Sub-topic 4.4 Water Pollution

Aquatic pollutants

Aquatic pollutants

floating debris, organic material, inorganic plan nutrients (nitrates and phosphates), toxic metals, synthetic compounds, suspended solids, hot water, oil, radioactive pollution, pathogens, light, noise and biological pollutants (invasive species)

Testing aquatic systems

pH, temperature, suspended solids (turbidity), metals, nitrates and phosphates

Biodegradation of organic material

uses oxygen which can lead to anoxic conditions and subsequent anaerobic decomposition

anaerobic decomposition

forms methane, hydrogen sulfide and ammonia (toxic gases)

Biochemical oxygen demand

a measure of the amount of dissolved oxygen required to break down the organic material in a given volume of water through aerobic biological activity. An indirect measure of the amount of organic matter within a sample

Indicator species

species that can be indicative of polluted waters (and other systems)

Biotic index

indirectly measures pollution by assaying the impact on species within the community according to their tolerance, diversity and relative abundance

Sources of freshwater pollution

runoff, sewage, industrial discharge and solid domestic waste

sources of marine pollution

rivers, pipelines, atmosphere and activities at sea (operational and accidental discharges)

Red tide blooms

occur in coastal eutrophication

eutrophication

when lakes, estuaries and coastal waters receive inputs of nutrients (nitrates and phosphates) which results in excess growth of plants and phytoplankton. This results in over production and death and decomposition uses up oxygen in water body leading to anoxic conditions (dead zones)

dead zones

in both oceans and fresh water where there is not enough oxygen dissolved in the water to support life

Water pollution management strategy - altering human activity

using alternatives to inorganic fertilizers and detergents

Water pollution management strategy - controlling release of pollutant

waste water treatment to remove nitrates and phosphates

Water pollution management strategy - removing pollutants from the environment and restoring ecosystems

removal of mud from eutrophic lakes and reintroduction of plant and fish species; using aerators.