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Environmental Etymology A - Z

What does it all mean?

For more definitions from the EPA, click this line

 

Definitions
A
Term
Definition
• AANWR Alaskan Arctic National Wildlife Refuge
• Abatement Debris Waste from remediation activities.
• Acclimatization The physiological and behavioral adjustments of an organism to changes in its environment.
• Acid Aerosol Acidic liquid or solid particles small enough to become airborne. High concentrations can irritate the lungs and have been associated with respiratory diseases like asthma.
• Acid Rain A complex chemical and atmospheric phenomenon that occurs when emissions of sulfur and nitrogen compounds and other substances are transformed by chemical processes in the atmosphere, often far from the original sources, and then deposited on earth in either wet or dry form. The wet forms, popularly called "acid rain," can fall to earth as rain, snow, or fog. The dry forms are acidic gases or particulates.
 
• Acid Mine Drainage Drainage of water from areas that have been mined for coal or other mineral ores.
• Activated Carbon A highly adsorbent form of carbon used to remove odors and toxic substances from liquid or gaseous emissions. In waste treatment, it is used to remove dissolved organic matter from waste drinking water. It is also used in motor vehicle evaporative control systems.
• Activated Sludge Product that results when primary effluent is mixed with bacteria-laden sludge and then agitated and aerated to promote biological treatment, speeding the breakdown of organic matter in raw sewage undergoing secondary waste treatment.
• Acute Toxicity The ability of a substance to cause severe biological harm or death soon after a single exposure or dose. Also, any poisonous effect resulting from a single short-term exposure to a toxic substance. (See: chronic toxicity, toxicity.)
• ACWA American Clean Water Association
• Adulterants Chemical impurities or substances that by law do not belong in a food, or pesticide.
 
• Aerosol 1. Small droplets or particles suspended in the atmosphere, typically containing sulfur. They are usually emitted naturally (e.g. in volcanic eruptions) and as the result of anthropogenic (human) activities such as burning fossil fuels.
2. The pressurized gas used to propel substances out of a container.
• Affected Landfill Under the Clean Air Act, landfills that meet criteria for capacity, age, and emissions rates set by the EPA. They are required to collect and combust their gas emissions.
• Affected Public 1.The people who live and/or work near a hazardous waste site.
2. The human population adversely impacted following exposure to a toxic pollutant in food, water, air, or soil.
• Agent Any physical, chemical, or biological entity that can be harmful to an organism (synonymous with stressors.
• Agent Orange A toxic herbicide and defoliant used in the Vietnam conflict, containing 2,4,5-trichlorophen-oxyacetic acid (2,4,5-T) and 2-4 dichlorophenoxyacetic acid (2,4-D) with trace amounts of dioxin.
 
• Agricultural Pollution Farming wastes, including runoff and leaching of pesticides and fertilizers; erosion and dust from plowing; improper disposal of animal manure and carcasses; crop residues, and debris.
• Agricultural Waste Poultry and livestock manure, and residual materials in liquid or solid form generated from the production and marketing of poultry, livestock or fur-bearing animals; also includes grain, vegetable, and fruit harvest residue.
• Air Curtain A method of containing oil spills. Air bubbling through a perforated pipe causes an upward water flow that slows the spread of oil. It can also be used to stop fish from entering polluted water.
• Air Pollutant Any substance in air that could, in high enough concentration, harm man, other animals, vegetation, or material. Pollutants may include almost any natural or artificial composition of airborne matter capable of being airborne. They may be in the form of solid particles, liquid droplets, gases, or in combination thereof. Generally, they fall into two main groups: (1) those emitted directly from identifiable sources and (2) those produced in the air by interaction between two or more primary pollutants, or by reaction with normal atmospheric constituents, with or without photoactivation. Exclusive of pollen, fog, and dust, which are of natural origin, about 100 contaminants have been identified. Air pollutants are often grouped in categories for ease in classification; some of he categories are: solids, sulfur compounds, volatile organic chemicals, particulate matter, nitrogen compounds, oxygen compounds, halogen compounds, radioactive compound, and odors.
 
• Air Pollution Episode 1.A period of abnormally high concentration of air pollutants, often due to low winds and temperature inversion, that can cause illness and death.
2. A program heard on the Rush Limbaugh show.
• Air Quality
  Standards		 The level of pollutants prescribed by regulations that are not be exceeded during a given time in a defined area.
• Air Toxics Any air pollutant for which a national ambient air quality standard (NAAQS) does not exist (i.e. excluding ozone, carbon monoxide, PM-10, sulfur dioxide, nitrogen oxide) that may reasonably be anticipated to cause cancer; respiratory, cardiovascular, or developmental effects; reproductive dysfunctions, neurological disorders, heritable gene mutations, or other serious or irreversible chronic or acute health effects in humans.
• Alar Trade name for daminozide, a pesticide that makes apples redder, firmer, and less likely to drop off trees before growers are ready to pick them. It is also used to a lesser extent on peanuts, tart cherries, concord grapes, and other fruits.
 
• Algae Simple rootless plants that grow in sunlit waters in proportion to the amount of available nutrients. They can affect water quality adversely by lowering the dissolved oxygen in the water. They are food for fish and small aquatic animals.
• Algal Blooms Sudden spurts of algal growth, which can affect water quality adversely and indicate potentially hazardous changes in local water chemistry.
• Allergen A substance that causes an allergic reaction in individuals sensitive to it.
• Alluvial Relating to and/or sand deposited by flowing water.
• Alternative Fuels AKA Renewable Energy. Substitutes for traditional liquid, oil-derived motor vehicle fuels like gasoline and diesel. Includes mixtures of alcohol-based fuels with gasoline, methanol, ethanol, compressed natural gas, and others. See Alternative Energy.
• Anaerobic A life or process that occurs in, or is not destroyed by, the absence of oxygen.
• Antarctic
  "Ozone Hole"		 Refers to the seasonal depletion of ozone in the upper atmosphere above a large area of Antarctica. (See: Ozone Hole.)
• Anthropogenic
  Climate Change		 Caused by man or resulting from human activities. Used in the context of greenhouse gas emissions produced as a result of human activities.
• Anti-Microbial An agent that kills microbes.
• Aromatics A type of hydrocarbon, such as benzene or toluene, with a specific type of ring structure. Aromatics are sometimes added to gasoline in order to increase octane. Some aromatics are toxic.
• Arsenicals Pesticides containing arsenic.
• Asbestos A mineral fiber that can pollute air or water and cause cancer or asbestosis when inhaled. (causes Asbestosis)
• Attainment Area An area considered to have air quality as good as or better than the national ambient air quality standards as defined in the Clean Air Act. An area may be an attainment area for one pollutant and a non-attainment area for others.
 
