GLOSSARY OF TERMS AND ACRONYMS A B C D E F G H I J K L M N O P Q R S T U V W X Y Z R Reactive One of four categories of hazardous waste; substances capable of changing into something else in the presence of other chemicals, usually violently or producing a hazardous by-product. Recharge areas Area in which an aquifer is replenished with water by the downward percolation of precipitation through soil and rock. Record of Decision (ROD) The Record of Decision (ROD) is a public document that explains which cleanup alternatives will be used to clean up a Superfund site. The ROD for sites listed on the NPL is created from information generated during the Remedial Investigation/Feasibility Study. Redd The depression created in the bed of a stream by a female fish during spawning in which the eggs are deposited for incubation. Release 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 (RA) The phase in Superfund site cleanup following the Remedial Design (RD) phase where the actual construction or implementation occurs. The RA is based on the specifications described in the Record of Decision (ROD). Remedial Design (RD) The phase in Superfund site cleanup where the technical specifications for cleanup remedies and technologies are designed. The RD is based on the specifications described in the Record of Decision (ROD). Remedial Design/Remedial Action (RD/RA) Remedial Design (RD) is the phase in Superfund site cleanup where the technical specifications for cleanup remedies and technologies are decided. Remedial Action (RA) follows the remedial design phase and involves the actual construction or implementation phase of Superfund site cleanup. The RD/RA is based on the specifications described in the record of decision (ROD). Remedial Investigation/Feasibility Study (RI/FS) Performed at the site after a site is listed on the National Priorities List (NPL). The RI serves as the mechanism for collecting data. The FS is the mechanism for the development, screening and detailed evaluation of alternative remedial actions. The RI and FS are conducted concurrently; data collected in the RI influence the development of remedial alternatives in the FS, which in turn affects the data needs and scope of treatability studies and additional field investigations. Remedy The method selected to clean up a Superfund site. Removal action See short-term cleanup. Residual contamination Amount of a pollutant remaining in the environment after a natural or technological process has taken place (e.g., the level of chemical remaining in soil after it has been treated). Resource Conservation and Recovery Act (RCRA) A federal law whose primary goals are to protect human health and the environment from the potential hazards of waste disposal, conserve energy and natural resources, reduce the amount of waste generated, and ensure that wastes are managed in an environmentally sound manner. Management of solid waste (e.g., garbage), hazardous waste, and underground storage tanks holding petroleum products or certain chemicals is regulated by RCRA. Response action An action taken by EPA or another federal, state or local agency to address the risks posed by the release or threatened release of hazardous substances--generally categorized as emergency response, short-term cleanup and long-term cleanup. Riparian The area adjacent to a stream or river. Risk management programs (RMP) The Clean Air Act (CAA) requires covered facilities (referred to as stationary sources) to develop risk management programs (RMP) to prevent accidental releases of dangerous chemicals. Covered stationary sources are those that have certain regulated substances present in excess of applicable thresholds.