Allotment holders in Cardiff have been warned their crops may be dangerous to eat after chemicals were discovered in the soil.
The council found 'unacceptable levels of contamination'
Vegetables grown at Leckwith allotments were found to contain enough lead and arsenic to be harmful in the long term.
Site-owner Cardiff Council has advised growers to wash their crops and limit the amount eaten, especially by children and pregnant women.
The allotments share a boundary with the former Leckwith Moors rubbish tip.
The chemical levels came to light during an investigation into methane at the old landfill site by the council.
Soil from Leckwith Moors was tested for a range of chemicals, as dictated by the Environmental Protection Act.
Attention turned to the allotments, which are worked by about 100 gardeners, when high levels of contaminants showed up in samples taken near the boundary.
Earth from the gardens was then found to contain lead, arsenic, and other chemicals created by burning fossil fuels, plant matter and rubbish.
Lettuces, leeks and carrots at the site could be affected
High levels of lead have also been specifically identified in leeks, carrots and lettuces. The council said it could not say whether other crops were safe to eat.
The exact source of the toxins is not known but they may have come from mixing the soil with ash to improve it or from airborne pollutants from Cardiff's industrial past.
Trevor Peterson, who has three allotments, said he was not unduly worried by the health scare but was concerned that developers might move onto the site if it had to be closed for safety reasons.:
"We grow all of the 'danger crops' - cabbage, carrots, lettuce," said Mr Peterson, who is on the allotment committee.
"My family have thrived. I'm 66 now and I'm in pretty good health. I would miss it - it's good exercise if you disregard the poison aspect!"
The council is working with expert bodies, including the Food Standards Agency and Environment Agency Wales, to find a way to clean the ground.
The council's chief regulatory services officer, Malcolm Evans, said: "The investigation at Leckwith allotments was taken as a precaution and has revealed unacceptable levels of contamination.
"Brian Paget, the chief highways and parks officers, stated that the council will consider every practicable option to rectify the situation as soon as possible."