Term
Definition
B
• Backyard   Composting Diversion of organic food waste and yard trimmings from the municipal waste stream by composting hem in one's yard through controlled decomposition of organic matter by bacteria and fungi into a humus-like product. It is considered source reduction, not recycling, because the composted materials never enter the municipal waste stream.
• Bacteria (Singular: bacterium) Microscopic living organisms that can aid in pollution control by metabolizing organic matter in sewage, oil spills or other pollutants. However, bacteria in soil, water or air can also cause human, animal and plant health problems.
• Baffle Chamber In incinerator design, a chamber designed to promote the settling of fly ash and coarse particulate matter by changing the direction and/or reducing the velocity of the gases produced by the combustion of the refuse or sludge.
• Basal Application In pesticides, the application of a chemical on plant stems or tree trunks just above the soil line.
• Basalt Consistent year-round energy use of a facility; also refers to the minimum amount of electricity supplied continually to a facility.
 
• BEN EPA's computer model for analyzing a violator's economic gain from not complying with the law.
• Benefit-Cost   Analysis An economic method for assessing the benefits and costs of achieving alternative health-based standards at given levels of health protection.
• 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.
• BACM Best Available Control Measures : A term used to refer to the most effective measures (according to EPA guidance) for controlling small or dispersed particulates and other emissions from sources such as roadway dust, soot and ash from wood stoves and open burning of rush, timber, grasslands, or trash.
• Bimetal Beverage containers with steel bodies and aluminum tops; handled differently from pure aluminum in recycling.
• Biomass We have used biomass energy, or "bioenergy"—the energy from plants and plant-derived materials since people began burning wood to cook food and keep warm. Wood is still the largest biomass energy resource today, but other sources of biomass can also be used. These include food crops, grassy and woody plants, residues from agriculture or forestry, oil-rich algae, and the organic component of municipal and industrial wastes. Even the fumes from landfills (which are methane, a natural gas) can be used as a biomass energy source. Learn more.
• Biodiversity Refers to the variety and variability among living organisms and the ecological complexes in which they occur. Diversity can be defined as the number of different items and their relative frequencies. For biological diversity, these items are organized at many levels, ranging from complete ecosystems to the biochemical structures that are the molecular basis of heredity. Thus, the term encompasses different ecosystems, species, and genes.
 
• Biological   Contaminants Living organisms or derivates (e.g. viruses, bacteria, fungi, and mammal and bird antigens) that can cause harmful health effects when inhaled, swallowed, or otherwise taken into the body.
• Biological
  Magnification 		Refers to the process whereby certain substances such as pesticides or heavy metals move up the food chain, work their way into rivers or lakes, and are eaten by aquatic organisms such as fish, which in turn are eaten by large birds, animals or humans. The substances become concentrated in tissues or internal organs as they move up the chain. (See: bioaccumulants.)
• Biological
  Pesticides		 Certain microorganism, including bacteria, fungi, viruses, and protozoa that are effective in controlling pests. These agents usually do not have toxic effects on animals and people and do not leave toxic or persistent chemical residues in the environment.
• Biological
  Stressors		 Organisms accidentally or intentionally dropped into habitats in which they do not evolve naturally; e.g. gypsy moths, Dutch elm disease, certain types of algae, and bacteria.
• Biomass All of the living material in a given area; often refers to vegetation.
• Biosphere The portion of Earth and its atmosphere that can support life.
• Biota The animal and plant life of a given region.
• Biotech(nology) Techniques that use living organisms or parts of organisms to produce a variety of products (from medicines to industrial enzymes) to improve plants or animals or to develop microorganisms to remove toxics from bodies of water, or act as pesticides.
 
• Blackwater Water that contains animal, human, or food waste.
• Bloom A proliferation of algae and/or higher aquatic plants in a body of water; often related to pollution, especially when pollutants accelerate growth.
• Bog A type of wetland that accumulates appreciable peat deposits. Bogs depend primarily on precipitation for their water source, and are usually acidic and rich in plant residue with a conspicuous mat of living green moss.
• Boom 1. A floating device used to contain oil on a body of water.
2. A piece of equipment used to apply pesticides from a tractor or truck.
• Botanical Pesticide A pesticide whose active ingredient is a plant-produced chemical such as nicotine or strychnine. Also called a plant-derived pesticide.
• Bottle Bill Proposed or enacted legislation which requires a returnable deposit on beer or soda containers and provides for retail store or other redemption. Such legislation is designed to discourage use of throw-away containers.
• Bottom Ash The non-airborne combustion residue from burning pulverized coal in a boiler; the material which falls to the bottom of the boiler and is removed mechanically; a concentration of non-combustible materials, which may include toxics.
 
• Brackish Mixed fresh and salt water.
• Brine Mud Waste material, often associated with well-drilling or mining, composed of mineral salts or other inorganic compounds.
• 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 under used industrial and commercial facilities/sites where expansion or redevelopment is complicated by real or perceived environmental contamination. They can be in urban, suburban, or rural areas. EPA's Brownfields initiative helps communities mitigate potential health risks and restore the economic viability of such areas or properties.
• Building Related
  Illness		 Diagnosable illness whose cause and symptoms can be directly attributed to a specific pollutant source within a building (e.g. Legionnaire's disease, hypersensitivity, pneumonitis.)
• Burial Ground   (Graveyard) A disposal site for radioactive waste materials that uses earth or water as a shield.
 
Term
Definition
C
• Cadmium (Cd) A heavy metal that accumulates in the environment.
• CAFE Standard See Fuel Economy Standard
• Capacity
  Assurance Plan		 A statewide plan which supports a state's ability to manage the hazardous waste generated within its boundaries over a twenty year period.
   
• Capillary Action Movement of water through very small spaces due to molecular forces called capillary forces.
• Carbon Adsorption A treatment system that removes contaminants from ground water or surface water by forcing it through tanks containing activated carbon treated to attract the contaminants.
• Carbon
  Dioxide (CO2)		 Aan atmospheric gas that is a major component of the carbon cycle. Although produced through natural processes, carbon dioxide is also released through human activities, such as the combustion of fossil fuels to produce electricity. Carbon dioxide is the predominate gas contributing to the greenhouse effect, and as such is known to contribute to climate change.
• Carbon
  Monoxide (CO)		 A colorless, odorless, poisonous gas produced by incomplete fossil fuel combustion.
• Carbon
  Sequestration		 The uptake and storage of carbon. Trees and plants, for example, absorb carbon dioxide, release the oxygen and store the carbon. Fossil fuels were at one time biomass and continue to store the carbon until burned. See Sinks. [Source: NASA's Earth Observatory library]
• Carbon
  Tetrachloride 		AKA: CC14. Compound consisting of one carbon atom ad four chlorine atoms, once widely used as a industrial raw material, as a solvent, and in the production of CFCs. Use as a solvent ended when it was discovered to be carcinogenic.
 
