Radionuclide distributions in seawater around the Sellafield pipeline

In September 1988 a detailed survey was made of the concentrations of 239+240Pu and 241Am in seawater within 10 km of the Sellafield marine discharge pipeline. Concentrations of 239+240Pu in filtered seawater were generally below 3 mBq l-1 but increased to 5 mBq l-1 to the south of the pipeline, while 241Am concentrations were <0.8 mBq l-1, rising to ∼2 mBq l-1. The proportion of the seawater actinide activity on suspended particulates was significantly lower than usual for the eastern Irish Sea, possibly due to the very low particulate loads observed, on average, resulting in ∼80% of 239+240Pu and 40% of 241Am being in solution. (author)