2019/2023: Wirrina Cove (South Australia) – Trihalomethanes, Haloacetic Acids, Bromodichloromethane, Dibromochloromethane, Sodium, Chloride, Hardness, Total Dissolved Solids, Taste & Odour, Haloacetonitriles

Wirrina Cove (South Australia) – Trihalomethanes

Breaches to Australian Drinking Water Guidelines Levels Only

1/7/19: Wirrina Cove Trihalomethanes 296mg/L (max)

31/7/19: Wirrina Cove Trihalomethanes 332mg/L (max)

28/8/19: Wirrina Cove Trihalomethanes 314mg/L (max)

11/10/19: Wirrina Cove Trihalomethanes 334mg/L (max)

8/11/19: Wirrina Cove Trihalomethanes 437mg/L (max)

22/11/19: Wirrina Cove Trihalomethanes 359mg/L (max)

29/11/19: Wirrina Cove Trihalomethanes 349mg/L (max)

6/12/19: Wirrina Cove Trihalomethanes 316mg/L (max)

13/12/19: Wirrina Cove Trihalomethanes 360mg/L (max)

10/1/20: Wirrina Cove Trihalomethanes 421mg/L (max)

5/2/20: Wirrina Cove Trihalomethanes 308mg/L (max)

14/2/20: Wirrina Cove Trihalomethanes 363mg/L (max)

21/2/20: Wirrina Cove Trihalomethanes 325mg/L (max)

28/2/20: Wirrina Cove Trihalomethanes 334mg/L (max)

6/3/20: Wirrina Cove Trihalomethanes 302mg/L (max)

13/3/20: Wirrina Cove Trihalomethanes 330mg/L (max)

20/3/20: Wirrina Cove Trihalomethanes 367mg/L (max)

27/3/20: Wirrina Cove Trihalomethanes 340mg/L (max)

9/4/20: Wirrina Cove Trihalomethanes 326mg/L (max)

8/5/20: Wirrina Cove Trihalomethanes 256mg/L (max)

5/6/20: Wirrina Cove Trihalomethanes 337mg/L (max)

2019/20: Wirrina Cove Trihalomethanes 338.38mg/L (av.)

5/2/21: Wirrina Cove Trihalomethanes 281ug/L

12/2/21: Wirrina Cove  Trihalomethanes 272ug/L

9/4/21: Wirrina Cove Trihalomethanes 252ug/L

7/1/22: Wirrina Cove Trihalomethanes 337ug/L (max) 227.3ug/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/contaminant

31/7/19 Wirrina Cove Bromoform (Trihalomethane) 243ug/L. (2019/20 av. 193ug/L)

Wirrina Cove (South Australia) – Bromodichloromethane

2019/20: Wirrina Cove Bromodichloromethane 60ug/L (max) 34.7ug/L (av.)

5/2/21: Wirrina Cove (South Australia) Bromodichloromethane 70ug/L

12/2/21: Wirrina Cove (South Australia) Bromodichloromethane 66ug/L

2022/23:  Wirrina Cove Bromodichloromethane 68ug/L (max), 34.56ug/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).

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)

Wirrina Cove (South Australia) – Dibromochloromethane

20/4/20: Wirrina Cove Dibromochloromethane  (Trihalomethane) 153ug/L (max). 2019/20 av. 103ug/L

5/2/21: Wirrina Cove Dibromochloromethane 123ug/L

12/2/21: Wirrina Cove Dibromochloromethane 122ug/L

9/4/21: Wirrina Cove Dibromochloromethane 109ug/L

7/5/21: Wirrina Cove Dibromochloromethane 107ug/L

8/4/22: Wirrina Cove Dibromochloromethane 144 ug/L (max). 94ug/L (av. 2021/22)

3/3/23: Wirrina Cove Dibromochloromethane 101 ug/L (max). 74.75ug/L (av. 2022/23)

WHO Guideline level Dibromochloromethane: 100ug/L (Australian Guideline for Dibromochloromethane is included in the Trihalomethane (THM) combined total of BDCM, Chloroform, Dibromochloromethane and Bromoform. THM guideline is 250ug/L)

