A watery mixture of insoluble matter resulting from some pollution control techniques. Small Quantity Generator (SQG-sometimes referred to as "Squeegee"): Persons or enterprises that produce 220-2200 pounds per month of hazardous waste; they are required to keep more records than conditionally exempt generators. The largest category of hazardous waste generators, SQGs, include automotive shops, dry cleaners, photographic developers, and many other small businesses. (See: conditionally exempt generators.) 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. Smog: Air pollution typically associated with oxidants. (See: photochemical smog.) Smoke: Particles suspended in air after incomplete combustion. Soft Detergents: Cleaning agents that break down in nature. Soft Water: Any water that does not contain a significant amount of dissolved minerals such as salts of calcium or magnesium. Soil Adsorption Field: A sub-surface area containing a trench or bed with clean stones and a system of piping through which treated sewage may seep into the surrounding soil for further treatment and disposal. Soil and Water Conservation Practices: Control measures consisting of managerial, vegetative, and structural practices to reduce the loss of soil and water. Soil Conditioner: An organic material like humus or compost that helps soil absorb water, build a bacterial community, and take up mineral nutrients. Soil Erodibility: An indicator of a soil's susceptibility to raindrop impact, runoff, and other erosive processes. Soil Gas: Gaseous elements and compounds in the small spaces between particles of the earth and soil. Such gases can be moved or driven out under pressure. Soil Moisture: The water contained in the pore space of the unsaturated zone. Soil Sterilant: A chemical that temporarily or permanently prevents the growth of all plants and animals, Solder: Metallic compound used to seal joints between pipes. Until recently, most solder contained 50 percent lead. Use of solder containing more than 0.2 percent lead in pipes carrying drinking water is now prohibited. Sole-Source Aquifer: An aquifer that supplies 50-percent or more of the drinking water of an area. 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. Technically, solid waste also refers to liquids and gases in containers. Solid Waste Disposal: The final placement of refuse that is not salvaged or recycled. Solid Waste Management: Supervised handling of waste materials from their source through recovery processes to disposal. Solidification and Stabilization: Removal of wastewater from a waste or changing it chemically to make it less permeable and susceptible to transport by water. Solubility: The amount of mass of a compound that will dissolve in a unit volume of solution. Aqueous Solubility is the maximum concentration of a chemical that will dissolve in pure water at a reference temperature. Soot: Carbon dust formed by incomplete combustion. Sorption: The action of soaking up or attracting substances; process used in many pollution control systems. Source Area: The location of liquid hydrocarbons or the zone of highest soil or groundwater concentrations, or both, of the chemical of concern. Source Characterization Measurements: Measurements made to estimate the rate of release of pollutants into the environment from a source such as an incinerator, landfill, etc. Source Reduction: Reducing the amount of materials entering the waste stream from a specific source by redesigning products or patterns of production or consumption (e.g., using returnable beverage containers). Synonymous with waste reduction. Source Separation: Segregating various wastes at the point of generation (e.g., separation of paper, metal and glass from other wastes to make recycling simpler and more efficient). Source-Water Protection Area: The area delineated by a state for a Public Water Supply or including numerous such suppliers, whether the source is ground water or surface water or both. Sparge or Sparging: Injection of air below the water table to strip dissolved volatile organic compounds and/or oxygenate ground water to facilitate aerobic biodegradation of organic compounds. Special Local-Needs Registration: Registration of a pesticide product by a state agency for a specific use that is not federally registered. However, the active ingredient must be federally registered for other uses. The special use is specific to that state and is often minor, thus may not warrant the additional cost of a full federal registration process. SLN registration cannot be issued for new active ingredients, food-use active ingredients without tolerances, or for a canceled registration. The products cannot be shipped across state lines. Special Review: Formerly known as Rebuttable Presumption Against Registration (RPAR), this is the regulatory process through which existing pesticides suspected of posing unreasonable risks to human health, non-target organisms, or the environment are referred for review by EPA. Such review requires an intensive risk/benefit analysis with opportunity for public comment. If risk is found to outweigh social and economic benefits, regulatory actions can be initiated, ranging from label revisions and use-restriction to cancellation or suspended registration. Special Waste: Items such as household hazardous waste, bulky wastes (refrigerators, pieces of furniture, etc.) tires, and