Residents assured drinking water safe

15 Nov 2010

https://www.abc.net.au/news/2010-11-15/residents-assured-drinking-water-safe/2336908

Moranbah and Nebo residents, south-west of Mackay in north Queensland, are being assured their water is safe to drink, after the discovery of benzene in three coal seam gas wells last week.

A spokesman for the Isaac Regional Council says Moranbah is supplied from groundwater supplies from the Burdekin and Eungella dam, and not from underground supplies. He says Nebo’s supply is from an underground aquifer. Arrow Energy says trace levels of benzene have been found in the three wells outside Moranbah and is unlikely to pose a public health risk. Nebo WTP (Queensland)  – Lead 2014/2015: Moura, Qld Lead 0.0046mg/L 2015/16: Nebo Road WTP Lead 0.00462mg/L (max), <0.001mg/L (min.) Lead Guideline reduced from 0.01mg/L to 0.005mg/L in June 2025. “The concentration of lead in water within premises may be higher, especially in older buildings, due to contact of the water with lead-containing plumbing products (enHealth 2021). A review found several Australian and international studies that detected up to 0.162 mg/L of lead in drinking water due to leaching from lead-containing plumbing materials including taps and lead service lines, suggesting that leaching of lead from lead-containing plumbing materials can be substantial (SLR 2023)… Based on health considerations, the concentration of lead in drinking water should not exceed 0.005 mg/L.” Nebo (Queensland) – Dissolved Oxygen 2016/17: Nebo (Queensland) Dissolved Oxygen 85.9% (max), av. 70.7%. 11 exceedences during year. 2015/16: Nebo (Queensland) Dissolved Oxygen 80.5% (max), av. 65.482%. 5 exceedences during year. Based on aesthetic considerations, it is desirable that the dissolved oxygen concentration in drinking water be greater than 85% saturation. No health-based guideline value has been set for dissolved oxygen. GENERAL DESCRIPTION Drinking water will generally contain an adequate concentration of dissolved oxygen; however, under some circumstances the oxygen concentration may be reduced. This may occur, for instance, where water has been drawn from deep storages, where there is considerable growth of microorganisms in a distribution system, or following prolonged periods of high water temperature. Low oxygen concentrations or anoxic conditions enable nuisance anaerobic microorganisms to grow, producing by-products that affect the aesthetic quality of the water and increase corrosion of pipes and fittings. There are a number of such nuisance microorganisms. Manganese-reducing bacteria produce black manganese deposits which can slough off pipes and soil laundry. Sulfate-reducing bacteria can produce hydrogen sulfide, giving drinking water a ‘rotten egg’ smell. Nitrate-reducing bacteria can produce nitrite. Iron-reducing bacteria can increase the concentration of ferrous ion in solution which will lead to the deposition of insoluble ferric salts when aeration is increased. Localised pH changes associated with the growth of nuisance microorganisms can cause rapid corrosion in metal pipes. Water from groundwater sources will generally have low oxygen concentrations and while this may cause no difficulties for most supplies, some supplies may need aeration to improve water quality (e.g. taste and odour). ADWG 2011 Nebo – (Queensland) – Hardness 2016/17: Nebo (Queensland) – Hardness 487.57mg/L (Highest Detection), (258.08mg/L av) 6 exceedences during year 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