• Carcinogen Any substance that can cause or aggravate cancer.
• Cap and Trade A market-based method of reducing dependence of fossil fuels. (More)
 
• Cask A thick-walled container (usually lead) used to transport radioactive material.
• 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.
• Cells 1. In solid waste disposal, holes where waste is dumped, compacted, and covered with layers of dirt on a daily basis.
2. The smallest structural part of living matter capable of functioning as an independent unit.
• CERCLIS The federal Comprehensive Environmental Response, Compensation, and Liability Information System is a database that includes all sites which have been nominated for investigation by the Superfund program.
• CH4 (Methane) The most abundant organic molecule in the Earth’s atmosphere and plays important roles in both the planet’s radiative energy budget and global atmospheric chemistry (Brasseur et al., 1999). It’s presence in the atmosphere was first noted in 1948 from features in the infrared absorption spectrum [Migeotte, 1948] and it is now routinely measured. CH4 is the third most important greenhouse gas after H2O vapor and carbon dioxide (CO2) and has a Global Warming Potential (GWP) 25 times that of CO2 on a 100 –year timescale (Forster et al., 2007).  
• 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.
• Chemical
  Stressors		 Chemicals released to the environment through industrial waste, auto emissions, pesticides, and other human activity that can cause illnesses and even death in plants and animals.
• Chemnet Mutual aid network of chemical shippers and contractors that assigns a contracted emergency response company to provide technical support if a representative of the firm whose chemicals are involved in an incident is not readily available.
• Chemosterilant A chemical that controls pests by preventing reproduction.
• Chemtrec The industry-sponsored Chemical Transportation Emergency Center; provides information and/or emergency assistance to emergency responders.
• Chilling Effect The lowering of the Earth's temperature because of increased particles in the air blocking the sun's rays. (See: greenhouse effect.)
• Chlorinated
  Hydrocarbons		 1. Chemicals containing only chlorine, carbon, and hydrogen. These include a class of persistent, broad-spectrum insecticides that linger in the environment and accumulate in the food chain. Among them are DDT, aldrin, dieldrin, heptachlor, chlordane, lindane, endrin, Mirex, hexachloride, and toxaphene. Other examples include TCE, used as an industrial solvent.
2. Any chlorinated organic compounds including chlorinated solvents such as dichloromethane, trichloromethylene, chloroform.
 
• Chlorination The application of chlorine to drinking water, sewage, or industrial waste to disinfect or to oxidize undesirable compounds.
• Chloro-
  fluorocarbons (CFCs) 		A family of inert, nontoxic, and easily liquefied chemicals used in refrigeration, air conditioning, packaging, insulation, or as solvents and aerosol propellants. Because CFCs are not destroyed in the lower atmosphere they drift into the upper atmosphere where their chlorine components destroy ozone. (See: the Ozone Hole.)
• Cholinesterase An enzyme found in animals that regulates nerve impulses by the inhibition of acetylcholine. Cholinesterase inhibition is associated with a variety of acute symptoms such as nausea, vomiting, blurred vision, stomach cramps, and rapid heart rate.
• Chromium (See: heavy metal toxicity.)
• Chronic Toxicity The capacity of a substance to cause long-term poisonous health effects in humans, animals, fish, and other organisms.
• Cistern Small tank or storage facility used to store water for a home or farm; often used to store rain water.
• Class I Substance One of several groups of chemicals with an ozone depletion potential of 0.2 or higher, including CFCS, Halons, Carbon Tetrachloride, and Methyl Chloroform (listed in the Clean Air Act), and HBFCs and Ethyl Bromide (added by EPA regulations). (See: Global warming potential.)
 
• Clean Coal
  Technology 		Any technology not in widespread use prior to the Clean Air Act Amendments of 1990. This Act os said to achieve significant reductions in pollutants associated with the burning of coal. Most people in the environmental movement believe this term to be a myth.
• Clean Fuels Blends or substitutes for gasoline fuels, including compressed natural gas, methanol, ethanol, and liquefied petroleum gas. Of course, the cleanest fuels are those that emit no CO2 or other pollutants, to which the aforementioned does not apply - specifically, Solar, Wind, Tidal, Geothermal, etc. See our page on Renewable Energy.
• Clear Cut Harvesting all the trees in one area at one time, a practice that can encourage fast rainfall or snow melt runoff, erosion, sedimentation of streams and lakes, and flooding, and destroys vital habitat.
• Climate Change (also referred to as 'global climate change'): The term 'climate change' is sometimes used to refer to all forms of climatic inconsistency, but because the Earth's climate is never static, the term is more properly used to imply a significant change from one climatic condition to another. In some cases, 'climate change' has been used synonymously with the term, 'global warming'; scientists however, tend to use the term in the wider sense to also include natural changes in climate.
 
• Co-fire Burning of two fuels in the same combustion unit; e.g., coal and natural gas, or oil and coal.
• 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. It is divided into fifty volumes, known as titles. Title 40 of the CFR (referenced as 40 CFR) lists all environmental regulations.
• Coefficient of
  Haze (COH) 		A measurement of visibility interference in the atmosphere.
• Cogeneration The consecutive generation of useful thermal and electric energy from the same fuel source.
• Coliform Index A rating of the purity of water based on a count of fecal bacteria.
• Combined Sewers A sewer system that carries both sewage and storm-water runoff. Normally, its entire flow goes to a waste treatment plant, but during a heavy storm, the volume of water may be so great as to cause overflows of untreated mixtures of storm water and sewage into receiving waters. Storm-water runoff may also carry toxic chemicals from industrial areas or streets into the sewer system.
• Commingled
  Recyclables 		Mixed recyclables that are collected together.
 
• Compact
  Fluorescent Lamp 		(CFL) Small fluorescent lamps used as more efficient alternatives to incandescent lighting. Also called PL, CFL, Twin-Tube, or BIAX lamps.
• Compliance Coal Any coal that emits less than 1.2 pounds of sulfur dioxide per million Btu when burned. Also known as low sulfur coal.
• Compost A humus or soil-like material created from aerobic, microbial decomposition of organic materials such as food scraps, yard trimmings, and manure. Note: Composting is the controlled biological decomposition of organic material in the presence of air to form a humus-like material. Controlled methods of composting include mechanical mixing and aerating, ventilating the materials by dropping them through a vertical series of aerated chambers, or placing the compost in piles out in the open air and mixing it or turning it periodically.
• 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. However, vehicles fueled with CNG do emit a significant quantity of nitrogen oxides.
• Conditionally Exempt   Generators (CE) Persons or enterprises which produce less than 220 pounds of hazardous waste per month. Exempt from most regulation, they are required merely to determine whether their waste is hazardous, notify appropriate state or local agencies, and ship it by an authorized transporter to a permitted facility for proper disposal.
• Confined Aquifer An aquifer in which ground water is confined under pressure which is significantly greater than atmospheric pressure.
 
