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Are pollutants shrinking polar bear gonads?

The more polluted a polar bear's fat, the more likely its reproductive organs will be undersize, scientists find.

They collected gonads from 55 male and 44 female bears killed legally by subsistence hunters in east Greenland. The scientists then tested the bears' fat for pollutants that might affect sex hormones.

Especially in immature males, testis length diminished with increasing concentrations of many of these compounds, including DDT, polybrominated diphenyl ether (PBDE) flame retardants, and banned termiticides called chlordanes. The weight and length of the baculum, a bone that supports a bear's penis, also decreased significantly with increasing concentrations of some of the compounds.

Ovary length diminished with increasing PCB and chlordane concentrations, and ovary weight decreased with increasing PBDEs, the team reports an upcoming issue of Environmental Science & Technology.

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