Hinkley Point Cancer Clusters
Report from Radioactive Times Volume 4, Number 1, June 2000 (content not updated)
Cancer data for small areas is rarely made available to researchers, so when, at the end of last year, the Office for National Statistics (ONS) released four years' worth of mortality data for the small areas of the census wards in England and Wales, LLRC quickly bought the entire database.
The data gave numbers of deaths from all cancers and also cancers of the lung, breast, prostate and stomach in men and women of all age groups for the years 1995 to 1998.
Research into the effects of low-level radiation near nuclear sites has been made almost impossible due to the secrecy which has built up around small area health data. The cancer registries just will not release it and apart from the anecdotal evidence of sufferers and their families or some results of studies of childhood leukemia it has been impossible to get any sort of evidence about the risks of living near nuclear sites.
The acquisition of this data will enable Green Audit to look at the cancer risk in Wales and bring independent evidence to bear on the disputes about the coastal effect on cancer found in the Irish Sea study. However, when the "Stop Hinkley" group learned of the existence of the data they asked Green Audit if a study could be made of adult cancer risk in the vicinity of Hinkley Point.
LANDSAT photograph of Hinkley Point nuclear power station (the large white object on the coast in the bottom left) and the 50 sq. km. mudbank at the mouth of the River Parrett. The town of Burnham on Sea is on the coast in the top right of the photo.
Riddle of the Welsh Sands
In the previous two Radioactive Times (Vol 3 Nos 1 and 2) we reported on the conclusions of the study of cancer incidence in Wales using the Wales Cancer Registry data for 1974-1989, and drew attention to the existence of high risk associated with proximity to the radioactive contaminated offshore mud banks in the north. Relative risk for most cancers was high in the narrow coastal strip with a trend away from the coast that mirrored that of plutonium concentration in air due to seaspray penetration.
It was thought that the radioactive silt from Sellafield, deposited on mudbanks like the Lavan Sands, near Bangor, was driven ashore and inhaled by the inhabitants.
And another riddle in Somerset?
For this reason, Hinkley Point represented a useful test of the theory, since the power station discharges liquid waste to the sea in a bay which has slack tidal conditions and a very large mud bank, the Steart flats, which extend from the outfall over an area of 50 sq:km.
Burnham on Sea
The largest local town to the contaminated mud is Burnham on Sea, a small seaside town of population 9000. A visit to Burnham at low tide reveals an expanse of muddy sand extending to the horizon, and when the tide comes in, if there is even the slightest breeze, the sea is a muddy brown colour due to a stirring of the sediment. Besides being close to the Steart Flats mud bank, Burnham is also directly downwind of Hinkley Point, in the path of airborne emissions of radioactive gases like Tritium and Carbon-14 dioxide, and Krypton-85.
The study began at the end of February and the first results, reported at the end of April, looked at breast cancer mortality. The method used was to calculate the expected numbers of deaths in each of the 103 wards for every five-year age group based on national death rates for the diseases being studied. Populations were obtained (at some cost, ONS charged about £250) from the 1991 Census. The expected total number of deaths was then compared with the observed number to provide a Standardised Mortality Ratio or Relative Risk (RR). Allowance was also made for the socioeconomic status of the wards by calculating from Census tables the numbers of households in each Social Class group.
The most immediate and clear finding was of a cluster of breast cancer deaths in Burnham on Sea. The ward Burnham North had twice the national average rate for the disease between 1995 and 1998 with 8.7 deaths expected and 17 deaths observed (RR = 1.95 p = 0.008). The paper reporting this finding was presented by Paul Dorfman at a public meeting in Bridgwater on April 26th arranged by "Stop Hinkley" to mark the anniversary of the Chernobyl accident.
Fig. 1: Map of relative risk of breast cancer mortality 1995-98.
