MAFF unsure how many BSE carcasses in tips
By Tony McDougal
MAFF has admitted it is unsure how many cows that died of BSE were buried in landfill sites between 1988 and 1991.
Although MAFF held records of numbers of contaminated carcasses placed in 59 sites in Great Britain, checks by the Environment Agency in March and April revealed problems in verifying information.
"We found details relating to 6117 contaminated carcasses after being asked to verify information from MAFF. We were able largely to do that but there could certainly be a few more buried without records," said an Environment Agency spokeswoman.
MAFF has asked the EA to look at the geology, hydrology and proximity to watercourses of six of the landfill sites to see if the BSE infectious agent could be leaching into rivers or contaminating topsoil.
The tests, which are currently under way, include Everleigh Tip, near Pewsey, Wilts, where up to 1200 carcasses could be buried. But preliminary results suggest that the chance of cross-contamination through soil or water is less than one in a million, according to the EA.
Jeff Almond, member of the BSE advisory committee SEAC, agreed the chance of infectivity through soil was minimal. "Our tests used carcasses of mice experimentally infected with the BSE prion, which were placed in plant pots. Although the infectivity survived, it was reduced by 10,000 times.
"Microbial activity breaks down the infectivity in the soil, though it is a slow process. In water, the prion protein generally sticks to clay particles in the soil," he said.
The Environment Agency is shortly to publish its long-awaited risk assessment of BSE prion emissions of meat and bonemeal incinerated in power stations by Powergen and National Power last July. Its findings are likely to have a bearing on tenders out for contract for MBM incineration.
Although reports have suggested the BSE prion can survive temperatures up to 1100C, Prof Almond said he thought this was highly improbable.
"The tests have been looking at the survival of pieces of protein. It seems that certain amino acids, but not all, can survive. The BSE prion depends on all the building blocks being in place. Intense heat alters the shape of the protein and I think the chance of that happening is remote in the extreme."
SEAC is expected to look at the final draft of the report at its next meeting on May 23.