2007/20 – Coomberdale (Western Australia) – Naegleria fowleri, pH, Total Dissolved Solids, Hardness, Iron, Chloride

Coomberdale (Western Australia) – Naegleria fowleri detection

2007/8: Coomberdale (WA) Naegleria fowleri 1/10 samples positive for Naegleria fowleri.

“GUIDELINE No guideline value is set for Naegleria fowleri in drinking water, but an ‘action level’ is recommended for water supplies likely to be contaminated. If the organism is detected, advice should be sought from the relevant health authority.

Naegleria fowleri is a free-living, thermophilic amoeboflagellate which causes the waterborne disease primary amoebic meningoencephalitis (PAM). This rare but fatal condition has followed use of water for swimming, or domestic bathing. The organism occurs naturally in freshwater of suitable temperature, feeding on bacteria. Its occurrence is only indirectly related to human activity, inasmuch as such activity may modify temperatures or promote bacterial production. PAM has been reported from many countries, usually associated with thermally polluted environments, geothermal water or heated swimming pools. N. fowleri is almost exclusively aquatic, and water is the only known source of infection. Numerous nonvirulent Naegleria species are known in Australia.

PAM cases have been recorded from South Australia, Western Australia, Queensland and New South Wales; Naegleria fowleri has been detected in water in each of these states and in the Northern Territory. Australia is the only country where N. fowleri has been detected in public water supplies (Dorsch et al. 1983). Most of the available data on the density of N. fowleri in water relates to water supplies in South Australia (including the highest reported densities). In temperate Australia, significant seasonal cycles of density occur, from below one organism per litre to hundreds or thousands per litre in poorly disinfected water (Robinson and Christy 1984). N. fowleri detected at water temperatures below 18°C is likely to be present as cysts, which are not infectious, but which may seed a suitable environment.” Australian Drinking Water Guidelines 2011

Coomberdale (Western Australia) – pH (alkaline)

Average pH: 2007 July-2008 June: 8.55 pH units

Average pH: 2009 July-2010 June: 8.65 pH units

2010/11 Coomberdale (Western Australia) pH 9.05 (av)

2011/12 Coomberdale (Western Australia) pH 8.98 (av)

2013/14 Coomberdale (Western Australia) pH 8.65 (av)

2014/15 Coomberdale (Western Australia) pH 8.58(av)

2015/16 Coomberdale (Western Australia) pH 8.58(av)

Based on the need to reduce corrosion and encrustation in pipes and fittings, the pH of
drinking water should be between 6.5 and 8.5.

New concrete tanks and cement-mortar lined pipes can significantly increase pH and
a value up to 9.2 may be tolerated, provided monitoring indicates no deterioration in
microbiological quality.

pH is a measure of the hydrogen ion concentration of water. It is measured on a logarithmic scale from 0 to 14. A pH of 7 is neutral, greater than 7 is alkaline, and less than 7 is acidic.

One of the major objectives in controlling pH is to minimise corrosion and encrustation in pipes and fittings. Corrosion can be reduced by the formation of a protective layer of calcium carbonate on the inside of the pipe or fitting, and the formation of this layer is affected by pH, temperature, the availability of calcium (hardness) and carbon dioxide. If the water is too alkaline (above pH 8.5), the rapid deposition and build-up of calcium carbonate that can result may eventually block the pipe.

Coomberdale – Western Australia – Total Dissolved Solids

2013/14 Coomberdale (Western Australia) Total Dissolved Solids 623mg/L (max), 614mg/L (av)

2014/15 Coomberdale (Western Australia) Total Dissolved Solids 645mg/L (max), 629mg/L (mean)

2015/16 Coomberdale (Western Australia) Total Dissolved Solids 611mg/L (max), 611mg/L (mean)

2016/17 Coomberdale (Western Australia) Total Dissolved Solids 666mg/L (max), 587mg/L (mean)

2018/19: Coomberdale (Western Australia) Total Dissolved Solids 633mg/L (max), 575mg/L (mean)


“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.

Total dissolved solids comprise: sodium, potassium, calcium, magnesium, chloride, sulfate, bicarbonate, carbonate, silica, organic matter, fluoride, iron, manganese, nitrate, nitrite and phosphates…” Australian Drinking Water Guidelines 2011

Coomberdale – Western Australia – Hardness

2013/14 Coomberdale (Western Australia) Hardness 240mg/L (max), 235mg/L (av)

2014/15 Coomberdale (Western Australia) Hardness 270mg/L (max), 250mg/L (mean)

2015/16 Coomberdale (Western Australia) Hardness 260mg/L (max), 250mg/L (mean)

2016/17 Coomberdale (Western Australia) Hardness 280mg/L (max), 177mg/L (mean)

2018/19: Coomberdale (Western Australia) Hardness 240mg/L (max), 156mg/L (mean)


“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

Coomberdale (Western Australia) Iron

2011/12 Coomberdale (Western Australia) Iron 0.300mg/L (max), 0.25mg/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.

Coomberdale (Western Australia) – Chloride

2016/17 Coomberdale (Western Australia) Chloride 260mg/L (max), 233mg/L (mean)

2017/18 Coomberdale (Western Australia) Chloride 250mg/L (max), 250mg/L (mean)

2018/19: Coomberdale (Western Australia) Chloride 255mg/L (max), 223mg/L (mean)

2019/20: Coomberdale (Western Australia) Chloride 265mg/L (max), 255mg/L (mean)

“Chloride is present in natural waters from the dissolution of salt deposits, and contamination from effluent disposal. Sodium chloride is widely used in the production of industrial chemicals such as caustic soda, chlorine, and sodium chlorite and hypochlorite. Potassium chloride is used in the production of fertilisers.

The taste threshold of chloride in water is dependent on the associated cation but is in the range 200–300 mg/L. The chloride content of water can affect corrosion of pipes and fittings. It can also affect the solubility of metal ions.

In surface water, the concentration of chloride is usually less than 100 mg/L and frequently below 10 mg/L. Groundwater can have higher concentrations, particularly if there is salt water intrusion.

Based on aesthetic considerations, the chloride concentration in drinking water should not exceed 250 mg/L.

No health-based guideline value is proposed for chloride.” 2011 Australian Drinking Water Guidelines