With cannabis becoming legal in Canada, municipalities are thinking ahead. They are asking if their drinking water treatment plants are equipped to handle cannabis’ active ingredients that may enter rivers and lakes used for drinking water production via sewage discharge. To keep tetrahydrocannabinol (THC) and cannabidiol (CBD) from entering our drinking water, they have turned to Sigrid Peldszus for insight.
Using modelling software, Peldszus and graduate student Sabrina Bedjera, together with Walkerton Clean Water Centre scientist Xiaohui Jin, were able to share a good news story. They looked at drinking water treatment plants on the Grand River and Lake Ontario and found that ozonation, a widely used water treatment method, can in fact degrade THC and CBD very efficiently. When ozonation is used in the treatment process, she says it is unlikely that these active ingredients will reach treated drinking water.
“Municipalities,” she says, “are vigilant about the need to prevent contaminants such as pesticides and pharmaceuticals from ending up in our drinking water, so it is natural they are concerned about cannabis as well.”