• Consent Decree A legal document, approved by a judge, that formalizes an agreement reached between EPA and potentially responsible parties (PRPs) through which PRPs will conduct all or part of a cleanup action at a Superfund site; cease or correct actions or processes that are polluting the environment; or otherwise comply with EPA initiated regulatory enforcement actions to resolve the contamination at the Superfund site involved. The consent decree describes the actions PRPs will take and may be subject to a public comment period.
• Conservation Preserving and renewing, when possible, human and natural resources. The use, protection, and improvement of natural resources according to principles that will ensure their highest economic or social benefits.
• Construction and
   Demolition Waste 		Waste building materials, dredging materials, tree stumps, and rubble resulting from construction, remodeling, repair, and demolition of homes, commercial buildings and other structures and pavements. May contain lead, asbestos, or other hazardous substances.
• Consumptive
   Water Use		 Water removed from available supplies without return to a water resources system, e.g. water used in manufacturing, agriculture, and food preparation.
• Contaminant Any physical, chemical, biological, or radiological substance or matter that has an adverse effect on air, water, or soil.
• Contingency Plan A document setting out an organized, planned, and coordinated course of action to be followed in case of a fire, explosion, or other accident that releases toxic chemicals, hazardous waste, or radioactive materials that threaten human health or the environment. (See: National Oil and Hazardous Substances Contingency Plan.)
• Conventional Power Power that is produced from non-renewable fuels, such as coal, oil, natural gas, and nuclear. Conventional fuels are finite resources that cannot be replenished once they are extracted and used.
• Core The uranium-containing heart of a nuclear reactor, where energy is released.
• Cost Sharing A publicly financed program through which society, as a beneficiary of environmental protection, shares part of the cost of pollution control with those who must actually install the controls. In Superfund, for example, the government may pay part of the cost of a cleanup action with those responsible for the pollution paying the major share.
 
• Cradle-to-Grave or
  Manifest System		 A procedure in which hazardous materials are identified and followed as they are produced, treated, transported, and disposed of by a series of permanent, linkable, descriptive documents (e.g. manifests). Commonly referred to as the cradle-to-grave system.
• Criteria Pollutants The 1970 amendments to the Clean Air Act required EPA to set National Ambient Air Quality Standards for certain pollutants known to be hazardous to human health. EPA has identified and set standards to protect human health and welfare for six pollutants: 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.
• Cross Contamination The movement of underground contaminants from one level or area to another due to invasive subsurface activities.
• Cryptosporidium A protozoan microbe associated with the disease cryptosporidiosis in man. The disease can be transmitted through ingestion of drinking water, person-to-person contact, or other pathways, and can cause acute diarrhea, abdominal pain, vomiting, fever, and can be fatal as it was in the Milwaukee episode.
• Cultural
  Eutrophication 		Increasing rate at which water bodies "die" by pollution from human activities.
• Cutie-Pie: An instrument used to measure radiation levels. Doesn't sound so cute to us?
 
Term
Definition
D
• Desalination The removal of salt from sea water to make it drinkable. Water can never be created or destroyed, it simply moves between physical states, i.e. ice, clouds, liquids.
• DDT he first chlorinated hydrocarbon insecticide chemical name: Dichloro-Diphenyl-Trichloroethane. 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 the United States in 1972 because of its persistence in the environment and accumulation in the food chain.
• Deep-Well
  Injection		 Deposition of raw or treated, filtered hazardous waste by pumping it into deep wells, where it is contained in the pores of permeable subsurface rock.
• Defluoridation The removal of excess fluoride in drinking water to prevent the staining of teeth.
• Defoliant An herbicide that removes leaves from trees and growing plants.
• Dermal Toxicity The ability of a pesticide or toxic chemical to poison people or animals by contact with the skin. (See: contact pesticide.)
• Desiccant A chemical agent that absorbs moisture; some desiccants are capable of drying out plants or insects, causing death.
 
• Desulfurization Removal of sulfur from fossil fuels to reduce pollution.
• Dicofol A pesticide used on citrus fruits.
• Dike A low wall that can act as a barrier to prevent a spill from spreading.
• Dioxin Any of a family of compounds known chemically as dibenzo-p-dioxins. Concern about them arises from their potential toxicity as contaminants in commercial products. Tests on laboratory animals indicate that it is one of the more toxic anthropogenic (man-made) compounds.
• Dispersant A chemical agent used to break up concentrations of organic material such as spilled oil./td>
• 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. Secondary and advanced waste treatment are generally designed to ensure adequate DO in waste-receiving waters.
• Drainage Well A well drilled to carry excess water off agricultural fields. Because they act as a funnel from the surface to the groundwater below. Drainage wells can contribute to groundwater pollution.
 
Term
Definition
E
• Ecological Entity In ecological risk assessment, a general term referring to a species, a group of species, an ecosystem function or characteristic, or a specific habitat or biome.
• Ecological/Environ-
  mental Sustainability		 Maintenance of ecosystem components and functions for future generations.
• Ecological Impact The effect that a man-caused or natural activity has on living organisms and their non-living (abiotic) environment.
• Ecology The relationship of living things to one another and their environment, or the study of such relationships.
• Ecosphere

The "bio-bubble" that contains life on earth, in surface waters, and in the air. (See: biosphere.)
• Ecosystem The interacting system of a biological community and its non-living environmental surroundings.
• Effluent Wastewater--treated or untreated--that flows out of a treatment plant, sewer, or industrial outfall. Generally refers to wastes discharged into surface waters. See Effluent Limitation.
 
• Electric Cars
  2012-13		 See the best electrics for 2012 and 2013. More information.
• 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.
• Emissions Trading The creation of surplus emission reductions at certain stacks, vents or similar emissions sources and the use of this surplus to meet or redefine pollution requirements applicable to other emissions sources. This allows one source to increase emissions when another source reduces them, maintaining an overall constant emission level. Facilities that reduce emissions substantially may "bank" their "credits" or sell them to other facilities or industries.
• Endangered
  Species		 Animals, birds, fish, plants, or other living organisms threatened with extinction by anthropogenic (man-caused) or other natural changes in their environment. Requirements for declaring a species endangered are contained in the Endangered Species Act.
• Endrin A pesticide toxic to freshwater and marine aquatic life that produces adverse health effects in domestic water supplies.
• Energy Efficiency Refers to products or systems using less energy to do the same or better job than conventional products or systems. Energy efficiency saves energy, saves money on utility bills, and helps protect the environment by reducing the demand for electricity. When buying or replacing products or appliances for your home, look for the ENERGY STAR® label -- the national symbol for energy efficiency. For more information on ENERGY STAR-labeled products, visit the ENERGY STAR Web site.
• Energy Recovery Obtaining energy from waste through a variety of processes (e.g. combustion).
• Environment The sum of all external conditions affecting the life, development and survival of an organism.
 