The red spot marks the centre of the mud flats (turquoise area) and the centre of the study area.
relative risk >1.9
relative risk 1.5 - 1.9
relative risk >1.1 - 1.5
relative risk >0.9 - 1.1
relative risk <0.9
Fig. 2: Trend
Vertical axis: mortality risk from breast cancer (circles) and prostate cancer (squares)
Horizontal axis: distance (Km) from the Steart Flats mud bank next to Hinkley PointIn addition to the Burnham on Sea breast cancer cluster, there were other discoveries which supported the initial hypothesis of sea-to-land transfer of radioactive particles. Risk in concentric rings drawn around the centre of the mud bank was highest in the first 5km ring. Thereafter it fell off significantly with distance in a pattern which is broadly similar both to that of seaspray penetration inland, and also to Plutonium penetration inland (as reported by Harwell researchers examining Plutonium concentration in air in Cumbria). The trend is given in Figure 2 which also shows the effect for prostate cancer and breast cancer mortality risk by proximity to the low land and rivers. This showed a significant difference between those living in wards on high land above the 200m contour line and those below (RR = 1.64 p = 0.02)
Health Authority response - desperate denials
A more serious accusation was made by the Somerset Health Authority. Their director, Virginia Pearson, told the Press that the ONS Census population figures used by Green Audit were wrong, and the use of their own updated figures wiped out the breast cancer clusters found. Although this seemed unlikely it would, if true, have been a reason for retracting the report. Chris Busby contacted Dr Pearson who promised to send the correct figures. Eventually they arrived on a disk in an envelope with a Berkshire postmark. Curious. The figures were for 10-year age groups and were therefore less accurate but it was a simple matter to compare their predictions with those of the ONS Census figures. There was a 10% difference in Relative Risk using the new population figures. The Relative Risk in Burnham North actually went up by a few percent from 1.95 to 2.02 . The response of the Health Authority must have been a desperate psychological denial.
The results for prostate cancer, released in May, showed similar effects. They were reported nationally in the Sunday Express. Again, the highest risk was in Burnham on Sea with 21 deaths observed and 14 expected in the two wards ( RR = 1.5 p = 0.05). Risk fell off significantly with distance from the mudflats in the same manner as for the breast cancer. The wards on high ground had significantly lower risk than the low ground wards. In addition there was one new piece of information.
In 1989, NRPB published the results of their study into Gamma Ray backgrounds in England and Wales. (Gamma Radiation Levels Outdoors in Great Britain - NRPB R191).
Using the tables and maps given by NRPB it was possible to compare areas of England and Wales on a 10km grid. This showed that average gamma background inland over the study area was 34nGy/hr (over a year, this represents about 0.3mGy or a fifth of the average Natural Background). p But comparable gamma figures were also available from the reports of the operators of the Hinkley Point nuclear power station. These gave gamma dose rates over the mud near the site at upward of 100nGy/hr. Also tabulated in these reports were figures for Burnham beach and nearby Combwich beach of 60 and 80nGy/hr. Why do the beaches confer twice to three times the gamma dose? Because they contain most of the accumulated radioactive waste discharged to the sea by the plant since its commissioning. This material attaches to the silt and is blown ashore with seaspray. It is rained out over Somerset and washes into the rivers where it re-joins the silt in a ghastly and dangerous cycle resulting in increased risk of exposure to those living near the sea, the tidal sediment and the tidal rivers.
The Second Event:
Hinkley A closes
Whether the discovery of the cancer clusters near Hinkley Point was too much for the movers and shakers or whether it was a coincidence is hard to say but shortly after the media interest in the cancer cluster reports reached its peak, the decision was made by BNFL to close Hinkley Point MAGNOX station.
LLRC must feel it has had some effect since a few years ago Chris Busby made calculations of the cancer yield that would result from the then proposed incineration of nuclear waste. A press release of this report and its coverage by the media coincided with the decision to cancel the proposed Hinkley C PWR reactor and the decision not to go ahead with the incineration. A report on "all cancers", lung cancer and stomach cancer in the area is being prepared and will be reported in the next RaT.
Copies of the breast cancer and prostate cancer reports, which show Relative Risk in each of the 103 wards near Hinkley Point are available from
tel. 01984- 632109
If you are seeing this page full screen (i.e. without a navigation bar on the left) you can't see how the rest of the site is organised.
This Home page link takes you to the index page, which has links to all the topics we discuss on the site [only use it if this page is full screen]
Use the Radioactive Times button to see links to the whole electronic edition on this site.
This page was last updated May 2001