Leyburn water “safe to drink”
2017 June: Southern Free Times (Warwick)
The council issued a statement on Wednesday last week advising that “low levels” of “pharmaceuticals” – along with artificial sweetener and caffeine – had been detected in the Leyburn town water supply, which comes from an aquifer bore.
Mr See has since told the Free Times that a council investigation of the issue could take “a month or so”, but has assured Leyburn locals the contamination is not a threat to health.
The council has said it believes the contamination is the result of an infiltration of the aquifer which supplies the town by either septic or agricultural material.
The Free Times understands the contamination is most likely to be septic in nature, with a vast array of substances found in septic wastewater, including residue from illicit drugs along with pharmaceuticals such as antibiotics, mood-stabilising medications and hormones from oral contraceptives, mostly passed in urine and faeces, with some coming from unneeded medication flushed down the toilet.
The council last Thursday issued a “question and answer” style information statement on the Leyburn contamination, in addition to the initial statement on Wednesday.
It described the test results as “unusual” but reiterated that the level of pharmaceuticals represented no threat to human health.
“Water Treatment Plant Operators collect the samples, Queensland Forensic and Scientific Services Lab analyse the results,” the statement said.
“Council has reported the findings to QHealth and the Department of Water and Energy Supply under the conditions of approval of the drinking water quality management plan as we were unsure of the significance of the result from a public health perspective.
“DEWS has stated that it is not a reportable incident and council is following the recommendations of QHealth.
“QHealth has advised a boil water advisory is not an appropriate response in this instance, and that the levels of pharmaceuticals in the water will not cause harm.
“Further testing has been carried out and the raw and treated water is free from E.coli, we also tested for cryptosporidium and giardia, and these were also not detected.
“SDRC is liaising regularly with QHealth.
“The water is considered safe.
“Investigations will continue to try to find the source. If this is not possible, consideration will be given to providing an additional treatment process for the bore water if this is deemed necessary.
“Various options will be considered depending on the outcome of investigations. However, as this investigation is the early stages, council has not yet finalised options.
“These options may include additional treatment processes or potentially the need for finding an alternative aquifer for supply.”
Leyburn (Qld) Hardness
2023/2024: Leyburn (Qld) Hardness 224mg/L (max), 225.2mg/L (mean).
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.”
Australian Drinking Water Guidelines 2011
Leyburn (Qld) – Sodium
2023/24: Leyburn (Qld) Sodium 250mg/L (max), 220 mg/L (mean)
“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
Leyburn (Queensland) – Chloride
2023/24: Leyburn (Qld) Chloride 270mg/L (max), 264mg/L (mean)
“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.
Leyburn (Queensland) – Chlorate
2023/24: Leyburn (Queensland) Chlorate 2.18mg/L (max), 0.77mg/L (mean)
Chlorite: ADWG Health 0.3mg/L.
Chlorite and chlorate are disinfection by-products of chlorine dioxide disinfection process.
“… industry are having serious problems meeting chlorite/chlorate limits that were proposed in the new Australian Drinking Water Guidelines, especially for disinfection in long distance pipelines that are dosed with sodium hyptochlorite” pers comm 18/5/11.
“Chlorite occurs in drinking water when chlorine dioxide is used for purification purposes. The
International Agency for Research on Cancer (IARC) has concluded that chlorite is not classifiable as carcinogenic to humans and is listed in the Group 3 category. Changes in red blood vessels due to oxidative stress are a major concern with excessive levels of Chlorite in drinking water. According to the US EPA, potential health problems for people drinking Chorite above safe drinking water guideline include: Anemia in infants and young children and nervous system effects.” https://water.epa.gov/drink/contaminants/index.cfm
“Chlorine dioxide (chlorite) is rarely used as a disinfectant in Australian reticulated supplies.
When used, the chlorite residual is generally maintained between 0.2mg/L and 0.4mg/L. It is
particularly effective inthe control of manganese-reducing bacteria. Few data are available on
chlorate levels in Australian water supplies….Chlorine dioxide, chlorite, and chlorate are all
absorbed rapidly by the gastrointestinal tract into blood plasma and distributed to the major
organs. All compounds appear to be rapidly metabolised. Chlorine dioxide has been shown to
impair neurobehavioural and neurological development in rats exposed before birth. Experimental studies with rats and monkeys exposed to chlorine dioxide in drinking water have shown some evidence of thyroid toxicity; however, because of the studies’ limitations, it is difficult to draw firm conclusions (WHO 2005) The primary concern with chlorite and chlorate is oxidative stress resulting in changes in red blood cells. This end point is seen in laboratory animals and, by analogy with chlorate, in humans exposed to high doses in poisoning incidents (WHO 2005).” Australian Drinking Water Guidelines – National Health and Medical Research Centre
“…Subchronic studies in animals (cats, mice, rats and monkeys) indicate that chlorite and chlorate cause haematological changes (osmotic fragility, oxidative stress, increase in mean corpuscular volume), stomach lesions and increased spleen and adrenal weights… Neurobehavioural effects (lowered auditory startle amplitude, decreased brain weight and decreased exploratory activity) are the most sensitive endpoints following oral exposure to chlorite…” https://www.hc-sc.gc.ca/ewh-semt/pubs/water-eau/chlorite-chlorate/indexeng.
php#sec10_1Guidelines for Canadian Drinking Water Quality.