Antidepressants found in fish

Drugs not removed by sewage treatment

St. Lawrence River fish are loaded with antidepressant drugs such as Prozac, leading scientists to wonder if the "happy hormone" is altering the lifestyle of the chronically grumpy-looking marine animals.

Researchers at the Universite de Montreal and Environment Canada have discovered large quantities of antidepressants in the liver, muscle and brain tissues of brook trout exposed to three months of various levels of treated effluent from Montreal's sewage treatment plant.

According to the peer-reviewed study, which is published this week in the journal Chemosphere, most of the drug was found in liver tissue. Slightly less was found in the brain. The least amount was found in muscle, which is the filet eaten by humans.

UdeM professor Sebastien Sauve, a co-author of the study, said that because relatively small amounts are found in meat tissue, he is not worried that these fish pose a danger to humans.

Research during the last two decades has revealed that pharmaceutical drugs and personal care products are a major source of pollution in the marine environment. Even in very low concentrations, they have altered the ecosystems.

Sauve said drugs such as chemotherapy medicines, hormones and antibiotics have been found in fish and they pose a greater danger to human health than antidepressants.

"My real concern is the effects on the fish," he said, adding that they "could be quite serious."

He said the study shows that fish exposed to the effluent have changes in their brains's nerve activity. "We don't know if these are positive or not."

The problem is how to measure behavioural changes in fish.

"It's very hard," Sauve said. "The question itself is quite interesting. You can't ask a fish whether it is happier or not. One of things they can do is use cameras to look at the male behaviour. Will it have the same behaviour in mating or feeding? Then you have to go back and look at its normal behaviour. It's quite tedious work and difficult."

Quebecers purchase about 555 million antidepressants a year. That works out to about one in four Quebecers taking one pill a day. That does not include the amount prescribed by psychiatric hospitals.

Residue from antidepressants leaves through bodily waste and ends up in our waterways. Sauve said that his study indicates that the problem of antidepressants contaminating marine animals is probably global.

Most treatment plants are not equipped to deal with pharmaceutical drugs. Montreal's sewage treatment plant treats only solids and does not remove chemicals.

"The chemical structure of antidepressants makes them extremely difficult to remove from sewage, even with the most sophisticated systems available," Sauve said.

The research team found eight different kinds of antidepressants in the fish. The highest concentrations came from Prozac.

The study is a result of a controlled experiment. The volume of antidepressants that can be found in river fauna will vary greatly depending on the kind of fish and its habitat.