Wirrina Cove (South Australia) Bromoform

3/6/22: Wirrina Cove (South Australia) Bromoform 137ug/L (max), 90.73ug/L (av. 2021/22)

WHO Bromoform Guideline 100ug/L. Bromoform is a Trihalomethane, which combined with Dibromochloromethane, Bromodichloromethane and Chloroform amount to Total Trihalomethanes. Trihalomethanes (combined) have an Australian Guideline of 250ug/L

Natural production of bromoform by phytoplankton and seaweeds in the ocean is thought to be its predominant source in the environment.[5] However, locally significant amounts of bromoform enter the environment formed as disinfection byproducts known as trihalomethanes when chlorine is added to drinking water to kill bacteria. It is somewhat soluble in water and readily evaporates into the air. Bromoform is the main trihalomethane produced in beachfront salt water swimming pools with concentrations as high as 1.2 ppm (parts per million). Concentrations in freshwater pools are 1000 times lower.[6] Occupational skin exposure limits are set at 0.5 ppm

Wirrina Cove (South Australia) – Haloacetic Acid

11/10/19: Wirrina Cove Total Haloacetic Acid 273ug/L

9/4/20: Wirrina Cove Total Haloacetic Acid 219ug/L

9/4/21: Wirrina Cove Total Haloacetic Acid (HAA9) 120ug/L

1/10/21: Wirrina Cove Total Haloacetic Acid (HAA 9) 143ug/L (max) 142ug/L (av. 2021/22)

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…

Wirrina Cove (South Australia) – Sodium

9/4/20: Wirrina Cove Sodium 384mg/L (max), 349.5mg/L (av. 2019/20)

2022/23: Wirrina Cove Sodium 233mg/L (max), 197mg/L (av. 2022/23)

“Based on aesthetic considerations (taste), the concentration of sodium in drinking water
should not exceed 180 mg/L….The sodium ion is widespread in water due to the high solubility of sodium salts and the abundance of mineral deposits. Near coastal areas, windborne sea spray can make an important contribution either by fallout onto land surfaces where it can drain to drinking water sources, or from washout by rain. Apart from saline intrusion and natural contamination, water treatment chemicals, domestic water softeners and
sewage effluent can contribute to the sodium content of drinking water.” ADWG 2011


Wirrina Cove (South Australia) – Chloride

2019/20: Wirrina Cove Chloride 605mg/L (max). 572mg/L av.

2022/23: Wirrina Cove Chloride 420mg/L (max). 295.6mg/L av.

“Chloride is present in natural waters from the dissolution of salt deposits, and contamination from effluent disposal. Sodium chloride is widely used in the production of industrial chemicals such as caustic soda, chlorine, and sodium chlorite and hypochlorite. Potassium chloride is used in the production of fertilisers.

The taste threshold of chloride in water is dependent on the associated cation but is in the range 200–300 mg/L. The chloride content of water can affect corrosion of pipes and fittings. It can also affect the solubility of metal ions.

In surface water, the concentration of chloride is usually less than 100 mg/L and frequently below 10 mg/L. Groundwater can have higher concentrations, particularly if there is salt water intrusion.

Based on aesthetic considerations, the chloride concentration in drinking water should not exceed 250 mg/L.

No health-based guideline value is proposed for chloride.” 2011 Australian Drinking Water Guidelines

Wirrina Cove (South Australia) – Hardness

2019/20: Wirrina Cove (South Australia) Total Hardness as CaCO3 296mg/L (max), 263mg/L av.


“To minimise undesirable build‑up of scale in hot water systems, total hardness (as calcium
carbonate) in drinking water should not exceed 200 mg/L.

Hard water requires more soap than soft water to obtain a lather. It can also cause scale to form on hot water pipes and fittings. Hardness is caused primarily by the presence of calcium and magnesium ions, although other cations such as strontium, iron, manganese and barium can also contribute.”

