[Pharmwaste] Scientists explore connection between pollution, intersex fish

[DeBiasi,Deborah]

http://www.fredericknewspost.com/sections/news/display.htm?StoryID=56738

Scientists explore connection between pollution, intersex fish
Originally published February 11, 2007


By Nancy Hernandez 
News-Post Staff 
 
  
Beginning in 2005, a team of researchers studied fish from the Monocacy
River near Walkersville. They captured live smallmouth bass in an effort
to determine if intersex characteristics in the fish were linked to
pollution from wastewater treatment plants. Here, a scientist takes a
sample from one fish while another fish waits to make its contribution
to the study. 
  
   

   
FREDERICK -- A biological role reversal of fish in the Monocacy River
and other local waterways has scientists wondering what problems might
lie ahead for aquatic life -- and humans.
Immature eggs have been found in male smallmouth bass while female fish
of the same species were lacking an egg yolk precursor, according to
Vicki Blazer of the U.S. Geological Survey.

She spoke at Hood College this week about the findings of a recent fish
study she led involving about 15 governmental agencies and universities
across several states.

Beginning in 2005, fish were collected at sites downstream and upstream
of several treatment plants on the Monocacy River and Conococheague
Creek in Pennsylvania. Scientists wanted to see what, if any, role
wastewater treatment plants have played in the problem, Blazer said. 

The gonads of male fish were not as  developed downstream of wastewater
treatment plants, with the biggest discrepancies found along
Conococheague Creek, she said.

As much as 100 percent of the male smallmouth bass in some locations
exhibited male and female characteristics, she said. The male fish had
sperm and immature eggs. Some also had produced vitellogenin, while
their female counterparts had not. Vitellogenin is an egg yolk producer
typically found only in female fish.

Male largemouth bass also possessed intersex characteristics, but not as
frequently, she said.

The sex abnormalities are not limited to the local region, she said. In
the south branch of the Potomac River, about 58 percent of roughly 230
male fish exhibited intersex characteristics.

Intersex fish have been discovered in recent years around the world,
Blazer said. The severity of the problem ranges from location to
location, even within watersheds, and from season to season, she said. 

What causes the sex abnormalities has not been determined, but chemical
pollution is a suspect.

Roughly 15 chemicals have been identified in the Monocacy River and
scientists estimate many more are present.

Under current regulations, water quality limits are set for individual
chemicals and not for the myriad of compound possibilities, said Robert
Ballinger, a spokesman for the Maryland Department of the Environment.

The Monocacy River meets water quality standards for the individual
chemicals, he said.

But chemicals do not necessarily pose health hazards individually,
rather creating toxic compounds when combined, Blazer said.

In local fish, compounds commonly called endocrine disrupters appear to
be the problem behind the gender confusion, Blazer said.

Endocrine disrupters that mimic estrogen are intercepting and distorting
the normal hormonal signals of the smallmouth and largemouth bass. Both
wild fish and those exposed to chemical compounds in the laboratory
developed the sex abnormalities, Blazer said.

She hopes to collect more fish this spring, before and after spawning
season, to study what influence the sex abnormalities might have on
reproduction and future fish populations.

Further south, researchers in Virginia are trying to determine if the
sex abnormalities played a role in the deaths of thousands of smallmouth
bass since 2000. One 2005 episode in the south fork of the Shenandoah
River wiped out about 80 percent of the smallmouth bass and redbreast
sunfish population, Blazer said.

While no data has definitely linked sex abnormalities with large numbers
of fish being killed, the two problems are likely related, said Drew
Ferrier, a biology professor at Hood College.

Endocrine disrupters also can intercept and distort other body
functions, such as the thyroid and immune system, he said. Humans are
susceptible to endocrine disrupters as well.

More study is needed to determine what chemical compounds lead to
intersex fish and to pinpoint where the chemicals are entering the
waterways, he said.

"There are many more questions on this topic than answers," he said.

Contamination is likely coming from multiple sources, such as human
wastewater, runoff from farms and industrial sites and atmospheric
pollution, Blazer said.

"Many times, we want to blame agriculture and industry but when we use
fertilizer to kill dandelions, use antibacterial soap, flush our
prescriptions down the toilet, we need to think about that," she said.

Blazer's team will continue to analyze the collected data and hope to
perform additional studies, such as chemical analysis of the soil where
smallmouth bass lay their eggs.

Figuring out what is harming the fish will benefit people as well,
Blazer said. Humans breathe the same air, drink the same water and eat
food grown in the same ground that animals do. Aquatic species that are
battling health problems offer clues that something is amiss in the
environment.

"Fish are an indicator of our ecosystem's health," she said. 
 

Deborah L. DeBiasi
Email:   dldebiasi at deq.virginia.gov
WEB site address:  www.deq.virginia.gov
Virginia Department of Environmental Quality
Office of Water Permit Programs
Industrial Pretreatment/Toxics Management Program
Mail:          P.O. Box 1105, Richmond, VA  23218 (NEW!)
Location:  629 E. Main Street, Richmond, VA  23219
PH:         804-698-4028
FAX:      804-698-4032