Module 2: evaluating water quality

Question 1

What are the different categories of water use?

Answer 1

• acquainting ecosystems (healthy water for animals and plants)
• primary contact recreation (swimming, diving etc)
• secondary contact recreation (boating)
• visual amenity (no human contact)
• irrigation water
• livestock drinking water
• human drinking water

Question 2

What issues and practices impact water quality?

Answer 2

Water quality can be impacted by an increase of the transport of dissolved nitrogen, both in runoff and below 60cm (leaching). It can also be impacted by the increase of sediment in water, and therefore the nitrogen and phosphorus in water is also increased.

• reduced dissolved oxygen levels in water.
• streambed and stream bank erosion (through increased flow rates).

Question 3

How is the quality of water determined?

Answer 3

The quality of water is determined by measuring the levels of contaminants and the characteristics of the water.

Question 4

What are the most common water contaminants?

Answer 4

The most common water contaminants include:

Acidity 
Bacteria 
Metals 
Nitrates 
Pesticides

Question 5

What is pH?

Answer 5

pH is a measure of acidity or alkalinity in a waterway, and influences the diversity of species in a waterway and the capacity to grow plants in soil. The pH scale goes from 1 to 14, with 7 being neutral. The lower the number, the more acidic the water is.

• every decrease of 1 is actually and increase of 10 times more acid. A pH of 5 is 10 times more acidic than a reading of 6

Question 6

Nitrates

Answer 6

Nitrates in water is a good indicator of the presence of organic matter or fertilisers.
Nitrates are essential for growth. However, if nitrate levels are too highly, they can cause overly abundant plant growth and reduce the amount of dissolved oxygen in water quality

Question 7

Electrical conductivity (EC)

Answer 7

• Electrical conductivity is a good indicator of the concentration of salts in water or total salinity.
• EC readings are recorded in microsiemebs per centimetre and provides an estimate of the total amount of solids dissolved in water (total dissolved solids -TDS)
• the natural conductivity of fresh water varies from low values to very high values

Question 8

What are the implications of water quality testing for classroom practice?

Answer 8

Data from water quality testing can be used to develop classroom learning activities such as:

Growing a garden
Unit of work on the great barrier to reef
Investigating a local water way
Regeneration work around the school.