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01-06-03
By Carol Savonen, 541-737-3380
SOURCE: Larry Curtis, 541-737-1764
CORVALLIS - After the first year of a two-year study, Oregon State University scientists have found about three times as many juvenile minnows with backbone deformities in the Newberg Pool of the Willamette River than at a site 80 miles upstream near Corvallis.
Larry R. Curtis, an OSU professor of environmental toxicology, will present preliminary results of a Oregon Watershed Enhancement Board-funded study on pike minnow fish deformities in the Willamette River to the Oregon Legislative Emergency Board in Salem this Thursday (Jan. 9).
 OSU researcher Gene Johnson and doctoral student Doolalai Sethajintanin clean samplers just pulled from the Willamette River. Click on image to go to downloadable photo |
"There's significant public concern over deformed fish in the Newberg Pool of the Willamette River, but little scientific basis for explaining the deformities," said Curtis, head of the OSU Department of Environmental and Molecular Toxicology. "These fish are sentinels for environmental contamination. People want to know what's causing the deformities and whether they have any implications for human health."
As the lead investigator of OSU's interdisciplinary study of the Willamette River and its deformed fish, Curtis has gathered together OSU's Agricultural Experiment Station toxicologists, chemists, microbiologists and fisheries biologists in an effort to determine the prevalence of skeletal deformities in juvenile fish in stretches of the Willamette River near Newberg and Corvallis.
The OSU researchers also are trying to determine what causes these deformities. They are comparing the physical and chemical conditions and the accumulated toxicants in ovaries of fish from adult northern pike minnows at Corvallis and Newberg and conducting laboratory studies that might show a link between physical or chemical conditions in the river and the incidence of deformities.
 OSU researcher Bobby Loper, doctoral student Doolalai Sethajintanin , bioresource research student Solyssa Visalli and Keaboletse Kgokong (visiting faculty from Botswana) test underwater equipment at Corvallis on the Willamette River. Click on image to go to downloadable photo |
There are no human health threats associated with this fish parasite, said Curtis.
So far, the researchers have found most of the physical and chemical characteristics of the water at Newberg and Corvallis to be similar. Temperature, pH, dissolved oxygen and nitrate levels did not vary significantly between the two sites.
The investigators detected similar low concentrations of heavy metals cadmium, copper, lead and zinc at both sites, although they found one high zinc sample measured in the Newberg Pool. They found concentrations of persistent organic contaminants including dieldrin, DDT, DDD and DDE to be two to four times higher in Newberg Pool than Corvallis, but all detections were extremely low, below one part per trillion, said Curtis.
They haven't yet completed analyses for other chemical classes, including currently used pesticides. The researchers are now measuring persistent bioaccumulative toxicants in ovaries collected from adult pike minnows in both sites on the river. Results are not yet available.
In recent experiments, newly fertilized eggs were exposed to river water from each site for 15 to 47 days. They didn't detect any differences in development between fish reared in water from either location.
The scientists have another field season, spring through the fall of 2003, to collect data and fish and study both sites on the Willamette. They will also conduct more laboratory experiments on zebrafish with various concentrations and fractionations of toxic materials from the river water from each site. The final report will come out in 2004.
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Last Update:Monday, 06-Jan-2003 16:35:28 PST