The latest in a string of contamination incidents in the River Lea navigation canal was reported last week, just a few months after thousands of fish died due to low levels of oxygen in the water.
On 9 October, resident Adam McAlavey saw the stretch of river between the Lea Bridge Road and Middlesex filter beds covered in thick oil.
Mr McAlavey is part of a network of local volunteers who regularly conduct water quality tests as ‘citizen scientists’ for the Love the Lea campaign run by the Thames 21 environmental charity.
While the Environment Agency investigated the call the following morning and confirmed that the water had cleared up, Mr McAlavey says the incident was not a one-off.
“The Lea is constantly polluted. Lots of homes are misconnected [with the sewage system] so there’s regularly raw sewage in there,” he said.
Theo Thomas, who manages the Love the Lea campaign, said: “That’s grim. Sadly something that happens regularly.”
Over the summer thousands of fish died in the River Lea catchment area after hot temperatures combined with heavy rainfall to wash oils, heavy metals and other pollutants from London’s roads into the river.
Mr McAlavey said that he had already reported a similar incident and it was discovered that “someone on the nearby industrial estate had illegally disposed lots of oil that had got into the canal”.
Peter Rudd, from the Environment Agency, confirmed that industrial sites have been polluting London’s waterways and has taken up the issue with them, but the process is complicated.
“Mainly because of the nature of the river, pollutants from as many as 80 kilometres away could end up in the catchment area and it is sometimes impossible to establish the source of the contamination. It could even be from people pouring oil down the drains much further north like Tottenham causing the problems.”
A study carried out by Thames 21 and University College London last year showed that the amount of faecal e-coli bacteria in the Lea regularly exceeds international standards by more than 40 times.
Thames 21 is campaigning for a comprehensive network of green drainage systems across north-east London. It aims to prevent residential wastewater that pollutes local rivers, and to construct rain gardens in unused parking spaces and roadsides, reducing road run-off that poisons rivers with chemicals and dirt.
