“With so many challenges facing a successful site clean-up program, it would be easy to overlook something as simple as the drinking water that comes from your tap. But municipal drinking water presents such challenges because the chemical composition of this ubiquitous resource may actually be “contaminating” based on the Ministry of Environment’s new site condition standards for groundwater.
Municipal drinking water contains trace concentrations of specific volatile organic compounds known as “trihalomethanes” that are formed as a result of chlorination in water treatment plants. Chloroform is the most common trihalomethane and according to Health Canada, the average chloroform concentration in Canadian drinking water is 47 µg/L. The new site condition standards for chloroform, which came into effect on July 1, 2011, varies between 2 and 22 µg/L. This means that a discharge of drinking water to the subsurface could exceed the site condition standard, implying that the property where the discharge occurred could be considered “contaminated”. This is particularly relevant for Table 3 (non-potable) sites, where the chloroform standard for groundwater has become much more stringent.
A common source of chloroform in groundwater is leakage from municipal water distribution systems and sanitary sewers; however, in some instances municipal water is used for environmental drilling and discharged into groundwater. In this circumstance, straight-forward technical measures can be applied to prevent any potential for chloroform “contamination”, such as aggressive well development to remove any injected water.
It remains to be seen whether this type of groundwater “contamination” ever becomes an obstacle to obtaining a Record of Site Condition. That said, it does raise the awkward possibility that your average municipal drinking water, while safe to drink, could potentially derail the success of a site cleanup program.”
Thank you, Eric!
