2010/20 – Roebourne (Western Australia). Thermophlic Naegleria, Hardness, Total Dissolved Solids

Roebourne (Western Australia) – Thermophilic Naegleria

2010/11 Roebourne (Western Australia) Thermophilic Naegleria 1/4 positive sample

“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.

Roebourne (Western Australia) – Hardness

2013/14 Roebourne  (Western Australia) Hardness 320mg/L (max), 230mg/L (mean)

2014/15 Roebourne (Western Australia) Hardness 250mg/L (max), 245mg/L (mean)

2015/16 Roebourne (Western Australia) Hardness 270mg/L (max), 245mg/L (mean)

2016/17 Roebourne (Western Australia) Hardness 270mg/L (max), 240mg/L (mean)

2017/18 Roebourne (Western Australia) Hardness 210mg/L (max), 170mg/L (mean)

2019/20: Roebourne (Western Australia) Hardness 250mg/L (max), 225mg/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

Roebourne (Western Australia) – Total Dissolved Solids

2013/14 Roebourne (Western Australia) Total Dissolved Solids 704mg/L (max), 514mg/L (mean)

2015/16 Roebourne (Western Australia) Total Dissolved Solids 628mg/L (max), 576mg/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