Antidepressants polluting rivers building up in brains of fish

A study of ecosystem of the Niagara River has discovered that antidepressants are building up in the brains of fish. The levels found in the river were due to the fact that water sanitation plants do not filter for such contaminants in the water, allowing levels to rise in parallel with human use of the drugs.

Due to the way the fish absorb the drugs, it led levels of the antidepressants in the fish being as high as a 100 times stronger than in the water itself. In one rock bass, the fish was found to have a cocktail of norsertraline, citalopram and nurfluoxetine in its system. Researchers also noted that every single fish they caught in the river had at least one chemical agent found in various kinds of antidepressants.

"These active ingredients from antidepressants, which are coming out from wastewater treatment plants, are accumulating in fish brains," said lead author, Diana Aga, Henry M. Woodburn Professor of Chemistry in the University at Buffalo College of Arts and Sciences. "It is a threat to biodiversity, and we should be very concerned.

She continued, "These drugs could affect fish behaviour. We didn’t look at behaviour in our study, but other research teams have shown that antidepressants can affect the feeding behaviour of fish or their survival instincts. Some fish won’t acknowledge the presence of predators as much."

As mentioned by Aga, fishes developing a suicidal instinct, by losing their fear of predators, could cause a serious imbalance within the ecosystem, especially as levels are tied to human use of antidepressants.

The drugs find their way into the water system through human urine, as excess chemicals leave the human body and find their way into waste water disposal centres. With the use of antidepressants in the US rising by 65% from 2002 and having doubled in the UK since 2005, it is likely that levels of antidepressants in water will continue to grow.

It is not thought that, at present, this poses an immediate risk to humans – as fish brains are not often consumed. Once levels become higher and spread more widely through the ecosystem, however, there could be severe knock-on effects.