CLARC GLOSSARY10 -6 Cancer Risk 10 -5 Cancer Risk Applicable or Relevant and Appropriate Requirement (ARAR) Brownfield BTEX Carcinogen Carcinogenesis / Cancer Carcinogenic potency factor (CPF) CERCLA Cleanup Cleanup Action Cleanup Action Alternative Cleanup Action Plan Cleanup Level Cleanup Standards Exposure route to route conversion – for obtaining MTCA Cleanup Level in the appropriate metric Ground water Hazard Quotient (HQ) Health Advisory (HA) Henry’s Law constant Inhalation Correction Factor (INH) Criteria Lowest Observed Adverse Effect Level (LOAEL) Maximum Contaminant Level (MCL) Maximum Contaminant Level Goal (MCLG) Method Detection Limit (MDL) Model Toxics Control Act (MTCA, “act”) Natural Background No Observed Adverse Effect Level (NOAEL) Non-cancer effects Practical Quantitation Limit (PQL) Reasonable Maximum Exposure (RME) Reference dose (RfD) Remediation Levels Risk Risk Assessment Target/Acceptable Risk Level
10 -6 Cancer Risk: The concentration of a chemical in different media (air, water or soil) corresponding to an excess estimated lifetime cancer risk of one in one million (1 in 1,000,000). The target cancer risk level in the Model Toxics Control Act used to establish a cleanup level where the reasonable maximum exposure is defined as unrestricted (residential) land use. 10 -5 Cancer Risk: The concentration of a chemical in different media (air, water or soil) corresponding to an excess estimated lifetime cancer risk of one in one hundred thousand (1 in 100,000). The target cancer risk level in the Model Toxics Control Act used to establish a cleanup level where the reasonable maximum exposure is defined as restricted (industrial) land use. Applicable or Relevant and Appropriate Requirement (ARAR): A federal or state legal standard out- side the immediate purview of the Model Toxics Control Act that must be met (applicable) or should be met (relevant and appropriate) when cleaning up a site. An example of an ARAR under MTCA are drinking water standards, Maximum Contaminant Levels (MCLs), as specified by the Safe Drinking Water Act as amended in 1996. Brownfield: Real property, the expansion, redevelopment, or reuse of which may be complicated by the presence or potential presence of a hazardous substance, pollutant, or contaminant. BTEX: An acronym for Benzene, Toluene, Ethylbenzene, and Xylenes, a group of toxic chemicals that are commonly associated with gasoline and other petroleum products. Carcinogen: Any substance or agent that produces or tends to produce cancer in humans. (WAC 173- 340-200). Carcinogenesis / Cancer: A multistage cellular processes characterized by initiation, promotion, and pro- gression. Initiation is the event that transforms a normal cell into a pre-cancerous intermediate (initiated) cell. Promotion is the proliferation of a single initiated cell into a clone many initiated cells. Progression is the transformation of one of these initiated cells into a malignant cell, which then proliferates into a detectable malignant tumor characterized by an unrestrained growth of cells. (Perspectives on Biologically Based Cancer Risk Assessment. Edited by Vincent James Cogliano, E. Georg Luebeck and Giovanni A. Zapponi; Kluwer Academic/Plenum Publishers © 1999). Carcinogenic potency factor (CPF): the upper 95 th percentile confidence limit of the slope of the dose- response curve and is expressed in unit of measure of (mg/kg-day) -1. (WAC 173-340-200) The cancer potency factor is referred to by EPA as a slope factor. CERCLA: The C omprehensive E nvironmental R esponse C ompensation and L iability A ct of 1980 as amended by the Superfund Amendments and Reauthorization Act of 1986. CERCLA is the federal law that created the Superfund program administered by the U.S. Environmental Protection Agency. Cleanup: The implementation of a cleanup action or interim action. (WAC 173-340-200). Cleanup Action: Any remedial action, except interim actions, taken at a site to eliminate, render less toxic, stabilize, contain, immobilize, isolate, treat, destroy, or remove a hazardous substance that complies with WAC 173-340-350 through 173-340-390. (WAC 173-340-200). Cleanup Action Alternative: One or more treatment technology, containment actions, removal action, engineered control, institutional control or other type of remedial actions (“cleanup action components”) that individually, or in combination, achieves a cleanup action at a site. (WAC 173-340-200). Cleanup Action Plan: The document prepared by the department under WAC 173-340-380 that selects the cleanup action and specifies cleanup standards and other requirements for the cleanup action. (WAC 173-340-200). Cleanup Level: The concentration of hazardous substance in soil, water, air, or sediment that is determined to be protective of human health and the environment under specified exposure conditions. Units of measure, metric, for cleanup levels are:
Cleanup Standards: Standards adopted under RCW 70.105D.030 (2) (d) which requires the following:
- For soils ( Csoil) and sediments, mg/kg (milligrams per kilogram, parts per million, PPM);
- For ground waters and surface waters, ug/L (micrograms per liter, parts per billion, PPB); and
- For air, µg/m 3. (WAC 173-340-200).
