Radioactive Times: LLRC Journal

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report from Radioactive Times Volume 3, Number 1, March 1999

Carlingford and Dundalk

Chris Busby and Molly Scott Cato recently visited County Louth on the east coast of Ireland to take samples for measurement of radioactivity and also to interview GPs in the town of Dundalk and on the Cooley peninsula. The question of health effects from Sellafield pollution on the Irish coast is one of the most lively issues in the area.

In the 1980s, a Dundalk doctor, Patricia Sheehan, discovered a cluster of Down’s syndrome children born to young mothers who had been at boarding school in Dundalk together and who she believed had been contaminated by the Windscale fire fallout in 1957. Her paper in the British Medical Journal was the first to draw attention to radioactivity effects in Dundalk.

Tragically, Dr Sheehan died in a car accident a few years ago but her work has been followed up by another local GP Dr Mary Grahan. Three years ago, Dr Grahan discovered anomalously low levels of Vitamin B12 in women in the town and neighbourhood of Dundalk and believes that her discovery is connected with the Windscale fire (RaT 1/3, p. 9). She told Chris Busby that she believed that the cancer rates in Dundalk were much higher than average near the river and also on the coast. Although Green Audit has applied to the recently formed Irish National Cancer Registry for the small area figures for 1995 and 1994 (currently in preparation), it is not certain when they will become available. In the meantime, Dr Sheehan has agreed to assist Green Audit setting up a survey of cancer incidence in the town of Dundalk. It is hoped that this can begin this year, 1999.

Radioisotopes from Sellafield are easily measurable in mud and sand from the beaches near Dundalk and also further up the coast in Carlingford Lough, with levels comparable to those in north Wales.

Cancer in Carlingford is apparently also higher (see RaT 2/3, p. 1) with Relative Risks as high as 4.6 or more for Childhood leukemia. The team spent some time measuring alpha activity of beach and river mud and silt at different depths and recording variations of activity across the ‘kentering’: the area between low and high tide levels. Samples were collected and brought back for radiochemical analysis. The concern is that ‘hot particles’ of plutonium may be collecting on the beach and offshore mudbanks and blowing inland, where they may be inhaled and provide high local doses people living in the area.

The effect of distance from Sellafield on the concentration of radioactive waste released to the Irish Sea is not simple. Because the isotopes stick to fine silt particles preferentially, it is the distribution of the fine silt in the Irish Sea that determines the level of pollution. Fine silt precipitates out in areas of low tidal energy, like estuaries and harbours. The silt comes up rivers and is deposited at high tides on saltmarsh.

Tidal flow the Irish Sea (chart above) results in some areas of water where there is no net current. The major area where this occurs is off the north-east of Ireland, near Dundalk Bay and Carlingford. This is where radioactive fine silty mud precipitates and where there are large offshore drying mudflats. The deeper part of this ‘gyre’ correspond with the area where the Tc-99 radioactive lobsters breed. Another mud bank forms off Bangor, where the Menai Straits interfere with tidal flow. Here, high levels of radioisotopes are found in the Lavan Sands.

Health problems result from the re-suspension of fine silt and radioactive ‘hot particles’ which fetch up on these mud banks. This picture shows an autoradiograph of a core sample of mud showing hot particles of high activity.

(12KB) Fig. 1. Beta-gamma autoradiograph of a sandy estuarine core sampled in Cumbria in September 1980, and exposed on x-ray film for 200 days.
The white spots and zones represent deposition of radionuclides. Note the hot particles, and that the white zones fall into strata deposited in the summer. ("w" = winter)
Eric Hamilton: Marine Pollution Bulletin 36 (1), 8-18 (1998)
figure 11.(20 KB)

Fig. 2. Inland penetration of Plutonium in air and seaspray (Eakins and Lally)
Horizontal axis = Distance downwind from sea (Km):
vertical axis (upper figure) = Relative concentration of 239,240Pu in air (pCi m3): lower figure Concentration of 239,240Pu (pCi g-1Na)

Figure 2 shows the concentration of plutonium caught in muslin screens deployed at various distances from the Irish Sea by a team from Harwell in 1980.
The lower figure shows air and seaspray concentration of plutonium inland, from J. D. Eakins and A. E Lally; Science of the Total Environmnent 35 23-32 (1984)

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