2007/18 – Mt Magnet (Western Australia) – Nitrate, Hardness, Total Dissolved Solids, Chloride, Sodium, Silica

Mt Magnet (Western Australia) – Nitrate

2016/17 Mt Magnet (Western Australia) Nitrate 72.49mg/L (max), 67.63mg/L av

2017/18 Mt Magnet (Western Australia) Nitrate 79.64mg/L (max), 65.74mg/L (av)

“…According to the Water Corporation (2013) in 1996, the Western Australian Department of Heath exempted the following remote towns from meeting the water quality guidelines regarding excessive nitrate levels in drinking water: Cue, Meekatharra, Mount Magnet, Nabawa, New Norcia, Sandstone, Wiluna, Yalgoo, Laverton, Leonora, and Menzies. These exemptions are still current. Community health nurses are instructed to provide bottled water free to nursing mothers, at no cost…” Unsafe drinking water quality in remote Western
Australian Aboriginal communities Geographical Research 184 • May 2019 • 57(2), 178–188

The most significant chemical issues for water quality come from nitrates and uranium, which occur naturally and are common in the Goldfields and Pilbara. Excessive nitrates in the diet reduce blood’s ability to carry oxygen. In infants, this can cause the potentially life-threatening Blue Baby Syndrome, where the skin takes on a bluish colour and the child has trouble breathing. Housing provides bottled water for infants under three months in communities with high nitrates. Long term solutions would likely include asset replacements or upgrades or finding new water sources, or a combination of these.

In 2013-14, fourteen of 84 communities in the Program recorded nitrates above the safe health level for bottle-fed babies under three months. Two communities had readings above the standard for adults (Figure 5).

Child Heath Levels Nitrate: 50mg/L. Adult Heath Levels Nitrate: 100mg/L

Mt Magnet – Western Australia – Hardness

2007/08: Mt Magnet (Western Australia) – Hardness 262mg/L (Highest Detection Only)

2008/09: Mt Magnet (Western Australia) – Hardness 230mg/L (max & mean)

2010/11 Mt Magnet (Western Australia) Hardness 270mg/L (max), 265mg/L (av)

2011/12 Mt Magnet (Western Australia) Hardness 270mg/L (max), 255mg/L (av)

2013/14 Mt Magnet (Western Australia) Hardness 280mg/L (max), 262mg/L (av)

2014/15 Mt Magnet (Western Australia) Hardness 270mg/L (max), 258mg/L (mean)

2015/16 Mt Magnet (Western Australia) Hardness 280mg/L (max), 260mg/L (mean)

2016/17 Mt Magnet (Western Australia) Hardness 280mg/L (max), 275mg/L (mean)

2017/18 Mt Magnet (Western Australia) Hardness 280mg/L (max), 280mg/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

Mt Magnet – Western Australia – Total Dissolved Solids

2008/09: Mt Magnet (Western Australia) – Total Dissolved Solids 859mg/L (max), 850mg/L (mean)

2009/10: Mt Magnet (Western Australia) – Total Dissolved Solids 894mg/L (max)

2010/11 Mt Magnet (Western Australia) Total Dissolved Solids 933mg/L (max), 932mg/L (av)

2011/12 Mt Magnet (Western Australia) Total Dissolved Solids 962mg/L (max), 935mg/L (av)

2013/14 Mt Magnet (Western Australia) Total Dissolved Solids 973mg/L (max), 940mg/L (av)

2014/15 Mt Magnet (Western Australia) Total Dissolved Solids 982mg/L (max), 934mg/L (mean)

2015/16 Mt Magnet (Western Australia) Total Dissolved Solids 994mg/L (max), 941mg/L (mean)

2016/17 Mt Magnet (Western Australia) Total Dissolved Solids 1004mg/L (max), 970mg/L (mean)

2017/18 Mt Magnet (Western Australia) Total Dissolved Solids 978mg/L (max), 977mg/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.

Mt Magnet (Western Australia) – Chloride

2013/14 Mt Magnet (Western Australia) Chloride 260mg/L (max), 239mg/L (av)

2014/15 Mt Magnet (Western Australia) Chloride 270mg/L (max), 243mg/L (mean)

2015/16 Mt Magnet (Western Australia) Chloride 280mg/L (max), 243mg/L (mean)

2016/17 Mt Magnet (Western Australia) Chloride 280mg/L (max), 263mg/L (mean)

2017/18 Mt Magnet (Western Australia) Chloride 280mg/L (max), 272.5mg/L (av)

“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

Mt Magnet (Western Australia) – Sodium

2013/14 Mt Magnet (Western Australia) Sodium  180mg/L (max), 165mg/L (av)

2014/15 Mt Magnet (Western Australia) Sodium 180mg/L (max), 165mg/L (mean)

2015/16 Mt Magnet (Western Australia) Sodium 180mg/L (max), 163mg/L (mean)

2016/17 Mt Magnet  (Western Australia) Sodium 185mg/L (max), 178mg/L (mean)

2017/18 Mt Magnet (Western Australia) Sodium 185mg/L (max), 180mg/L (av)

“Based on aesthetic considerations (taste), the concentration of sodium in drinking water
should not exceed 180 mg/L….The sodium ion is widespread in water due to the high solubility of sodium salts and the abundance of mineral deposits. Near coastal areas, windborne sea spray can make an important contribution either by fallout onto land surfaces where it can drain to drinking water sources, or from washout by rain. Apart from saline intrusion and natural contamination, water treatment chemicals, domestic water softeners and
sewage effluent can contribute to the sodium content of drinking water.” ADWG 2011

Mt Magnet (South Australia) – Silica

2013/14 Mt Magnet  (Western Australia) Silica 80mg/L (max), 78mg/L (av)

2015/16 Mt Magnet (Western Australia) Silica 80mg/L (max), 77mg/L (mean)

2016/17 Mt Magnet (Western Australia) Silica 80mg/L (max), 77.5mg/L (av)

2017/18 Mt Magnet (Western Australia) Silica 80mg/L (max), 80mg/L (av)

To minimise an undesirable scale build up on surfaces, silica (SiO2) within drinking waters should not exceed 80 mg/L.
Silica present in water is usually referred to as amorphous silica (i.e. lacking any crystalline structure). When silica is dissolved within water it forms monosilicic acid:
SiO2 + 2H2O à Si(OH)4
When the concentrations of monosilicic acid increase, polymerisation of the silica occurs, forming polysilicic acids followed by formation of colloidal silica. Monosilicic acid and polysilicic acids are the forms of silica analysed when determining dissolved silica content.
The deposition of silica from solutions can occur via various mechanisms. The deposition of silica that can cause the most problems for the water industry is via silica’s ability to deposit on solid surfaces that have hydroxyl (OH) groups present. Surfaces that commonly have hydroxyl groups present are glass and metallic surfaces. For example, dissolved silica will react with the surfaces of glass and begin to form a white precipitate. The silica forms silicates on the surface, resulting in silica build-up. In cases where customer complaints occur due to scale build-up, water hardness and silica concentrations should be investigated to determine the cause.
Silica can be a problem in water treatment due to its ability to cause fouling of reverse osmosis (RO) membranes (Sheikholeslami and Tan, 1999, Ning 2002, Sahachaiyunta and Sheikholeslami 2002). This occurs when the dissolved silica of the concentrate becomes super-saturated, causing silicates to form in the presence of metals, and these deposit on the membrane surface. The silicate then dehydrates, forming hard layers on the membrane that reduce the effectiveness of the process… 2011 ADWG