Unlike municipal water which is generally subject to regular testing, very few regulations exist to govern private well and bore water supplies. The onus therefore lies on the user to check the pH and conduct regular testing for microorganisms, pesticides, nitrates and other contaminants.
Following are a few adverse health effects associated with the contaminants found in bore / well water:
- Local Impurities – Ground water quality varies from place to place depending on the geographical location. This determines the presence or absence of natural impurities such as nutrients from rocks and soil, heavy metals, radon gas, boron, selenium and proximity to farming and other industries. For example, in some parts of India and Australia, concentrations of naturally occurring elements such as arsenic, fluoride and uranium, or nitrates from agricultural land uses, may exceed safe levels (National Health and Medical Research Council, 2004).
- Radioactive Impurities – Radioactive minerals such as uranium maybe found naturally within the ground. Uranium breaks down into several isotopes one of which is radon gas which may cause lung cancer when inhaled. A preliminary survey of the radioactive content of Australian drinking water found that ground water contains higher levels of radioactivity when compared with surface water and that these levels were considerably higher than the world wide average (Long et al, 2008).
- Agricultural Run-Off – Nitrates and nitrites found in fertilisers (from agricultural run-off), animal wastes, septic tanks and sewage treatment systems are a common problem with ground water. High levels of nitrates may lead to blue baby syndrome (methemoglobinemia).
- Underground Salts – High salt levels can be a problem with ground water which may make it undrinkable.
- Pesticides – Pesticide drift is a very real threat in farming communities and timber plantations (that spray prior to felling) which makes regular testing vital to account for accidents and seasonal variations.
- Microbial Contamination – Micro-organisms may occur as a result of seepage from septic tanks or manure from livestock and domestic animals or from storm water contamination. Micro-organisms are generally more of a problem during drought conditions as a result of shallow water or they can be introduced into the well from flooding.
- Heavy metals from Pipeline & Tanker – Heavy metals such as lead and copper may occur as a result of corroding domestic pipe, walls of metallic tanks or heavy metals could be generated from nearby industry such as mining, metal smelting, timber milling or building construction.