COLUMBIA, Mo. Manufactured until 1977, and banned by the Environmental Protection Agency in 1979, pentachlorobiphenyls (PCBs) are chemicals still commonly found in the environment because they break down slowly. Now, a husband and wife research team at the University of Missouri and Westminster College in Fulton, Mo., have found that exposure to one of the chemicals has effects on growth and bone density in turtles. This knowledge could lead to insights on PCBs effects on humans and the environment.
"Turtles also are known as an 'indicator species' because they are often used as a gauge for the health of an entire ecosystem," said Dawn Holliday, co-researcher and assistant professor of biology at Westminster College in Fulton, Mo. "By finding the effects of PCBs on turtles, we can understand possible effects the chemicals might have on humans."
Researchers studied PCB 126, a version of the chemical compound once used in pesticides and electric transformers. PCBs are absorbed by eating exposed animals or drinking exposed water and are stored in fat cells. PCBs can affect the endocrine system and, thus, the regulation of hormones that control growth and other body functions.
Scientists know that people harbor PCBs in many tissues; however, little is known about the effect the chemicals have on people. Dawn Holliday said previous research on people accidentally exposed to the chemical through spills or accidents has shown correlations between exposure and stunted growth in humans.
"By studying the effect of PCB exposure on turtles, we can better understand how PCB exposure impacts people," said Casey Holliday, co-researcher and assistant professor of anatomy in the MU School of Medicine. "People are high on the food chain, and thus more susceptible to accumulation of PCBs. Smaller animals ingest PCBs. As large animals eat these smaller animals, the chemical stays in the food chain, as it is deposited in fat cells and doesn't
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University of Missouri-Columbia