The findings highlight the importance of accounting for assessments of pharmaceuticals in rivers and lakes (Photo: FIS stock)
SSRI contamination endangers survival rate of fish
Thursday, March 08, 2012, 15:30 (GMT + 9)
Fish exhibit abnormal behaviour and lower levels of anxiety when exposed to drugs containing Selective Serotonin Reuptake Inhibitors (SSRI), tells a study by Baylor University researchers. The fish were found to expose themselves to greater predation risk.
The study also found that human data for drug activity can help predict surface water concentrations of SSRIs which negatively impact fish behaviour.
The results were published online in the journal Environmental Science & Technology.
This research has implications for communities planning to implement wastewater reuse programmes.
"This research is an important step in determining the long-term consequences of drugs taken up by fish in the environment and has direct implications for both survival and fitness of fish," said Bryan Brooks, Ph.D., professor of environmental science and biomedical studies and director of environmental health science in Baylor's College of Arts & Sciences.
In the study, the shelter-seeking behaviour of fathead minnows was supervised under laboratory conditions for 28 days using digital tracking software to diagnose abnormal behaviour while they were exposed to the SSRI sertraline, a drug used to treat panic attacks and other disorders. Sertraline concentrations and lighting conditions strongly impacted the time the minnows spent in a sheltered area.
During dark conditions, sertraline-exposed fish spent about 67-78 per cent of the time that control fish spent in the shelter. During light intervals, fish exposed to sertraline spent between 18-42 per cent less time in the shelters.
"The shelter was the only dark area during light conditions in the observation tanks; therefore, control fish apparently retreated to the shelter to reduce anxiety, whereas fish exposed to sertraline appeared to display reduced anxiety and did not exhibit this behavior," Brooks explained.
"Based on our observations, we hypothesize that fish exposed to sertraline displayed reduced levels of anxiety and consequently were more willing to explore outside of their shelters during both light and dark conditions. Fish willing to spend more time away from shelters face greater predation risk, and their overall survival rate may be reduced," he elaborated.
These findings highlight the importance of accounting for the pH of rivers and lakes in surface water quality assessments of pharmaceuticals and other weak acid and weak base contaminants.
"Conservation and water reuse strategies will become paramount to meet water resource needs of future generations. Understanding emerging risks to water quality, from pharmaceuticals and other contaminants present at trace levels, is equally important to support responsible management decisions and meet environmental protection goals," Brooks added.
A previous study by Baylor found residues of sertraline and fluoxetine, another SSRI, and their metabolites in three different types of fish living in the Pecan Creek in North Texas. A follow-up study there detected three more medications in fish -- diphenhydramine, an over-the-counter antihistamine commonly used as a sedative in sleep aids and motion sickness; diltiazem, a drug for high blood pressure; and carbamazepine, a treatment for epilepsy and bipolar disorder.
By Natalia Real