Coles Bay (Tasmania) – Trihalomethanes

Breaches to Australian Drinking Water Guidelines Levels Only

18/5/2016: Coles Bay Trihalomethanes – Total 280 ug/L

2016/17: Coles Bay Trihalomethanes – 357 ug/L (max), 209.3ug/L (mean). DBPs were detected above the ADWG health limits in July 2016 and March, April and May 2017. Due to a lack of filtration barriers, precursors to DBPs such as organic matter are not removed. In accordance with the recommendation in the ADWG, chlorine residuals are maintained to provide appropriate disinfection. DBP samples not collected December 2016 and January 2017 due to sampling error.

14/11/2017: Coles Bay Total Trihalomethane exceedance at GCSTE86 of 271 ug/L

12/12/17: Total Trihalomethane exceedance at GCSTE86 of 331 ug/L

13/2/18: Total Trihalomethane exceedance at GCSTE86 of 335 ug/L

13/3/18: Total Trihalomethane exceedance at GCSTE86 of 290 ug/L

10/4/18: Total Trihalomethane exceedance at GCSTE86 of 283 ug/L

15/5/18: Total Trihalomethane exceedance at GCSTE86 of 254 ug/L

14/8/18: Total Trihalomethane exceedance 255ug/L

23/10/18: Total Trihalomethane exceedance 258ug/L

20/11/18: Total Trihalomethane exceedance 261ug/L

27/11/18: Total Trihalomethane exceedance 281ug/L

5/12/18: Total Trihalomethane exceedance 274ug/L

11/12/18: Total Trihalomethane exceedance 270ug/L

18/12/18: Total Trihalomethane exceedance 298ug/L

31/12/18: Total Trihalomethane exceedance 275ug/L

8/1/19: Total Trihalomethane exceedance 263ug/L

15/1/19: Total Trihalomethane exceedance 264ug/L

22/1/19: Total Trihalomethane exceedance 257ug/L

7/1/20: Total Trihalomethane exceedance in compliance sample at GCSTE86 Coles Bay/Park
Esplanade of 255 ug/L

21/2/20: ADWG exceedance in compliance sample at GCSTE86 Coles Bay on
21/01/2020 of 254 μg/L

9/2/2021: THM’s 270 ug/l

9/03/2021: THM’s 305ug/l

2021/22: THM’s 244ug/L (max), 117ug/L (min), 201ug/L (av.)

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

Coles Bay (Tasmania) – HAA’s

7/1/20: Coles Bay (Tasmania) Total Haloacetic Acid (HAA7) 123 ug/L

14/1/20: Coles Bay (Tasmania) Total Haloacetic Acid (HAA7) 105 ug/L

21/1/20: Coles Bay (Tasmania) Total Haloacetic Acid (HAA7) 114 ug/L

10/11/20: Coles Bay (Tasmania) Total Haloacetic Acid (HAA7) 114 ug/L

Australian Guidelines Trichloroacetic Acid 0.100mg/L, Dichloroacetic Acid 0.100mg/L

“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…

Coles Bay – Tasmania – Iron

September 2 2015: Coles Bay (Tasmania) – Iron 1030ug/L

September 2 2015: Coles Bay (Tasmania) – Iron 800ug/L

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

Coles Bay (Tasmania) – Bromodichloromethane

10/11/20: Coles Bay (Tasmania) – Bromodichloromethane 70ug/L

WHO Guideline level BDCM: 60ug/L (Australian Guideline for BDCM is included in the 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).

Since bromodichloromethane was listed in the Sixth Annual Report on Carcinogens, additional studies in rats have been identified. Administration of bromodichloromethane in the drinking water increased the combined incidence of benign and malignant liver tumors (hepatocellular adenoma or carcinoma) in males (George et al. 2002) and caused benign liver tumors (hepatocellular adenoma) in females (Tumasonis et al. 1987).

Cancer Studies in Humans
The data available from epidemiological studies are inadequate to evaluate the relationship between human cancer and exposure specifically to bromodichloromethane. Several epidemiological studies indicated a possible association between ingestion of chlorinated drinking water (which typically contains bromodichloromethane) and increased risk of
cancer in humans, but these studies could not provide information on whether any observed effects were due to bromodichloromethane or to one or more of the hundreds of other disinfection by-products also present in chlorinated water (ATSDR 1989).” (1)