2007/17 – Tara (Northern Territory) – E.coli, Hardness, Total Dissolved Solids, Iodine, Chloride, Sodium

Tara (Northern Territory) – E.coli

14 Feb 2017: Tara E.coli 1 detection. 1 MPN/100mL

“Coliforms are Gram-negative, non-spore-forming, rod-shaped bacteria that are capable of aerobic and facultative anaerobic growth in the presence of bile salts or other surface active agents with similar growth-inhibiting properties. They are found in large numbers in the faeces of humans and other warm-blooded animals, but many species also occur in the environment.

Thermotolerant coliforms are a sub-group of coliforms that are able to grow at 44.5 ± 0.2°C. E. coli is the most common thermotolerant coliform present in faeces and is regarded as the most specific indicator of recent faecal contamination because generally it is not capable of growth in the environment. In contrast, some other thermotolerant coliforms (including strains of Klebsiella, Citrobacter and Enterobacter) are able to grow in the environment and their presence is not necessarily related to faecal contamination. While tests for thermotolerant coliforms can be simpler than for E. coli, E. coli is considered a superior indicator for detecting faecal contamination…” ADWG 2011

Tara – Northern Territory – Hardness

2007/08: Tara Hardness 344mg/L

2008/09: Tara Hardness 348mg/L

2009/10: Tara Hardness 326mg/L

2010/11: Tara Hardness 292mg/L

2013/14: Tara Hardness 304mg/L

2015/16: Tara Hardness 359mg/L

2016/17: Tara Hardness 316mg/L


“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

Tara – Northern Territory – Total Dissolved Solids

2007/08: Tara Total Dissolved Solids 1013mg/L

2008/09: Tara Total Dissolved Solids 1000mg/L

2010/11: Tara Total Dissolved Solids 1039mg/L

2013/14: Tara Total Dissolved Solids 1026mg/L

2015/16: Tara Total Dissolved Solids 1086mg/L

2016/17: Tara Total Dissolved Solids 1005mg/L


“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

Tara – (Northern Territory) – Iodine

2007/08: Tara Iodine 0.4mg/L

2008/09: Tara Iodine 0.34mg/L

2009/10: Tara Iodine 0.32mg/L

2009/10: Tara Iodine 0.33mg/L

2013/14: Tara Iodine 0.3mg/L

2015/16: Tara Iodine 0.27mg/L

2016/17: Tara Iodine 0.27mg/L

Iodide: Based on health considerations, the concentration of iodide in drinking water should
not exceed 0.5 mg/L.
Iodine: No guideline value has been set for molecular iodine.
The element iodine is present naturally in seawater, nitrate minerals and seaweed, mostly in the form of iodide salts. It may be present in water due to leaching from salt and mineral deposits. Iodide can be oxidised to molecular iodine with strong disinfectants such as chlorine.
Molecular iodine solutions are used as antiseptics and as sanitising agents in hospitals and laboratories.
Iodine is occasionally used for the emergency disinfection of water for field use but is not used for disinfecting larger drinking water supplies. Iodide is used in pharmaceutical and photographic materials. Iodine has a taste threshold in water of about 0.15 mg/L.
Iodide occurs in cows’ milk and seafood. Some countries add iodide to table salt to compensate for iodide-deficient diets.

Tara (Northern Territory) – Chloride

2007/08: Tara Chloride 337mg/L

2008/09: Tara Chloride 355mg/L

2013/14: Tara Chloride 435mg/L

2015/16: Tara Chloride 357mg/L

2016/17: Tara Chloride 352mg/L

“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

Tara (Northern Territory) – Sodium

2007/08: Tara Sodium 221mg/L

2008/09: Tara Sodium 220mg/L

2009/10: Tara Sodium 212mg/L

2010/11: Tara Sodium 209mg/L

2013/14: Tara Sodium 214mg/L

2015/16: Tara Sodium 232mg/L

2016/17: Tara Sodium 207mg/L

“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