2007/22 – Imanpa (Northern Territory) – Uranium, Hardness, Total Dissolved Solids, Iodine, Chloride, Turbidity, Iron, Sodium, Sulphate

Imanpa – Northern Territory – Uranium

2016/17: Imanpa – Uranium 0.013mg/L

Uranium (Information Sourced From 2011 Australian Drinking Water Guidelines)
“Based on health considerations, the concentration of uranium in drinking water should not exceed 0.017 mg/L.”

Imanpa – Northern Territory – Hardness

2007/08: Imanpa Hardness 451mg/L

2008/09: Imanpa Hardness 451mg/L

2009/10: Imanpa Hardness 418mg/L

2010/11: Imanpa Hardness 432mg/L

2013/14: Imanpa Hardness 431mg/L

2015/16: Imanpa Hardness 454mg/L

2016/17: Imanpa Hardness 510mg/L

2021/22: Imanpa Hardness 500mg/L (av.)


“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

Imanpa – Northern Territory – Total Dissolved Solids

2007/08: Imanpa Total Dissolved Solids 1300mg/L

2008/09: Imanpa Total Dissolved Solids 1300mg/L

2010/11: Imanpa Total Dissolved Solids 1300mg/L

2013/14: Imanpa Total Dissolved Solids 1271mg/L

2015/16: Imanpa Total Dissolved Solids 1263mg/L

2016/17: Imanpa Total Dissolved Solids 1360mg/L

2021/22: Imanpa Total Dissolved Solids 1400mg/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

Imanpa – (Northern Territory) – Iodine

2007/08: Imanpa Iodine 0.61mg/L

2009/10: Imanpa Iodine 0.63mg/L

2013/14: Imanpa Iodine 0.53mg/L

2015/16: Imanpa Iodine 0.45mg/L

2016/17: Imanpa Iodine 0.3mg/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.

Imanpa (Northern Territory) – Chloride

2007/08: Imanpa Chloride 374mg/L

2010/11: Imanpa Chloride 389mg/L

2013/14: Imanpa Chloride 376mg/L

2015/16: Imanpa Chloride 380mg/L

2016/17: Imanpa Chloride 395mg/L

2021/22: Impanpa Chloride 430mg/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

Imanpa (Northern Territory) – Turbidity

2010/11: Imanpa Turbidity 8.2NTU

2013/14: Imanpa Turbidity 8.6NTU

Chlorine-resistant pathogen reduction: Where filtration alone is used as the water treatment
process to address identified risks from Cryptosporidium and Giardia, it is essential
that filtration is optimised and consequently the target for the turbidity of water leaving
individual filters should be less than 0.2 NTU, and should not exceed 0.5 NTU at any time
Disinfection: A turbidity of less than 1 NTU is desirable at the time of disinfection with
chlorine unless a higher value can be validated in a specific context.

Aesthetic: Based on aesthetic considerations, the turbidity should not exceed 5 NTU at the
consumer’s tap.

Imanpa (Northern Territory) Iron

2013/14: Imanpa Iron 0.64mg/L

2015/16: Imanpa Iron 0.61mg/L

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

Imanpa (Northern Territory) – Sodium

2007/08: Imanpa Sodium 230mg/L

2008/09: Imanpa Sodium 230mg/L

2009/10: Imanpa Sodium 239mg/L

2013/14: Imanpa Sodium 228mg/L

2015/16: Imanpa Sodium 232mg/L

2016/17: Imanpa Sodium 254mg/L

2021/22: Imanpa Sodium 220mg/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
Imanpa (Northern Territory) – Sulfate
2021/22: Imanpa Sulphate 290mg/L (max), 280mg/L (av.)
“Sulfate occurs naturally in a number of minerals, and is used commercially in the manufacture of  numerous products including chemicals, dyes, glass, paper, soaps, textiles, fungicides and insecticides.
Sulfate, including sulfuric acid, is also used in mining, pulping, and the metal and plating industries.
Barium sulfate is used as a lubricant in drilling rigs for groundwater supply.
In the water industry, aluminium sulfate (alum) is used as a flocculant in water treatment, and copper  sulfate is used for the control of blue-green algae (cyanobacteria) in water storages.
The highest concentrations reported in drinking water overseas are from groundwater supplies where  the presence of sulfate is due to natural leaching from rocks. Concentrations have been reported up to  2200 mg/L. In source waters, concentrations are typically less than 100 mg/L.
The taste threshold for sulfate is in the range 250–500 mg/L.
Under anoxic conditions, the reduction of sulfate to sulfide by sulfate-reducing bacteria can result in  unpleasant taste and odour due to the release of hydrogen sulfide, and can increase corrosion in pipes.
Food is probably the major source of intake of sulfate. In areas where the concentration of sulfate in  water is high, drinking water may constitute the principal source of intake.
In major Australian reticulated supplies, sulfate concentrations range from 1 mg/L to 240 mg/L, with  a typical concentration of 20 mg/L. Sulfate concentrations can vary markedly in different parts of  the country.” 2011 ADWG