2016/18: Gladstone (Queensland) Lake Awoonga Scheme – Bromate
2016/17: Gladstone (Queensland) Bromate 0.047mg/L (max), 0.004mg/L (av.)
2017/18: Gladstone (Queensland) Bromate 0.046mg/L (max), 0.001mg/L (av.)
Two bromate results in the Lake Awoonga scheme exceeded the ADWG lifetime exposure health guideline of 0.02mg/L, with the highest result being 0.046mg/L. The average result for the scheme was 0.001mg/L, which is significantly below the lifetime exposure guideline value…
During routine monitoring in March 2018 it was identified that there were exceedances in Bromate levels in the Lake Awoonga Scheme within the Clinton Park Reservoir Zone and at the Wurdong Reservoir. Both these Reservoirs are fed by the Gladstone WTP which is operated by the Gladstone Area Water Board (GAWB). Investigation and Cause: • This is likely due to bromine within Lake Awoonga, but the source has not been identified.
Gladstone Drinking Water Quality Management Plan 2017/18
GUIDELINE: Based on health considerations, the concentration of bromate in drinking water should not exceed 0.02 mg/L.
Bromate is not a normal component of water but may be formed from bromide during ozonation. Concentrations up to 0.09 mg/L have been reported in ozonated drinking water. Bromate is a strong oxidant and will probably react with organic matter in water, forming bromide as a by-product.
Bromate is used in home hair permanent-wave neutralising solutions. Although it is used in some foods overseas, Australian Food Standards do not allow bromate to be used in food in Australia.
TYPICAL VALUES IN AUSTRALIAN DRINKING WATER
It is unlikely that bromate would be present in Australian reticulated drinking water supplies unless ozonation is used for disinfection.
Based on aesthetic considerations, true colour in drinking water should not exceed 15 HU.
“… Colour is generally related to organic content, and while colour derived from natural sources such as humic and fulvic acids is not a health consideration, chlorination of such water can produce a variety of chlorinated organic compounds as by-products (see Section 6.3.2 on disinfection by-products). If the colour is high at the time of disinfection, then the water should be checked for disinfection by-products. It should be noted, however, that low colour at the time of disinfection does not necessarily mean that the concentration of disinfection by-products will be low…
2015/17 – Gladstone – Turbidity
2015/16: Gladstone – Turbidity 5.63NTU (max), 0.126NTU (av.)
2016/17: Gladstone – Turbidity 5.85NTU (max), 0.166NTU (av.)
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
2016/17 Gladstone (Queensland) – Iron
2016/17: Gladstone (Queensland) – Iron 0.36mg/L (max), 0.007mg/L (av.)
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