Brookton (Western Australia) – Trihalomethanes
Western Australia THM’s Highest readings Ballingup 0.361mg/L (2003/4)
In Western Australia 2002-11: 27 THM readings above 0.250mg/L.
Australian Drinking Water Guideline Level (Trihalomethanes) 0.250mg/L (250ug/L) (US Guideline 0.08mg/L)
Classical trihalomethanes consist of chloroform (CHCl3), dichlorobromoform (CHCl2Br),
dibromochloroform (CHBr2Cl) and bromoform (CHBr3).
“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 odorless, but harmful and potentially toxic. The quantity of byproducts 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”.
Brookton – Western Australia – Iron
2011/12 Brookton (Western Australia) Iron 0.3mg/L (max), 0.195mg/L (av)
Based on aesthetic considerations (precipitation of iron from solution and taste),
the concentration of iron in drinking water should not exceed 0.3 mg/L.
No health-based guideline value has been set for iron.
Iron has a taste threshold of about 0.3 mg/L in water, and becomes objectionable above 3 mg/L. High iron concentrations give water an undesirable rust-brown appearance and can cause staining of laundry and plumbing fittings, fouling of ion-exchange softeners, and blockages in irrigation systems. Growths of iron bacteria, which concentrate iron, may cause taste and odour problems and lead to pipe restrictions, blockages and corrosion. ADWG 2011