Background

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.

Learning Intentions

In this program students will:

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

Activities

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:
  1. 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.
  2. 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

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.