7/9/22 – Clermont (Queensland) – Formaldehyde
7/9/22 – Clermont (Queensland) – Formaldehyde 0.7mg/L (maximum detection)
Guideline: Based on health considerations, the concentration of formaldehyde in drinking water should not exceed 0.5 mg/L.
GENERAL DESCRIPTION
Formaldehyde may be present in drinking water through ozonation of naturally occurring humic material, contamination by accidental spills, or deposition from the atmosphere. Typical concentrations in air are probably in the low parts-per-billion range. Overseas, formaldehyde has been detected in ozonated drinking water at concentrations up to 0.03 mg/L.
Formaldehyde is used industrially in the wood, paper and textile industries. It is also used in the production of a number of chemicals and for the preservation of biological material. It is occasionally used as a disinfectant, sometimes to disinfect water filters. Other sources of exposure include cigarette smoke and food. Formaldehyde is present in almost all common foods, and adult dietary intake is estimated at 11 mg/day. Drinking water would contribute less than 10% of total intake.
TYPICAL VALUES IN AUSTRALIAN DRINKING WATER
No data are available on the concentrations of formaldehyde in Australian drinking waters
6/1/21 Clermont (Queensland) – Trihalomethanes
6/1/21 Clermont (Queensland) – Trihalomethanes 0.254ug/L (max) ex clear well
Australian Drinking Water Guideline THM’s 0.25ug/L
Why and how are THMs formed?
“When chlorine is added to water with organic material, such as algae, river weeds, and decaying leaves, THMs are formed. Residual chlorine molecules react with this harmless organic material to form a group of chlorinated chemical compounds, THMs. They are tasteless and odourless, but harmful and potentially toxic. The quantity of by-products formed is determined by several factors, such as the amount and type of organic material present in water, temperature, pH, chlorine dosage, contact time available for chlorine, and bromide concentration in the water. The organic matter in water mainly consists of a) humic substance, which is the organic portion of soil that remains after prolonged microbial decomposition formed by the decay of leaves, wood, and other vegetable matter; and b) fulvic acid, which is a water soluble substance of low molecular weight that is derived from humus”.
Clermont (Queensland) – Manganese
2016/17: Clermont (Queensland) – Manganese 0.1061mg/L (maximum). 0.13mg/L (average)
1ADWG exceedence.
2015/16: Clermont (Queensland) – Manganese 0.2mg/L (maximum). 0.102mg/L (average)
3 ADWG exceedences.
Manganese: ADWG Guidelines 0.5mg/L. ADWG Aesthetic Guideline 0.1mg/L
Manganese is found in the natural environment. Manganese in drinking water above 0.1mg/L can give water an unpleasant taste and stain plumbing fixtures and laundry.
20/9/23: Clermont (Queensland) Turbidity
20/9/23: Clermont (Queensland) Turbidity 8NTU (max)
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
Clermont (Queensland) – Dissolved Oxygen
2016/17: Clermont (Queensland) Dissolved Oxygen 99% (max), av. 87%. 6 exceedences during year.
2015/16: Clermont (Queensland) Dissolved Oxygen 92% (max), av. 83.317%. 3 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