Male fish that used to be feminized after chemicals, such as the pharmaceutical ethinylestradiol, made it through the Boulder, Colo., Wastewater Treatment Plant and into Boulder Creek, are taking longer to become feminized after a plant upgrade to an activated sludge process, according to a new study. The results will be presented Sunday at The Endocrine Society's 92nd Annual Meeting in San Diego.
Although the levels of the chemicals that the fish swam in were very low even before the upgrade, the chemicals are endocrine disrupters. They mimic estrogen and may disrupt the endocrine (hormone) system of both animals and humans, said the study's principal investigator, David Norris, PhD, an integrative physiology professor at the University of Colorado at Boulder.
Norris' team reported in 2006 that native male fish in Boulder Creek decreased in numbers with respect to females and numerous intersex fish were found downstream of the wastewater treatment plant. After a technology upgrade to the wastewater treatment plant in 2008, the reproductive disruption in the fish was far less pronounced. However, Norris said the study results should still concern people.
"The fish are a wake-up call," Norris said. "Our bodies and those of the much more sensitive human fetus are being exposed everyday to a variety of chemicals that are capable of altering not only our development and physiology but that of future generations as well."
With other scientists, Norris studied samples of the wastewater effluent, the plant-treated water that enters the stream and becomes another city's drinking water. Grants from the U.S. Environmental Protection Agency (EPA) and the city of Boulder supported this research.
They found other endocrine disrupters, including synthetic and natural reproductive steroids. They believe the chemicals come from natural female hormones and birth control pills excreted via urine and from detergents, cosmetics and ot
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The Endocrine Society