For the purposes of this chapter, the following definitions shall apply:

"Administrative Procedure Act" or "APA" means the Washington Administrative Procedure Act, chapter 34.05 RCW.

"Bioaccumulation" means the process by which substances increase in concentration in living organisms as they take in contaminated air, water, soil, sediment or food because the substances are very slowly metabolized or excreted.

"Bioaccumulation factor" or "BAF" means the ratio of the concentration of a chemical in an organism to the concentration of the chemical in the surrounding environment. The BAF is a measure of the extent to which the organism accumulates the chemical as a result of uptake through ingestion as well as contact from contaminated media, such as water.

"Bioconcentration factor" or "BCF" means the ratio of the concentration of a chemical in an aquatic organism to the concentration of the chemical in water. The BCF is a measure of the extent of chemical partitioning between an aquatic organism and water.

"Carcinogen" means a chemical or chemical group that has been identified as "carcinogenic to humans" or "likely to be carcinogenic to humans" by the Environmental Protection Agency, as a Group 1, 2A or 2B carcinogen by the International Agency for Research on Cancer or as a "known to be a human carcinogen" or "reasonably anticipated to be a human carcinogen" by the National Toxicology Program.

"Chemical" means a naturally occurring element, mixture, or group of organic and inorganic compounds that is produced by or used in a chemical process.

"Chemical action plan" or "CAP" means a plan that identifies, characterizes and evaluates uses and releases of a specific PBT, a group of PBTs or metals of concern and recommends actions to protect human health or the environment.

"Chemical group" means a grouping of chemicals which share a common chemical structure and common toxicological properties.

"Credible scientific information" means information that is based on a theory or technique that is generally accepted in the relevant scientific community or has been collected or derived using standard or generally accepted methods and protocols and appropriate quality assurance and control procedures.

"Cross-media transfer of chemicals" means the movement of a chemical from one medium, such as air, water, soil, or sediment, to another.

"Degradation" means the processes by which organic chemicals are transformed into derivative chemicals and ultimately broken down.

"Developmental or reproductive toxicant" means a chemical or chemical group identified as posing developmental or reproductive hazards by the National Toxicology Program or chemicals or chemical groups with sufficient evidence of a developmental or reproductive hazard in humans or experimental animals consistent with the United States Environmental Protection Agency's Guidelines for Reproductive Toxicity Risk Assessment and Guidelines for Developmental Toxicity Risk Assessment as set forth in 61 FR 56274 et seq. and 56 FR 63798 et seq., respectively.

"Ecology" means the department of ecology.

"Environment" means any plant, animal, natural resource, surface water (including underlying sediments), groundwater, drinking water supply, land surface (including tidelands and shorelands) or subsurface strata, or ambient air.

"Environmental half-life" means the time required for the concentration of a chemical to diminish to half its original value. The environmental half-life of a chemical is a measure of a chemical's persistence in the environment.

"Feasible" means reasonably capable of being accomplished or brought about or capable of being utilized or dealt with successfully.

"High-exposure populations" means groups of people that have a higher potential for exposure than the general population.

"Log-octanol water partition coefficient" or "Log Kow" means the ratio of a chemical's concentration in the octanol phase to its concentration in the aqueous phase of a two-phase octanol/water system as expressed in a logarithmic format.

"Media" or "medium" means a component of the environment (air, water, soil or sediment) in which a contaminant is measured and an organism lives its life, and from which an organism can accumulate contaminants.

"Neurotoxicant" means a chemical or chemical group with sufficient evidence of a neurotoxic hazard in humans or experimental animals consistent with the United States Environmental Protection Agency's Guidelines for Neurotoxicity Risk Assessment as set forth in 63 FR 26926 et seq.

"No observed effect concentration" or "NOEC" means the highest concentration of a chemical evaluated in an aquatic toxicity test that does not cause a statistically and biologically significant difference in effects compared with controls.

"Persistent bioaccumulative toxin" or "PBT" means a chemical or chemical group that meets or exceeds the criteria for persistence, bioaccumulation and toxicity criteria established in WAC 173-33-320.

"Persistence" means the tendency of a chemical to remain in the environment without transformation or breakdown into another chemical form. It refers to the length of time a chemical is expected to reside in the environment and be available for exposure.

"Reference dose" means a numerical estimate of a daily exposure to the human population, including sensitive subgroups such as children, that is likely to be without harmful effects during a lifetime.

"Sensitive population group" means groups of people that exhibit a different or enhanced response to a chemical than most people exposed to a similar level of the chemical because of genetic makeup, age, nutritional status or exposure to other toxic substances.

"Toxicity" means the degree to which a substance or mixture of substances can harm humans, plants or wildlife.