Sources and chronology of combustion-derived pollution to Shilianghe Reservoir, eastern China: Evidences from PAHs profiles, As, Hg, Pb and Pb isotopes

Abstract

The sedimentary records of polycyclic aromatic hydrocarbons (PAHs), mercury (Hg), arsenic (As), lead (Pb) and stable Pb isotopic ratios were studied in a sediment core collected from Shilianghe Reservoir in eastern China. Accumulations and distributions of these pollutants were measured in terms of PAHs concentrations, PAHs fluxes, and enrichment factor (EF) of Hg, As, Pb and Pb isotopic ratios. The accumulations showed a synchronous trend throughout the core, due to close correlation with rapid economic and industrial development of the catchment, Linyi City in eastern China. The results from PAH isomer ratios reveal that PAHs in sediments are dominantly from anthropogenic pyrogenic sources, mainly from the combustion of coal and biomass. Furthermore, the Pb isotopic composition clearly indicates that coal combustion dust mainly contributed to the Pb burden in the reservoir sediments. Based on mixing end-member model of Pb isotopic ratios, contributions of coal combustion dust are ranged from 31% to 62%, mainly from anthropogenic Pb sources. The contribution of leaded gasoline was lower than average at 25%. In addition, a steady increase in the contribution from coal combustion sources was found in the sediment core, while the contribution of leaded gasoline showed a decline in recent decades, due to the phase-out of leaded gasoline in China. Capsule abstractPAHs, Hg, As and Pb burden in a reservoir of China were chronicled. Increasing coal combustion dust is responsible for contamination of lake by end-member model of Pb isotopic ratios.