Evaluation of heavy metal contents and Pb isotopic compositions in the Chao Phraya River sediments: Implication for anthropogenic inputs from urbanized areas, Bangkok

In order to elucidate the sources of metals in urbanized areas, heavy metal contents and Pb isotope ratios were determined in the Chao Phraya River sediments. The sediment samples were leached using 1% HNO3 and metal concentrations (Cd, Cu, Cr, Pb, and Zn) and Pb isotopic ratios (Pb-208/Pb-206 and Pb-207/Pb-206) in the solutions were analyzed by Inductively Coupled Plasma-Mass Spectrometry (ICP-MS). The highest ranking of potential pollutant evaluations of Cd, Cu, Cr, Pb, and Zn contents was found from samples that were located near to the center of Bangkok. Pb isotope ratios (Pb-208/Pb-206: 2.075-2.113 and Pb-207/Pb-206: 0.834-0.868) in the Chao Phraya River sediments near to the center of Bangkok agreed well to those in the Bangkok road side dust and pond sediments suggesting that river sediments may be contributed from road-side dust and pond sediments. Moreover, Pb isotope ratios confirmed that the polluted sediments were contributed as Pb products of fly ashes (municipal waste combustors) in Bangkok (Pb-208/Pb-206: 2.100-2.120 and Pb-207/Pb-206: 0.867-0.870). (C) 2012 Elsevier B.V. All rights reserved.