The quantities of bezafibrate and enalapril detected in the raw wastewater, treated wastewater and surface water at the treatment station outlet are respectively 50 nanograms per litre, 35 ng L and 8 ng L for bezafibrate and 280 ng L, 240 ng L and 39ng L for enalapril.
"All in all, these quantities are minimal, yet we don't yet know their effects on the fauna and flora of the St. Lawrence," Professor Sauv explains. "It is possible that some species are sensitive to them. Other ecotoxicological studies will be necessary. As for the chemotherapy products detected in the raw wastewater but not in the treated wastewater, one question remains: did we not detect them because the treatment process succeeded in eliminating them or because our detection method is not yet sophisticated enough to detect them?"
A new threat to the aquatic environment
The release locations of wastewaters treated by the treatment stations are the main source of drug dispersion into the environment. Because of their high polarity and their acid-base character, some of the pharmaceutical compounds studied have the potential to be transported and dispersed widely in the aquatic environment. In Montreal, the wastewater treatment station treats a water volume representing 50 percent of the water treated in Quebec and has a capacity of about 7.6 million cubic metres per day, making it the largest physicochemical treatment station in the Americas. This is why it is important to develop a simple, rapid, precise and inexpensive method, Professor Sauv points out.
|Contact: Julie Gazaille|
University of Montreal