Due to a growing interest in the occurrence of pharmaceutically active compounds (PhACs) and endocrine disrupting compounds (EDCs) in the aquatic environment and their potential impacts on humans and the environment, a collaborative study was conducted on these emerging contaminants in the effluents from the wastewater treatment plants (WWTPs) and in the drinking water supply system of Calgary, Alberta. A number of PhACs and EDCs were detected in the WWTP effluents, at concentrations ranging from ng/L to low µ-g/L. Although these compounds were generally removed from WWTP effluents during wastewater treatment, some compounds, such as carbamazepine were more persistent. Some target PhACs and EDCs were detected at low ng/L levels in the surface and potable water in this study. Currently, there is no evidence that trace amounts of PhACs and EDCs in Calgary's waterways can have a health impact on humans, but they may pose adverse chronic effects on aquatic life.

Disinfection by-products (DBPs) have been monitored in Calgary's drinking water for approximately 15 years. The variability of the DBPs has typically exhibited similar patterns over the period of monitoring. Due to the nature of the surface waters supplying the water treatment plants, the level of DBPs was largely influenced by surface runoff events where the level of natural organic matter (NOM) increased, which was characterized by a relatively high total organic carbon (TOC) content. Principal component analysis (PCA) was utilized for this study to quickly identify the key underlying correlations present within the very large, complex multivariate data matrix. Apart from TOC, chlorine demand, chlorine residual and temperature were observed to correlate with the formation of DBPs in the finished drinking water. In addition to TOC, PCA also indicates that pH and temperature in the distribution system could have an influence on the variability of DBPs in Calgary's drinking water. It was apparent that upgrades to the water treatment systems in Calgary have resulted in an improved removal of DBP precursors such as NOM prior to chlorination, which is a key factor in reducing the DBP levels in the drinking water, thereby providing an enhanced level of public health protection.

Key Takeaways Lead in drinking water is a top public health issue in the United States and Canada, with similarities and differences in how each country addresses it. Although lacking specifics in some aspects, Canada's new legislation for lead levels in drinking water means more stringent rules and more comprehensive methods for testing and treating. Strategies for sampling and testing are less prescriptive with this new guideline, allowing more flexibility in setting up a lead monitoring and service replacement program. The strategies used to replace and pay for lead service lines differ among various Canadian water utilities.