Rising Levels of Banned Toxic Chemicals Found in Welsh Otters
New research reveals a concerning rise in banned polychlorinated biphenyls (PCBs) in Welsh otters since 2010. A study by Cardiff University found PCBs in every otter tested, with 16% exceeding toxic levels that impair reproduction. These legacy pollutants, banned over 40 years ago, are re-entering the environment from river and coastal sediments, a process likely accelerated by climate change. Scientists urge continued monitoring and stronger international action to protect wildlife and river ecosystems.
A recent study by the Cardiff University Otter Project and Natural Resources Wales has found increasing levels of polychlorinated biphenyls (PCBs), banned industrial chemicals, in Eurasian otters across Wales. Analysing liver samples from otters collected between 2010 and 2019, researchers detected PCBs in every single otter, with a significant 16% exceeding a toxic threshold known to impair reproductive health. This finding is particularly alarming given that earlier data showed a decline in PCB levels between 1992 and 2009, indicating a reversal of this positive trend.PCBs were widely used in electrical equipment, paints, and plastics until their ban in the 1980s. However, their extreme environmental persistence means they continue to accumulate in wildlife, particularly in top predators like otters through the food chain. Dr. Emily O’Rourke, the lead author, highlighted that while PCB concentrations in water are often low, they accumulate to harmful levels in top predators, suggesting current water quality standards may be inadequate. The research indicates that higher PCB concentrations in otters from coastal and low-lying areas are due to the remobilisation of PCBs stored in river and coastal sediments. This process is likely accelerated by climate change, with increased storm events, flooding, and erosion releasing these legacy pollutants back into the environment. Both Dr. O'Rourke and Dr. Elizabeth Chadwick, Principal Investigator of the Otter Project, emphasized the critical need for continued monitoring and robust international efforts to manage these persistent chemicals and safeguard river ecosystems.
