Great Western (Victoria) – Trichloroacetic Acid
2009/10: Great Western 0.130mg/L Trichloroacetic Acid (Highest Level)
2010/11: Great Western 0.180mg/L Trichloroacetic Acid (Highest Level)
2011/12: Great Western 0.110mg/L Trichloroacetic Acid (Highest Level)
2012/13: Great Western 0.110mg/L Trichloroacetic Acid (Highest Level)
2012/13: Great Western 0.110mg/L Trichloroacetic Acid (Highest Level)
2016/17: Great Western 0.160mg/L Trichloroacetic Acid (Highest Level)
2018/19: Great Western 0.100mg/L Trichloroacetic Acid (Highest Level), 0.056mg/L (av.)
2022/23: Great Western 0.210mg/L Trichloroacetic Acid (max), 0.089mg/L (av.)
(Australian Drinking Water Guideline Trichloroacetic Acid: 0.100mg/L)
“Chloroacetic acids are produced in drinking water as by-products of the reaction between chlorine and naturally occurring humic and fulvic acids. Concentrations reported overseas range up to 0.16mg/L and are typically about half the chloroform concentration. The chloroacetic acids are used commercially as reagents or intermediates in the preparation of a wide variety of chemicals. Monochloroacetic acid can be used as a pre-emergent herbicide, dichloroacetic acid as an ingredient in some pharmaceutical products, and trichloroacetic acid as a herbicide, soil sterilant and antiseptic.” Australian Drinking Water Guidelines – National Health and Medical Research Council…
There are no epidemiological studies of TCA carcinogenicity in humans. Most of the human health data for chlorinated acetic acids concern components of complex mixtures of water disinfectant by-products. These complex mixtures of disinfectant by-products have been associated with increased potential for bladder, rectal, and colon cancer in humans [reviewed by Boorman et al. (1999); Mills et al. (1998)].” Ref: tmp/Trichloroacetic acid (TCA) CASRN 76-03-9 IRIS US EPA.htm
Great Western (Victoria) – Trihalomethanes
2007/8: Great Western Trihalomethanes 0.270mg/L (Highest level)
2016/17: Great Western Trhalomethanes 0.450mg/L (Highest level)
2022/23: Great Western Trihalomethanes 0.25mg/L (max), 0.154mg/L (av.)
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: https://water.epa.gov/drink/contaminants/index.cfm