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AoS 1 When pollution becomes a hazard – Environmental indicators

Full Day
Book Program
Year Levels
Unit 2 — How can pollution be managed?


The environment is complex, and determining its quality can be difficult. It would be costly and time-consuming to assess the condition of a particular environment by measuring every variable, and in many cases we do not yet have the knowledge to do so. Therefore, environmental indicators are used to assess the condition of an environment and to track environmental change. Environmental indicators are physical, chemical and biological measures that assess the key elements of a complex system or environmental issue. They can be used to assess components of natural resources and parts of environmental quality.

A physical indicator measures a physical feature of the environment, such as the amount of sunlight reaching the forest floor.

A chemical indicator measures a chemical factor affecting the environment, such as the amount of dissolved oxygen in a body of water.

A biological indicator measures effects on a plant or animal, such as macroinvertebrates, which vary in their sensitivity to changes in their environment.

Prior Knowledge

No prior knowledge required.

Learning Intentions

In this program students will:

  • Assess the quality of the Werribee River using both biological and chemical indicators.


Identify environmental indicators for pollution. Students will visit the Werribee River to assess the impact of stormwater on the river habitat, use chemical and biological indicators to determine the quality of various water samples taken from the river:

a) Part 1: Biological indicators

  • Sample and identify macroinvertebrate species in the Werribee River
  • Follow the instructions provided and use the SWAMPS (Swan Wetlands Aquatic Macroinvertebrate Pollution Score) to form an objective opinion of the water quality.

b) Part 2: Chemical indicators

  • Test the water quality of different water samples including water from the Werribee river and the Ecolinc wetland.
  • The following water quality tests will be conducted:
    • Temperature
    • Turbidity
    • pH
    • Salinity
    • Nutrients such as phosphates and nitrates
  • Interpret the chemical indicator results to determine the health of the Werribee River.

VCE links

Students will gain key knowledge of:

Characteristics, sources and transport mechanisms of pollutants

  • The distinction between wastes, contaminants and pollution, including natural and manufactured sources
  • The physical and chemical characteristics of common pollutants that have a negative effect on terrestrial, aquatic, atmospheric and living systems with reference to their persistence, mobility, toxicity and likelihood of bioaccumulation, including one pollutant that results in bioaccumulation and one air- or water-borne pollutant
  • The distinction between various sources of pollutants including point or diffuse (fugitive or mobile), direct or indirect, intentional or neglectful, and pollution sinks, and implications for management strategies
  • Direction, distance and rate of dispersal of pollutants through different processes that transport pollutants, including air circulation, the water cycle and bioaccumulation.

Measurement and monitoring of pollutants

  • The physical, chemical and biological indicators for monitoring the state of a local ecosystem or environmental issue including turbidity, pH, light intensity, biological oxygen demand in streams; salinity level in soils or water; presence/absence of pollution intolerant species in streams; and presence/absence of introduced species
  • The setting of safety standards based on concentrations that are hazardous for living organisms
  • Risk assessment tools, monitoring technologies and remediation techniques
  • Evaluation strategies measuring direct and indirect impacts of pollutants for human and environmental health with reference to risk, exposure, dosage, tolerance limits, LD50, chronic and acute toxicity, allergies, specificity, disruption of system regulation, and synergistic action.

Treatment and management of pollutants

  • Bio-physical and/or chemical inactivation, substitution or elimination of pollutants
  • The natural processes and the human engineered machines that mimic the natural processes that act as pollution sinks
  • The factors that can change the rate of removal of active pollutants or the rate of decay, including the presence of aerobic or anaerobic conditions, and the length of time
  • New technologies that reduce pollution.