2009/20: Pyalong (Victoria) – Chloral Hydate, Dichloroacetic Acid, Trichloroacetic Acid, Trihalomethanes, Total Dissolved Solids, Hardness, Iron

Pyalong (Victoria) – Chloral Hydrate

2011/12: Pyalong 0.021mg/L  Chloral Hydrate (Highest Detection)

2010/11: Pyalong 0.065mg/L Chloral Hydrate (Highest Detection)

2009/10: Pyalong 40ug/L Chloral Hydrate (Highest Detection)

2004 Australian Drinking Water Guideline: Trichloroacetaldehyde (chloral hydrate): 0.02mg/L

2011 Australian Drinking Water Guideline: Trichloroacetaldehyde (chloral hydrate): 0.1mg/L

Based on health considerations, the concentration of chloral hydrate in drinking water
should not exceed 0.1 mg/L. Action to reduce chloral hydrate is encouraged, but must not compromise disinfection, as non-disinfected water poses significantly greater risk than chloral hydrate. (2011 ADWG)

Pyalong (Victoria) – Chloroacetic Acids

2010/11: Pyalong 0.120mg/L  Dichloroacetic Acid

2010/11: Pyalong 0.160mg/L Trichloroacetic Acid

Australian Guidelines Trichloroacetic Acid 0.100mg/L, Dichloroacetic 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

Pyalong (Victoria) – Trihalomethanes

2017/18: Pyalong Trihalomethanes 0.250mg/L

2015/16: Pyalong Trihalomethanes 0.280mg/L

2012/13: Pyalong Trihalomethanes 0.240mg/L

2009/10: Pyalong Trihalomethanes 0.310mg/L

2008/9: Pyalong Trihalomethanes 0.380mg/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: https://water.epa.gov/drink/contaminants/index.cfm

Pyalong (Victoria)  Total Dissolved Solids

2013/14: Pyalong (Victoria) – Total Dissolved Solids 1200mg/L (μS/cm)

2014/15: Pyalong (Victoria) – Total Dissolved Solids 1200mg/L (μS/cm)

2015/16: Pyalong (Victoria) – Total Dissolved Solids 1900mg/L (μS/cm)

2016/17: Pyalong (Victoria) – Total Dissolved Solids 1200mg/L (μS/cm)

2018/19: Pyalong (Victoria) – Total Dissolved Solids 960mg/L (μS/cm) (max)

2019/20: Pyalong (Victoria) – Total Dissolved Solids 1100mg/L (μS/cm) (max)


“No specific health guideline value is provided for total dissolved solids (TDS), as there are no
health effects directly attributable to TDS. However for good palatability total dissolved solids
in drinking water should not exceed 600 mg/L.

Total dissolved solids (TDS) consist of inorganic salts and small amounts of organic matter that are dissolved in water. Clay particles, colloidal iron and manganese oxides and silica, fine enough to pass through a 0.45 micron filter membrane can also contribute to total dissolved solids.

Pyalong (Victoria) Hardness

2013/14: Pyalong (Victoria) – Hardness 300mg/L (max)

2014/15: Pyalong (Victoria) – Hardness 250mg/L (max)

2015/16: Pyalong (Victoria) – Hardness 270mg/L (max)

2018/19: Pyalong (Victoria) – Hardness 200mg/L (max)

2019/20: Pyalong (Victoria) – Hardness 320mg/L (max)


“To minimise undesirable build‑up of scale in hot water systems, total hardness (as calcium
carbonate) in drinking water should not exceed 200 mg/L.

Hard water requires more soap than soft water to obtain a lather. It can also cause scale to form on hot water pipes and fittings. Hardness is caused primarily by the presence of calcium and magnesium ions, although other cations such as strontium, iron, manganese and barium can also contribute.”

Australian Drinking Water Guidelines 2011

Pyalong (Vic) – Iron

2020/21: Pyalong (Vic) – Iron 0.42mg/L (max)

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