Kaewtubtim Pungtip, Meeinkuirt Weeradej, Seepom Sumalee, Pichtel John
Department of Science, Faculty of Science and Technology, Prince of Songkla University, Pattani Campus, Pattani, 94000, Thailand.
Mahidol University, Nakhonsawan Campus, Nakhonsawan, 60130, Thailand.
Environ Sci Pollut Res Int. 2017 Mar;24(8):7630-7639. doi: 10.1007/s11356-016-8266-9. Epub 2017 Jan 25.
Mangrove ecosystems in Pattani Bay, Thailand are considered representatives for monitoring the occurrence of anthropogenic and natural pollution due to metal and radionuclide contamination. Sediments and seawater were collected from five locations to determine metal (Cd, Cr, Cu, Mn, Ni, Zn, and Pb) and radionuclide (Ra, Th, and K) concentrations. Spatial variations in metal and radionuclide concentrations were determined among the sampling sites. A geoaccumulation index (I ) and enrichment factor (EF) were used to classify the impacts of metals from anthropogenic point sources. Significant values for I and EF were measured for Pb in site 4 (I 0.65; EF 28.2) and Cd in site 1 (I 1.48; EF 46.2). EF values in almost all sampling sites were >1 which indicates anthropogenic pollution. To assess the potential public hazard of radioactivity, the average radium equivalent activity (Ra), the external hazard index (H ), the internal hazard index (H ), the absorbed dose rate in air (D), and the annual effective outdoor dose rate (E) were determined. Based on these measurements, it is concluded that the probability of human health risk from radionuclides is low. However, the absorbed dose in air (D) values in sites 4 and 5 were greater than the global average value of 55 nGy h, indicating that sediments in these locations pose a radiological hazard. The data obtained in this study provides useful information on metal and radionuclide background levels in mangrove sediments and seawater, and can be applied toward human health risk assessment and metal and radionuclide mapping.
泰国北大年湾的红树林生态系统被视为监测由于金属和放射性核素污染导致的人为和自然污染发生情况的代表。从五个地点采集了沉积物和海水，以确定金属（镉、铬、铜、锰、镍、锌和铅）和放射性核素（镭、钍和钾）的浓度。测定了采样点之间金属和放射性核素浓度的空间变化。利用地积累指数（I ）和富集因子（EF）从人为点源角度对金属的影响进行分类。在第4号地点测得铅的I （0.65；EF 28.2）和第1号地点镉的I （1.48；EF 46.2）具有显著值。几乎所有采样点的EF值均>1，这表明存在人为污染。为评估放射性的潜在公共危害，测定了平均镭当量活度（Ra）、外部危害指数（H ）、内部危害指数（H ）、空气中吸收剂量率（D）和年有效室外剂量率（E）。基于这些测量结果，得出放射性核素对人类健康造成风险的概率较低的结论。然而，第4号和第5号地点的空气中吸收剂量（D）值大于全球平均值55 nGy h，表明这些地点的沉积物存在辐射危害。本研究获得的数据提供了关于红树林沉积物和海水中金属和放射性核素背景水平的有用信息，可应用于人类健康风险评估以及金属和放射性核素绘图。