• Environmental
  Equity/Justice		 Equal protection from environmental hazards for individuals, groups, or communities regardless of race, ethnicity, or economic status. This applies to the development, implementation, and enforcement of environmental laws, regulations, and policies, and implies that no population of people should be forced to shoulder a disproportionate share of negative environmental impacts of pollution or environmental hazard due to a lack of political or economic strength levels.
• EPA The Federal Environmental Protection Agency. Let's keep it funded so that it can do its job, namely to protect us from environmental hazards. Experience shows that industry cannot be its own watchdog.
• Estuary

Region of interaction between rivers and near-shore ocean waters, where tidal action and river flow mix fresh and salt water. Such areas include bays, mouths of rivers, salt marshes, and lagoons. These brackish water ecosystems shelter and feed marine life, birds, and wildlife. (See: wetlands.)
• Eutrophication The slow aging process during which a lake, estuary, or bay evolves into a bog or marsh and eventually disappears. During the later stages of eutrophication the water body is choked by abundant plant life due to higher levels of nutritive compounds such as nitrogen and phosphorus. Human activities can accelerate the process.
• Excess
  Lifetime Risk		 The additional or extra risk of developing cancer due to exposure to a toxic substance incurred over the lifetime of an individual.
• Executive
  Order 13423
 
Strengthening Federal Environmental, Energy and Transportation Management -- Executive Order 13423 calls for Federal agencies sets goals in the areas of energy efficiency, acquisition, renewable energy, toxics reductions, recycling, sustainable buildings, electronics stewardship, fleets, and water conservation.
• Exotic Species A species that is not indigenous to a region. (see Native Species.)
• Extraction Proce-
  dure (EP Toxic)		 Determining toxicity by a procedure which simulates leaching; if a certain concentration of a toxic substance can be leached from a waste, that waste is considered hazardous, i.e."EP Toxic."
• Extremely Hazard-
  ous Substances		 Any of 406 chemicals identified by EPA as toxic, and listed under SARA Title III. The list is subject to periodic revision.
 
Term
Definition
F
• FIFRA Pesticide
  Ingredient		 An ingredient of a pesticide that must be registered with EPA under the Federal Insecticide, Fungicide, and Rodenticide Act. Products making pesticide claims must register under FIFRA and may be subject to labeling and use requirements.
• Flash Point The lowest temperature at which evaporation of a substance produces sufficient vapor to form an ignitable mixture with air.
• 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.
• Flue Gas The air coming out of a chimney after combustion in the burner it is venting. It can include nitrogen oxides, carbon oxides, water vapor, sulfur oxides, particles and many chemical pollutants. (See Desulfurization.)
• Fluorocarbons
  (FCs)		 Any of a number of organic compounds analogous to hydrocarbons in which one or more hydrogen atoms are replaced by fluorine. Once used in the United States as a propellant for domestic aerosols, they are now found mainly in coolants and some industrial processes. FCs containing chlorine are called chlorofluorocarbons (CFCs). They are believed to be modifying the ozone layer in the stratosphere, thereby allowing more harmful solar radiation to reach the Earth's surface.
• Fly Ash Non-combustible residual particles expelled by flue gas. Dangers
 
• Food Chain A sequence of organisms, each of which uses the next, lower member of the sequence as a food source.
• Formaldehyde A colorless, pungent, and irritating gas, CH20, used chiefly as a disinfectant and preservative and in synthesizing other compounds like resins. Obviously: Should not be used in travel trailers.
• Forward
  Osmosis (FO)		 FO is a remarkable new technology that turns muddy, contaminated water, into a clean and refreshing drink. See also Reverse Osmosis
• Fossil Fuels The nation's principal source of electricity. Fossil fuels come in three major forms: coal, oil, and natural gas. Because fossil fuels are a finite resource and cannot be replenished once they are extracted and burned, they are not considered renewable.
• Friable Asbestos Any material containing more than one-percent asbestos, and that can be crumbled or reduced to powder by hand pressure. (May include previously non-friable material which becomes broken or damaged by mechanical force.) Dangers
• Fuel Cells Similar to batteries, fuel cells store energy that can be used to power all sorts of things. Unlike a battery though, fuel cells do not "run out" and do not need to be recharged or replaced.
• Fuel Economy
  Standard		 The Corporate Average Fuel Economy Standard (CAFE) effective in 1978. It enhanced the national fuel conservation effort imposing a miles-per-gallon floor for motor vehicles. New standard announced.
• Fukishima
  Nuclear Disaster		 Some scientists say Fukushima is worse than the 1986 Chernobyl accident, with which it shares a maximum level-7 rating on the sliding scale of nuclear disasters. Read more.
 
Term
Definition
G
• Gasohol Mixture of gasoline and ethanol derived from fermented agricultural products containing at least nine percent ethanol. Gasohol emissions contain less carbon monoxide than those from gasoline.
• Gasification Conversion of solid material such as coal into a gas for use as a fuel.
• Genetic
  Engineering		 A process of inserting new genetic information into existing cells in order to modify a specific organism for the purpose of changing one of its characteristics.
• Genotoxic Damaging to DNA; pertaining to agents known to damage DNA. More on this.
• Geothermal Many technologies have been developed to take advantage of geothermal energy—the heat from the earth. This heat can be drawn from several sources: hot water or steam reservoirs deep in the earth that are accessed by drilling; geothermal reservoirs located near the earth's surface, mostly located in the western U.S., Alaska, and Hawaii; and the shallow ground near the Earth's surface that maintains a relatively constant temperature of 50°-60°F. Learn More.
• Global Warming An increase in the near surface temperature of the Earth. Global warming has occurred in the distant past as the result of natural influences, but the term is most often used to refer to the warming predicted to occur as a result of increased emissions of greenhouse gases. Scientists generally agree that the Earth's surface has warmed by about 1 degree Fahrenheit in the past 140 years. The Intergovernmental Panel on Climate Change (IPCC) recently concluded that increased concentrations of greenhouse gases are causing an increase in the Earth's surface temperature and that increased concentrations of sulfate aerosols have led to relative cooling in some regions, generally over and downwind of heavily industrialized areas. (See: climate change)
 
