Hundreds of fish have died in London rivers as the hot weather concentrates pollution in the water, environmentalists said today.
The heat has caused extremely low water levels and depleted oxygen, which is crucial for marine life.
The affected waterways include Beverley Brook, which runs through Richmond Park , the Wandle in south-west London, and the River Lea and River Roding in the east. Images taken by the Moo Canoes clean-up team show roach and perch floating dead in the lower Lea, and the environmental charity Thames21 said the estimate of hundreds of deaths was “conservative” according to their data.
Other species, including trout and salmon, are particularly sensitive to oxygen levels.
Thames21 said the heatwave was “intensifying two types of pollution problem suffered by rivers — pollution from misconnected household plumbing and heavy metals from road run-off”.
Campaigners also fear that despite efforts to oxygenate the Lea’s water, its quality is also being worsened by the continuing effects of nearly 80,000 litres of engine oil spilled into the river in February, which took two months to clean up.
Litter thrown into the water and a blanket of green duckweed blooming on the surface of the warm water is adding to the choking effect. Sophie Scott, who represents the Lea Boaters Collective, said: “If the parks are our lungs, the rivers are London’s veins.
“There’s not enough water in the river, which means there’s depleted oxygen, not just for fish but the invertebrates they feed on.
“After recent weeks without rain the usual pollution on our roads from cars, industry, cigarette butts and litter builds up. Then when we do get rain it all washes straight into the rivers.”
