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Dioxin causes disease, reproductive problems across generations

Michael Skinner
Michael Skinner

By Eric Sorensen, WSU science writer

Since the 1960s, when the defoliant Agent Orange was widely used in Vietnam, military, industry, and environmental groups have debated the toxicity of one of its ingredients, the chemical dioxin, and how it should be regulated.

But even if all the dioxin were eliminated from the planet, Washington State University researchers say its legacy would live on in the way it turns genes on and off in the descendants of people exposed over the past half century.

Writing in the journal PLoS ONE, biologist Michael Skinner and members of his lab say dioxin administered to pregnant rats resulted in a variety of reproductive problems and disease in subsequent generations. The first generation of rats had prostate disease, polycystic ovarian disease, and fewer ovarian follicles, the structures that contain eggs. To the surprise of Skinner and his colleagues, the third generation had even more dramatic incidences of ovarian disease and, in males, kidney disease.  Continue story →

Fish carcass tossing helps track food chain nutrients

Black bear
Grizzly bears and black bears feed on naturally spawning salmon and distribute nutrients into the forest. Photo by U.S. Fish & Wildlife Service.

By Bob Hoffmann, College of Agricultural, Human, and Natural Resource Sciences

A slender, dark-haired woman in her forties shoulders a backpack loaded with dead fish as she hikes a long, rocky trail to a mountain stream in southern Idaho. Arriving on the bank, she drops the pack and starts winging fish carcasses into the water.

This is science. And this is Laura Felicetti, a research scientist in the lab of Charles Robbins, professor in the School of the Environment and School of Biological Sciences at Washington State University. Felicetti is a member of a team that’s trying to quantify the success of nutrient replacement in an area where dams have stopped salmon and steelhead from migrating.

Nutrient-poor soil

Soils in Idaho’s Boise-Payette-Weiser sub-basin are nutrient poor, according to Katy Kavanagh, a University of Idaho forest ecology professor and a collaborator on the project. One reason is that natural processes in this ecosystem poorly incorporate atmospheric nitrogen into the soil in a form that is usable to plants. Also, the region’s dry summers and cold winters are not favorable to decomposition, so dead trees are slow to decay and make their nutrients available to other plants.  Continue story →