Assessment of naturally-occurring radionuclides in England and Wales
Posted: Tuesday 13th March 2007
Scientists, industry regulators and environmentalists involved in the monitoring and management of ionising radiation in wildlife and the environment now have access to the latest research into naturally-occurring radioactive materials in terrestrial and freshwater ecosystems in England and Wales.
The Environment Agency report, entitled ‘Assessment of naturally-occurring radionuclides in England and Wales’, reveals the levels of natural radionuclides in the environment to which plants and animals may be exposed, primarily the Uranium 238 and Thorium 232 series and Potassium 40. The report covers soils, stream and river sediments, saltmarsh, wild animals and plants and freshwater ecosystems.
“Many natural materials contain low levels of radionuclides. However, their impact on plants and animals had not been comprehensively assessed, before. The aim of the study was to establish the activity concentrations of these radionuclides, and to estimate background radiation levels in terrestrial and freshwater ecosystems,” explained Environment Agency Principal Scientist David Copplestone.
“We first collated and reviewed available data from existing scientific literature and in-house collections, such as the annual Radioactivity in Food and the Environment report, and the Centre for Ecology and Hydrology’s wildlife sample archive. We then identified gaps in the existing data and put together a field and archive sampling and analysis strategy to fill the gaps.
“Particular emphasis was placed on finding and collating data suitable for use by the International Commission on Radiation Protection, which suggested using standard adult stage animals and plants as reference points when assessing radiation effects.”
Field surveys were carried out from December 2005 to February 2006. Samples collected included flying insects, predominantly moths, from each of the eight terrestrial Environmental Change Network sites in England and Wales, lodgepole pine, grey heron liver, earthworms, rabbits, pike, toads, mallards, trout and grass snakes. Some data for natural radionuclides in marine organisms were also obtained.
Estimates of radionuclides in soil, sediments and stream waters were derived using concentrations taken mainly from the British Geological Survey’s on-going geochemical survey of the UK, and Imperial College’s Wolfson Geochemical Atlas data. Additional data was collated by geological extrapolation using relationships between soil/sediments and bedrock/superficial geology.
“Not only will the datasets compiled be invaluable to UK scientists and regulators, but they will also be used in other collaborative research projects such as the European Commission’s ERICA project looking at the environmental risk from ionising radiation and contaminants on wildlife and ecosystems,” concluded Copplestone.