• Gray Water Domestic wastewater composed of wash water from kitchen, bathroom, and laundry sinks, tubs, and washers.
• Greenhouse Effect he warming of the Earth's atmosphere attributed to a buildup of carbon dioxide or other gases; some scientists think that this build-up allows the sun's rays to heat the Earth, while making the infra-red radiation atmosphere opaque to infra-red radiation, thereby preventing a counterbalancing loss of heat.
• Green Energy
  Certificates (RECs)		 A REC (pronounced: r?k) represents the property rights to the environmental, social, and other nonpower qualities of renewable electricity generation. A REC, and its associated attributes and benefits, can be sold separately from the underlying physical electricity associated with a renewable-based generation source. RECs provide buyers flexibility: In procuring green power across a diverse geographical area. In applying the renewable attributes to the electricity use at a facility of choice. This flexibility allows organizations to support renewable energy development and protect the environment when green power products are not locally available.
• Greenhouse Gas A gas, such as carbon dioxide or methane, which contributes to potential climate change.
• Green Power
  Purchasing		 Green power can be purchased nationwide from several sources. Green power marketers offer green power products to consumers in deregulated markets, such as New Jersey, Pennsylvania, and New England. In states that do not allow retail competition in the electricity markets, many utilities offer green power products through green pricing programs. In addition, all customers nationwide have the opportunity to buy green power and stimulate the development of renewable generation sources through renewable energy certificates. Finally, customers can choose to install on-site generation, such as solar photovoltaics.
• Ground Water The supply of fresh water found beneath the Earth's surface, usually in aquifers, which supply wells and springs. Because ground water is a major source of drinking water, there is growing concern over contamination from leaching agricultural or industrial pollutants or leaking underground storage tanks.
• Ground-Water
  Discharge		 Ground water entering near coastal waters which has been contaminated by landfill leachate, deep well injection of hazardous wastes, septic tanks, etc.
 
Term
Definition
H
• Habitat The place where a population (e.g. human, animal, plant, microorganism) lives and its surroundings, both living and non-living.
• Half-Life 1. The time required for a pollutant to lose one-half of its original coconcentrationor example, the biochemical half-life of DDT in the environment is 15 years.
2. The time required for half of the atoms of a radioactive element to undergo self-transmutation or decay (half-life of radium is 1620 years).
3. The time required for the elimination of half a total dose from the body.
• Hard Water Alkaline water containing dissolved salts that interfere with some industrial processes and prevent soap from sudsing.
• Hazard 1. Potential for radiation, a chemical or other pollutant to cause human illness or injury.
2. In the pesticide program, the inherent toxicity of a compound. Hazard identification of a given substances is an informed judgment based on verifiable toxicity data from animal models or human studies.
• Hazardous
  Air Pollutants		 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 Waste By-products of society that can pose a substantial or potential hazard to human health or the environment when improperly managed. Possesses at least one of four characteristics (ignitability, corrosivity, reactivity, or toxicity), or appears on special EPA lists.
 
• Heavy Metals Metallic elements with high atomic weights; (e.g. mercury, chromium, cadmium, arsenic, and lead); can damage living things at low concentrations and tend to accumulate in the food chain. See Heavy Metal Toxicity.
• High-Level Radio-
  active Waste (HLRW)

Waste generated in core fuel of a nuclear reactor, found at nuclear reactors or by nuclear fuel reprocessing; is a serious threat to anyone who comes near the waste without shielding. See: low-level radioactive waste.
• Host 1. In genetics, the organism, typically a bacterium, into which a gene from another organism is transplanted.
2. In medicine, an animal infected or parasitized by another organism.
• Household Hazard-
  ous Waste		 Hazardous products used and disposed of by residential as opposed to industrial consumers. Includes 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.
• Hydroelectric
  (Small Scale)		 In addition to very large hydroelectric plants in the West, the United States also has many smaller hydroelectric facilities. Like large plants, small-scale hydroelectric systems capture the energy in naturally flowing water and convert it to electricity. Although the potential for small hydroelectric systems depends on the availability of suitable water flow, these systems can provide cheap, clean, reliable electricity where the resource exists.
• Hydroelectric
   (Large Scale)		 The process of generating electricity by harnessing the power of moving water. Hydroelectric power (hydropower) is generated by forcing water that is flowing downstream, often from behind a dam, through a hydraulic turbine that is connected to a generator. The water exits the turbine and is returned to the stream or riverbed. Much of the hydroelectricity in the United States is generated at large facilities and in the Pacific Northwest, where it meets about two-thirds of the electricity demand. In the United States, hydroelectricity contributes about 10% of the total electricity supply.
• Hydrocarbons (HC) Chemical compounds that consist entirely of carbon and hydrogen.
• Hydrologic Cycle Movement or exchange of water between the atmosphere and earth. More on this.
• Hypoxia/
  Hypoxic Waters		 Waters with dissolved oxygen concentrations of less than 2 ppm, the level generally accepted as the minimum required for most marine life to survive and reproduce.
 
Term
Definition
I
• In Situ In its original place; unmoved unexcavated; remaining at the site or in the subsurface.
• Incineration A treatment technology involving destruction of waste by controlled burning at high temperatures; e.g., burning sludge to remove the water and reduce the remaining residues to a safe, non-burnable ash that can be disposed of safely on land, in some waters, or in underground locations.
• Indirect Discharge Introduction of pollutants from a non-domestic source into a publicly owned waste-treatment system. Indirect dischargers can be commercial or industrial facilities whose wastes enter local sewers.
• Industrial Sludge Semi-liquid residue or slurry remaining from treatment of industrial water and wastewater.
• Industrial Waste Unwanted materials from an industrial operation; may be liquid, sludge, solid, or hazardous waste.
• Infectious Waste Hazardous waste capable of causing infections in humans, including: contaminated animal waste; human blood and blood products; isolation waste, pathological waste; and discarded sharps (needles, scalpels or broken medical instruments).
• Injection Well A well into which fluids are injected for purposes such as waste disposal, improving the recovery of crude oil, or solution mining.
• Inversion A layer of warm air that prevents the rise of cooling air and traps pollutants beneath it; can cause an air pollution episode.
• IRIS EPA's Integrated Risk Information System, an electronic data base containing the Agency's latest descriptive and quantitative regulatory information on chemical constituents.
• Irradiated Food Food subject to brief radioactivity, usually gamma rays, to kill insects, bacteria, and mold, and to permit storage without refrigeration.
 
Term
Definition
J
  Jar Test A laboratory procedure that simulates a water treatment plant's coagulation/flocculation units with differing chemical doses, mix speeds, and settling times to estimate the minimum or ideal coagulant dose required to achieve certain water quality goals.
• Joint & Several
  Liability		 Under CERCLA, this legal concept relates to the liability for Superfund site cleanup and other costs on the part of more than one potentially responsible party (i.e. if there were several owners or users of a site that became contaminated over the years, they could all be considered potentially liable for cleaning up the site.)
 
