Radiocesium in the foodchain of lamb in the Faroe Islands. Results from the RAD-3 and EKO-2 programmes. In NKS report: NKS(97)FR5

The paper summarizes the results from an eight-year investigation of transfer of radiocesium from soil to grass and further to lamb. The investigation is part of RAD3 (1990-93) and EKO-2 (1994-97), being inter-Nordic radioecology projects under the Nordic Committee for Nuclear Safety research, NKS. Nine uncultivated pastures have been selected for the Faroese part of the projects. The sample program involves lamb meat lamb, mixed grass and soil from the uppermost 10cm. Lamb faeces have been included since 1995. The deposition of radiocesium is now around 5 kBq/m2. About 60 Bq/kg(d.w.) is observed in mixed grass and around 12 Bq/kg(f.w.) in lamb meat. However, despite the limited geographical extent of the Faroe Islands, a significant variation is observed between pastures. Significant inter-annual variation is observed within the pastures as well. Taking all stations together gives the following estimates of transfer in 1997: Grass/soil concentration ratio around 0.3, meat/soil concentration ratio around 0.05, and meat/grass concentration ratio around 0.5. The aggregated transfer factors are about 15.10-3m2/kg and 2.5.10-3m2/kg for grass/soil and meat/soil, respectively. These are low compared to other Nordic countries. The meat/faeces and faeces/grass concentration ratios are found to be 0.20 2.32.0, respectively. These are comparable to results found in a feeding experiment. 0.14 and The effective ecological half-life, T1/2, of radiocesium in mixed grass and lamb meat is estimated, assuming an exponential decay model. Data from single pastures give T1/2(grass) and T1/2(meat) to be in the range 2.0-2.8y and 4.0-12.6y, respectively.