2016/18 – Wondai (Queensland) – E.coli, Trihalomethanes, Hardness, Chloride, Total Dissolved Solids

2016/17 – Wondai (Queensland) – E.coli

The 4th non-compliance was detected on 22/12/2016 of E.coli 1 mpn/100mL, located at Tingoora Reservoir

The 5th non-compliance was a detection of E.coli on 13/1/2016 of 2 mpn/100mL located at the Tingoora Reservoir.

South Burnett Regional Council Annual Drinking Water Quality Management Plan 2016/17

“Coliforms are Gram-negative, non-spore-forming, rod-shaped bacteria that are capable of aerobic and facultative anaerobic growth in the presence of bile salts or other surface active agents with similar growth-inhibiting properties. They are found in large numbers in the faeces of humans and other warm-blooded animals, but many species also occur in the environment.

Thermotolerant coliforms are a sub-group of coliforms that are able to grow at 44.5 ± 0.2°C. E. coli is the most common thermotolerant coliform present in faeces and is regarded as the most specific indicator of recent faecal contamination because generally it is not capable of growth in the environment. In contrast, some other thermotolerant coliforms (including strains of Klebsiella, Citrobacter and Enterobacter) are able to grow in the environment and their presence is not necessarily related to faecal contamination. While tests for thermotolerant coliforms can be simpler than for E. coli, E. coli is considered a superior indicator for detecting faecal contamination…” ADWG 2011

2016/18 – Wondai (Queensland) – Trihalomethanes

2016/17: Wandai (Queensland) Trihalomethanes 242μg/L (max) (site Wonda 3)

2017/18: Wandai (Queensland) Trihalomethanes 260μg/L (max), 194.5μg/L (av) (site Wonda 3)

2016/17: Wandai (Queensland) Trihalomethanes 254μg/L (max) (site Wonda 12)

2017/18: Wandai (Queensland) Trihalomethanes 330μg/L (max), 209.1μg/L (av) (site Wonda 12)

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”. US EPA

Wandai – (Queensland) – Hardness

2016/17: Wandai (Queensland) – Hardness 333mg/L (Highest Detection), (Site Wond 10)

2017/18: Wandai (Queensland) – Hardness 296mg/L (max), 225.4mg/L (av.) (Site Wond 10)


“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

2016/17 – Wandai (Queensland) – Chloride

2016/17: Wandai (Queensland)  Chloride 300mg/L (Highest Level) [site Wond 10]

“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

Wondai (Queensland) Total Dissolved Solids

2017/18: Wondai Total Dissolved Solids 694mg/L (max), 521mg/L (av.) [Wondai 10]


“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