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.

In this program students will:

• Assess the quality of the Werribee River using physical, biological and chemical indicators
• Identify environmental indicators for pollution and explore the condition of the Werribee River

Students will:

• Assess the physical condition of the Werribee River discussing key stakeholders along the river, the impact of urbanisation on the riparian habitat and sources of pollution. Students will return to Ecolinc to use chemical and biological indicators to determine the quality water samples taken from the river.
• Collect and assess macroinvertebrate samples as a biological indicator of water quality and biodiversity. They will use the SWAMPS (Swan Wetlands Aquatic Macroinvertebrate Pollution Score) to form an objective opinion of the water quality.
• Test water samples and assess chemical indicators to analyse the water quality of those samples. Water quality testing will include:
  • Temperature
  • Turbidity
  • PH
  • Salinity
  • Nutrients such as phosphates and nitrates

Note: The selection of learning contexts should allow students to develop practical techniques and undertake fieldwork to assess and monitor air, water and soil quality. Students develop their skills in the use of scientific equipment and apparatus. They perform standard laboratory tests for pollution indicators such as dissolved oxygen and phosphate levels and select sampling techniques that determine the number and relative abundance of introduced species, such as the use of pond nets or kick sampling.

Area of Study 1: How can we manage pollution to sustain Earth’s systems?

Pollution effects on Earth’s systems

• Chemical and physical characteristics of pollutants that influence dispersal of emissions from natural and manufactured sources
• The transport mechanisms, persistence, fate and toxicity of pollutants throughout Earth’s four interrelated systems