Dolphin fertility is harmed by chemical pollutants

Dolphins are struggling to reproduce because of industrial chemical pollution in European waters that can linger in the animals' bodies for a lifetime, a study out Wednesday said.

Researchers focused on polychlorinated biphenyls (PCBs), which were used widely in industrial equipment and paints until they were banned over 30 years ago.

Scientists were surprised to see that PCBs remained in the fat tissue of harbour porpoises (Phocoena phocoena) at moderately high levels.

The study led by the Zoological Society of London appears in the open-access journal PLOS ONE.

Researchers focused on porpoises in the UK harbor, and found that almost 20 percent of sexually mature females showed evidence of stillbirth, fetal death or recent miscarriage.

"A further 16.5 percent had infections or tumors of reproductive organs that could have contributed to breeding failure," said the study.

When they compared the UK harbor porpoises to those living in much less PCB-polluted regions, they found lower pregnancy rates in the UK harbor group.

The pollution can pass from mother to calf when the babies suckle, leading to problems through the generations.

"UK harbour porpoises are part of a larger northeast Atlantic population and our research suggests a population-level risk from PCB exposure," said lead researcher Sinead Murphy.
Source: AFP