Bhuiyan Md Khurshid Alam, Siddique Mohammad Abdul Momin, Zafar Mohammad, Mustafa Kamal Abu Hena
a Department of Animal Science and Fishery, Faculty of Agriculture and Food Sciences , Universiti Putra Malaysia , Campus Bintulu Sarawak, Bintulu , Sarawak , Malaysia.
Isotopes Environ Health Stud. 2014;50(1):134-41. doi: 10.1080/10256016.2013.830613. Epub 2013 Oct 4.
Concentrations of natural and fall-out radionuclides in the offshore seawater and sediment from some parts of the Bay of Bengal, Bangladesh, were determined using a coaxial germanium detector. The average activities of (238)U, (232)Th, (40)K and (137)Cs were recorded as 31.2±5.8, 51.9±9.4, 686.4±170.5 and 0.5±0.6 Bq kg(-1) dry weight, respectively, for sediment, and 4.8±1.2, 5.4±1.2 and 39.1±8.6 Bq L(-1) for (238)U, (232)Th and (40)K, respectively, in seawater. The concentration of (137)Cs in seawater was below the detection limit. The concentration of sediment (238)U was found to be positively correlated with (232)Th ([Formula: see text], p<0.05) and (40)K (r=0.96, p<0.01), while (232)Th was positively correlated with (40)K (r=0.91, p<0.05). In sediment, the concentration of (238)U was negatively correlated (r=-0.86, p<0.05) with sea depth. In the seawater sample, the only significant relationship found was between concentration of (232)Th and water depth (r=-0.86, p<0.05). One-factor analysis of variance (ANOVA) showed that the level of radioisotope concentrations of seawater and sediment was highly significant for (238)U (F=122, df=11, p=0.01), (232)Th (F=143, df=11, p=0.01) and (40)K (F=86, df=11, p=0.01). The results showed that the level of radioactivity decreased from coast to open sea. Imminent threat due to radioactivity was not observed in these parts of the Bay of Bengal.
使用同轴锗探测器测定了孟加拉国孟加拉湾部分地区近海海水和沉积物中天然和沉降放射性核素的浓度。沉积物中（238）U、（232）Th、（40）K和（137）Cs的平均活度分别记录为31.2±5.8、51.9±9.4、686.4±170.5和0.5±0.6 Bq kg⁻¹干重，海水中（238）U、（232）Th和（40）K的浓度分别为4.8±1.2、5.4±1.2和39.1±8.6 Bq L⁻¹。海水中（137）Cs的浓度低于检测限。发现沉积物中（238）U的浓度与（232）Th呈正相关（[公式：见原文]，p<0.05），与（40）K呈正相关（r=0.96，p<0.01），而（232）Th与（40）K呈正相关（r=0.91，p<0.05）。在沉积物中，（238）U的浓度与海深呈负相关（r=-0.86，p<0.05）。在海水样本中，发现的唯一显著关系是（232）Th的浓度与水深之间的关系（r=-0.86，p<0.05）。单因素方差分析（ANOVA）表明，海水和沉积物中放射性同位素浓度水平对于（238）U（F=122，df=11，p=0.01）、（232）Th（F=143，df=11，p=0.01）和（40）K（F=86，df=11，p=0.01）具有高度显著性。结果表明，放射性水平从海岸向公海降低。在孟加拉湾的这些区域未观察到因放射性带来的紧迫威胁。
