The vertical distributions of 237Np in soil profiles collected from west Cumbria, UK, have been measured by ICP-MS. They show, in general, exponential decreases with depth, similar to those of the other transuranic and fission product nuclides. The maximum 237Np activity concentration in any of the soil samples was 2·87 ± 0·68 (2σ) Bq kg−1 (dry) for the 0–5 cm section of a gley soil, compared to 3660±460 (2σ) Bq kg−1 (dry) for 239,240Pu in the same sample. A significant proportion of the total 237Np inventory is observed at depth in most sites, implying a greater mobility of neptunium than other transuranium nuclides within the profiles studied.
- Irish Sea
- sediment contamination