Pharmaceuticals and pesticides in rural community drinking waters of Quebec, Canada – a regional study on the susceptibility to source contamination

In Canada, the presence of pharmaceuticals and pesticides in municipal drinking water has been examined primarily in larger urban centres which draw their supplies from surface water. However, few studies have examined this issue in smaller and rural communities, which represent nearly one-third of the Canadian population and which draw their drinking water mainly from groundwater. This study presents a regional-scale assessment of the presence of these contaminants in the drinking waters of 17 smaller rural communities, compared with two larger urban communities, in south-central Quebec. From a total of 70 chemicals examined, 15 compounds (nine pharmaceuticals and six pesticides) were detected. The three most frequently detected contaminants were caffeine, atrazine and naproxen, respectively, in 29%, 24% and 21% of the samples. Detections reported here for the first time in Quebec drinking water include the known human carcinogen cyclophosphamide and the fungicide thiabendazole. Maximum concentrations of pharmaceuticals ranged from 30 to 1,848 ng L−1 and of pesticides from 21 to 856 ng L−1. This study provides direct evidence that drinking water in smaller, rural communities of Quebec, Canada, whether sourced from groundwater or surface water, can contain measurable levels of pharmaceuticals and pesticides, indicative of their susceptibility to source contamination.This article has been made Open Access thanks to the kind support of CAWQ/ACQE (https://www.cawq.ca).