Term
Definition
K
• Karst A geologic formation of irregular limestone deposits with sinks, underground streams, and caverns.
• Keystone XL
  Pipeline		 The Tar Sands delivery system. From extraction to processing to shipping to combustion, tar sands are far and away the dirtiest form of all fuels. It demands enormous amounts of energy to simply extract and then process into crude that can move through a pipeline. It has a 20-percent larger carbon footprint (PDF) than plain old dirty oil. And it leaves toxic wastelands wherever the sands are removed. Click for a Map
• Kilowatt-hour (kWh) A is a standard metric unit of measurement for electricity. (1) One kilowatt-hour (kW) is equal to 1,000 watt-hours (Wh). (2) A watt-hour is the amount of energy delivered at a rate of one watt (W) for a period of one hour. (3) One watt is the amount of power rate of one joule of work per second of time. (4) Example: A 100 watt light bulb in use for 10 hours uses 1000 watt-hours, or 1 kilowatt of electricity. (100 watts x 10 hours = 1000 watt-hours = 1 kWh)
• Kinetic Energy Energy possessed by a moving object or water body.
• Kinetic Rate
  Coefficient		 A number that describes the rate at which a water constituent such as a biochemical oxygen demand or dissolved oxygen rises or falls, or at which an air pollutant reacts.
 
Term
Definition
L
• Lagoon 1. A shallow pond where sunlight, bacterial action, and oxygen work to purify wastewater; also used for storage of wastewater or spent nuclear fuel rods.
2. Shallow body of water, often separated from the sea by coral reefs or sandbars.
• Land Ban Phasing out of land disposal of most untreated hazardous wastes, as mandated by the 1984 RCRA amendments.
• Land Farming
  (of Waste)		 A disposal process in which hazardous waste deposited on or in the soil is degraded naturally by microbes.
• Landfills 1. Sanitary landfills are disposal sites for non-hazardous solid wastes spread in layers, compacted to the smallest practical volume, and covered by material applied at the end of each operating day.
2. Secure chemical landfills are disposal sites for hazardous waste, selected and designed to minimize the chance of release of hazardous substances into the environment.
• Landscape   Ecology The study of the distribution patterns of communities and ecosystems, the ecological processes that affect those patterns, and changes in pattern and process over time.
• Langelier
  Index (LI)		 An index reflecting the equilibrium pH of a water with respect to calcium and alkalinity; used in stabilizing water to control both corrosion and scale deposition.
 
• Latency Time from the first exposure of a chemical until the appearance of a toxic effect.
• LD 50/
  Lethal Dose:		 The dose of a toxicant or microbe that will kill 50 percent of the test organisms within a designated period. The lower the LD 50, the more toxic the compound. (More)
• Leachate Water that collects contaminants as it trickles through wastes, pesticides or fertilizers. Leaching may occur in farming areas, feedlots, and landfills, and may result in hazardous substances entering surface water, ground water, or soil.
• Lead (Pb) 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.
• LEED Certification LEED, or Leadership in Energy and Environmental Design, is an internationally-recognized green building certification system. Developed by the U.S. Green Building Council (USGBC) in March 2000, LEED provides building owners and operators with a framework for identifying and implementing practical and measurable green building design, construction, operations and maintenance solutions.More
• Lethal Concentra-
  tion (LC50) or
  Lethal Dose (LD50)		 LC50: A concentration of a pollutant or effluent at which 50 percent of the test organisms die; a common measure of acute toxicity.
LD50: The dose of a toxicant that will kill 50 percent of test organisms within a designated period of time; the lower the LD 50, the more toxic the compound.
• Life Cycle (Product) All stages of a product's development, from extraction of fuel for power to production, marketing, use, and disposal.
• Light-Emitting
  Diode (LED)

A long-lasting illumination technology used for exit signs which requires very little power.
 
• Limnology The study of the physical, chemical, hydrological, and biological aspects of fresh water bodies.
• Lindane A pesticide that causes adverse health effects in domestic water supplies and is toxic to freshwater fish and aquatic life. Effects
• Listed Waste Wastes listed as hazardous under RCRA but which have not been subjected to the Toxic Characteristics Listing Process because the dangers they present are considered self-evident.
• Low Emissivity
  (low-E) Windows		 New window technology that lowers the amount of energy loss through windows by inhibiting the transmission of radiant heat while still allowing sufficient light to pass through.
• Low-Level Radio-
  active Waste (LLRW)		 Wastes less hazardous than most of those associated with a nuclear reactor; generated by hospitals, research laboratories, and certain industries. The Department of Energy, Nuclear Regulatory Commission, and EPA share responsibilities for managing them. (See: high-level radioactive waste.)
   
 
Term
Definition
M
• Mandatory
  Recycling		 Programs which by law require consumers to separate trash so that some or all recyclable materials are recovered for recycling rather than going to landfills.
• Margin of Safety Maximum amount of exposure producing no measurable effect in animals (or studied humans) divided by the actual amount of human exposure in a population.
• Marsh A type of wetland that does not accumulate appreciable peat deposits and is dominated by herbaceous vegetation. Marshes may be either fresh or saltwater, tidal or non-tidal. (See: wetlands mapper.)
• Material Safety
  Data Sheet (MSDS)		 A compilation of information required under the OSHA Communication Standard on the identity of hazardous chemicals, health, and physical hazards, exposure limits, and precautions. Section 311 of SARA requires facilities to submit MSDSs under certain circumstances.
• Materials Recovery
  Facility (MRF)		 A facility that processes residentially collected mixed recyclables into new products available for market.
• Megawatt-hour
  (MWh)		 Equal to 1,000 kWh.
• Mercury (Hg) A heavy metal that can bioaccumulate in the environment and is highly toxic if breathed or swallowed.
• Methane (CH4) See CH4
• Microorganisms Tiny living organisms that can be seen only with the aid of a microscope. Some microorganisms can cause acute health problems when consumed in drinking water.
           
Term
Definition
N
• Net Metering A method of crediting customers for electricity that the customer generates on site in excess of their own electricity consumption. Customers with their own generation offset the electricity they would have purchased from their utility. If such customers generate more than they use in a billing period, their electric meter turns backwards to indicate their net excess generation. Depending on individual state or utility rules, the net excess generation may be credited to their account (in many cases at the retail price), carried over to a future billing period, or ignored. See state by state net metering rules.
• Nitric Acid (HNo3) An acid that can be produced from nitrogen oxide, a pollutant that results from the burning of fossil fuels.
• Nitrogen Oxides Gases consisting of one molecule of nitrogen and varying numbers of oxygen molecules. Nitrogen oxides are produced in the emissions of vehicle exhausts and from power stations. In the atmosphere, nitrogen oxides can contribute to formation of photochemical ozone (smog), can impair visibility, and have health consequences; they are thus considered pollutants.
 