Exposure route to route conversion – for obtaining MTCA Cleanup Level in the appropriate metric As of January 1991, IRIS and NCEA databases no longer present RfDs or slope factors (Cancer Potency Factors, CPFs) for the inhalation route. These criteria have been replaced with reference concentrations (RfCs) for noncarcinogenic effects and unit risk factors (URF) for carcinogenic effects. However, for purposes of estimating risk and calculating risk-based concentrations, inhalation reference doses and inhalation slope factors have the appropriate metrics. To calculate an RfDi from an RfC use MTCA equations (adapted from Region 9) as follows: RfDi mg/(kg-day) = RfC (mg/m 3) X 20m 3/day X 1/70kg To calculate an SFi from an inhalation Unit Risk Factor, the following equation and assumptions are used: SFi (CPFi) (kg-day)/mg = URF (m 3/µg) X (day/20m 3) X 70kg X 10 3µg/mg An additional exposure route to route conversion is the use of measures of toxicity for cancer (Cancer Potency Factors, CPFs) and non-cancer (Reference Doses, RfDs) based on the oral route of exposure (ingestion) for dermal toxicity. Since there is insufficient information to define the measures of toxicity for the dermal route of exposure then extrapolations are used to adjust an administered dose to an absorbed dose based on a chemical’s oral absorption efficiency. Consistent with MTCA terminology the following adjustments are made to a reference dose (RfDo) and cancer potency factor (CPFo) based on the oral route of exposure to evaluate the dermal route of exposure: RfDo X Gastrointestinal absorption conversion factor (GI) = RfDd CPFo / Gastrointestinal absorption conversion factor (GI) = CPFd The RfDd and CPFd are measures of toxicity for non-cancer and cancer, respectively, adjusted for the dermal route of exposure. In the absence of chemical specific information the gastrointestinal absorption conversion factor is obtained from the default exposure parameters for MTCA equations 740-4, 740-5, 745-4, and 745-5. [For more detailed information see Z://Dermal Chemical Specific and Default Information for CLARC.doc]. Ground water: Water in a saturated zone or stratum beneath the surface of land or below a surface water; water that fills spaces between soil and rock particles underground. (WAC 173-340-200). Hazard Quotient (HQ): The ratio of the dose of a single hazardous substance over a specified time period to a reference dose for that hazardous substance derived for a similar exposure period. (WAC 173-340-200). Health Advisory (HA): An estimate of acceptable drinking water levels for a chemical substance based on health effects information; a Health Advisory is not a legally enforceable Federal standard, but serves as a technical guidance to assist Federal, State, and local officials. (U.S. EPA 2004 Edition of the Drinking Water Standards and Health Advisories).
- Hazardous substance concentrations that protect human health and the environmental (“cleanup levels”);
- The location on the site where those cleanup levels must be attained (“points of compliance”); and
- Additional regulatory requirements that apply to a cleanup action because of the type of action and/or the location of the site. These requirements are specified in appli- cable state and federal laws and are generally established in conjunction with the selection of specific cleanup action. (WAC 173-340-200).
