ENVIRONMENT officials are still trying to find out how pollution got into a Ribble Valley stream and killed more than 2,500 fish.

The Environment Agency is still trying to trace the source of the farm slurry which polluted several kilometres of Kirk Beck in Bolton-by-Bowland 10 days ago.

A member of the public alerted the agency on Friday, August 11 and staff tried to raise oxygen levels in the stream by adding peroxide to the water. The dead fish included 150 brown trout.

An agency spokesman said that they are certain that farm slurry polluted the stream, but the actual source has yet to be traced. Officials are trying to pinpoint how it got into the water.

"We cannot release any more details because legal action may be taken," he said.

The agency is also considering replacing the dead fish, but this may not happen until winter -- the best time of year to restock the stream.

In June, pollution killed at least 100 fish in a Pendle river. A member of the public raised the alarm after spotting dead trout floating in Earby Beck, which runs through Sough Park, near Earby.

The agency is appealing for anyone with information to call the free 24-hour emergency hotline is 0800 807060.