2011/12 May: Renmark (South Australia). Mercury, Trihalomethanes

Renmark (South Australia) – Mercury

Mercury: Australian Drinking Water  Guideline 0.001mg/L

Highest SA Water Mercury Readings 2000-12: 19/12/06 Port Lincoln Mercury 0.001mg/L, 8/5/12 Renmark Mercury 0.001mg/L.

Mercury, if it enters the ecosystem can transform into the more toxic methylmercury where it can bioaccumulate. Methylmercury is highly toxic to human embryos, fetuses, infants and children. Mercury has numerous sources including old gold mines, where mercury was used in gold recovery process. It has been estimated that 950 tonnes of
mercury was deposited into Victorian soil, rivers and streams during the various gold rushes.
http://ntn.org.au/wp-content/uploads/2010/05/mercury_brief20101.pdf

Renmark (South Australia) – Trihalomethanes

Breaches to Australian Drinking Water Guidelines Levels Only

19/01/2011 Renmark Cnr Alma St / Pyap St Trihalomethanes – Total 272 ug/L

Trihalomethanes Australian Guideline Level 250μg/L (0.25mg/L)

Why and how are THMs formed?
“When chlorine is added to water with organic material, such as algae, river weeds, and decaying leaves, THMs are formed. Residual chlorine molecules react with this harmless organic material to form a group of chlorinated chemical compounds, THMs. They are tasteless and odourless, but harmful and potentially toxic. The quantity of by-products formed is determined by several factors, such as the amount and type of organic material present in water, temperature, pH, chlorine dosage, contact time available for chlorine, and bromide concentration in the water. The organic matter in water mainly consists of a) humic substance, which is the organic portion of soil that remains after prolonged microbial decomposition formed by the decay of leaves, wood, and other vegetable matter; and b) fulvic acid, which is a water soluble substance of low molecular weight that is derived from humus”. Source: http://water.epa.gov/drink/contaminants/in