title: Occurrence of heavy metals and radionuclides in sediments and seawater in mangrove ecosystems in Pattani Bay, Thailand.
abstract: 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 (226Ra,232Th, and40K) concentrations. Spatial variations in metal and radionuclide concentrations were determined among the sampling sites. A geoaccumulation index (Igeo) and enrichment factor (EF) were used to classify the impacts of metals from anthropogenic point sources. Significant values for Igeoand EF were measured for Pb in site 4 (Igeo0.65; EF 28.2) and Cd in site 1 (Igeo1.48; 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 (Raeq), the external hazard index (Hex), the internal hazard index (Hin), 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-1, 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.
authors.affiliation: Department of Science, Faculty of Science and Technology, Prince of Songkla University, Pattani Campus, Pattani, 94000, Thailand.
authors.forename: Pungtip
authors.initials: P
authors.lastname: Kaewtubtim
authors.affiliation: Mahidol University, Nakhonsawan Campus, Nakhonsawan, 60130, Thailand. phytoplankton8@gmail.com.
authors.forename: Weeradej
authors.initials: W
authors.lastname: Meeinkuirt
authors.affiliation: Department of Science, Faculty of Science and Technology, Prince of Songkla University, Pattani Campus, Pattani, 94000, Thailand.
authors.forename: Sumalee
authors.initials: S
authors.lastname: Seepom
authors.affiliation: Department of Natural Resources and Environmental Management, Ball State University, Muncie, IN, 47306, USA.
authors.forename: John
authors.initials: J
authors.lastname: Pichtel
mesh_terms: D061006:Bays; D017753:Ecosystem; D004784:Environmental Monitoring; D019015:Geologic Sediments / Q000032:analysis; D006801:Humans; D019216:Metals, Heavy / Q000032:analysis*; D011868:Radioisotopes / Q000032:analysis*; D018570:Risk Assessment; D012623:Seawater / Q000032:analysis; D013785:Thailand; D014874:Water Pollutants, Chemical / Q000032:analysis*
chemical_list: D019216:Metals, Heavy; D011868:Radioisotopes; D014874:Water Pollutants, Chemical
keywords: Enrichment factor; Geoaccumulation index; Heavy metals; Mangrove coastal area; Pattani Bay; Radiological risk assessment; Radionuclides; Sediment