Black clouds

New Scientist, 28 March 1985:

There is much in Sir Douglas Black’s article on Sellafield (7 March, p 12) with which even his sternest critics would agree. Thus, there is no doubt about the inability of epidemiological studies to provide indisputable evidence of causality. Equally, no one disputes that a causal relationship between Sellafield discharges and local cases of childhood leukaemia is biologically possible.

It is widely realised that radioactive contamination along the Cumbrian coast is unique, both in terms of level, and duration of exposure, that the alpha discharges result in bone marrow exposures which are unparalleled in any other civilian population, and that the placenta does not offer an effective barrier to fetal exposure. Consequently, if nuclear establishments are going to produce any biological effects at all, it is in the population of Cumbria that those effects will be most apparent.

Black’s inquiry identified some biological phenomena, but omitted several others. For example, it failed to mention that of the 675 electoral wards surveyed in the North of England, four of the ten with the highest incidence of leukaemia are located along the Cumbrian coastline. It excluded two cases of leukaemia diagnosed in Seascale in 1983, and did not update its information on the other “top ten” electoral wards. It failed to observe that leukaemia was not the only malignancy present in excess around Sellafield. It failed to draw the obvious parallel between Cumbria and Denver, where an increased rate of malignancy, including leukaemia, has been documented downwind of a local plutonium production plant, which also caught fire in the late 1950s.

Black argues that the causal relationship between Sellafield discharges and local cases of childhood leukaemia is no more than a possibility. Yet, he fails to consider any of the above points, all of which support the causal hypothesis. Instead, he presents two new arguments in support of his own position, both of which are of doubtful scientific value.

First, he argues that, if the incidence of leukaemia in Cumbrian children returns to normal as the radioactive discharges are reduced, then that will reinforce the causal hypothesis. In fact, one could argue the opposite case equally well. Since plutonium-239 has a half-life of 24000 years, and since americium-241 is being formed from the decay of plutonium-241 at a rate which will increase over the next 50 years, the high incidence of leukaemia in Cumbria could be maintained well into the next century.

Black also argues that ionising radiation is associated with myeloid rather than lymphatic leukaemia. This argument is equally specious. Chronic lymphatic leukaemia may not be related to radiation, but excess numbers of cases of acute lymphoblastic leukaemia have been found in atomic-bomb survivors from Japan. If Black believes that the incidence of acute lymphoblastic leukaemia in Cumbrian children argues against a radiation link, he has been seriously misinformed by his scientific advisers.

Finally, Black avoids the main issue in pretending that the only solution is closure of the reprocessing plant. Environmental groups are only too well aware that Sellafield in a military role, which the government regards as indispensable. The current proposal is to lower the authorisation limits, but this will still allow British Nuclear Fuels to discharge several hundred curies of alpha-emitters annually.

Sellafield will remain the dirtiest nuclear facility in Europe.

Russell Jones
Stoke Poges, Bucks

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