Contaminants Canadian drinking water

Table I. Concentration of Contaminants in Canadian Drinking Water Supplies...

Groundwater significantly exceeds Canadian Drinking Water Guidelines (CDWG) by >2x or known contact of contaminants... 

Review chemical data and evaluate groundwater quaUfy. If contamination at or beyond the property boundary exceeds Canadian Drinking Water Guidelines (CDWG) or applicable provincial/territorial guidelines or policies, or if contaminants are known to be in contact with groundwater, then evaluate the site as high. 

Both atrazine and metolachlor are classified as potential human carcinogens by the USEPA, which has established a maximum contaminant level in drinking water of 3000 ng/L [78]. The maximum concentrations of atrazine and metolachlor measured in the 1994-2000 Great Lakes survey were 1039 ng/L and 736 ng/L, respectively. The effects of long-term, low-level concentrations of atrazine and metolachlor on aquatic ecosystems are largely unknown [79]. The Canadian guidelines for the protection of aquatic fife and drinking water (Table 8) were not exceeded for either of these herbicides [80-83]. 

In 1990 there were 3 reports of the low level occurrence of benzene in beverages. Bottled mineral water was contaminated with benzene originated from an underground source of carbon dioxide which was inadequately carbon treated [23]. Two manufacturers found benzene in fmit flavoured mineral waters at levels greater than 5.0 pg/kg [24], The US EPA maximum contaminant level (MAE) for benzene is 0.005 mg/L [25] which is also the Canadian guideline as maximum acceptable concentration (MAC) in drinking water [26]. The manufacturers attributed the benzene to the presence of ascorbic acid and sodium benzoate in combination in their drink formations [27], omitting either of these additives eliminated the benzene. 

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