Chernobyl sheep movement restrictions 'unnecessary'
Restrictions imposed on the sale of livestock in Wales at the time of the Chernobyl nuclear disaster 30 years ago were probably unnecessary, a senior academic has claimed.
Radioactive fallout fell in rain about a week after the 1986 explosion in northern Ukraine, with restrictions affecting 334 farms in north Wales.
The movement of sheep was heavily restricted until 2012.
Prof Gerry Thomas said she understood why the restrictions were enforced.
The explosion and subsequent fire on 26 April 1986 at the Chernobyl nuclear power plant released large quantities of radioactive particles into the atmosphere.
"We'd never had a nuclear accident like that before so I think it was sensible at the time to be precautious," she said.
"But I think we now learn from what we know about the science 30 years later and say actually caesium is not really something we need to be that concerned about."
Prof Thomas, who researches the effects of radiation on health at London's Imperial College, added: "We've got plenty of evidence for that from the Chernobyl area where people have been followed now over 30 years and it looks as if there is nothing to be seen.
"And that's because the doses from caesium are very very low."
Restrictions were placed on farms to prevent sheep with unacceptable levels of radioactivity from entering the food chain.
Any sheep and lambs grazing on high ground had to be brought down to lower-lying areas to allow radiation measurements to decrease, before they could be sold.
But while the monitoring on sheep in Wales ended when the last restrictions were lifted four years ago, there is an argument against dismissing the risk too quickly.
Prof Glyn O Phillips, an advisor at the International Atomic Energy Authority, believes sheep on the Welsh uplands should continue to be checked for radiation.
"When you come to low levels of radiation there is very great uncertainty," he said.
"To extrapolate to low levels and to see the degree of damage is very strange and very difficult.
"So I think the extrapolation is only possible with time and we will only see in the next generation and the generation after that whether there are significant effects to be demonstrated then."