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Revised guideline for trichloroethylene (TCE)
in drinking water, Canada
13 Jul 2005
Canadian Health Minister Ujjal Dosanjh today announced that Health Canada and the Federal-Provincial-Territorial Committee on Drinking Water has agreed to a more stringent guideline for the amount of trichloroethylene (TCE) in drinking water.
The new guideline is 10 per cent of the previous limit, lowered from 0.05 mg/L to 0.005 mg/L.
"The quality of drinking water is a priority for Canadians and their governments," said Minister Dosanjh. "Our collaborative work with provinces and territories on establishing guidelines, such as this one provides benchmarks that ensure that our drinking water is safe."
TCE is a volatile solvent used extensively in the automotive and metal industries for degreasing and cleaning of metal parts. TCE can enter groundwater as a result of industrial effluents or spills, or leaking from old dump sites. Regulations under the Canadian Environmental Protection Act, designed to phase out the use and sale of TCE in Canada, came into force in July 2003.
TCE is not a concern for most Canadians, particularly those whose drinking water comes from surface water as opposed to underground water; because surface water (i.e, water from lakes, rivers and streams) is exposed to air, TCE would evaporate. Where TCE is detected in Canadian drinking water supplies, levels are generally less than 0.001 mg/L. Health Canada and the Federal-Provincial-Territorial Committee on Drinking Water have not identified any area or region in which the current level of TCE exceeds the new guideline of 0.005 mg/L.
While studies suggest only very low rates of health effects even at high concentrations of TCE, a possible link between long-term exposure to high levels of TCE and cancer has been observed. In addition, preliminary studies indicate a possible link between exposure to high levels of TCE and potential reproductive effects associated with fetal heart development. Further studies are required to confirm these effects. The Canadian guideline of a maximum acceptable concentration of 0.005 mg/L of TCE in drinking water is protective against both the cancer risks and potential reproductive effects.
Monitoring for TCE is fairly extensive, however, there is little information available for individuals or small communities on private wells. TCE contamination of groundwater or wells could be a potential problem if the wells are located near an old industrial dump site. If people with wells are concerned, they should consult with their local medical officer of health or local provincial, territorial or municipal environment officials.
