[env-trinity] Fish sex change investigated: CU group establishes treatment plant effluent as culprit

[Josh Allen]

Fish sex change investigated:CU group establishes treatment plant
effluent as culprit


http://www.dailycamera.com/news/2006/dec/10/fish-sex-change-investigated
x1/  

By Boonsri Dickinson and Todd Neff, Camera Staff Writers
Sunday, December 10, 2006 

In 2004, David Norris reported that fish just below the Boulder
Wastewater Treatment Plant's outflow pipe were changing sex.

Two years later, the University of Colorado integrative physiology
professor has expanded his study, which now involves one "Fish Exposure
Mobile" research trailer in operation and a second on the way.

Science done in the trailer has verified Norris' 2004 study and shown
that surprisingly low concentrations of treatment-plant effluent can
change male fish into females.

The 2004 study showed that certain chemicals from pharmaceuticals and
personal-care products made it through the Boulder Wastewater Treatment
Plant and into Boulder Creek. Ninety percent of the white suckers
swimming downstream of the plant were female. Upstream, there was an
even split.

"What we see in the fish downstream is as if they are taking birth
control pills," Norris said.

The female fish - both the transsexuals and the original girls - had
smaller-than-average ovaries. The remaining males produced less sperm,
showing the water effluent also has contraceptive effects, he said.

The chemicals are believed to come 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 intended for hormones and garbling the body's chemical
communications.

To bolster his evidence, in 2005 Norris and colleague Alan Vajda, a CU
research associate, set up the Fish Exposure Mobile in a trailer
borrowed from the Colorado Division of Wildlife. U.S. Geological Survey
scientists Larry Barber and James Gray also are working with Norris'
team, and the city of Boulder's cooperation also has been vital, the
scientists say.

"I consider the city an equal partner," Barber said. "Without their
cooperation and encouragement to do good science and answer questions
regardless of implications, it wouldn't have happened."

Where Norris and Vajda are what Barber called "world-class
endocrinologists," Barber and Gray are chemists who have advanced
detection techniques to the point they can spot human estrogen in
concentrations as low as 0.2 parts per trillion.

They needed such exactitude because human estrogen, or 17 beta
estradiol, affects fish at concentrations as low as one part per
trillion - the equivalent of a pinch of salt in an Olympic pool, Norris
said.

Barber said volumes of human estrogen in the pure treatment-plant
effluent range from one part per trillion to about 10 parts per
trillion.

The Fish Exposure Mobile, parked next to the creek on sewage treatment
plant property, pulls water directly from the plant's outflow pipe and
can dilute it using precise volumes of upstream Boulder Creek water.

Fathead minnows swim in two identical tanks inside, each 200 gallons.
One fills with upstream creek water; the other with varying degrees of
wastewater plant effluent. Such control lets researchers see how fish
react to varying effluent concentrations.

They aimed to create a controlled experiment and confirm if estrogen and
other compounds from the treatment plant were responsible for the fish
sex change.

"The males were feminized in seven days," Norris said. "You don't need a
Ph.D. to sex them."

The males have bumps on the forehead and often attack each other. The
fish exposed to the effluent water lost their bumps and acted like
girls. It confirmed effluent to be the culprit.

The Fish Exposure Mobile's ability to control effluent concentrations is
providing new insights.

Diluting the treatment plant's effluent 50 percent feminized breeding
male fish in a week to 15 days, Norris said. Some of the effects
remained evident even when the wastewater plant effluent was diluted 75
percent.

"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.

Norris said CU and USGS researchers are converting a second trailer
donated by the state health department. They hope to have it ready by
next spring.

Fish Exposure Mobile II will travel to different sewage-treatment
plants, starting in Vail and later in Grand Junction. The researchers
suspect they will find similar chemistry in treatment-plant effluent
elsewhere.

Sheila Murphy, a hydrologist with the U.S. Geological Survey in Boulder,
said the Fish Exposure Mobile work has been important to counter
skeptics who attribute transsexual fish in the Potomac River and other
waterways to temperature changes or other environmental influences.

"What it's showing is that it's indeed from the wastewater plant,"
Murphy said.

Contact Camera Staff Writer Todd Neff at (303) 473-1327 or
nefft at dailycamera.com. 

 

-------------- next part --------------
An HTML attachment was scrubbed...
URL: <http://www2.dcn.org/pipermail/env-trinity/attachments/20061215/ba2fb80a/attachment.html>