Volunteer litter pickers are pleading for help in cleaning up an environmentally disastrous dump of industrial waste from cannabis farms in a brook near Dore.

Heat lamps, fertiliser bottles and cannabis roots were among the items found by a team from Sheffield Litter Pickers in the massive fly-tip, which stretches for a quarter of a mile along Redcar Brook – the source of the River Sheaf.

Maggie Ewan, a 66-year-old volunteer from Dore, said the “disgusting” scene is likely the result of years of fly-tipping by cannabis farmers and unlicensed waste carriers, who dump rubbish from a bridge over the brook at night when the road is quiet.

She said: “A few expletives came out when we first saw it. Obviously they can’t take [the waste] to the commercial tip, so a lot of it was disguised cannabis plants in cardboard boxes.

Five volunteers from the group began work on the site on 20 February, clearing around 60 bags of cannabis paraphernalia and other household waste.

Mrs Ewan said: “The smell down here was very fragranced. I didn’t really know what cannabis smells like, but it seems to permeate your clothes. It sort of lingered in my car for a while.”

However, when the volunteers returned to resume their clean-up two days later, they were horrified to discover that the culprits had struck again.

Julie Gay, a 64-year-old volunteer from Totley, who was recently awarded an honour from the King for litter-picking in the community, said she was left in “tears of utter despair and frustration” after finding that more waste had been deposited by the criminals.

She said: “We all swore a bit, and then we just had to laugh and think ‘right, what are we going to do?’. So we cleared that again, and then I came home and decided to contact the council and anybody else I could think of.

“It’s too big for the volunteers to deal with on our own. At the end of the day, it’s about working together to help our environment, and teamwork is the only way we can do it.”

As well as contacting councillors and local MPs, the volunteers reached out to environmental charity The Sheaf and Porter Rivers Trust, which has rallied to support the clean-up.

Andy Buck, a trustee at the charity, said: “We don’t know exactly what chemicals might be present in the fly-tipped compost, but those chemicals should not be in our watercourses.

“It’s bad news for fish, amphibians and invertebrates, and bad news for water-based flora.”

Mr Buck said the charity is hoping to enlist a “small army of volunteers” to clear the brook as part of their river clean-up programme along the Sheaf.

He added: “It’s utterly dispiriting. We’re relying on volunteers to deal with the consequences of what’s a pretty serious environmental crime.

“But we’re very fortunate that we’ve got people in the city who are willing to voluntarily undertake this pretty unpleasant task.”

Mr Buck said he hoped the full clean-up would take place as soon as a 1.8m tall fence has been erected along Sheephill Road by Sheffield City Council to stop people dumping rubbish in the brook.

The new fencing, approved on 31 January, is part of a wider plan by the council to crackdown on fly-tipping, which has already seen measures installed at 15 sites in the city to deter illegal waste disposal.

Councillor Joe Otten, Chair of the Waste and Street Scene Policy Committee at Sheffield City Council, said: “The areas covered in this project were chosen by the respective local area committees (LACs) in Sheffield, who ultimately decide where to spend their portion of funding that is equally divided amongst the LACs.

“We encourage people to continue to report any incidents of fly-tipping to us, so that we can look into rectifying those, as well as keeping detailed records of those areas which do fall foul to this.”

Anyone who spots a fly-tip can report it to the council online here.