Assessment of radionuclide transfer factors and transfer coefficients near phosphate industrial areas of South Tunisia

The activity concentrations of naturally occurring and anthropogenic radionuclides in agriculture soils as well as in several food products at four locations within the phosphate area of South Tunisia were investigated. Soil-to-plant transfer factors as well as feed-to-animal products transfer coefficients were determined for the first time for the region. Activity concentrations of 40 K, 210 Pb, 226 Ra, 228 Ra and 137 Cs in soils of agriculture fields were lower than worldwide average values. The soil-to-plant transfer factors (TFs) for 40 K in leafy vegetables were higher than those in fruit vegetables. Soil-to-grass transfer factor ( F v ) values were in the following order: 40 K > 210 Pb > 226 Ra. The grass-to-milk transfer coefficient ( F m ) values for 40 K and 210 Pb ranged between 2 × 10 −3 and 4 × 10 −3 (day L -1 ). The concentration ratios for the animal products (CR milk-feed , CR meat-feed and CR egg-feed ) varied in the ranges of 2 × 10 −2 –4 × 10 −2 L kg −1 , 1 × 10 −2 –2 × 10 −1 (L kg -1 ) and 5 × 10 −2 –1 (L kg -1 )for 40 K, 210 Pb and 226 Ra, respectively. Transfer parameters determined in the present study were compared with those reported in International Atomic Energy Agency reports and other published values. The absorbed gamma dose rate in air and the external hazard index associated with these natural radionuclides were computed to assess the radiation hazard of radioactivity in this region, and the results indicated that these areas are within set safety limits.