Wastewater’s Affect on Fish: Boys Will Be Girls

[Brandon-K]

Wastewater’s Affect on Fish: Boys Will Be Girls

A continuing study being conducted at the University of Colorado has confirmed what many fisheries biologists have believed for several years—that chemicals passing through municipal wastewater treatment plants before returning to the natural ecosystem can alter the sexual traits of fish.

In 2004, University of Colorado integrative physiology professor David Norris discovered fish found below the Boulder, Colo. treatment plant’s outflow pipe were changing from male to female.

Since that time, Norris, an associate and U.S. Geological Survey scientists have used a mobile laboratory to measure treatment-plant effluent for certain chemicals, primarily human estrogen.

The scientists believe the chemicals affecting fish gender originate from excreted birth-control hormones, natural female hormones and detergents flushed down toilets and drains. In the ecosystem, they are known as “endocrine disrupters,” settling into cell receptors and derailing natural chemical communications.

Norris’ original study below the Boulder Wastewater Treatment Plant indicated that 90 percent of the white suckers swimming downstream of the facility were female. Upstream, the split was a normal 50/50.

The Scripps-Howard News Service reports that Norris’ current research uses fathead minnows in separate tanks--one filled with pure upstream creek water; the other with varying degrees of wastewater plant effluent.

The results?

“The males were feminized in seven days (in the effluent),” Norris said. “You don’t need a Ph.D. to sex them.”

According to the news story, hydrologists believe the new study will help convince skeptics that treated effluent is responsible for similar fish genetic disruptions in the Potomac River and elsewhere.

“We were excited to get these results, but at the same time we’re a little bit appalled at what we’ve seen,” Norris said.

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