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Pollution Blamed for 'Feminization' of Male Fish Along Basque Coast

Scientists have found more evidence that male fish in the estuaries of Basque Country are acquiring female features due to chemical pollutants from everyday products.

The first cases of male fish "feminized" by pollution in Basque Country, a region spanning an area in northeastern Spain and southwestern France, were detected in the Urdaibai estuary in 2007-2008. Now, researchers at the University of the Basque Country in northern Spain (UPV/EHU) have found feminized fish in seven other area estuaries.

They say endocrine-disrupting chemical pollutants acting as estrogens, the primary female sex hormones, are seeping into the waters and causing immature eggs to develop in male fish. These chemicals are found in relatively modern products such as plasticizers, pesticides, contraceptive pills, fragrances and detergents.

Miren P. Cajaraville, director of the research group, said in a statement that there are clear biological indicators of fish feminization. Moreover, "in each of the places studied we have measured which pollutants have appeared recently and their respective concentrations, and we have confirmed the correlation existing between the presence of the pollutants and the feminization phenomenon."

Some of the chemicals reach the waters after getting through wastewater treatment plants; others come from industrial or farming activities, researchers said.

The research was recently published in the journal of Science of the Total Environment and in the journal Marine Environmental Research.