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Casting Prozac
Upon the Waters

by Kelli Whitlock


Intro/ Chemicals Out of Place  |  Provacative Results

Marsha Black studies how Prozac affects growth and development of aquatic species such as frogs, fish, and insects.


Marsha Black has learned that sometimes the best way to see the big picture is to study the small details. The University of Georgia ecotoxicologist has examined water-quality issues for decades, spending most of that time trying to better understand the biological impact that pollutants can have on even the tiniest of aquatic organisms. Recently, she has turned her attention to a new concern — the steady deposit of antidepressant drugs such as Prozac into wastewater, their ultimate presence in creeks, streams, and other surface waters, and the consequent effects of these chemicals on wildlife.

Ironically, when Black’s collaborator, Mississippi State University scientist Kevin Armbrust, was younger, his father used to joke that “the world would be a better place if its drinking water supply had a little bit of Prozac in it.” But while Prozac and related medications offer hope to millions of people who experience a range of mental-health problems, such drugs have properties similar to other pollutants when they wind up in unintended places. And the damage they wreak on aquatic species there could be just as great. Black and Armbrust are discovering, for example, that when certain types of fish and frogs are exposed to “a little bit” of these medications, they experience problems that include slowed rates of development and a sluggish state that leaves them vulnerable to predators.

The intricate relationships among animals and plants that make up an ecosystem depend upon a certain balance. Therefore the question that haunts Black, Armbrust and others is: What happens to those organisms — and to us — if that balance is upset? “We used to think that only compounds in the water would harm humans, and only through direct exposure,” Black said. But scientists have come to realize that the harm may occur indirectly by disrupting ecological biodiversity.

Chemicals Out of Place

Up to 90 percent of many prescription drugs that humans consume ultimately find their way to sewage-treatment plants. While treatment plants that process drinking water remove these chemicals and their metabolic byproducts, these compounds pass through sewage-treatment facilities, which are designed to remove solids and bacteria but are not equipped to screen for pharmaceuticals. Armbrust, who is also the state chemist for Mississippi, was particularly taken aback by a 1999 paper in the journal Environmental Health Perspectives that documented a steady stream of pharmaceuticals — including Prozac and other selective serotonin re-uptake inhibitors, or SSRIs — being passed into the nation’s waters. SSRIs are among the 200 most-prescribed medications in the United States; the number of adults taking antidepressants has nearly tripled since Prozac was first introduced to the market in 1987, according to the Centers for Disease Control and Prevention.

In some people who have depression, the brain doesn’t produce enough of the neurotransmitter serotonin — a natural chemical that helps transport electrical impulses by shuttling back and forth across the spaces between neurons. So SSRIs are deployed to keep the chemical’s concentration high. In animals, serotonin also performs a critical role of “regulating a broad spectrum of behaviors, ranging from mating to feeding,” said Christian Daughton, chief of the Environmental Chemistry Branch of EPA’s National Exposure Research Laboratory and a co-author of the 1999 paper that first piqued Armbrust’s and Black’s interest.

Soon after that study was published, Black and Armbrust teamed up to investigate the possible ecological impact of these new contaminants. The two scientists secured a three-year grant for $522,000 from the U.S. EPA to determine what happens to SSRIs in the water and what effect, if any, they have on frogs, fish and other aquatic life.

Black, who came to UGA in 1995, first examined water-quality issues as a graduate student at the University of Tennessee. Her focus on the biological aspects of contamination — the impacts of pollutants on aquatic life — neatly complements Armbrust’s interest in the chemistry of contaminants. While Black (who serves as principal investigator on the EPA grant) and her group observe the effects of SSRIs on aquatic invertebrates, fish and frogs, Armbrust’s team analyzes the chemical behavior of the drugs — what’s getting through the wastewater-treatment facilities, how quickly the SSRIs biodegrade once they’re in the environment, what they break down into and how long all these chemicals persist. Basically, said Armbrust, “we’re measuring exposure and they’re measuring effects.”


Intro/Chemicals Out of Place  |  Provacative Results


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