Australian Drinking Water Guidelines 2011

Wirrina Cove (South Australia) – Total Dissolved Solids.

2019/20: Wirrina Cove Total Dissolved Solids (by EC) 1400mg/L (max), 1314mg/L av.

2022/23: Wirrina Cove Total Dissolved Solids (by EC) 947mg/L (max), 732.6mg/L av.


“No specific health guideline value is provided for total dissolved solids (TDS), as there are no
health effects directly attributable to TDS. However for good palatability total dissolved solids
in drinking water should not exceed 600 mg/L.

Total dissolved solids (TDS) consist of inorganic salts and small amounts of organic matter that are dissolved in water. Clay particles, colloidal iron and manganese oxides and silica, fine enough to pass through a 0.45 micron filter membrane can also contribute to total dissolved solids.

Total dissolved solids comprise: sodium, potassium, calcium, magnesium, chloride, sulfate, bicarbonate, carbonate, silica, organic matter, fluoride, iron, manganese, nitrate, nitrite and phosphates…” Australian Drinking Water Guidelines 2011

Wirrina Cove (South Australia) – Haloacetonitriles

8/4/22: Wirrina Cove (South Australia) Dibromoacetonitrile 18.6* ug/L (max), (15.9ug/L av. 2021/22) *highest detection in South Australia for year

Data are inadequate to set guideline values for haloacetonitriles in drinking water
Haloacetonitriles are formed from organic precursors during chlorination or chloramination of drinking water. Concentrations of dihaloacetonitriles reported overseas range up to 0.04 mg/L but are typically  less than 0.003 mg/L. Concentrations of trichloroacetonitrile are less than 0.001 mg/L. Trichloroacetonitrile has been used as an insecticide. No data are available on uses for the other  haloacetonitriles.

Upgrades to improve Wirrina Cove’s drinking water begin


June 8 2020

Upgrades to SA Water’s Wirrina Cove treatment plant are set to improve the quality of drinking water for local customers.

SA Water took the reins of Wirrina Cove’s water network from the District Council of Yankalilla in July 2019, assuming responsibility of its operation and maintenance, and now work is underway to improve the overall network.

SA Water asset operations and delivery general manager Mark Gobbie said while Wirrina Cove’s water supply currently did not look ideal, it was safe to drink.

“We acknowledge there’s still a way to go to bringing the aesthetic quality of the water to an acceptable standard for local residents and businesses, but I assure you the water remains safe to drink, and we are committed to improving supply in a timely and cost-efficient way,” he said.

He said new and extra treatment infrastructure installed at the water treatment plant would improve water quality and the overall management of the Wirrina Cove drinking water network.

“A specialised aerator will assist in improving the taste and smell of our local customers’ tap water and our compliance with the Australian Drinking Water Guidelines,” he said.

“It works by removing chlorine disinfection by-products from the water, which are created by the interaction of chlorine with organic matter in the reservoir.”

Infrastructure at Wirrina Cove Reservoir was also upgraded, with a new pontoon installed at the edge to make loading and unloading and equipment onto small boats safer and more efficient before they headed out to complete monitoring, testing and treatment activities.

These tasks are conducted to give a detailed picture of “how the body of water is behaving or whether there are any localised issues such as algae”.

“The presence of algae in open water sources is a common event during warmer weather when conditions are favourable for growth, but can also occur as a result of an excess of nutrients entering the water through rain runoff or bank erosion,” Mr Gobbie said.

“Algal blooms cause a naturally-occurring compound called geosmin, which can affect water aesthetics, but is harmless to human health. The Wirrina Cove Reservoir is no exception to this water quality challenge.”

Across Australia, targeted activated carbon dosing at water treatment facilities absorb geosmin in the water before the carbon is removed through the plant’s usual treatment process – but this process is unable to be done at the Wirrina Cove plant.

Mr Gobbie said specialised equipment is being built to enable the carbon dosing can soon occur there.

“We will continue updating the community as further investigations and improvement work progresses, with information sheets currently included with each quarterly water bill sent to local SA Water customers,” he said.