Health Canada is conducting a consultation on a report recently released by the Federal-Provincial-Territorial Committee on Drinking Water (“CDW”) in July 2014 (the “Report”) that proposes lowering the maximum acceptable concentration (“MAC”) in water of a chemical, commonly used in dry-cleaning, grain fumigation and other industrial applications.
The Report recommends lowering the MAC for tetrachloroethylene (the “compound”) in drinking water from the current 0.030 mg/L (30 µg/L) to 0.010 mg/L (10 µg/L). New Brunswick, Quebec, Ontario, Manitoba, Saskatchewan and British Columbia provided comments to the CDW, all indicating that observed concentrations of the compound are already below the proposed MAC and therefore should have minimal or no impacts including costs.
The compound is also known under the names of tetrachloroethene, perchloroethylene, PERC, PER, PCE and ethylene tetrachloride. While this compound has not been produced in Canada since 1992, it continues to be imported from the United States, albeit in ever-decreasing quantities.
The compound is primarily used as a solvent in the dry cleaning industry and as an intermediate in chemical synthesis (such as in the case of fluorocarbons). However, it has a number of other uses, including processing and finishing in the textile industry, as an extraction solvent, as an anthelmintic (a drug used to treat parasitic worm infections), as a heat exchange fluid and in grain fumigation. It is also used as an insulating fluid and cooling gas in electrical transformers and is found in paint removers, printing inks, adhesive formulations, paper coatings and aerosol formulations such as water repellents.
The compound can be removed from drinking water either at the municipal or the household level. At the municipal level, conventional treatment techniques have generally been found to be ineffective at removing the compound. Granular activated carbon absorption, packed tower aeration and various advanced oxidation processes have proven to be more effective. At the residential level, point-of-use (faucet) or point-of-entry (home) filtration systems can be installed to remove the compound, but this is recommended only where municipally treated water is not available.
Health Canada will accept feedback and comments on the Report until September 16, 2014.
