New study confirms breast cancer risks near radioactive estuary
Official responses characterised by secrecy and denial
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Environmental consultants Green Audit have released new findings (1 available on this site) on cancer mortality near the Blackwater Estuary, Essex, close to the Bradwell nuclear power station. They have confirmed the existence of doubled breast cancer mortality in wards affected by sea-to-land transfer of radioactivity. Green Audit has corrected computing errors in previous reports; this has made the estuary effect more apparent. Newly acquired figures for two years have also been added, further strengthening the effect and increasing the statistical significance of the findings. The report shows that women living near the estuary have roughly double the risk of dying of breast cancer, compared with the national average. [Mortality data can be purchased from the Office for National Statistics (ONS) in contrast to incidence data, which are potentially more informative and are closely guarded by regional Cancer Registries. The Low Level Radiation Campaign (LLRC) is negotiating for release of incidence data for Essex.]
In 2001 local campaigners who were concerned about the possible impact of incineration of contaminated material at Bradwell commissioned Green Audit to investigate the hypothesis that radioactivity attached to fine particles of silt coming ashore from the estuary would increase cancer rates in people living nearby. In two reports (2), (3) delivered in 2001 Green Audit used data for mortality in local authority wards for breast cancer, prostate cancer, all malignancies male and all malignancies female. The hypothesis was found to be correct and statistically significant for breast cancer and female all malignancies; rates in women who had lived in wards near the estuary were double the national average, while rates in non-estuarine wards were below average. The men's diseases showed only a weak association with residence near the estuary.
There were other sources of information and concern about cancer rates in the area, as shown by the 1999 Essex Sustainability Report (4) and local news coverage (5).
Early in 2001, apparently prompted by an upsurge of public interest in activities at Bradwell, the North Essex Health Authority commissioned a study (6) of cancer near the power station from the Small Area Health Statistics Unit at Imperial College London. LLRC advised local groups that SAHSU was likely to employ a methodology of drawing concentric rings around the power station and comparing cancer in the nearest ring with cancer in the more distant one. Absence of a higher risk in the inner ring would be taken as absence of a detrimental health impact. LLRC warned that in the case of the Blackwater this method would put the populations exposed to the radioactivity into the outer ring and was therefore likely to show that living near the power station was good for health. SAHSU's report did use concentric rings and it contains caveats about its method (it says Our study design assumes that distance from the power plant is a proxy for exposure .... this does not take into account the influence of weather conditions, water movements, occupation, lifestyles etc. which will all influence actual exposure.). Predictably, SAHSU reported that the people living closest to the Bradwell power plant showed no statistically significant excess risk of incidence or mortality. At the same time as commissioning the concentric ring study from SAHSU the Health Authority had asked them to attempt to reproduce Green Audit's findings; they had not been able to as there was a discrepancy in the numbers of deaths.
Health Authority covers up
In August 2002 an off-the-record source told Green Audit that COMARE and ONS had ascertained that the data used by both SAHSU and Green Audit were wrong.
This was the first time Green Audit had heard of errors, but SAHSU must have been alerted many months previously - they had delivered a second report (7) to the Health Authority in March 2002. Local campaign groups had not been informed.
Green Audit investigated and found that their error had been caused by a typographical mistake in computing. The present report (1) corrects the error, strengthening earlier findings.
SAHSU's error was the omission of 10% of cases where the records contained out of date ("terminated") postcodes. All the terminated postcodes were in the Maldon and Heybridge wards, which according to the Green Audit hypothesis were "high risk" areas close to radioactive mud. Once all the cases were included significant excess risks appeared but the second SAHSU report employed a statistical method - Empirical Bayesian Smoothing - which had not been used in the first report and on that basis denied them.
SAHSU covers up
Dr Busby has used the provisions of the Data Protection Act to obtain information from a number of bodies. Imperial College of Science Technology and Medicine has supplied copies of emails with over 90% of the text obliterated (... to anonymise personal data about third parties, says the College Data Protection Office, Chris Ince). Parts of the text which can be deciphered show that the authors are Prof. Paul Elliott, Director of SAHSU, Dr Paul Aylin, SAHSU, and Dr Mike Quinn, head of National Cancer Registration Bureau at ONS. It can also be seen that part of the obliterated text specifically refers to Dr Busby. The subject line of some of the messages is "Busby!!!"; the correspondence concerns data discrepancies in the Blackwater reports, and the authors are anxious to defend the reputation of SAHSU. ICSTM has refused to release more information. Busby has applied to the Data Commissioner for redress. click here to see a sample of SAHSU's data disclosure policy. (Contains an image file of 60Kb)
All three Green Audit studies contain an "internal control" - the town of Burnham on Crouch can be compared with the similar town of Maldon, which lies at the inland end of the Blackwater estuary. The Blackwater is known to be contaminated, and highest level of radioactivity have been officially measured at Maldon. The Crouch is protected from Bradwell's discharges by tidal flows and by sandbars extending into the North Sea. Use of this control shows that the estuarine effect is associated with the Blackwater but not the Crouch.
Authors of the report
Dr Chris Busby, Director of Research, Green Audit, member of Committee Examining Radiation Risk for Internal Emitters, Scientific Secretary of European Committee on Radiation Risk.
Richard Bramhall, Secretary of Low Level Radiation Campaign, member of Committee Examining Radiation Risk for Internal Emitters.
1 Chris Busby C, Bramhall R; Breast Cancer Mortality and Proximity to Bradwell Nuclear Power Station in Essex 1995-1999. Correction and Update to 2001 with a commentary on Official Responses. Green Audit: Aberystwyth Occasional Paper 2002/6 December 2002 Get the report (as a pdf file 407Kb)
2 Busby C.C, Dorfman P, Bramhall R, Cancer Mortality and Proximity to Bradwell Nuclear Power Station in Essex, 1995-1999 Green Audit Occasional Paper 2001/4A March 2001
3 Busby C.C, Dorfman P, Bramhall R, Environmental Risk Methodology and Breast Cancer Mortality near Bradwell Nuclear Power Station in Essex, 1995-1999 Green Audit Occasional Paper 2001/8 July 2001
4 The Essex Sustainability Report: 22 indicators of sustainability in Essex for the 21st Century, (page 44, Indicator 17b). Association of Essex Councils; published by Essex County Council. 1999
5 Council crackdown on breast cancer; Maldon and Burnham Standard June 7 2001 (News report in full)
6 The Small Area Health Statistics Unit (SAHSU) Rapid Inquiry Facility (RIF) on Bradwell, North Essex (unpublished) delivered to North Essex Health Authority June 2001.
7 Small Area Health Statistics Unit (SAHSU) Rapid Inquiry Facility (RIF) on Bradwell, North Essex: Ward Analysis 1995-1999 (S821) 14th March 2002.
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This page was last updated May 2001