Raw sewage may be to blame for Sellafield leukaemia cases

Raw sewage and not radiation may have caused the cluster of childhood leukaemias near British Nuclear Fuel's Sellafield reprocessing plant in Cumbria, a group of experts has concluded.

The children of the local village of Seascale may have developed leukaemia as a result of infection - by some virus as yet unknown - brought into the area by construction workers who arrived to build the plant in the late 1940s and early 1950s, according to Professor Bryn Bridges, chairman of the Committee on the Medical Aspects of Radiation in the Environment (Comare). He cautioned however, that this idea was still "speculative".

Professor Bridges said that radioactivity discharged from the plant could not account for the clusters of childhood cancers. He also discounted the idea that the cancers had been caused because fathers who worked at Sellafield had been irradiated just before their children were conceived.

Since 1954, 17 people under the age of 24 resident in Seascale have been diagnosed as suffering from some form of cancer, almost all from leukaemia and Non-Hodgkin's Lymphoma (NHL). In an exhaustive report published yesterday, which surveys the evidence, the members of Comare say "we are in no doubt that the raised incidence of leukaemia and NHL which has occurred in the young people of Seascale, and its persistence over several decades, is probably unique in this country".

None the less, Comare is recommending that no further intensive research should be carried out into the cluster of cancers in the Seascale. Although the incidence of cancer in the area should continue to be monitored, local people should be left in peace while basic research into the mechanisms by which leukaemia develops in children is pursued elsewhere.

Professor Bridges said that Comare had made a complete reassessment of all the routine and accidental discharges of radioactive effluent from the Sellafield plant and had concluded that "environmental radioactivity is unlikely to explain childhood leukaemias". Similarly, there was no evidence consistent with the idea put forward, amid a blaze of publicity in 1990, by the late Professor Martin Gardner, that paternal preconception irradiation might be responsible.

Unable to get the conventional theories to pass muster, the committee is looking at the idea first put forward by Dr Leo Kinlen of Oxford University, that childhood leukaemias may result from the influx into an isolated rural population of a large group of people from elsewhere - possibly bringing agents of infectious disease with them.

At least one form of human leukaemia is known to be caused by a virus, so it is possible that the childhood leukaemias may be due either to an as yet unknown human leukaemia virus, or may be a reaction to infection by other pathogens.

But many communities around Sellafield experienced a large influx of new populations in the 1950s and 1960s without suffering childhood leukaemias, so why is Seascale special?

"I was visiting Sellafield a year ago," Professor Bridges said, "and was shown a an aerial photograph of the site in the 1950s and saw a row of Nissen huts beside the river Ehen." The professor discovered that the sewage from the construction workers' huts went straight into the river and drifted to the coastline, a mile from Seascale. "This is the only unique factor we can see that Seascale has," he said.

Although Professor Bridges stressed that no virus had been identified, he noted that no one born after 1984, when a sewage treatment works was installed, had yet gone down with leukaemia.