Definitions

Definitions. Definitions. In this chapter: (1) “Aquifer” means a saturated subsurface geological formation of rock or soil. (1m) “Ceiling limit concentration” means a preset non-risk based concentration of an inorganic or semi-volatile chemical. (2) “Contaminant of concern” means a hazardous substance that is present at a site or facility in such concentrations that the contaminant poses an actual or potential threat to human health, safety, or welfare or the environment based upon: (a) The toxicological characteristics of the hazardous substance that influence its ability to adversely affect human health or the environment relative to the concentration of the hazardous substance at the site or facility; (b) The chemical and physical characteristics of the hazardous substance which govern its tendency to persist in the environment and the chemical, physical and biological characteristics at the site or facility which govern the tendency for the hazardous substance to persist at the site or facility; (c) The chemical and physical characteristics of the hazardous substance which govern its tendency to move into and through environmental media; (d) The naturally occurring background concentrations of the hazardous substance; (e) The thoroughness of the testing for the hazardous substance at the site or facility; (f) The frequency that the hazardous substance has been detected at the site or facility; and (g) Degradation by-products of the hazardous substance. (3) “Cumulative excess cancer risk” means the upper bound on the estimated excess cancer risk associated with exposure to multiple hazardous substances or multiple exposure pathways. (3m) “Dermal absorption” means systemic exposure via skin absorption. However, because dermal toxicity factors are not available, oral-to-dermal extrapolation is done by adjusting for gastrointestinal absorption in order to derive toxicity values in terms of a dermally-absorbed dose. (4) “Direct contact” means human exposure to substances in soil through one or more of the following pathways: inhalation of particulate matter, dermal absorption, incidental ingestion, or inhalation of vapors from the soil. (5) “Hazard index” means the sum of 2 or more hazard quotients for multiple hazardous substances or multiple exposure pathways. (6) “Hazard quotient” means the ratio of the exposure of a single hazardous substance over a specified time period to a reference dose, or reference concentration where appropriate, for that hazardous substance derived for a similar exposure period. (7) “Incidental ingestion of soil” means ingestion of soil by humans as a result of normal hand-to-mouth behaviors. (8) “Inhalation of particulate matter” means inhalation by humans of contaminants adsorbed to respirable soil particles less than 10 microns in diameter. (9m) “Inhalation of vapors” means inhalation by humans of soil contaminants that volatilized into outdoor air. (11) “Pathway” means the route a substance takes in traveling to a receptor or potential receptor or the specific portal of entry, such as lungs, skin or digestive tract, the substance takes to potentially express its toxic effect, or both. (12m) “Performance standard” means a remedial action or, in some cases existing site conditions that prevent exposure to contaminants or will result in a decrease in contaminant concentrations, or both. (13) “Restricted access areas” means land immediately adjacent to highways or railroad right-of-ways, where the presence of structural controls, such as fencing, has eliminated pedestrian ingress by the public. (14) “Risk” means the probability that a hazardous substance, when released to the environment, will cause carcinogenic effects in exposed humans or other biological receptors. (15) “Soil cleanup standard” means either a residual contaminant level determined in accordance with ss. NR 720.10 or 720.12 , or a soil performance standard determined in accordance with s. NR 720.08 . (16) “Soil saturation concentration” or “Csat” means the contaminant concentration in soil at which the absorptive limits of the soil particles, the solubility limits of the soil particles, the solubility limits of the soil pore-water, and saturation of soil pore-air have been reached. At concentrations greater than Csat, the soil contaminant may be present in free phase for contaminants that are liquid at ambient soil temperatures and pure solid phases for compounds that are solid at ambient soil temperatures.