Rhyll (Victoria)
2006/7: Rhyll THM’s 0.280mg/L (Highest Level Only)
2007/8: Rhyll THM’s 0.280mg/L (Highest Level Only)
2010/11: Rhyll 0.250mg/L THM’s (Highest Level Only)
Trihalomethanes Australian Guideline Level 250μg/L (0.25mg/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”. Source: https://water.epa.gov/drink/contaminants/index.cfm
Rhyll – Victoria – Turbidity
2006/07: Rhyll (Victoria) – Turbidity 5.4 NTU (Maximum detection during year)
2008 October 14: Rhyll (Victoria) – Turbidity 13 NTU (Maximum detection during year)
2012/13: Rhyll (Victoria) – Turbidity 7.6 NTU (Maximum detection during year)
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.
Rhyll – Victoria – Iron
2006/7: Rhyll (Victoria) – Iron 1300ug/L (Highest level only)
2007/8: Rhyll (Victoria) – Iron 1100ug/L (Highest level only)
2008/9: Rhyll (Victoria) – Iron 630ug/L (Highest level only)
20012/13: Rhyll (Victoria) – Iron 570ug/L (Highest level only)
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
Rhyll (Victoria) – Copper
2005/6: Rhyll (Victoria) – Copper ~2.2mg/L
Based on health considerations, the concentration of copper in drinking water should not
exceed 2 mg/L.
Based on aesthetic considerations, the concentration of copper in drinking water should
not exceed 1 mg/L.
Copper is widely distributed in rocks and soils as carbonate and sulfide minerals.
Copper is relatively resistant to corrosion and is used in domestic water supply pipes and fittings. It is also used in the electroplating and chemical industries, and in many household goods. Copper sulfate is used extensively to control the growth of algae in water storages.
Copper is present in uncontaminated surface waters at very low concentrations, usually less than 0.01 mg/L. The concentration can rise substantially when water with a low pH and hardness remains in stagnant contact with copper pipes and fittings. Under these conditions, the concentration of copper can reach 5 mg/L or higher. In one extreme case overseas, a concentration of 22 mg/L was reported.