Term
Definition
O
• Ocean Thermal
  Energy Conversion		 Ocean Thermal Energy Conversion (OTEC) uses the heat energy stored in the Earth's oceans to generate electricity.

It works best when the temperature difference between the warmer, top layer of the ocean and the colder, deep ocean water is about 20°C (36°F). These conditions exist in tropical coastal areas, roughly between the Tropic of Capricorn and the Tropic of Cancer. To bring the cold water to the surface, OTEC plants require an expensive, large diameter intake pipe, which is submerged a mile or more into the ocean's depths.

Some energy experts believe that if it could become cost-competitive with conventional power technologies, OTEC could produce billions of watts of electrical power. Learn More.
• Oil Sands See Tar Sands
• On-site
  Renewable
  Generation		 Electricity generated by renewable resources using a system or device located at the site where the power is used. On-site generation is a form of distributed energy generation. For more information about distributed energy technologies that are renewable and non-renewable, visit the Department of Energy's Distributed Energy Resources Web site.
• Ozone (o2) A chemical that is made of three oxygen atoms joined together, and found in the Earth's atmosphere. There are two kinds of ozone: good ozone, and bad ozone. Good ozone is found high in the Earth's atmosphere, and prevents the sun's harmful rays from reaching the Earth. Bad ozone is found low to the ground, and can be harmful to animals and humans because it damages our lungs, sometimes making it difficult to breathe. See Ozone Layer.
 
Term
Definition
P
• Pathogen A disease-causing organism.
• pH A scale that denotes how acidic or basic a substance is. Pure water has a pH of 7.0 and is neither acidic nor basic. For more information, see the pH page.
Photosynthesis The process that plants use to convert sunlight to energy to live and grow. Basically, plants "inhale" Co2, and "exhale" oxygen.
Photovotaic The word “photovoltaic” combines two terms – “photo” means light and “voltaic” means voltage. A photovoltaic system in this discussion uses photovoltaic cells to directly convert sunlight into electricity. More.
 
Term
Definition
Q-R
• Radionuclides Any man-made or natural element that emits radiation and that may cause cancer after many years of exposure through drinking water.
• REC (Renewable
  Energy Certificate		 See Green Energy Certificate
• Renewable Energy
  Sources		 The energy from natural sources It is so named because, unlike fossil fuels, can never really run out. The world is shifting to renewable energy sources because of the scarcity of and rising prices of oil, natural gas and coal. Unlike the aforementioned, renewable energy is clean.

More info on: Biomass, Geothermal, Hydro, Solar, Tidal, Wind
• Renewable
  Portfolio Standard		 The requirement that an electric power provider generate or purchase a specified percentage of the power it supplies/sells from renewable energy resources, and thereby guarantee a market for electricity generated from renewable energy resources.
• Risk Assessment The evaluation of scientific information on the hazardous properties of environmental agents (hazard characterization), the dose-response relationship (dose-response assessment), and the extent of human exposure to those agents (exposure assessment). The product of the risk assessment is a statement regarding the probability that populations or individuals so exposed will be harmed and to what degree (risk characterization).
   
 
Term
Definition
S
• Solar Energy The rays of the sun can produce energy in a variety of ways. Solar energy can be Passive, Photovoltaic or Solar Hot-water.
• Sulfate Aerosols Particulate matter that consists of compounds of sulfur formed by the interaction of sulfur dioxide and sulfur trioxide with other compounds in the atmosphere. Sulfate aerosols are injected into the atmosphere from the combustion of fossil fuels and the eruption of volcanoes like Mt. Pinatubo. Recent theory suggests that sulfate aerosols may lower the Earth's temperature by reflecting away solar radiation (negative radiative forcing). General Circulation Models which incorporate the effects of sulfate aerosols more accurately predict global temperature variations.
• Sulfur Dioxide
  (SO2)		 High concentrations of SO2 affect breathing and may aggravate existing respiratory and cardiovascular disease. Sensitive populations include asthmatics, individuals with bronchitis or emphysema, children, and the elderly. Sulfur dioxide is also a primary contributor to acid rain, which causes acidification of lakes and streams and can damage trees, crops, historic buildings, and statues. In addition, sulfur compounds in the air contribute to visibility impairment in large parts of the country. This is especially noticeable in national parks. Sulfur dioxide is released primarily from burning fuels that contain sulfur (such as coal, oil, and diesel fuel). Stationary sources such as coal- and oil-fired power plants, steel mills, refineries, pulp and paper mills, and nonferrous smelters are the largest releasers.
• Superfund The program operated under the legislative authority of the Comprehensive Environmental Response, Compensation and Liability Act of 1980 (CERCLA) 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.
 
Term
Definition
T
• Tar Sands Northern Alberta’s oil sands are increasingly becoming a source of political conflict, both domestically and globally, as scrutiny of the world’s second-largest known oil reserve intensifies. While recent production in the oil sands has driven rapid economic growth in Alberta, there is increasing concern that this growth is causing unprecedented ecological harm. Major environmental non-government organizations (ENGOs), such as Greenpeace and the Pembina Institute, and local First Nations have begun to call for a moratorium on new oil sands projects until associated environmental destruction can be mitigated. Read More
• Tidal Energy Some of the oldest ocean energy technologies use tidal power. All coastal areas consistently experience two high and two low tides over a period of slightly greater than 24 hours. For those tidal differences to be harnessed into electricity, the difference between high and low tides must be at least five meters, or more than 16 feet. There are only about 40 sites on the Earth with tidal ranges of this magnitude.

Currently, there are no tidal power plants in the United States. However, conditions are good for tidal power generation in both the Pacific Northwest and the Atlantic Northeast regions of the country. Learn More.
• Trichloroethylene A stable, low boiling-point colorless liquid, toxic if inhaled. Used as a solvent or metal decreasing agent, and in other industrial applications.
 
Term
Definition
U-V
• Ultraviolet
  Radiation (UV)		 The energy range just beyond the violet end of the visible spectrum. Although ultraviolet radiation constitutes only about 5 percent of the total energy emitted from the sun, it is the major energy source for the stratosphere and mesosphere, playing a dominant role in both energy balance and chemical composition.
• UNFCCC United Nations Framework Convention on Climate Change. The Convention on Climate Change sets an overall framework for intergovernmental efforts to tackle the challenge posed by climate change. It recognizes that the climate system is a shared resource whose stability can be affected by industrial and other emissions of carbon dioxide and other greenhouse gases. The Convention enjoys near universal membership, with 189 countries having ratified. Under the Convention, governments:
 
Term
Definition
W-Z
• Watershed The land area from which water drains into a stream, river, or reservoir.