2018/25: Mount Barker (South Australia). Mercury, pH, Ammonia, Chlorine, Iron, Monochloramine, Turbidity

Mercury: Australian Drinking Water  Guideline 0.001mg/L Mercury, if it enters the ecosystem can transform into the more toxic methylmercury where it can bioaccumulate. Methylmercury is highly toxic to human embryos, fetuses, infants and children. Mercury has numerous sources including old gold mines, where mercury was used in gold recovery process. It has been estimated that 950 tonnes of mercury was deposited into Victorian soil, rivers and streams during the various gold rushes. https://ntn.org.au/wp-content/uploads/2010/05/mercury_brief20101.pdf

16/10/20: Mt Barker Ammonia – Free – as NH3 0.56mg/L 13/11/20: Mt Barker Ammonia – Free – as NH3 0.53mg/L 16/4/25: Mt Barker Ammonia – Free – as N 0.77mg/L (av. 2024/25 0.318mg/L) 16/4/25: Mt Barker Ammonia – Free – as NH3 0.93mg/L (av. 2024/25 0.38mg/L) Based on aesthetic considerations (corrosion of copper pipes and fittings), the concentration of ammonia (measured as ammonia) in drinking water should not exceed 0.5 mg/L. No health-based guideline value is set for ammonia. “…Most uncontaminated source waters have ammonia concentrations below 0.2 mg/L. High concentrations (greater than 10 mg/L) have been reported where water is contaminated with animal waste. Ammonia is unlikely to be detected in chlorinated supplies as it reacts quickly with free chlorine. Ammonia in water can result in the corrosion of copper pipes and fittings, causing copper stains on sanitary ware. It is also a food source for some microorganisms, and can support nuisance growths of bacteria and algae, often with a resultant increase in the nitrite concentration.” ADWG 2011 2024/25: Mount Torrens (South Australia) Chlorine 27/325: Mount Torrens (South Australia) Chlorine Total 4.9mg/L (max). 2024/25 31/51 detections >4mg/L GENERAL DESCRIPTION Chlorine dissociates in water to form free chlorine, which consists of aqueous molecular chlorine, hypochlorous acid and hypochlorite ion. Chlorine and hypochlorites are toxic to microorganisms and are used extensively as disinfectants for drinking water supplies. Chlorine is also used to disinfect sewage and wastewater, swimming pool water, in-plant supplies, and industrial cooling water. Chlorine has an odour threshold in drinking water of about 0.6 mg/L, but some people are particularly sensitive and can detect amounts as low as 0.2 mg/L. Water authorities may need to exceed the odour threshold value of 0.6 mg/L in order to maintain an effective disinfectant residual. In the food industry, chlorine and hypochlorites are used for general sanitation and for odour control. Large amounts of chlorine are used in the production of industrial and domestic disinfectants and bleaches, and it is used in the synthesis of a large range of chemical compounds. Free chlorine reacts with ammonia and certain nitrogen compounds to form combined chlorine. With ammonia, chlorine forms chloramines (monochloramine, dichloramine and nitrogen trichloride or trichloramine) (APHA 2012). Chloramines are used for disinfection but are weaker oxidising agents than free chlorine. Free chlorine and combined chlorine may be present simultaneously (APHA 2012). The term total chlorine refers to the sum of free chlorine and combined chlorine present in a sample. Chlorine (Free) ADWG Guideline: 5mg/L (Chlorine in chloraminated supplies 4.1mg/L). Chlorine dissociates in water to form free chlorine, which consists of aqueous molecular chlorine, hypochlorous acid and hypochlorite ion. Chlorine (Total) ADWG Guideline 5mg/L (chloraminated supplies 4.1mg/L): The term total chlorine refers to the sum of free chlorine and combined chlorine present in a sample

