Mount Pleasant (South Australia) – Trihalomethanes
Breaches to Australian Drinking Water Guidelines Levels Only
18/11/2016 Mount Pleasant Melrose St Trihalomethanes – Total 289 ug/L
16/12/2016 Mount Pleasant Melrose St Trihalomethanes – Total 277 ug/L
13/1/2017 Mount Pleasant Melrose St Trihalomethanes – Total 274 ug/L
25/3/22: Mount Pleasant Melrose St Trihalomethanes 280ug/L (max) 180.6ug/L (av. 2021/22)
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/contaminan
Mount Pleasant (South Australia) – Total Haloacetic Acids
6/11/20: Mount Pleasant (South Australia) Total Haloacetic Acid (HAA9) 152ug/L
5/11/21: Mount Pleasant (South Australia) Total Haloacetic Acid (HAA 9) 263ug/L (max) 175ug/L (av. 2021/22)
5/11/21: Mount Pleasant (South Australia) Trichloracetic Acid 122ug/L (max) 76ug/L (av. 2021/22)
4/11/22: Mount Pleasant (South Australia) Total Haloacetic Acid 263ug/L (max) 146.5ug/L (av. 2022/23)
8/11/24: Mount Pleasant (South Australia) Total Haloacetic Acid 122ug/L (max) 106.5ug/L (av. 2024/25)
“Chloroacetic acids are produced in drinking water as by-products of the reaction between chlorine and naturally occurring humic and fulvic acids. Concentrations reported overseas range up to 0.16mg/L and are typically about half the chloroform concentration. The chloroacetic acids are used commercially as reagents or intermediates in the preparation of a wide variety of chemicals. Monochloroacetic acid can be used as a pre-emergent herbicide, dichloroacetic acid as an ingredient in some pharmaceutical products, and trichloroacetic acid as a herbicide, soil sterilant and antiseptic.” Australian Drinking Water Guidelines – National Health and Medical Research Council
Mount Pleasant (South Australia) – Chloroketones >10ug/L
4/11/22: Mount Pleasant (South Australia): 1,1,1-trichloropropan-2-one 13.6ug/L
Data are inadequate to set guideline values for chloroketones in drinking water.
GENERAL DESCRIPTION
The chloroketones are produced in drinking water as by-products of the reaction between naturally occurring organic matter and chlorine. No data are available on other sources or uses for these compounds. Concentrations of chloroketones in drinking water reported overseas are very low and are estimated at less than 0.01 mg/L.
TYPICAL VALUES IN AUSTRALIAN DRINKING WATER
In major Australian reticulated supplies 1,1,1-trichloropropanone has been recorded in concentrations up to 0.02 mg/L, but it is usually below the limit of determination of 0.0005 mg/L. No data are available for other chloroketones.
LIMITING FORMATION IN DRINKING WATER
The presence of chloroketones in drinking water can be minimised by removing naturally occurring organic matter from the source water, by reducing the amount of chlorine added, or by the use of alternative disinfectants.” 2011 ADWG
Mount Pleasant (South Australia) – Bromodichloromethane
2022/23: Mount Pleasant (South Australia) Bromodichloromethane 67ug/L (max), 39.84ug/L (av. 2022/23)
2023/24: Mount Pleasant (South Australia) Bromodichloromethane 76ug/L (max), 51.36ug/L (av. 2023/24)
WHO Guideline level BDCM: 60ug/L (Australian Guideline for BDCM is included in the Trihalomethane (THM) combined total of BDCM, Chloroform, Dibromochloromethane and Bromoform. THM guideline is 250ug/L)
“Carcinogenicity : Bromodichloromethane is reasonably anticipated to be a human carcinogen based on sufficient evidence of carcinogenicity from studies in experimental animals.
Cancer Studies in Experimental Animals: Oral exposure to bromodichloromethane caused tumors at several different tissue sites in mice and rats. Administration of bromodichloromethane by stomach tube caused benign and malignant kidney tumors (tubular-cell adenoma and adenocarcinoma) in male mice and in rats of both sexes, benign and
malignant liver tumors (hepatocellular adenoma and carcinoma) in female mice, and benign and malignant colon tumors (adenomatous polyps and adenocarcinoma) in rats of both sexes (NTP 1987, ATSDR 1989, IARC 1991, 1999).
2022/23 Mount Pleasant (South Australia) Chloropicrin
2022/23: Mount Pleasant (South Australia) Chloropicrin 2ug/L (max), 1ug/L (av.)
No Guideline level for Chloropicrin
Chloropicrin is formed in water by the reaction of chlorine with humic acids, amino acids,
and nitrophenols. The presence of nitrates increases the amount formed (6). Chloropicrin has
been detected in drinking-water; however, in the presence of reducing agents, it is converted
into chloroform