Now that you have completed this study session, you can assess how well you have achieved its Learning Outcomes by answering these questions.

Which of the following statements are false? In each case explain why it is incorrect.

  1. Exhaust gases from industries and motor vehicles are major causes of air pollution.
  2. Medical wastes should be collected and disposed of with normal household waste.
  3. Organic solid waste from households, cafeterias and restaurants provide breeding places for pathogens and vectors.
  4. Faeces are an environmental pollutant when left in the open, as in the case of flying toilets.
  5. Industrial wastewater can cause water pollution if discharged directly into a river but is safe to spread over bare ground.

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2 is false. Medical waste should not be handled with normal household waste. It needs special disposal because it may contain hazardous substances including body fluids from patients, pharmaceutical chemicals and sharp objects such as needles.

5 is false. Industrial wastewater can cause water pollution if discharged into a river but can also pollute soil and groundwater if spread over the ground.

By what route do pollutants get into rivers and other surface waters?

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Contaminants can flow directly into surface water sources, such as rivers, from pipes and drainage channels, e.g. industrial wastewater from a factory. They may also enter rivers in rainwater run-off that has washed over surrounding land and collected pollutants from any wastes discarded there, including faeces. Another possible route is from groundwater. If groundwater in the area has become contaminated, this may seep out into the river. You may also have thought of direct contamination from activities in the river water such as cleaning dirty vehicles.