Toxic chemicals from past decades could be hindering the recovery of Britain’s urban rivers, concludes a recent study by scientists from Cardiff University, the University of Exeter, and the Centre for Ecology and Hydrology.
Toxic chemicals from past decades could be hindering the recovery of Britain’s urban rivers, concludes a recent study by scientists from Cardiff University, the University of Exeter, and the Centre for Ecology and Hydrology.
During the 1970s, over 70% of the rivers in the South Wales valleys were classified as grossly polluted, by a combination of poor sewage treatment, colliery waste and industrial discharge. Since then, industry has declined, deep mining has ceased and sewage treatment has improved to the point that clean water species such as salmon and otters have returned to rivers such as the Taff.
However, Welsh rivers in urban locations still have damaged food chains and fewer species of invertebrates in comparison to more rural rivers. According to the researchers, these effects might be explained by the higher concentrations of former industrial pollutants such as PCBs (Polychlorinated Biphenyls) and flame-retardant chemicals (PBDEs) that persist in these rivers despite being phased out.
Fred Windsor, a doctoral student at Cardiff University, explained: “Despite major success in controlling sewage pollution in South Wales’ rivers over the last three decades, something appears to be holding back biological recovery. Our investigations show that persistent contaminants might be responsible as they still occur widely in invertebrates, particularly in urban river environments.”
Read more at Cardiff University
Photo credit: 12019 via Pixabay
