Sea of Troubles
report from Radioactive Times Volume 3, Number 1, March 1999 (content not updated)
In the period 1974-1989, cancer incidence for most age groups and cancer sites was significantly and in some cases alarmingly high in people who were living in a narrow strip, 800 metres wide, along Irish Sea coast of Wales. This was the conclusion of the Green Audit study of the small-area Wales Cancer Registry database released to LLRC in April 1996. The work, which was carried out by Dr Chris Busby and others, was funded by the Irish Government in support of the STAD litigation against BNFL and began in December 1997. The first result, for childhood leukemia in the 0-4 age group, was released as a preliminary occasional paper in August 1998, and was reported by BBC TV in Wales and faxed to Environment Minister Michael Meacher in time for the OSPAR meeting in Portugal in September .
In the event, John Prescott was substituted for Meacher and Sellafield discharges to the Irish Sea continue.
Child leukemia excess
The results of the leukemia analysis showed a 4.6-fold excess in 0-4 year olds over the whole period 1974-89 in small areas with populations centroids below 800 metres from the coast. The risk, which is based on England and Wales populations and rates for 1979, falls off with distance from the coast, sharply to begin with, then rising slightly for the mountains, and falling towards the England border where rates were comparable with English rates. The TV reporting of this finding drew an immediate hostile response from the Wales Cancer Intelligence and Surveillance Unit, a new agency which took over cancer registration from the Welsh Office after the surprising and sudden closure of the Wales Cancer Registry in 1996. WCISU Director Dr John Steward denied that leukemia rates were high in Wales (see this link to X-files story).
Areas of Residence
The analysis was based on the incidence numbers and populations of 194 ‘Areas of Residence’(AOR) covering Wales. These units, which have populations of about 2000-8000 vary in area but include 18 which are coastal towns like Bangor, Newquay and Fishguard. For the purpose of the study, the industrial South Wales valleys and south east coastal areas were excluded.
A Relative Risk for each AOR was calculated by applying age-specific rates for England and Wales 1979 to the 1981 census populations of each AOR to generate the expected number of cases of cancer. The observed number was then divided by this to produce the RR, or relative risk.
AORs were then aggregated into bands by distance from the Irish Sea and the total number of cases in each band compared with that expected on the basis of the England and Wales rate for 1979. The AORs are shown on the map opposite. Statistical significance was obtained either by applying cumulative Poisson calculations in the case of the small number cancers like childhood cancer, or by using chi-squared for the large numbers of adult cancers. Most of the results were highly significant. In the case of the adult cancers looked at so far, the possibility that the result could have occurred by chance was less that 1 in 10,000. Over the period, 1974-89, which included peak emissions from Sellafield and peak levels of radioactive pollution to the coast of Wales, there were 5,500 excess cases in the 1km strip along the Welsh coast. It follows that more than three thousand of these people died of cancer who would not have died of this disease if they had lived, for example, on the English border.
Child cancer near the coast
Although childhood cancers are very rare, cancer is the third most common cause of death in children aged 0-14. Leukemia usually dominates childhood cancers (33%), but in Wales, and particularly along the coastal strip, levels of brain cancer in the 0-4 age group were higher. In the <0.8 km coastal strip RR = 6.9; (P=0.0000; 14 cases observed and 2.04 expected). This fell off with distance according to the same pattern as the leukemias. In the adjacent 0.9-2km strip the RR was 4.1 (P=0.0000) and the RR then flattened out to 3.6 (P = 0.0000) for the next two strips from 2.1-11 and 11.1-20 km. The risk fell to 2.9 for the 11.1 to 40km strip but rose again for the final strip to 3.4. Childhood cancer excesses were mostly in the 0-4 age group. Significant excess rates in the 0-14 group were driven by the 0-4s. The coastal effect, dominated by the brain cancers and leukemias could be measured as significant excess relative risk in both the 0-4s and 0-14s. Despite the small numbers it was possible to break down the period 1974-89 into three five-year blocks to show that the highest excess risk occurred in the most recent period 1984-88 by which time, for the coastal <.8km strip and the 0-4 year olds RR had reached 3.6 based on 17 cases (P=0.0000).
