Section 58.01.24.010 - DEFINITIONSFor the purpose of the rules contained in IDAPA 58.01.24, "Standards and Procedures for Application of Risk Based Corrective Action at Petroleum Release Sites," the following definitions apply:
01.Acceptable Target Hazard Index. The summation of the hazard quotients of all chemicals and routes of exposure to which a receptor is exposed and equal to a value of one (1). If the initial value exceeds one (1), further evaluation, including individual organs, can be completed.02.Acceptable Target Hazard Quotient. A hazard quotient of 1 for a specified receptor when applied to individual chemicals.03.Acceptable Target Risk Level. Acceptable risk level for human exposure to carcinogens. For exposure to individual carcinogens a lifetime excess cancer risk of less than or equal to one per one million (1 E-6) for a receptor at a reasonable maximum exposure. For combined exposure to all carcinogens and routes of exposure, a lifetime excess cancer risk of less than or equal to one per one hundred thousand (1 E-5) for a receptor at a reasonable maximum exposure.04.Activity and Use Limitations. Restrictions or obligations, with respect to real property, created by an environmental covenant. Activity and use limitations may include, but are not limited to, land use controls, activity and use restrictions, environmental monitoring requirements, and site access and security measures. Also known as institutional controls.05.Background. Media specific concentration of a chemical that is consistently present in the environment in the vicinity of a site which is the result of human activities unrelated to release(s) from that site under investigation.06.Board. The Idaho Board of Environmental Quality.07.Corrective Action Plan. A document, subject to approval by the Department, which describes the actions and measures that will be implemented to ensure that adequate protection of human health and the environment is achieved and maintained. A corrective action plan also describes the applicable remediation standards. Also may be known as a risk management plan or a remediation workplan.08.Delineated Source Water Protection Area. The physical area around a public drinking water supply well or surface water intake identified in an approved Department source water assessment that contributes water to a well (the zone of contribution). The size and shape of the delineated source water area depend on the delineation method and site specific factors. The area may be mapped as a one thousand (1000) ft. fixed radius around the well (transient public water systems) or divided into three (3), six (6), and ten (10) year time of travel zones (e.g. zones indicating the number of years necessary for a particle of water to reach a well or surface water intake). For the purposes of these rules, where ground water time of travel zones have been delineated, the three (3) year time of travel zone shall apply. Where surface water systems have been delineated, this area includes a five hundred (500) ft. buffer around a lake or reservoir, or a five hundred (500) ft. buffer along the four (4) hour upstream time of travel of streams. See the Idaho Source Water Assessment Plan.09.Department. The Idaho Department of Environmental Quality.10.Environmental Covenant. As defined in the Uniform Environmental Covenant Act (UECA), Chapter 30, Title 55, Idaho Code, an environmental covenant is a servitude arising under an environmental response project that imposes activity and use limitations.11.Exposure Point Concentration. The average concentration of a chemical to which receptors are exposed over a specified duration within a specified geographical area. The exposure point concentration is typically a conservative estimate of the mean. Also referred to as the representative concentration.12.Hazard Quotient. The ratio of a dose of a single chemical over a specified time period to a reference dose for that chemical derived for a similar exposure period.13.Method Detection Limit. The minimum concentration of a substance that can be reported with ninety-nine percent (99%) confidence is greater than zero. Method detection limits can be operator, method, laboratory, and matrix specific.14.Operator. Any person presently or who was at any time during a release in control of, or responsible for, the daily operation of the petroleum storage tank (PST) system.15.Owner. Any person who owns or owned a PST system any time during a release and the current owner of the property where the PST system is or was located.16.Person. An individual, public or private corporation, partnership, association, firm, joint stock company, joint venture, trust, estate, state, municipality, commission, political subdivision of the state, state or federal agency, department or instrumentality, special district, interstate body, or any legal entity which is recognized by law as the subject of rights and duties.17.Petroleum. Crude oil or any fraction thereof that is liquid at standard conditions of temperature and pressure (sixty (60) degrees Fahrenheit and fourteen and seven-tenths (14.7) pounds per square inch absolute). This includes petroleum-based substances comprised of a complex blend of hydrocarbons derived from crude oil through processes of separation, conversion, upgrading, and finishing, such as motor fuels, jet fuels, distillate fuel oils, residual fuel oils, and lubricants.18.Petroleum Storage Tank (PST) System. Any one (1) or combination of storage tanks or other containers, including pipes connected thereto, dispensing equipment, and other connected ancillary equipment, and stationary or mobile equipment, that contains petroleum or a mixture of petroleum with de minimis quantities of other regulated substances.19.Practical Quantitation Limit. The lowest concentration of a chemical that can be reliably quantified among laboratories within specified limits of precision and accuracy for a specific laboratory analytical method during routine laboratory operating conditions. Specified limits of precision and accuracy are the criteria listed in the calibration specifications or quality control specifications of an analytical method. Practical quantitation limits can be operator, method, laboratory, and matrix specific.20.Reasonable Maximum Exposure. The highest exposure that can be reasonably expected to occur for a human or other living organism at a site under current and potential future site use.21.Reference Dose. For chronic or long-term exposures an estimate of a daily exposure level to a chemical for the human population, including sensitive subpopulations, that is likely to be without an appreciable risk of deleterious noncarcinogenic effects during a lifetime, expressed in units of milligrams per kilogram body weight per day.22.Release. Any spilling, leaking, emitting, discharging, escaping, leaching, or disposing from a PST into soil, ground water, or surface water.23.Remediation Standard. A media specific concentration which, when attained, is considered to provide adequate protection of human health and the environment.24.Residential Use. Residential use means land uses which include residential or sensitive populations.25.Risk Based Concentration. The residual media specific concentration of a chemical that is determined to be protective of human health and the environment under specified exposure conditions.26.Risk Evaluation. The process used to determine the probability of an adverse effect due to the presence of a chemical. A risk evaluation includes development of a site conceptual model, identification of the chemicals present in environmental media, assessment of exposure and exposure pathways, assessment of the toxicity of the chemicals present, characterization of human risks, and characterization of impacts or risks to the environment.27.Screening Level. A media specific concentration which, based on specified levels of risk or hazard, exposure pathways and routes of exposure, expected land use, and exposure factors, can be used to assess the need for additional investigation or corrective action.28.Slope Factor. A plausible upper-bound estimate of the probability of an individual developing cancer as a result of a lifetime of exposure to a particular level of a potential carcinogen. It is expressed as the probability of a response per unit intake of a chemical over a lifetime.29.Uniform Environmental Covenant Act (UECA). UECA is found in Chapter 30, Title 55, Idaho Code. UECA provides a statutory mechanism for creating, modifying, enforcing and terminating environmental covenants.Idaho Admin. Code r. 58.01.24.010