Ground Water Contaminants

There are many sources of ground water pollution that can cause nasty tastes and odours, and that may be a risk to human health. Contamination of your well water may occur naturally or be a result of human activity.

• Microorganisms – There are many different types of microorganisms that can cause human illness or result in discolouration of the water or produce nasty tastes and odours. Microorganisms include bacteria, viruses, algae, parasites and many more. Shallow wells are most at risk from contamination by microorganisms, as are those located near farms, wildlife hotspots and high risk flood zones. Water run-offs from these areas are usually the cause of contamination.
• Nitrates and nitrites – High levels of nitrates are usually a direct result of human activity. They are contained in fertilisers which are used on farms, with the potential to run-off and contaminate ground water. If a large amount is consumed this can be damaging to human health.
• Heavy Metals – Much of the underground rocks and soil contain heavy metals such as lead, chromium and many others. They can be damaging to human health but are not usually found to contaminate wells that are properly constructed and maintained.
• Radionuclides – These may lie in the ground water or underlying rock of the well. They are radioactive substances, such as radium, that may be carcinogenic and damaging to human health.
• Radon – The natural breakdown of uranium in the soil produces radon gas. This is a carcinogenic gas that is most threatening when inhaled.

What Can You Do?

If you have a private well there are many steps you can take to ensure that contamination does not become a problem.

• The construction of your well should be done professionally. Poorly constructed wells result in a higher risk of contamination. Monitor your well regularly and fix any problems as quickly as possible. Make sure that the water system is disinfected after construction before it used for drinking water.
• There are many contaminants that are not considered to be a health risk, such as iron and sulphate, but they can give drinking water an unpleasant taste, odour or colour. You could solve many of these problems by conditioning the water supply using water softeners, iron removal techniques, aeration, reverse osmosis or water filters.
• Make sure that the well water is tested periodically for potential contaminants. It is recommended that your well water be tested on a yearly basis for coliform bacteria, nitrates, dissolved solids and pH levels. If you suspect other contaminants due to taste, colour or odour differences, test for those when you notice a problem.
• Make sure you know your area well, identify nearby human activities such as agricultural practices and industry. Find out what flood protection is nearby if you live in a high risk area. This will help you to recognise potential problems and give you a better idea of what contaminants to test for.