In the 1950s, scientists officially declared the River Thames biologically dead. The water was so polluted with sewage, industrial runoff and toxic metals that virtually no life could survive in it. Seventy years later, that same river is home to harbour porpoises, thriving populations of wading birds, and more than 125 species of fish, and a major new health assessment by the Zoological Society of London confirms the comeback is not just real but measurably accelerating. Zinc levels in the river have dropped by 50 percent since 1990, copper concentrations have fallen to just a quarter of what they once were, and oxygen levels have improved significantly for the underwater life that depends on them. Since autumn of last year alone, nearly 13 million tonnes of sewage that would previously have been discharged directly into the river have been captured instead.
Some of the progress has come from surprisingly simple regulatory wins. Plastic cotton bud sticks were once among the most common items of litter found along the Thames shoreline. The UK banned their sale in 2022, and they have almost completely disappeared from the riverbanks since. A similar ban on plastic wet wipes, another major source of river pollution, is set to take effect later this year. Conservationists at the Zoological Society of London launched an ambitious partnership last year called Transforming the Thames, bringing together conservation organizations, communities, government bodies and landowners to restore habitats across the entire Thames estuary, including planned oyster reefs, seagrass meadows and saltmarshes. The report’s authors are careful to note that climate change and rising water temperatures remain genuine threats to the river’s recovery, but the story of the Thames stands as one of the clearest modern examples of what decades of determined environmental action can actually accomplish.
Source: https://www.sciencedaily.com/releases/2026/03/260326064200.htm