used oil. Species: 1. A reproductively isolated aggregate of interbreeding organisms having common attributes and usually designated by a common name.2. An organism belonging to belonging to such a category. Specific Conductance: Rapid method of estimating the dissolved solid content of a water supply by testing its capacity to carry an electrical current. Specific Yield: The amount of water a unit volume of saturated permeable rock will yield when drained by gravity. Spill Prevention, Containment, and Countermeasures Plan (SPCP): Plan covering the release of hazardous substances as defined in the Clean Water Act. Spoil: Dirt or rock removed from its original location--destroying the composition of the soil in the process--as in strip-mining, dredging, or construction. Sprawl: Unplanned development of open land. Spray Tower Scrubber: A device that sprays alkaline water into a chamber where acid gases are present to aid in neutralizing the gas. Spring: Ground water seeping out of the earth where the water table intersects the ground surface. Spring Melt/Thaw: The process whereby warm temperatures melt winter snow and ice. Because various forms of acid deposition may have been stored in the frozen water, the melt can result in abnormally large amounts of acidity entering streams and rivers, sometimes causing fish kills. Stabilization: Conversion of the active organic matter in sludge into inert, harmless material. Stabilization Ponds: (See: lagoon.) Stable Air: A motionless mass of air that holds, instead of dispersing, pollutants. Stack: A chimney, smokestack, or vertical pipe that discharges used air. Stack Effect: Air, as in a chimney, that moves upward because it is warmer than the ambient atmosphere. Stack Effect: Flow of air resulting from warm air rising, creating a positive pressure area at the top of a building and negative pressure area at the bottom. This effect can overpower the mechanical system and disrupt building ventilation and air circulation. Stack Gas: (See: flue gas.) Stage II Controls: Systems placed on service station gasoline pumps to control and capture gasoline vapors during refuelling. Stagnation: Lack of motion in a mass of air or water that holds pollutants in place. 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. Standard Sample: The part of finished drinking water that is examined for the presence of coliform bacteria. Standards: Norms that impose limits on the amount of pollutants or emissions produced. EPA establishes minimum standards, but states are allowed to be stricter. Start of a Response Action: The point in time when there is a guarantee or set-aside of funding by EPA, other federal agencies, states or Principal Responsible Parties in order to begin response actions at a Superfund site. State Emergency Response Commission (SERC): Commission appointed by each state governor according to the requirements of SARA Title III. The SERCs designate emergency planning districts, appoint local emergency planning committees, and supervise and coordinate their activities. State Environmental Goals and Indication Project: Program to assist state environmental agencies by providing technical and financial assistance in the development of environmental goals and indicators. State Implementation Plans (SIP): EPA approved state plans for the establishment, regulation, and enforcement of air pollution standards. State Management Plan: Under FIFRA, a state management plan required by EPA to allow states, tribes, and U.S. territories the flexibility to design and implement ways to protect ground water from the use of certain pesticides. Static Water Depth: The vertical distance from the centerline of the pump discharge down to the surface level of the free pool while no water is being drawn from the pool or water table. Static Water Level: 1. Elevation or level of the water table in a well when the pump is not operating. 2. The level or elevation to which water would rise in a tube connected to an artesian aquifer or basin in a conduit under pressure. Stationary Source: A fixed-site producer of pollution, mainly power plants and other facilities using industrial combustion processes. (See: point source.) Sterilization: The removal or destruction of all microorganisms, including pathogenic and other bacteria, vegetative forms, and spores. Sterilizer: One of three groups of anti-microbials registered by EPA for public health uses. EPA considers an antimicrobial to be a sterilizer when it destroys or eliminates all forms of bacteria, viruses, and fungi and their spores. Because spores are considered the most difficult form of microorganism to destroy, EPA considers the term sporicide to be synonymous with sterilizer. Storage: Temporary holding of waste pending treatment or disposal, as in containers, tanks, waste piles, and surface impoundments. Storm Sewer: A system of pipes (separate from sanitary sewers) that carries water runoff from buildings and land surfaces. Stratification: Separating into layers. Stratigraphy: Study of the formation, composition, and sequence of sediments, whether consolidated or not. Stratosphere: The portion of the atmosphere 10-to-25 miles above the earth's surface. Stressors: Physical, chemical, or biological entities that can induce adverse effects on ecosystems or human health. Strip-Cropping: Growing crops in a systematic arrangement of strips or bands that