Australian Drinking Water Map

2023/24 Texas (Queensland) – Trihalomethanes

February 2023 Texas (Queensland) Trihalomethanes 260ug/L

2023/24: Texas (Queensland) Trihalomethanes 280ug/L (max), 69ug/L (min)

There were detections of trihalomethanes (THMs – a family of disinfection byproduct that forms as a result of disinfecting the water supply to kill bacteria and viruses) in Texas in February 2023, and 3 detections of THMs in Talwood in January and March 2023. The Australian Drinking Water Guidelines notes that actions to reduce trihalomethanes is encouraged, but must not compromise disinfection as non-disinfected water poses significantly greater risks that trihalomethanes. Further, the THM fact sheet indicates that concentrations fluctuating occasionally (for a day or two annually) up to 1 mg/L are unlikely to pose a significant health risk. In Texas, the initial sample result of 260 ug/L is slightly above the 250 ug/L health guideline value. Resample results were all below the relevant limit. Since this time, planning has commenced to install a reservoir mixer and to “trim dose” chlorine into the reservoir. Similarly in Talwood, the initial detection was 290 ug/L. A follow up sample detected 260 ug/L and another sample in March was 370 ug/L. Council is reconfiguring the reservoirs so that the first reservoir is a chlorine contact tank, and the second reservoir is mixed and trim dosed. These improvements to the treated water storages will allow Council to apply a lower initial chlorine dose that is still sufficient to ensure effective disinfection, and then maintain the chlorine level in the treated water reservoir with trim dosing. This strategy is intended to minimise the reactions that form these disinfection byproducts – Goondiwindi Regional Council 2022/23

Australian Drinking Water Guideline THM’s 0.25ug/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

Texas (Queensland) – Hardness

2018/19: Texas (Queensland) – Hardness 220mg/L (av. 121mg/L)

GUIDELINE

“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.”

Texas (Queensland) – Turbidity

2018/19: Texas (Queensland) Turbidity 13 NTU (max), (av. 1.3 NTU)

2023/24: Texas (Queensland) Turbidity 17 NTU (max), (av. 0.5 NTU)

Chlorine-resistant pathogen reduction: Where filtration alone is used as the water treatment process to address identified risks from Cryptosporidium and Giardia, it is essential that filtration is optimised and consequently the target for the turbidity of water leaving individual filters should be less than 0.2 NTU, and should not exceed 0.5 NTU at any time
Disinfection: A turbidity of less than 1 NTU is desirable at the time of disinfection with chlorine unless a higher value can be validated in a specific context.

Aesthetic: Based on aesthetic considerations, the turbidity should not exceed 5 NTU at the consumer’s tap

Texas – Queensland – Total Dissolved Solids

2022/24: Texas (Queensland) Total Dissolved Solids 5870mg/L (max), 104mg/L (mean)

GUIDELINE

“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.

2018/24 – Texas (Queensland) – Trihalomethanes, Hardness, Turbidity

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2023/24 Texas (Queensland) – Trihalomethanes February 2023 Texas (Queensland) Trihalomethanes 260ug/L 2023/24: Texas (Queensland) Trihalomethanes 280ug/L (max), 69ug/L (min) There were detections of trihalomethanes (THMs – a family of disinfection byproduct that forms as a result of disinfecting the water supply to kill bacteria and viruses) in Texas in February 2023, and 3 detections of THMs in Talwood in January and March 2023. The Australian Drinking Water Guidelines notes that actions to reduce trihalomethanes is encouraged, but must not compromise disinfection as non-disinfected water poses significantly greater risks that trihalomethanes. Further, the THM fact sheet indicates that concentrations fluctuating occasionally (for a day or two annually) up to 1 mg/L are unlikely to pose a significant health risk. In Texas, the initial sample result of 260 ug/L is slightly above the 250 ug/L health guideline value. Resample results were all below the relevant limit. Since this time, planning has commenced to install a reservoir mixer and to “trim dose” chlorine into the reservoir. Similarly in Talwood, the initial detection was 290 ug/L. A follow up sample detected 260 ug/L and another sample in March was 370 ug/L. Council is reconfiguring the reservoirs so that the first reservoir is a chlorine contact tank, and the second reservoir is mixed and trim dosed. These improvements to the treated water storages will allow Council to apply a lower initial chlorine dose that is still sufficient to ensure effective disinfection, and then maintain the chlorine level in the treated water reservoir with trim dosing. This strategy is intended to minimise the reactions that form these disinfection byproducts – Goondiwindi Regional Council 2022/23 Australian Drinking Water Guideline THM’s 0.25ug/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 Texas (Queensland) – Hardness 2018/19: Texas (Queensland) – Hardness 220mg/L (av. 121mg/L) GUIDELINE “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.”
Texas (Queensland) – Turbidity 2018/19: Texas (Queensland) Turbidity 13 NTU (max), (av. 1.3 NTU) 2023/24: Texas (Queensland) Turbidity 17 NTU (max), (av. 0.5 NTU) Chlorine-resistant pathogen reduction: Where filtration alone is used as the water treatment process to address identified risks from Cryptosporidium and Giardia, it is essential that filtration is optimised and consequently the target for the turbidity of water leaving individual filters should be less than 0.2 NTU, and should not exceed 0.5 NTU at any time Disinfection: A turbidity of less than 1 NTU is desirable at the time of disinfection with chlorine unless a higher value can be validated in a specific context. Aesthetic: Based on aesthetic considerations, the turbidity should not exceed 5 NTU at the consumer’s tap Texas – Queensland – Total Dissolved Solids 2022/24: Texas (Queensland) Total Dissolved Solids 5870mg/L (max), 104mg/L (mean) GUIDELINE “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.