| Nov 08, 2007

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Feature Article - November 8, 2007

How Safe is Sydenham Water?by Wilma Kenny

There has been rising concern in Sydenham that the water from the new treatment system may not be safe to drink. Township and Health Unit officials agree that since July 2006 when the plant opened, the water has contained a higher than recommended level of the chemicals (THMs) which form when chlorine interacts with organic matter.

The plant operators have now been granted permission by the Ministry of the Environment to change the substance used in the filtration process. Initial tests have been encouraging, and by the time you are reading this, the improved filtration process will have been in operation almost a week, and results should soon be available.


The Sydenham Water System has been in operation since July 2006. At the beginning of October 2007, Council was informed that Kingston Utilities had applied to the Ministry of the Environment for permission to change coagulants, with the intent to filter more organic matter out of the lake water before it is chlorinated, thus reducing THM levels.

Trihalomethanes (THMs) are chemicals that are created when the chlorine used to disinfect drinking water reacts with organic matter such as decaying vegetation. THMs are present to some degree in all water systems treated by chlorine: they enter the body through drinking, bathing and showering.

Health Canada’s guideline for the maximum acceptable concentration of THMs in drinking water is 0.1 mg/L. One of the four compounds in THMs is a 7-syllable item called bromodichloromethane (BDCM). It is of sufficient concern for Health Canada to have established its acceptable concentration at a much lower level: 0.016 mg/L. Health Canada states: "BDCM is considered to be a probable carcinogen in humans, with sufficient evidence in animals and inadequate evidence in humans. Exposure at levels higher than the guideline value has also been linked to a possible increase in reproductive effects (increased risk for spontaneous abortion or stillbirth) above what can normally be expected. Further studies are required to confirm these effects."

The system was designed by Totten, Sims & Hubicki to use aluminum sulphate as the coagulating agent. A coagulating agent causes tiny particles of organic matter to clump together, so they can be filtered out. According to Food & Agriculture, aluminum sulphate is the most common substance used in Canadian water treatment systems, and is considered safe when used in recommended amounts. However, in order to obtain more complete filtration of organic matter than aluminum sulphate has provided, Utilities Kingston will now use ferric chloride. (Trade name Hyperion.) It is considered to provide better removal of organic matter, and does not add aluminum to the water. They hope it will lower the THMs to acceptable levels within a week.

Township CAO Gord Burns said the Kingston Health Unit has been kept fully informed of the THM levels: "We have to rely on the experts: if the Health Unit has a problem (with the THM levels) they would shut us down."

Burns said there has not been enough water moving through the system: when the water sits too long in the pipes, the chlorine dissipates. Higher amounts of chlorine then have to be added to maintain the required level of disinfection throughout. So far, only about 40% of the village has hooked up to the system, even though the township by-law requires it.

Kevin Riley of Kingston Utilities is in charge of the plant. He said that the operator was not included in the design process, and that any change (eg to a different coagulant) is a slow process, requiring a certificate of approval from the Ministry of the Environment. He said the local MOE office has been helpful in dealing with the levels of bureaucracy, and added that contrary to rumours, the lake water is filtered prior to chlorination, not after.

According to Dr Ian Gemmill, Medical Officer of Health, a significant safety factor is built into any health guideline, and the levels of chemicals in the Sydenham water present "no immediate health risk." He said that there was a possible cancer risk only if high levels of THMs were consumed for more than 30 years: they did not pose a short-term risk. He added that to date, most of the few studies that had been performed were on rats and mice, not humans. When asked about concerns that have been raised over pregnancy and THM levels, he was less forthcoming.

Although some studies have associated low birth weight with the consumption of water with high THM levels in late pregnancy. However, information provided by the Grey-Bruce Public Health Unit discounts this possibility. “Studies exploring the link between high levels of THMs and adverse pregnancy outcomes are not conclusive. While some studies have shown a weak association, others have not demonstrated any effect. This is an issue that Health Canada is continuing to actively investigate,” says a document called Trihaomethanes on the Grey Bruce Health Unit website.

This viewpoint is supported in an article that was published in the American Journal of Epidemiology in 2006, which said that a study which looked at 258 pregnancy losses in the United States “they did not find an increased risk of pregnancy loss in relation to trihalomethane,”.

Dr. Gemmil said that Utilities Kingston takes these kinds of things seriously, and although there have been elevated chemical levels for a limited time, remediation is being provided as soon as possible. He said he is considering issuing an information letter to village residents.

All authorities were worried that residents might panic about the water, but at the time this is being written, they still have not provided the village with any information, apparently preferring to wait until the THM levels have been reduced. In the meantime, without factual information from the township, rumours continue to spread.

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