According to a recent research study about 25 percent of Montreal residents take an anti-depressant, and human waste that enters the Montreal sewage system contains these drugs. The system is similar to sewage treatment facilities in other major cities around the world, so there is some chance a similar effect may be occurring there as well. The Montreal system treats solid waste but does not disinfect wastewater, so anti-depressants are present in the system, which empties into the Saint Lawrence river ecosystem. Researchers found anti-depressants accumulate in fish and can alter their brain activity.
“We know that antidepressants have negative side effects on human beings, but we don’t know how exactly these chemicals are affecting the fish, and by extension, the Saint Lawrence River’s ecosystem. Nevertheless, we are seeing an impact on the river’s ecosystem, which should concern cities everywhere,” said Dr. Sébastien Sauvé. (Source: eurekaalert.org)
Last year research conducted in England discovered a similar scenario, but with shrimp instead of fish. Dr. Alex Ford from the University of Porthsmouth revealed anti-depressants in wastewater released into rivers and estuaries have probably already altered shrimp behavior making them more likely to be eaten by predators. So when Dr. Sauvé referenced the impact on the whole St. Lawrence river ecosystem, that is a very real possibility.
If trout behavior was altered as significantly as the shrimp’s was in England, they may not play their normal role any longer and their habitat could also change. Additionally, whatever species consume them when they are alive or dead could be affected by the ingestion of tissue containing anti-depressants. The amount of anti-depressants in the fish is very small, but we don’t know how little of the drugs can cause a change in small marine creatures, or even in birds that may consume contaminated fish. Once a chemical has entered the food chain it may be recycled many times. There is no immediate danger to humans from the presence of anti-depressants in the Montreal waters.
It isn’t known exactly if the anti-depressants are having negative effects on Montreal fish, but in humans they can cause decreased libido, weight gain, nausea, dizziness, insomnia, dry mouth, blurred vision, nervousness and constipation.
Last year the United States Geological Service conducted research in Colorado and Iowa showing anti-depressants in water and fish downstream from sewage treatment plants. “The antidepressants were found in fish collected over 8 kilometers (approximately 5 miles) downstream of the location of the wastewater discharge. The scientists detected several commonly used antidepressants in water, streambed sediment, and the brain tissue of white suckers, a native fish species. Fish collected upstream from the wastewater discharge did not have antidepressants present in their brain tissues.” (Source: USGS)
