The radiation dose received by plaice (Pleuronectes platessa) from the waste discharged into the north-east Irish Sea from the fuel reprocessing plant at Windscale

A large proportion of the radioactive waste discharged into the north-east Irish Sea from the nuclear fuel reprocessing plant at Windscale is reconcentrated on to the seabed silt and sediment in the vicinity of the outfall. This results in an extensive environment in which benthic and demersal organisms receive a radiation dose rate significantly greater than the natural background. Calculations based on seabed radioactivity measurements made during routine environmental monitoring surveys indicated that the dose rate to the plaice (Pleuronectes platessa), a commercially important species in the area, could range up to 5 mrad hr−1 from beta- and gamma-radiation. In situ measurements of the dose rate regime experienced by the plaice have been made with lithium fluoride dosimeters combined with the "Petersen disc" tag normally used for fish population surveys. The results show substantial agreement with the calculated dose rates and the data have been used to derive an estimate of the mean dose rate to the plaice gonad. It is concluded that the increased radiation exposure experienced by the plaice will not have any discernible effect at either the individual or population level.