2024/25 Mount Barker (South Australia) – Iron

30/9/24 – Mount Barker (South Australia) – Iron 0.963mg/L (max), 2024/25 (av.): 0.21mg/L

tions (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

Mount Barker (South Australia) – Monochloramine 27/3/25: Mount Barker Monochloramine 4.9mg/L (highest level only) According to the ADWG 2011: “Based on health considerations, the concentration of monochloramine in drinking water should not exceed 3mg/L (equivalent to 4.1mg Cl as C12/L) [Note: this changed in 2015 to 5 mg Cl as C12/L] Some water supplies may also be disinfected through a process called Chloramination where ammonia is added to the water prior to the chlorine, which in turn can create Monochloramines. Sunlight does not degrade Monochloramines to the same extent as chlorine, meaning that water can be stored for longer periods of time. “Chloramines are produced by combining chlorine and ammonia…Chloramines are weaker disinfectants than chlorine, but are more stable, thus extending disinfectant benefits throughout a water utility’s distribution system. They are not used as the primary disinfectant for your water. Chloramines are used for maintaining a disinfectant residual in the distribution system so that disinfected drinking water is kept safe. Chloramine can also provide the following benefits: • Since chloramines are not as reactive as chlorine with organic material in water, they produce substantially lower concentrations of disinfection byproducts in the distribution system. Some disinfection byproducts, such as the trihalomethanes (THMs) and haloacetic acids (HAAs), may have adverse health effects at high levels. These disinfection byproducts are closely regulated by EPA. EPA recently reduced the allowable Maximum Contaminant Levels for total THMs to 80 ug/L (250ug/L in Australia) and now limit HAAs to 60 ug/L. The use of chlorine and chloramines is also regulated by the EPA. We have Maximum Residual Disinfectant Levels of 4.0 mg/L for both these disinfectants. However, our concern is not from their toxicity, but to assure adequate control of the disinfection byproducts. • Because the chloramine residual is more stable and longer lasting than free chlorine, it provides better protection against bacterial regrowth in systems with large storage tanks and dead-end water mains. • Chloramine, like chlorine, is effective in controlling biofilm, which is a slime coating in the pipe caused by bacteria. Controlling biofilms also tends to reduce coliform bacteria concentrations and biofilm-induced corrosion of pipes. • Because chloramine does not tend to react with organic compounds, many systems will experience less incidence of taste and odor complaints when using chloramine. (12) “Chloramine (as CI2) is a water additive used to control microbes, particularly as a residual disinfectant in distribution system pipes. It is formed when ammonia is added to water containing free chlorine. Monochloramine is one form of chloramines commonly used for disinfection by municipal water systems. Other chloramines (di- and tri-) are not intentionally used to disinfect drinking water and are generally not formed during the drinking water disinfection process. Some people who use water containing chloramine in excess of the maximum residual disinfectant level could experience irritating effects to their eyes and nose, stomach discomfort or anemia.” (13) “Although monochloramine has been shown to be mutagenic in some in vitro studies, it has not been found to be genotoxic in vivo. In the absence of data on human cancer and on the basis of inadequate evidence for the carcinogenicity of monochloramine in experimental animals, monochloramine was evaluated by IARC as not classifiable as to its carcinogenicity (Group 3). The US EPA classified monochloramine in group D, not classifiable as to its human carcinogenicity, in that there is inadequate human and animal evidence. IPCS did not consider that the increase in mononuclear cell leukaemia was treatment-related. In the NTP bioassay in two species, the incidence of mononuclear cell leukaemias in female F344/N rats was increased, but no other increases in tumour incidence were observed”. (14) (12) https://www.epa.gov/region9/water/chloramine.html (13) https://water.epa.gov/drink/contaminants/basicinformation/disinfectants.cfm (14) Monochloramine in Drinking-water Background document for development of WHO Guidelines for Drinkingwater Quality 2004 Mount Barker (South Australia) – Turbidity 11/9/24: Mount Barker – Turbidity 7.6NTU + 7.9NTU 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