Environmental Terms and Definitions

Ambient
Occurring over a short time, usually a few minutes or hours. An acute exposure can result in short term or long term health effects. An acute effect happens within a short time after exposure.

World Health Organization (WHO)
WHO, an agency of the United Nations, carries out public and environmental health programs throughout the world.

Concentration
Any substance that enters a system (the environment, human body, food, etc.) where it is not normally found. Contaminants are usually referred to in a "negative" sense and include substances that spoil food, pollute the environment or cause other adverse effects.

HSWA
Hazardous and Solid Waste Amendments (1984); amendments to RCRA establishing a timetable for landfill bans and more stringent UST requirements.

Exposure assessment
A process that estimates the amount of a chemical that enters or comes into contact with people or animals. An exposure assessment also describes how often and for how long an exposure occurred, and the nature and size of a population exposed to a chemical.

HMIS
The hazardous materials identification system, developed by NPCA to provide information on the acute health hazards, reactivity, and flammability encountered in the workplace at room temperatures.

Preliminary Site Assessment (PSA)
A process followed by the NYS Department of Environmental Conservation (DEC) to determine if a site contains hazardous waste and its potential for harming the public health or environment.

Absorption
The process of taking in, as when a sponge takes up water. Chemicals can be absorbed into the bloodstream after breathing or swallowing. Chemicals can also be absorbed through the skin into the bloodstream and then transported to other organs. Not all of the chemical breathed, swallowed, or touched is always absorbed.

OSHA
Occupational Safety and Health Administration

Gradient
The change in a property over a certain distance. For example, lead can accumulate in surface soil near a road due to automobile exhaust. As you move away from the road, the amount of lead in the surface soil decreases. This change in the lead concentration with distance from the road is called a gradient.