2017 & 2021/23- Ottoway (South Australia) – Trihalomethanes, Bromodichloromethane, Chloropicrin

Ottoway (South Australia) – Trihalomethanes

Breaches to Australian Drinking Water Guidelines Levels Only

23/1/2017 Ottoway May Tce Trihalomethanes – Total 251 ug/L

20/2/2017 Ottoway May Tce Trihalomethanes – Total 287 ug/L

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

Ottoway (South Australia) – Bromodichloromethane

2021/22: Ottoway (South Australia) Bromodichloromethane 60ug/L (max), 46.67ug/L (av.)

2022/23: Ottoway (South Australia) Bromodichloromethane 91ug/L (max), 64.92ug/L (av.)

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 Ottoway (South Australia) Chloropicrin

2022/23: Ottoway (South Australia) Chloropicrin 1.4ug/L (max), 0.8ug/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