No significant excess effect could be found for Non Hodgkin Lymphoma, all lymphoma, or eye cancer.
|Km. sea distance||Obs. cases||Exp'd. cases||RR||P value||No. of AORs|
|0.9 - 2||1689||1235||1.37||<0.000||17|
|2.1 - 5||1613||1137||1.42||<0.000||15|
|5.1 - 11||1900||1515||1.25||<0.000||17|
|11.1 - 21||669||570||1.17||<0.001||14|
|21.1 - 40||1403||1016||1.4||<0.000||18|
Adult cancers also show effect
All-malignancy Relative Risk in adults of all ages was 1.29 for the 0.8km coastal strip, falling off with distance in the same curious pattern shown by the effect in children. A locally smoothed plot of the scatter of RR with distance in all malignancies is given in Figure 2, opposite. The shape of the relationship with distance is common to all the cancers and sites that show the effect and may be due to the pattern of deposition of radioactivity with rainfall, a possibility which is being investigated further. The common and surprising finding is the sharp rise in cancer in the narrow coastal strip.
What caused the effect?
Cancer is a genetic disease expressed at the cellular level. The existence of a developing cancer excess indicates the existence of an agent, a carcinogen to which the population is exposed several years prior to the expression. As Chris Busby has indicated in Wings of Death, Wales was exposed to high levels of radioactive fallout in the period 1959-63. Much of the radioactivity will have washed to the estuaries and the sea. But Wales has also been exposed to large amounts of radioCaesium, Plutonium and other isotopes from the releases from Sellafield. Peak releases occurred in the early to mid 1970s and the increases in cancer in the Welsh coastal strip reached a maximum in latter part of the study period 1984-89, ten to fifteen years later.
There is no doubt that the radiation from Sellafield turned up on the coast of Wales: Harwell scientists measured it there in 1986. DoE Report DoE/RW.89.108 by J.A.Garland et al. gives measurements of Plutonium-239+240 for many sites along the Welsh coast. What the report shows is that the areas of low tidal energy - like harbours, tidal slacks and estuaries - have the highest burden of Plutonium and other radio-isotopes (see story on p. 10). If the Sellafield radiation were the cause of the cancer excess, then we should expect to find the highest RRs where the isotope levels are also high.And this is what was found.
Estuaries and mud banks
The highest area of radioactive pollution is the large mud bank called the Lavan Sands in north Wales near the town of Bangor. Garland et al estimated an inventory of 285GBq of Pu239+240 in the Lavan Sands.
When the database was examined to see which areas had the highest individual RRs, it was areas like Bangor, Conway, Caernarfon and Colwyn Bay, areas with large populations adjacent to expanses of fine silt that were driving the coas-tal effect. The childhood leukemia RR in Bangor was 10, in Caernarfon 7.2. For brain tumours in the 0-4 group Bangor was 11 (2 cases), Llandudno 18 (4 cases), Prestatyn 7 (4 cases). Although the numbers were too small for statistical significance in the children, the effect was there in adults also. In three five-year periods, the RR for all malignancy in Bangor was greater than the 1.29 coastal strip excess for the whole study area. By 1985-9, there were 412 cases of cancer recorded, with an expected number of 250, (RR = 1.65; P<.000)
Fear in a handful of dust
The significant cancer increase near the Welsh coast and its connection with the northern areas close to silty mudflats is the first firm evidence that Sellafield has been having a serious effect on the health of those people living near the Irish Sea. It is this belief that led to the legal case that the STAD group is taking against BNFL. Wales Cancer Registry data is of some importance for the case since Ireland did not have a registry over the period of peak releases from Sellafield. The researchers at Green Audit believe that the effect in Wales will also be shown by the 1995 and 1994 data being assembled in Ireland by the new Irish National Cancer Registry in Cork.
The most likely explanation of the cancer increases very near the coast is that radioactive micron-sized ‘hot particles’ are washed up along the coast, especially in areas of low tidal activity (see story pp. 10 & 11). These particles are resuspended by wave action, wind or electrostatic effects and are inhaled. Tissue volumes local to these internal particles can be very high, especially for alpha emitters like Plutonium and Americium.
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