Module 4: Human Impacts

Question 1

What amount of freshwater is available to animals and plants?

Answer 1

Less than 1%

Question 2

How can industrial wastewater be treated and reused?

Answer 2

Manufacturers can remove inorganic compounds by filtration and skimming. Mine tailings can be treated by neutralising the water and removing heavy metal contaminants (precipitation and filtration)

Question 3

How can sewage be treated and reused?

Answer 3

Tanks of sewerage are mixed and aerated to provide oxygen to decomposers to help support the decomposition process. The waste water is chemically treated, similarly to the tailings of a mine. Solid particles are allowed to settle before they are filtered and removed.
This effluent can be reused, and the sludge can be disinfected (UV) and used as fertiliser or a biofuel

Question 4

How can stormwater be treated and reused?

Answer 4

Natural systems such as plants and soils act as biofilters, removing nutrient pollutants to prevent eutrophication, creating artificial wetlands with vegetation bands

Question 5

How can human activity directly influence the availability and quality of water?

Answer 5

Over extraction (think: water table effects, e.g. Jakarta)

Question 6

How can human activity indirectly influence the availability and quality of water?

Answer 6

Algal blooms and eutrophication

Question 7

What are some causes of salinisation?

Answer 7

Land clearing and irrigation
Also the erosion of connate/fossil salt from the formation of sedimentary rocks and aeolian movement of sea-spray of salt-bearing sedimentary deposits

Question 8

What is the most efficient soil cover to prevent erosion?

Answer 8

Vegetation, then humus (e.g. mulch), then none