Glossary
Acceptable Daily Intake (ADI): The maximum amount of a chemical that can be ingested daily over a lifetime with no appreciable health risk
Background Levels: The known concentration of a contaminant in an area. This can be from natural sources (such as geologic sources) or from industrial activity that deposited contaminants. NOTE: Just because there is a background level of something doesn’t mean it’s safe. Remember, there are areas of the U.S. that have naturally high uranium!
Chronic effects: May refer to a number of long term illnesses caused by a contaminant.
Concentration: The amount of a chemical in a given mass of water, soil, or plant tissue.
Endocrine disruptor (EDC): Refers to contaminants that can harm your endocrine system, which are your hormones.
Ecological soil screening levels (ECO-SSL): A set of screening levels developed for contaminants that are frequently found in soil at Superfund sites.
Hepatorenal: Has to do with your liver and kidney functions.
Micrograms per kilogram (µg/kg, which is also equal to parts per billion): A measure of how many micrograms of a substance (such as a metal) are in a kilogram of solid (such as soil).
Milligrams per kilogram (mg/kg, which is also equal to parts per million): A measure of how many milligrams of a substance (such as a metal) are in a kilogram of a solid (such as soil).
Maximum level (ML): A concentration that shouldn’t be exceeded for a contaminant.
Reference dose (RfD): Environmental Protection Agency's maximum acceptable oral dose of a toxic substance.
Screening level (SL): A level (usually based on health standards) to not exceed in soils, plants, or water.
EPA Regional Screening Level (RSL): Risk-based concentrations of contaminant in soils that are calculated using the exposure to a contaminant and what the EPA knows about the toxicity of the chemical. NOTE: These are not national cleanup standards.