4.4 - Water Pollution

Water Pollution

the contamination of bodies of water by pollutants either directly or indirectly.

Types of Water Pollution

Anthropogenic (created by human activities), Natural (eg. volcanic eruption, algal bloom), Point Source, Non-point source, Organic, Inorganic, Direct, Indirect

How to measure water pollution in Marine Ecosystems

Abiotic Factors: Salinity, pH, temperature, dissolved oxygen, wave action

Biotic Factors: Kick sampling, sweep nets

How to measure water pollution in Freshwater Ecosystems

Abiotic Factors: Turbidity, flow, velocity, pH, temperature, dissolved oxygen

Biotic FactorsL Kick sampling, sweep nets

Biochemeical oxygen demand (BOD)

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

Used to indirectly measure the amount of organic matter within a sample

More organic matter = less dissolved oxygen

Indicator Species

Plants and animals that show something about the environment by their presence, absence, abundance & scarcity

Biotic Index

Measures the impact on species within the community according to their tolerance, diversity & relative abundance

Indirect measurement

Advantages of Indicator Species & Biotic Indices

• Measures the widespread effects/impacts of pollutants on the system

• Impacts ar emore significant than the quantity/concentration/nature of the pollutant

• Are specific to the characteristics of a given habitat

• Address the combined/integrated impact of many pollutants/human activities

• Cost-effective, it’s cheap

Disadvantages of Indicator Species & Biotic Indices

• Does not identify the specific pollutant

• Leaving the possible source of pollution unclear

• The quality of a given community may vary for reasons other than pollution/initial quality may not be known

• May require counting/identification of organisms which are difficult to collect/identify (eg. lichen, invertebrates, prone to human error

Impacts of Eutrophication

• Oxygen deficient water

• Loss of biodiversity / shortened food chains

• Death of higher plants

• Death of aerobic organisms (inverterbrates/fish/amphibians)

• Increased turbidity

• Produce toxic (smelly) gases such as methane, hydrogen sulfide, and ammonia