In what is the second Wandle pollution incident in a week, illegally dumped cooking oil has leaked from a surface water drain into one of the side channels of the River Wandle in Morden Hall Park.
Oil was reported leaking into the river on Saturday and a small number of fish died as a result. The EA and Thames Water quickly deployed booms and have stopped the pollution spreading more than 100m downstream.
Two tankerloads of oily sludge have been removed and a further tanker was on site this afternoon.
Water pumps have also been deployed to aerate the water in the channel and raise dissolved oxygen levels.
The source of the oil is being traced and a green dye used to do this can be seen in the water as a result. This is harmless and no cause for concern.
Our thanks to the EA and Thames Water once again for a speedy response that has limited the effects of the pollution on the river.