Preliminary estimates of cumulative caesium and plutonium deposition in the Irish terrestrial environment

A number of soil and peat cores, sampled throughout Ireland from November 1987 to March 1988, have been analyzed for fallout caesium and plutonium. Specifically,¹³⁴Cs and¹³⁷Cs levels were measured by high resolution gamma spectrometry while²³⁸Pu and^239,240Pu were determined after chemical extraction by alpha spectrometry. The inventories of these nuclides at the locations sampled have been calculated from the resulting profiles and, by extrapolation, preliminary estimates made of the cumulative deposition throughout Ireland. The relative contribution from weapons testing in the atmosphere and the Chernobyl accident to the total caesium inventory have been determined by the¹³⁴Cs/¹³⁷Cs isotopic ratio. As expected, no plutonium of Chernobyl origin was detected in surface layers. The cumulative²³⁸Pu/^239,240Pu ratio measured in Irish soils was found to be consistant with mid-latitude ratios reported by others.