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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 40K, 210Pb, 226Ra, 228Ra and 137Cs in soils of agriculture fields were lower than worldwide average values. The soil-to-plant transfer factors (TFs) for 40K in leafy vegetables were higher than those in fruit vegetables. Soil-to-grass transfer factor (Fv) values were in the following order: 40K > 210Pb > 226Ra. The grass-to-milk transfer coefficient (Fm) values for 40K and 210Pb ranged between 2 × 10−3 and 4 × 10−3(day L-1). The concentration ratios for the animal products (CRmilk-feed, CRmeat-feed and CRegg-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 40K, 210Pb and 226Ra, 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.

Effluents containing tritium (H) dispersed into the fresh water or marine environment from nuclear facilities can be taken up by biota. Aquatic and marine organisms are among the important pathways through which tritium can enter into the human body, and hence, assessment of the extent of pollution of these ecosystems is very important for radiation dose assessments. Tritium present in environmental matrices can be classified as tissue-free water tritium (TFWT) and organically bound tritium (OBT). Optimization of a method for the determination of OBT in fish, based on thermal oxidation of the sample, is discussed. Samples were subjected to thermal oxidation in a pyrolyser system, and the water produced from the combustion was analyzed by liquid scintillation spectrometry. Results show that a maximum of ~2 g of processed fish sample can be combusted efficiently in the pyrolyser. Using this method, a recovery of 84% was achieved, and minimum detectable activity (MDA) for the method was determined to be 8.5 Bq kg (sample weight = 2 g, counting time = 30,000 s, and detection efficiency = 20%).

The activity concentration of natural and anthropogenic radionuclides was determined in different vegetable samples, and foods derived from animal origin, from different locations in the four cities of Southern Tunisia, where large-scale phosphate industries are operating. The aim of the studies was to establish a baseline database on radionuclide concentration in food materials and to evaluate the radiation dose to the general population due to its ingestion through the food chain. The activity concentrations of 40K, 210Pb, 226Ra, 228Ra and 137Cs was determined by gamma spectrometry using a HPGe detector, and from the measured activity concentrations, the doses were estimated using the dose coefficients given by the ICRP. The dose due to intake of radionuclides through mineral water was also determined. The total annual effective doses were found to be 2.2, 1.4, and 0.7 mSv y−1 for 1 y, 5–15 y and adult (>17 y) age groups, respectively. Among the radionuclides studied, 210Po was the highest contributor to the total dose, followed by 210Pb.

The use of Cesium-137 ( 137 Cs) as a potential environmental marker was examined for estimating soil erosion induced carbon losses on slopping agricultural land. Depth-wise incremental soil samples were taken from uneroded reference sites and four levels of cultivated slopping lands representing different erosion phase in Doon valley region of India. Comparing the 137 Cs inventories for eroded sites with the reference inventory, the erosion rates were computed. The estimated erosion rates were then compared with the actual measured values of erosion at each erosion phase. Since soil erosion preferentially removes the finer soil particles, these results were used to assess erosion induced loss of OC. The result indicated that erosion in different phases relocate 137 kg C ha –1 in slightly eroded plots to 384 kg C ha –1 in severely eroded plots which in turn contributes to 27 to 77 kg C ha –1 the atmosphere as net source of C respectively.

Laser-Induced Fluorimetry has been used to measure the concentration of uranium in the ground water samples collected from the selected study locations of Bangalore city, India. The concentration of uranium in the collected water samples is found to be in the range 0.24 μg/l to 770.1 μg/l, with a geometric mean (GM) value of 18.9 μg/l. About 35% of the water samples show the concentration of uranium above the safe limit of 30 μg/l, set by the United States Environmental Protection Agency (USEPA). The annual effective dose associated with the ingestion of uranium by the adult population of the region has been estimated using the International Commission on Radiation Protection (ICRP) and World Health Organization (WHO) guidelines. Few physicochemical parameters of water such as pH, Total dissolved solids (TDS), major cations, major anions, and trace elements were also measured. The correlation coefficient among the measured parameters was determined to find the dependence, if any, on the concentration of uranium in the water samples.