In combusion, solid residue that
remains after waste has been
completely burned.

A tract of land in which the
ground is broadly tilted toward a
common point. Water that falls
onto any portion of the basin is
carried toward the common point by
a single river system.

The solid rock found on the
surface of the land or just below
the soil

Build up of toxic substances in
fish flesh. Toxic effects may be
passed on to humans eating the
fish.

Able to be broken down into
simpler products by microscopic
plants and animals.

The amount of oxygen required by
aerobic microorganisms to
decompose the organic matter in
sample of water. Used as a measure
of the degree of water pollution.

A secondary product of a
manufacturing process. A waste
byproduct is an unwanted byproduct
that can either be disposed of or
recycled.

A heavy, colorless, odorless gas,
present in the atmosphere or
formed by the burning of fuels
containing carbon. Carbon dioxide
is also exhaled by animals and
used by plants in photosynthesis.

A colorless, toxic gas produced by
incomplete burning of carbon-based
fuels, including: gasoline, oil
and wood. Carbon monoxide is also
produced from incomplete
combustion of many natural and
synthetic products. For instance,
cigarette smoke contains carbon
monoxide. When carbon monoxide
gets into the body, the carbon
monoxide combines with chemicals
in the blood and prevents the
blood from bringing oxygen to
cells, tissues and organs. The
human body needs oxygen for

An cancer causing substance or
agent.