Metal Contents and Pb Isotopes in the Surface Seawater of the Gulf of Prigi, Indonesia: Detection of Anthropogenic and Natural Sources

In order to investigate the anthropogenic and natural sources of metals in the Gulf of Prigi, Indonesia, it was analyzed their metal contents and Pb isotopes of surface seawater together with sediment, grouper fish, mosh, seaweed, soil, and sharp grass for protecting the environmental pollution of the study area. Samples were leached using a microwave digestion technique. Metal (Ca, Fe, Mn, Cu and Pb) concentrations and 206Pb, 207Pb and 208Pb in the leached solutions were analyzed using inductively coupled plasma-mass spectrometry (ICP-MS). The level concentrations of Ca (491436 µg kg–1), Fe (12123 µg kg–1), Mn (37.2 µg kg–1), Cu (84.0 µg kg–1) and Pb (34.5 µg kg-1) in the surface seawater were low compared with those of background seawater levels issued by World Health Organization (WHO). The range of Pb isotope ratios (207Pb / 206Pb = 0.7966-0.9945 and 208Pb / 206Pb = 2.2600-2.8243) in surface seawater was higher in the plotted Pb growth curve suggesting unpolluted Pb reflected by natural sources such as mineral sources or lithogenic from marine sediment.