arizona, and extending from Alaska to New Mexico and from Hawaii to North Dakota and South Dakota.

Wetlands: An area that is saturated by surface or groundwater with vegetation adapted for life under those soil conditions, as swamps, bogs, fens, marshes, and estuaries.

Wood-burning-stove Pollution: Air pollution caused by emissions of particulate matter, carbon monoxide, total suspended particulates, and polycyclic organic matter from wood-burning stoves.

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