Mvondo S, Ben-Bolie G H, Ema'a J M Ema'a, Ateba P Owono, Ele Abiama P, Ateba J F Beyala
Nuclear Physics Laboratory, Faculty of Science, University of Yaounde I, Cameroon; National Radiation Protection Agency, P.O. Box 33732 Yaounde, Cameroon.
Nuclear Physics Laboratory, Faculty of Science, University of Yaounde I, Cameroon.
J Environ Radioact. 2017 Dec;180:114-119. doi: 10.1016/j.jenvrad.2017.10.007.
This study was carried out in the localities Melondo and Ngombas located in the Southern Region of Cameroon where there are known to be uranium-bearing and high background radiation areas. Activity concentrations of naturally occurring radionuclides Po, U, U, U, Th, Th, Th and Ra were determined in soil and fern (filicophyta) samples collected at 10 points in both localities. In soil, the average values of these activity concentrations (in Bq.kg d.w.) were Po(130 ± 10), U(126 ± 11.6), U(5 ± 1), (131 ± 10), Th(400 ± 22), Th(145 ± 11), Th(381 ± 21) and Ra(154 ± 28) at Melondo; and Po(228 ± 1), U(170 ± 11), U(9 ± 2), U(179 ± 12), Th(200 ± 18), Th(184 ± 18), Th(228 ± 22) and Ra(416 ± 7) at Ngomba. In fern the average activity concentrations were: Po(35 ± 3), U(0.68 ± 0.05), U(0.042 ± 0.01), U(0.90 ± 0.05), Th(1.2 ± 0.2), Th(0.7 ± 0.1), Th(39 ± 3) and Ra(14 ± 3) at Melondo and Po(24 ± 2), U(0.82 ± 0.06), U(0.046 ± 0.01), U(0.92 ± 0.06), Th(0.8 ± 0.2), Th(0.9 ± 0.2), Th(15 ± 5) and Ra(14 ± 3) at Ngomba. The soil-fern transfer factors (TF) (in kg.kg) were respectively Po(1.64 × 10), U (5 × 10), U(7 × 10), U(6 × 10), Th(3 × 10), Th(5 × 10), Th(7.9 × 10), and Ra(5.1 × 10). The highest TF for fern was for Po, probably because of atmospheric deposition. The TFs of uranium and thorium were comparable to those given in the IAEA handbook for grass.
本研究在喀麦隆南部地区的梅隆多和恩贡巴斯两地开展，这两个地方是已知的含铀地区和高本底辐射区。在两地的10个采样点采集的土壤和蕨类植物（羊齿植物）样本中，测定了天然存在的放射性核素钋（Po）、铀（U）、U、U、钍（Th）、Th、Th和镭（Ra）的活度浓度。在梅隆多的土壤中，这些活度浓度（单位为Bq.kg干重）的平均值分别为：Po（130±10）、U（126±11.6）、U（5±1）、U（131±10）、Th（400±22）、Th（145±11）、Th（381±21）和Ra（154±28）；在恩贡巴斯的土壤中，其平均值分别为：Po（228±1）、U（170±11）、U（9±2）、U（179±12）、Th（200±18）、Th（184±18）、Th（228±22）和Ra（416±7）。在蕨类植物中，梅隆多的平均活度浓度分别为：Po（35±3）、U（0.68±0.05）、U（0.042±0.01）、U（0.90±0.05）、Th（1.2±0.2）、Th（0.7±0.1）、Th（39±3）和Ra（14±3）；恩贡巴斯的平均活度浓度分别为：Po（24±2）、U（0.82±0.06）、U（0.046±0.01）、U（0.92±0.06）、Th（0.8±0.2）、Th（0.9±0.2）、Th（15±5）和Ra（14±3）。土壤 - 蕨类植物转移因子（TF）（单位为kg.kg）分别为：Po（1.64×10）、U（5×10）、U（7×10）、U（6×10）、Th（3×10）、Th（5×10）、Th（7.9×10）和Ra（5.1×10）。蕨类植物中转移因子最高的是钋，这可能是由于大气沉降所致。铀和钍的转移因子与国际原子能机构手册中给出的草的转移因子相当。
