Assessment of naturally occurring radionuclides around England and Wales: application of the G-BASE dataset to estimate doses to non-human species

An assessment of the natural radiation dose to wildlife in England and Wales was made
to determine the contribution it may make to the total radiation dose estimated during environmental
impact assessments. Significant use was made of systematic datasets for environmental media (stream
sediments, stream waters and soils), in particular those produced by the Geochemical Baseline Survey
of the Environment (G-BASE) project. This provided extensive, although variable, coverage for different
elements and sample types after normalisation of data to account for changes in sampling and analysis over
time. Almost complete coverage for K in stream sediments was achieved by merging G-BASE andWolfson
Atlas data. This required normalisation of theWolfson data to the G-BASE results. Coverage was improved
greatly for U and Th in sediments, and K, U and Th in soils, by using the strong relationship between soils
and sediments and geology (both solid and superficial) to extrapolate the data. The total U, Th and K data
were used to derive activity concentrations of 238U and 232Th series radionuclides and 40K. External dose
rates to wildlife were then estimated from derived media concentrations; internal dose rates were estimated
from measured activities in biota or activities predicted using recommended concentration ratios.