Henry’s Law constant: The ratio of a hazardous substance’s concentration in the air to its concentration in water. Henry’s Law constant can vary significantly with temperature for some hazardous substances. The dimensionless form of Henry’s Law constant is used in the MTCA equations and the units of measure of atm-m3/mole for Henry’s Law constant are used to help identify the volatility of a chemical for the inhalation correction factor. (WAC 173-340-200). Inhalation Correction Factor (INH) Criteria: Tiered Criteria to Determine Chemical Volatility & Selection of INH Factor Used for CLARC 1/ Chemical volatility based on EPA’s analytical methods specified in WAC 173-340-200 Definitions: “Volatile organic compound” means those carbon-based compounds listed in EPA methods 502.3, 524.2, 551, 601, 602, 603, 624, 1624C, 1661, 1671, 8011, 8015B, 8031, 8032A, 8033, 8260B, and those with similar vapor pressures or boiling points. [Definition continues for petroleum related chemicals]. 2/ ● Vapor pressure > 6.75 E-03 mmHg or ● Boiling point < 218.5 degrees C. 3/ In the absence of a chemical’s volatility being defined by the vapor pressure or boiling point then the chemical’s Henrys Law Constant is considered by the following criteria: HLC > 10 -5atm-m 3/mol (11/02, EPA Draft Guidance: “Evaluating the Vapor Intrusion to Indoor Air Pathway from Groundwater and Soil”). Non - volatile chemicals are assigned an INH factor of 1; Volatile chemicals are assigned an INH factor of 2 based on the above criteria. As a change from previous policy, there will be a designation of “no data available” when there is insufficient information (no boiling point, vapor pressure or Henrys Law Constant) to determine chemical volatility and subsequently selection an INH factor. Lowest Observed Adverse Effect Level (LOAEL): The lowest exposure level of chemical in a study,or group of studies, that produces statistically or biologically significant increases in frequency or severity of adverse effects between the exposed population and its appropriate control. Maximum Contaminant Level (MCL): Maximum concentration of a contaminant that is allowed in drinking waster as established by either the Washington State Board of Health or the United States Environmental Protection Agency under the Federal Safe Drinking Water Act (42 U.S.C. 300f et seq.) and published in chapter 248-54 WAC or 40 C.F.R. 141. (WAC 173-340-200). Maximum Contaminant Level Goal (MCLG): Maximum concentration of a contaminant established by either the Washington State Board of Health or the United States Environmental Protection Agency under the Federal Safe Drinking Water Act (42 U.S.C. 300f et seq.) and published in chapter 248-54 WAC or 40 C.F.R. 141 for which no known or anticipated adverse effects on human health occur, including an adequate margin of safety. (WAC 173-340-200). Method Detection Limit (MDL): The minimum concentration of a substance that can be measured and reported with 99% confidence that the analyte (contaminant) concentration is greater than zero. (Washington State Department of Ecology, Toxics Cleanup Program, Guidance on Sampling and Data analysis Methods, January 1995, Publication No. 94-49). Model Toxics Control Act (MTCA, “act”): Chapter 70.105D RCW, Revised Code of Washington, first passed by the voters in the November 1988 general election as Initiative 97 and as since amended by the legislature February 2001. Natural Background: The concentration of a hazardous substance consistently present in the environ- ment that has not been influenced by localized human activities. No Observed Adverse Effect Level (NOAEL): The dose of a chemical at which there were no statistically or biologically significant increases in frequency or severity of adverse effects seen between the exposed population and its appropriate control. Effects may be produced at this dose, but they are not considered to be adverse. Non-cancer effects: Adverse biological effects not related to cancer. Practical Quantitation Limit (PQL): The concentration that can be reliably measured within specified limits during routine laboratory operating conditions using Ecology approved methods; in the absence of a specified PQL, then, by convention, the PQL is determined by 10 times the MDL. Reasonable Maximum Exposure (RME): The highest exposure that can be reasonably expected to occur for a human or other living organisms at a site under current and potential future site uses. (WAC 173-340-200) MTCA cleanup and remediation levels are based on estimates of current and future resource uses and reasonable maximum exposure expected to occur under both current and potential future site use conditions. [WAC 173-340-708 (3)] Resource uses, residential and industrial land uses define the reasonable maximum exposure for purposes of establishing a cleanup level. For an overview of the process for establishing cleanup standards please see the following focus sheets: [Links to these focus sheets are provided]. ● Developing Ground Water Cleanup Standards; ● Developing Surface Water Cleanup Standards; ● Developing Soil Cleanup Standards; and ● Developing Air Cleanup Standards. Reference dose (RfD): or reference concentration for noncancer toxicity is an estimate with uncertainty spanning perhaps an order of magnitude of daily exposure to the human population (including sensitive subgroups) that is anticipated to be without appreciable deleterious effects during a lifetime, expressed in units of milligrams per kilogram body weight per day. It is arrived at by dividing empirical data (NOAEL or LOAEL) on effects by uncertainty factors that consider inter- and intraspsecies variability, extent of data on all important chronic exposure endpoints, and availability of chronic as opposed to subchronic data. The RfDs are not applicable to nonthreshold effects such as cancer. (Methodology for Deriving Ambient Water Quality Criteria for the Protection of Human Health (2000) Technical Support Document Volume 1: Risk Assessment; WAC 173-340-200). Remediation Levels: Remediation levels are not the same as cleanup levels. A cleanup level defines the concentration of hazardous substances above which a contaminated medium (e.g., soil) must be remediated in some manner (e.g., treatment, containment, institutional controls). A remediation level, on the other hand, defines the concentration (or other method of identification) of a hazardous substance in a particular medium above or below which a particular cleanup action component (e.g., soil treatment or containment) will be used. Remediation levels, by definition, exceed cleanup levels. (Concise Explanatory Statement for the Amendments to the Model Toxics Control Act Cleanup Regulation Chapter 173-340 WAC). Risk: The probability (possibility or chance) that a hazardous substance, when released into the environment, will cause an adverse effect in exposed humans or other living organisms. (WAC 173-340-200). Risk Assessment: Evaluation of the risks to human health and the environment posed by contamination at a hazardous waste site. Risks are calculated using exposure factors, which provide numerical values for different types of exposures to contaminants, such as soil or drinking water ingestion rates and child or adult average body weights. Risk assessments may evaluate the risks to people, plants or animals; and may calculate risk as a specific value (point estimate) or a range of values (distribution). Some of the different types of risk assessments include the following:
- One-Day HA: The concentration of a chemical in drinking water that is not expected to cause any adverse non-carcinogenic effects for up to one day of exposure. The one-day health advisory is normally designed to protect a 10-kg child consuming 1 liter of water per day.
- Ten-Day HA: The concentration of a chemical in drinking water that is not expected to cause any adverse non-carcinogenic effects for up to ten days of exposure. The one-day health advisory is normally designed to protect a 10-kg child consuming 1 liter of water per day.
- Lifetime HA: The concentration of a chemical in drinking water that is not expected to cause any adverse non-carcinogenic effects for up to a lifetime of exposure. The lifetime health advisory is based on exposure of a 70-kg adult consuming 2 liters of water per day.
Target/Acceptable Risk Level: The level of contamination at a site below which no significant harm (risk) will occur to people, plants or animals. Target risk is used to calculate risk-based cleanup levels at hazardous waste site under the Model Toxics Control Act (MTCA).
- Baseline Risk Assessment: Risk assessment conducted before cleanup occurs.
- Ecological Risk Assessment: Risk assessment that evaluates the threats, risks, posed to plants and animals on and/or near a hazardous waste site.
- Human Health Risk Assessment: Risk assessment that evaluates the threats, risks, posed to people at a hazardous waste site, coming onto the hazardous waste site, living near the hazardous waste site, or potential exposure from contaminants at hazardous waste site that may migrate to other media or food sources.
- Probabilistic Risk Assessment: Risk assessment where some or all of the exposure factor values are expressed as a distribution.
- Residual Risk Assessment: Risk assessment that evaluates the threats, risks, posed by contamination that remains on site after cleanup.