Radionuclide ((226)Ra, (232)Th, (40)K) accumulation among plant species in mangrove ecosystems of Pattani Bay, Thailand.

Little is known regarding phytoremediation of radionuclides from soil; even less is known about radionuclide contamination and removal in tropical ecosystems such as mangrove forests. In mangrove forests in Pattani Bay, Thailand, 18 plant species from 17 genera were evaluated for radionuclide concentrations within selected plant parts. Two shrub species, Avicennia marina and Pluchea indica, accumulated the highest (232)Th (24.6Bqkg(-1)) and (40)K (220.7Bqkg(-1)) activity concentrations in roots, respectively. Furthermore, the aquatic species Typha angustifolia accumulated highest (232)Th, (40)K and (226)Ra activity concentrations (85.2, 363.5, 16.6Bqkg(-1), respectively) with the highest transfer factors (TFs) (3.0, 2.0, 5.9, respectively) in leaves. Leaves of T. angustifolia had an absorbed dose rate in air (D) over the recommended value (74.8nGyh(-1)) that was considered sufficiently high to be of concern for human consumption.