Identification of Pb sources in Yellow Sea sediments using stable Pb isotope ratios

Abstract

Rapid economic developments in East Asian countries have inevitably resulted in environmental degradation in the surrounding seas, and concern for both the environment and protection from pollutants is increasing. Identification of sources of contaminants is essential to environmental pollution management. In this study, the provenance of anthropogenic lead (Pb), a major pollutant of Yellow Sea sediments, was determined for river mouth sediments, including those of the Changjiang, Huanghe, Han, and Geum Rivers, and for age-determined shelf core sediments through the measurement of Pb isotope ratios in the HCl-Ieached fraction using multi-collector inductively coupled plasma-mass spectrometry (MC ICP/MS). Anthropogenic Pb has accumulated in shelf core sediments since 1910, and its isotope ratios were estimated as 0.863-0.866 and 2.119-2.125 for Pb-207/Pb-206 and Pb-208/Pb-206, respectively, from the mixing relationships of the two endmembers. River mouth sediments exhibited enough distinction in anthropogenic, Pb isotope ratios to be discriminated: 0.874 (2.144) in the Huanghe, 0.856 (2.129) in the Han, 0.857 (2.122) in the Geum, and 0.854 (2.101) in the Changjiang for Pb-207/Ph-206 (Pb-208/Pb-206), respectively. Although isotope ratios of geogenic Pb in sediments datingbefore 1910 showed narrow ranges (0.842-0.845 and2.088-2.100 for Pb-207/Pb-206 and Pb-208/Pb-206, respectively), distinct isotope ratios in each core permitted source identification of sediments in the Yellow Sea based on geographic locations and the geogenic Ph of each river. By comparing the isotope ratios of the estimated anthropogenic Ph to source-related materials, the provenances of anthropogenic Pb in Chinese river sediments were presumed to be Chinese coal or ore, which is also a major source of atmospheric particulate Pb. The anthropogenic Ph in the shelf core sediments in the northern Yellow Sea originated from northern Chinese cities such as Beijing and Tianjin through atmospheric pathways. Pb isotope ratios indicated that Ph in Korean river sediments was characteristic of local Korean ores. (c) 2007 Elsevier B.V. All rights reserved.