serve as barriers to wind and water erosion. Strip-Mining: A process that uses machines to scrape soil or rock away from mineral deposits just under the earth's surface. Structural Deformation: Distortion in walls of a tank after liquid has been added or removed. Subchronic: Of intermediate duration, usually used to describe studies or periods of exposure lasting between 5 and 90 days. Subchronic Exposure: Multiple or continuous exposures lasting for approximately ten percent of an experimental species lifetime, usually over a three-month period. Submerged Aquatic Vegetation: Vegetation that lives at or below the water surface; an important habitat for young fish and other aquatic organisms. Subwatershed: Topographic perimeter of the catchment area of a stream tributary. Sulfur Dioxide (SO2): A pungent, colorless, gasformed primarily by the combustion of fossil fuels; becomes a pollutant when present in large amounts. Sump: A pit or tank that catches liquid runoff for drainage or disposal. Superchlorination: Chlorination with doses that are deliberately selected to produce water free of combined residuals so large as to require dechlorination. Supercritical Water: A type of thermal treatment using moderate temperatures and high pressures to enhance the ability of water to break down large organic molecules into smaller, less toxic ones. Oxygen injected during this process combines with simple organic compounds to form carbon dioxide and water. 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. Superfund Innovative Technology Evaluation (SITE) Program: EPA program to promote development and use of innovative treatment and site characterization technologies in Superfund site cleanups. Supplemental Registration: An arrangement whereby a registrant licenses another company to market its pesticide product under the second company's registration. Supplier of Water: Any person who owns or operates a public water supply. Surface Impoundment: Treatment, storage, or disposal of liquid hazardous wastes in ponds. Surface Runoff: Precipitation, snow melt, or irrigation water in excess of what can infiltrate the soil surface and be stored in small surface depressions; a major transporter of non-point source pollutants in rivers, streams, and lakes.. Surface Uranium Mines: Strip mining operations for removal of uranium-bearing ore. Surface Water: All water naturally open to the atmosphere (rivers, lakes, reservoirs, ponds, streams, impoundments, seas, estuaries, etc.) Surface-Water Treatment Rule: Rule that specifies maximum contaminant level goals for Giardia lamblia, viruses, and Legionella and promulgates filtration and disinfection requirements for public water systems using surface-water or ground-water sources under the direct influence of surface water. The regulations also specify water quality, treatment, and watershed protection criteria under which filtration may be avoided. Surfacing ACM: Asbestos-containing material that is sprayed or troweled on or otherwise applied to surfaces, such as acoustical plaster on ceilings and fireproofing materials on structural members. Surfacing Material: Material sprayed or troweled onto structural members (beams, columns, or decking) for fire protection; or on ceilings or walls for fireproofing, acoustical or decorative purposes. Includes textured plaster, and other textured wall and ceiling surfaces. Surfactant: A detergent compound that promotes lathering. Surrogate Data: Data from studies of test organisms or a test substance that are used to estimate the characteristics or effects on another organism or substance. Surveillance System: A series of monitoring devices designed to check on environmental conditions. Susceptibility Analysis: An analysis to determine whether a Public Water Supply is subject to significant pollution from known potential sources. Suspect Material: Building material suspected of containing asbestos; e.g., surfacing material, floor tile, ceiling tile, thermal system insulation. Suspended Loads: Specific sediment particles maintained in the water column by turbulence and carried with the flow of water. Suspended Solids: Small particles of solid pollutants that float on the surface of, or are suspended in, sewage or other liquids. They resist removal by conventional means. Suspension: Suspending the use of a pesticide when EPA deems it necessary to prevent an imminent hazard resulting from its continued use. An emergency suspension takes effect immediately; under an ordinary suspension a registrant can request a hearing before the suspension goes into effect. Such a hearing process might take six months. Suspension Culture: Cells growing in a liquid nutrient medium. Swamp: A type of wetland dominated by woody vegetation but without appreciable peat deposits. Swamps may be fresh or salt water and tidal or non-tidal. (See: wetlands.) Synergism: An interaction of two or more chemicals that results in an effect greater than the sum of their separate effects. Synthetic Organic Chemicals (SOCs): Man-made (anthropogenic) organic chemicals. Some SOCs are volatile; others tend to stay dissolved in water instead of evaporating. System With a Single Service Connection: A system that supplies drinking water to consumers via a single service line. Systemic Pesticide: A chemical absorbed by an organism that interacts with the organism and makes the organism toxic to pests.