As water moves through soils or landfills, chemicals in the soil may dissolve in the water thereby contaminating the groundwater. This is called leaching.

Generally considered as originating from plants or animals, and made primarily of carbon and hydrogen. Scientists use the term organic to mean those chemical compounds which are based on carbon.

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 bloods [..]

The concentration of a substance in air, water or soil. A nanogram per kilogram is the same as one part per trillion. One ppt means that there is one part of a substance for every trillion parts of su [..]

The concentration of a substance in air, water or soil. A milligram per kilogram is the same as one part per million. One ppm means that there is one part of a substance for every million parts of sub [..]

A way of expressing the concentration of a substance in air, water, soil or food. A microgram per kilogram is the same as one part per billion. One ppb means that there is one part of a substance for [..]

A unit that expresses the concentration of a substance in a solution. A millligram per liter is one one-thousandth of a gram of substance per liter of solution. One mg/L of sugar in water is about the [..]

A unit that expresses the concentration of a substance in air. A milligram per cubic meter is one one-thousandth of a gram per cubic meter of air. The milligram (1,000 micrograms) is used with higher [..]

A unit that expresses the concentration of a substance in air. A microgram per cubic meter is one one-millionth of a gram of substance per cubic meter of air.

A milliliter is one one-thousandth (1/1,000) of a liter. One teaspoon holds about 5 ml of water.