WASHINGTON STATE UNIVERSITY
LONG BEACH RESEARCH AND EXTENSION UNIT
LONG BEACH, PACIFIC COUNTY, WASHINGTON
March 20, 2003
Washington State Department of Health
Under a Cooperative Agreement with the
Agency for Toxic Substances and Disease Registry
TABLE OF CONTENTS
- Occurring over a short time [compare with chronic].
- Agency for Toxic Substances and Disease Registry (ATSDR):
- The principal federal public health agency involved with hazardous waste issues, responsible for preventing or reducing the harmful effects of exposure to hazardous substances on human health and quality of life. ATSDR is part of the U.S. Department of Health and Human Services.
- Occurring over a long time (more than 1 year) [compare with acute].
- Comparison value (CV):
- Calculated concentration of a substance in air, water, food, or soil that is unlikely to cause harmful (adverse) health effects in exposed people. The CV is used as a screening level during the public health assessment process. Substances found in amounts greater than their CVs might be selected for further evaluation in the public health assessment process.
- The amount of a substance present in a certain amount of soil, water, air, food, blood, hair, urine, breath, or any other media.
- A substance that is either present in an environment where it does not belong or is present at levels that might cause harmful (adverse) health effects.
- Dermal Contact:
- Contact with (touching) the skin [see route of exposure].
- The amount of a substance to which a person is exposed over some time period. Dose is a measurement of exposure. Dose is often expressed as milligram (amount) per kilogram (a measure of body weight) per day (a measure of time) when people eat or drink contaminated water, food, or soil. In general, the greater the dose, the greater the likelihood of an effect. An "exposure dose" is how much of a substance is encountered in the environment. An "absorbed dose" is the amount of a substance that actually got into the body through the eyes, skin, stomach, intestines, or lungs.
- Environmental Media Evaluation Guide (EMEG):
- A concentration in air, soil, or water below which adverse non-cancer health effects are not expected to occur. The EMEG is a comparison value used to select contaminants of potential health concern and is based on ATSDR's minimal risk level (MRL).
- Environmental Protection Agency (EPA):
- United States Environmental Protection Agency.
- Contact with a substance by swallowing, breathing, or touching the skin or eyes. Exposure may be short-term [acute exposure], of intermediate duration, or long-term [chronic exposure].
- Exposure pathway:
- The route a substance takes from its source (where it began) to its end point (where it ends), and how people can come into contact with (or get exposed to) it. An exposure pathway has five parts: a source of contamination (such as an abandoned business);an environmental media and transport mechanism (such as movement through groundwater); a point of exposure (such as a private well); a route of exposure (eating, drinking, breathing, or touching), and a receptor population (people potentially or actually exposed). When all five parts are present, the exposure pathway is termed a completed exposure pathway.
- Water beneath the earth's surface in the spaces between soil particles and between rock surfaces [compare with surface water].
- Hazardous substance:
- Any material that poses a threat to public health and/or the environment. Typical hazardous substances are materials that are toxic, corrosive, ignitable, explosive, or chemically reactive.
- The act of swallowing something through eating, drinking, or mouthing objects. A hazardous substance can enter the body this way [see route of exposure].
- The act of breathing. A hazardous substance can enter the body this way [see route of exposure].
- Soil, water, air, plants, animals, or any other part of the environment that can contain contaminants.
- Minimal Risk Level (MRL):
- An ATSDR estimate of daily human exposure to a hazardous substance at or below which that substance is unlikely to pose a measurable risk of harmful (adverse), noncancerous effects. MRLs are calculated for a route of exposure (inhalation or oral) over a specified time period (acute, intermediate, or chronic). MRLs should not be used as predictors of harmful (adverse) health effects [see reference dose].
- Monitoring wells:
- Special wells drilled at locations on or off a hazardous waste site so that water can be sampled at selected depths and studied to determine the movement of groundwater and the amount, distribution, and type of contaminant.
- No apparent public health hazard:
- A category used in ATSDR's public health assessments for sites where human exposure to contaminated media might be occurring, might have occurred in the past, or might occur in the future, but where the exposure is not expected to cause any harmful health effects.
- Oral Reference Dose (RfD):
- An amount of chemical ingested into the body (i.e., dose) below which health effects are not expected. RfDs are published by EPA.
- Compounds composed of carbon, including materials such as solvents, oils, and pesticides which are not easily dissolved in water.
- Parts per billion (ppb)/Parts per million (ppm):
- Units commonly used to express low concentrations of contaminants. For example, 1 ounce of trichloroethylene (TCE) in 1 million ounces of water is 1 ppm. 1 ounce of TCE in 1 billion ounces of water is 1 ppb. If one drop of TCE is mixed in a competition size swimming pool, the water will contain about 1 ppb of TCE.
- Route of exposure:
- The way people come into contact with a hazardous substance. Three routes of exposure are breathing [inhalation], eating or drinking [ingestion], or contact with the skin [dermal contact].
- Volatile organic compound (VOC):
- Organic compounds that evaporate readily into the air. VOCs include substances such as benzene, toluene, methylene chloride, and methyl chloroform.