GLOSSARY OF TERMS

Acute Toxicity: Immediate, or short-term health effects.

Category I: The most highly toxic substances of the four classes of pesticides in U.S. EPA's classification system. These substances cause death or severe illness in very small doses through ingestion, inhalation, and skin contact; they must be labeled "DANGER POISON."

Chronic Toxicity: Delayed, or long-term health effects.

Degradation: The breakdown of a chemical in the environment. Usually occurs via the action of sunlight, temperature, and microorganisms in the soil. This process can transform a toxic chemical into a benign chemical, or can create new, toxic breakdown products.

Endocrine Disruptor: A substance which interferes with natural hormones.

Exposure: Occurs when a person comes into contact with a chemical in their environment. May involve oral ingestion, inhalation, and absorption through the skin or the mucus membranes of the eyes, nose, or mouth.

Groundwater: Water that flows in aquifers underground rather than in rivers, streams, and lakes on the surface. Groundwater is generally accessed via wells and is frequently used for drinking.

Hormones: Natural chemicals produced by our bodies that are responsible for successful reproduction, development, normal behavior, and maintenance of normal body processes.

Integrated Pest Management (IPM) : A pest management strategy that uses field monitoring of pest populations, established guidelines, and economic thresholds to determine if and when pesticide treatments should be utilized. Emphasizes the use of a number of crop management techniques including the conservation of natural enemies and the use of resistant varieties to manage pests.

LOEL/LOAEL: Lowest Observable (Adverse) Effect Level, the lowest dose of a chemical that produces a measurable (adverse) health effect on a laboratory animal.

Metabolism: The breakdown of a chemical in the body. Often occurs via the action of enzymes in the liver. This process can inactivate toxic chemicals or can create toxic metabolic products.

n-Methyl Carbamates: A class of insecticide that interferes with acetylcholinesterase (see organophosphates) but acts reversibly rather than irreversibly. Nonetheless these pesticides can cause acute and chronic neurologic health effects. Examples of carbamates include carbaryl (Sevin®) and aldicarb (Temik®).

NOEL/NOAEL: No Observable (Adverse) Effect Level, the highest dose of a chemical that does not produce a measurable (adverse) health effect on a laboratory animal.

Organochlorines (OCs): A class of insecticide of which DDT is the most well-known member. OCs are frequently persistent in the environment, and often accumulate in fat. Most OCs are known or suspected endocrine disruptors. Examples of currently used OCs include dicofol, endosulfan, methoxychlor, and lindane.

Organophosphates (OPs) : A class of insecticide that was originally synthesized during World War II as a nerve warfare agent. Organophosphates irreversibly bind to, and inhibit, an important enzyme called acetylcholinesterase. This enzyme is responsible for rapidly breaking down a chemical (acetylcholine), which transmits nerve impulses in insects and humans alike. Failure to break down acetylcholine can cause numerous acute and chronic health effects. Examples of OPs include chlorpyrifos (Dursban®), diazinon, malathion, and parathion.

Pesticides: Any chemical substance intended to kill pests, including herbicides (to kill weeds), insecticides (to kill insects), fungicides (to kill mold), and rodenticides (to kill rats and mice).

Quantitative Risk Assessment: The characterization of the health effects expected from exposure to a toxicant, estimation of the probability of occurrence of health effects, the doses at which these health effects may occur, and recommendation of an acceptable concentration of the toxicant in air, water, food, or in the workplace.

Reference Dose (RfD) : A dose of a pesticide that the U.S. EPA considers safe for regular daily consumption by humans without adverse health effects. Generated by taking the NOAEL from animal studies and adding uncertainty factors to account for differences between animals and humans, and susceptibility within the human population.

Serum: The liquid portion of blood with the red and white blood cells removed. Often used for measurement of chemical substances in the body.

Toxic: Damaging to health.

Toxicant: A chemical that can produce adverse health effects.

Threshold: A level of exposure below which no health effects are expected to occur.