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.)
GUIDELINE
“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
GUIDELINE
“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
GUIDELINE
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.
GENERAL DESCRIPTION
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.
TYPICAL VALUES IN AUSTRALIAN DRINKING WATER
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
Imanpa (Northern Territory) – Selenium
2009/2010: Imanpa Selenium 0.004mg/L (max)
2010/2011: Imanpa Selenium 0.004mg/L (max)
2013/2014: Imanpa Selenium 0.004mg/L (95% percentile)
2015/2016: Imanpa Selenium 0.004mg/L (95th percentile)
Based on health considerations, the concentration of selenium in drinking water should not exceed 0.004 mg/L (2011-2025 guideline 0.01mg/L). “General description Selenium (Se) and selenium salts are widespread in the environment. Selenium is released from natural and human-made sources (such as the burning of coal). Selenium is also a by-product of the processing of sulfide ores, chiefly in the copper refining industry. The major use of selenium is in the manufacture of electronic components. It is used in several other industries, and selenium compounds are used in some insecticides, in hair shampoos as an antidandruff agent, and as a nutritional feed additive for poultry and livestock. Selenium copper alloys have also been identified as a potential replacement for lead copper alloys in plumbing products. Further information on lead replacements in plumbing products (such as selenium copper alloys) is available in Information Sheet 4.1 – Metal and metalloid chemicals leaching from plumbing products. Selenium concentrations in drinking water source waters are generally very low and depend on local geochemistry, climatic conditions (e.g. drought), pH and the presence of iron salts. Selenium in water is mainly present as inorganic compounds, predominantly selenate. Weathering of rocks and soil may result in low levels of selenium in water, which may be taken up by plants (SLR 2022). Food is the major source of intake for Australians. Cereal and grain products contribute most to intake, while fish and liver contain the highest selenium concentrations.” ADWG 2025
