ENVIRONMENTAL authorities and conservation groups are investigating oil slicks which have started to appear on the Leeds and Liverpool Canal, near Rishton, after heavy rain.

Experts have so far been unable to trace the source of the oil, which could come from an old fuel tank on farm or industrial land, or have been dumped.

The Environment Agency has erected a boom across the canal to stop oil spreading and to allow removal.

Local anglers and members of a community environmental group have been working with the agency to try to locate the source of the fuel.

Rishton Prospects Panel undertakes practical improvements to the local countryside and its secretary Colin Cooper said: "Oil seems to be getting into the canal at the Whitebirk area and floating east toward Rishton for a mile or two.

"It moves with the wind and currents. Although the canal doesn't flow fast like a river, its level generally falls as it travels west from the Pennines.

"But, due to wind and currents, the oil can actually flow against the general drift. We've been working with the Environment Agency and British Waterways to see what the cause is.

"However, it doesn't seem to have affected fishing too much because the angling society still holds its competitions on the stretch of canal through Rishton." Graham Parkes is secretary of Hyndburn and Blackburn Angling Association, and also works as a bailiff and fishing officer. He said the oil was breaking up and emulsifying.

He added: "I've seen the oil which has a white appearance, a bit like heating oil. And it looks a right mess. The boom was stretched across the canal near Cut Lane, at Rishton, to hold the oil back.

"It's a shame this oil is appearing. I don't know where it's coming from. It could be an old fuel tank buried in a tip, which becomes flooded with rainwater. Or it could be dumped by people who aren't disposing of oil correctly.

"Thankfully, it doesn't seem to have harmed the fish. The canal is a lot cleaner than it used to be."

An Environment Agency spokesman declined to give many details about the investigation, but said: "We still have not found the source of the oil, although we have a couple of interesting leads that we are pursuing. We're working hard to get the problem sorted with what appears to be a diesel-type oil.

"Booms make it easier to collect the oil, which can be sucked up into tankers or soaked up with special absorbent pads."