4.4 Water Pollution

Significant Ideas

• Water pollution, both to groundwater and surface water, is a major global problem, the effects of which influence human and other biological systems.

Knowledge and Understanding

• 1. There are a variety of freshwater and marine pollution sources.

  2. Types of aquatic pollutants include floating debris, organic material, inorganic plant nutrients (nitrates and phosphates), toxic metals, synthetic compounds, suspended solids, hot water, oil, radioactive pollution, pathogens, light, noise and biological pollutants (invasive species).

  3. A wide range of parameters can be used to directly test the quality of aquatic systems, including pH, temperature, suspended solids (turbidity), metals, nitrates and phosphates.

  4. Biodegradation of organic material utilizes oxygen, which can lead to anoxic conditions and subsequent anaerobic decomposition, which in turn leads to formation of methane, hydrogen sulfide and ammonia (toxic gases).

  5. Biochemical oxygen demand (BOD) is 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. BOD is used to indirectly measure the amount of organic matter within a sample.

  6. Some species can be indicative of polluted waters and can be used as indicator species.

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

  8. Eutrophication can occur when lakes, estuaries and coastal waters receive inputs of nutrients (nitrates and phosphates), which results in an excess growth of plants and phytoplankton.

  9. Dead zones in both oceans and fresh water can occur when there is not enough oxygen to support marine life.

  10. Application of figure 3 to water pollution management strategies includes:

      1. • reducing human activities that produce pollutants (for example, alternatives to current fertilizers and detergents)

         • reducing release of pollution into the environment (for example, treatment of waste water to remove nitrates and phosphates)

         • removing pollutants from the environment and restoring ecosystems (for example, removal of mud from eutrophic lakes and reintroduction of plant and fish species).

Applications and Skills

1. Analyze water pollution data.

2. Explain the process and impacts of eutrophication.

3. Evaluate the uses of indicator species and biotic indices in measuring aquatic pollution.

4. Evaluate pollution management strategies with respect to water pollution.

Guidance

• Sources of freshwater pollution should include runoff, sewage, industrial discharge and solid domestic waste.

• Sources of marine pollution should include rivers, pipelines, atmosphere and activities at sea (operational and accidental discharges).

• The role of positive and negative feedback in the process of eutrophication should be covered. Coastal eutrophication can lead to red tide blooms.

• With respect to measuring aquatic pollution, a polluted and an unpolluted site (for example, upstream and downstream of a point source) should be compared.

Key Vocabulary

• XYZ

Textbook Reading and/or Activities

Click HERE for a pdf of chapter 4.

• Pages x-xx

  • Challenge Yourself (p.x)

  • Worked Example (p.x-xx)

  • Exercises (p.x)

Notes

i-Biology Notes (Not available)

A detailed set of notes, created by Stephen Taylor, examining U1 - U8 and A1 - A4.

i-Biology Study Questions (Not available)

A series of questions, created by Stephen Taylor, to help check your understanding of the IB learning expectations. This is VERY GOOD practice.

Bioknowledgy Notes (Not available)

A detailed set of notes, created by Chris Paine, examining all of the IB learning expectations.

Bioknowledgy Study Questions (Not available)

A series of questions, created by Chris Paine, to help check your understanding of the IB learning expectations. This is VERY GOOD practice.

Learning Activities

Lab - Examining Eutrophication

This lab activity, adapted from the Changing Hudson Project by the Cary Institute of Ecosystem Studies, will enable students to better understand the effects of nutrient loading on primary productivity.

Virtual Lab - Assessing Water Quality

This virtual lab, prepared by McGraw-Hill, will help you better understand how indicator species are used to assess the quality of aquatic systems.

Supplemental Reading