It has long been known that the industrial chemicals Polychlorinated biphenyls (PCBs) have negative effects on humans and the environment. Due to its toxicity, the chemical had been widely banned in the 1970s. However, its long-lived traits and widespread occurrence in old plastics and paints still lead to a persistently high concentration lingering in the environment. Especially landfill sites are prone for runoffs of the chemical into waterways and on into the sea.
Even with a moderate concentration in the water, PCBs can quickly accumulate along the food chain and cause physical problems in high-level predators such as marine mammals. A high concentration in those animals has been associated with population declines in multiple species, and lower fertility rates in females.
A new study by Rosie Williams and colleagues has now shown that male fertility in porpoises might also be affected by PCB. 267 samples of harbour porpoises stranded in the UK between 1991 and 2017 were assessed. They showed that PCB exposure was associated with decreased testes weights, a strong indicator for lower fertility, in adult porpoises of otherwise good physical conditions.
The researchers suggest that PCB exposure should thus be included in population-level impact assessments. Given the worldwide threat of PCB on the reproductive health of long-lived mammals, more effective controls and interventions should be implemented to ensure adequate action and management of the most vulnerable cetacean populations.
Source: Williams, R. S., Curnick, D. J., Brownlow, A., Barber, J. L., Barnett, J., Davison, N. J., ... & Jobling, S. Polychlorinated biphenyls are associated with reduced testes weights in harbour porpoises (Phocoena phocoena). Environment International, 106303.
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