Male fish with female characteristics have been discovered in ocean waters off Los Angeles and Orange counties, raising concerns that treated sewage released offshore contains hormone-disrupting compounds that are deforming the sex organs of marine life.
Scientists around the world have found sexual abnormalities in frogs, fish, alligators and other wild animals exposed to sewage effluent and industrial contaminants that mimic estrogens and other hormones. But the latest research in the waters off Southern California is among the first to find such effects in ocean creatures.
Eleven male bottom-dwelling fish out of 64 caught between Santa Monica and Huntington Beach had ovary tissue in their testes. No such sexual defects were found elsewhere off Southern California, even though fish were collected from Point Conception to the U.S.-Mexico border.
Two other studies found other signs of feminized fish in the same ocean areas. Two-thirds of male turbot and sole caught near Orange County's sewage outfall had egg-producing proteins. And when males were exposed in a laboratory to ocean sediment collected off the Palos Verdes Peninsula and Huntington Beach -- where huge volumes of sewage effluent are pumped out to sea -- all of them developed female egg proteins.
Dan Schlenk, an aquatic ecotoxicologist at UC Riverside who co-wrote two of the three studies to be reported today at a national conference, said it is clear that the ocean floor at the sewage outfalls is contaminated with estrogenic compounds that are feminizing fish. But effects on the overall health and abundance of fish populations and the rest of the marine ecosystem are unknown.
"There's definitely estrogenic activity out there; no doubt," Schlenk said. "But whether it affects populations of the animals is the question we need to answer."
Every day, nearly 1 billion gallons of treated wastewater from an area that includes about 9 million people are discharged into deep waters off Huntington Beach, the Palos Verdes Peninsula and Playa del Rey via three long undersea pipelines, called outfalls, operated by the two counties and the city of Los Angeles.
Sewage effluent contains several dozen chemicals -- both natural and man-made -- that can alter animal hormones, environmental scientists say. Women excrete natural estrogen and man-made forms from birth-control pills, and some industrial chemicals, pesticides and compounds in household items are endocrine disruptors, which mimic hormones.
