4.4 Water Pollution

Question 1

Pollution

Answer 1

The addition of any substance or form of energy (e.g. heat, sound, radioactivity) to the environment at a rate faster than the environment can accommodate it by dispersion, breakdown, recycling or storage in some harmless form.

Question 2

Anoxic Water

Answer 2

An area of seawater or fresh water that is depleted of dissolved oxygen.

Question 3

Biochemical Oxygen Demand (BOD)

Answer 3

The amount of oxygen required by aerobic microorganisms to decompose the organic matter in a sample of water such as that polluted by sewage. It is an indirect indicator used as a measure of the degree of water pollution.

Question 4

Macro - Invertebrates

Answer 4

Animals without backbones that can be seen with the naked eye. Examples include water fleas, dragonfly nymphs, mayflies and worms.

Question 5

Biotic Index

Answer 5

An indirect measurement of pollution that assays the impact on species according to their tolerance, diversity and abundance.

Question 6

Indicator Species

Answer 6

Species that by their presence or absence can be indicative of polluted water (or other systems).

Question 7

Eutrophication

Answer 7

Refers to the natural or artificial addition of nutrients, particularly nitrates and phosphates, to a body of water, resulting in depletion of the oxygen content. Human activity can accelerate the process by the addition of sewage, detergents and agricultural fertilizers.

Question 8

Algal Bloom

Answer 8

A large accumulation of algae on the surface of a body of water.

Question 9

Dead Zones

Answer 9

Areas in oceans or fresh water where there is not enough oxygen to support life.