CORVALLIS - The Black Triangle in eastern Europe is one of the most polluted places on earth - the result of years of unregulated industry that deposited heavy metals across the landscape of Poland and the Czech Republic. Zinc, copper, cadmium and lead fan out in toxic drifts from industrial centers to neighborhoods where people live and grow food, and to sensitive wildlife habitats.
In a recent study published in the journal, Comparative Biochemistry and Physiology, researchers from Oregon State University and the Jagiellonian University in Krakow, Poland, examined insects from polluted soils in Poland to learn how such a toxic environment affects ecosystem processes. They measured detoxification enzyme activity in predatory beetles as a way to gauge the insects' ability to tolerate stress when pesticides are applied to farmland in an already chronically polluted environment.
"The question is not limited to beetles," said Paul Jepson, OSU entomologist and co-author of the report. "We need to know how much pollution these systems can tolerate before they lose the ability to recover."
The researchers collected beneficial predatory beetles across a gradient of pollution that stretched from areas with moderately low heavy metal concentrations to areas that were so toxic that very few beetles could survive.
"Beetles in heavy-metal polluted soil reach a point where they have no more metabolic capacity to detoxify the pesticides to which they are also exposed," said Jepson. "Pesticide doses that might normally kill pests and spare a proportion of the predators may be too much for predators already stressed by environmental toxins."
When the predatory beetles are reduced, pest outbreaks are much more severe. The process contributes to something called the pesticide treadmill, where more pesticides are added in response to new pest outbreaks that kill more of the beneficial predators, leading to more severe pest outbreaks and greater pesticide use.
Short-circuiting the pesticide treadmill is an important part of regaining ecosystem function. So it is important to understand how beneficial beetles respond to pesticides in polluted soils. The researchers in this study hope to use detoxification enzymes and heavy metal accumulation in beetles as indicators to help guide appropriate management practices, including pesticide use.
The research was sponsored by the NATO science program, which offers support to partner countries to engage in new forms of scientific collaboration. With the accession of Poland and the Czech Republic to the North Atlantic Treaty in 1999, scientists from these countries have been able to participate in the NATO science program.
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Paul Jepson, 541-737-9503