This phenomenon of occasional female organ growth in males, is called “intersex.”
A nationwide study of sexual fish aberrations by the U.S. Geological Survey found that 40 percent of smallmouth bass and one-third of largemouth bass sampled in the Colorado River were intersex. The Colorado River data were from 2003, and nationwide it covered the period 1995-2004.
The pollutants and various chemicals affect hormone activity in animals and humans are collectively called endocrine disruptors or endocrine active compounds.
The Colorado River Regional Sewage Coalition has been concerned with the presence of the endocrine disruptors, particularly because Colorado River water is consumed by millions in Arizona, Nevada and California.
One member of CRRSCO, Southern Nevada Water Authority, has been testing for chemicals in Lake Mead and Las Vegas drinking water. Monitoring has shown that levels of a number of endocrine disruptors exist in drinking water for Las Vegas at substantial percentages of levels that are detected in Lake Mead near the sewage outfall.
For example, the popular insect repellant DEET and the herbicide atrazine have been detected (at low unregulated levels in parts per trillion) when sampled in both the lake and potable Las Vegas drinking water.
SNWA also is assisting Lake Havasu City Water Resources Coordinator Doyle Wilson to sample for endocrine disruptors in Lake Havasu as well as in water supply wells and a huge sewage storage repository two miles from the lake constructed within the last two years. Doyle said that his principal concern with the USGS study is that the fish data are already dated.
Wilson added that CRRSCO is pinning some of its hopes for future monitoring of endocrine disruptors and many pollutants on the Lower Colorado River Protection Act, which was introduced July 31 by Rep. Raul Grijalva, D-Ariz. The bill would create and implement an EPA-overseen, long-term plan to protect water quality in the lower Colorado to prevent and eliminate pollution with continuous ecosystem monitoring.
Some of the highest intersex percentages were found in the southeastern U.S. At 111 sites nationwide, 3,080 fish were examined and all had contaminants in their bodies.
Forty percent of largemouth bass examined at Imperial Dam and at the Gila River in Hayden were intersex, and 70 percent of smallmouth bass in the upper Colorado in the Yampa River were intersex.
Among other species examined, the only intersex carp found nationwide was at Willow Beach, below Lake Mead. One intersex channel catfish was found in the lower Colorado basin in the Gila River at Phoenix, and one at each of three sites in the upper Colorado.
Lead author of the report, JoEllen Hincke, of the USGS Columbia Missouri Environmental Research Lab, said that the report “is the first synthesis of USGS efforts to measure contamination in water, fish and intersex occurrence.”
The U.S. Centers for Disease Control — and governments worldwide — have gathered substantial evidence that human health is affected by exposure to hormone-disrupting chemicals. Pregnant women and babies, particularly boys, are considered at highest potential risk but serious conditions affecting women such as infertility, ovarian damage and adult male hormonal disruption are considered to be likely impacts of the chemicals.
Wastewater discharges into sources of drinking water are one major pathway of contamination that may include bodily discharges of concentrations of chemicals or from pollutants themselves being discharged into surface and groundwater.