Tracking lead origin in the Yellow River Estuary and nearby Bohai Sea based on its isotopic composition

• First reported the Pb isotope compositions in the YRE and nearby Bohai Sea.
• Pb in YRE-NL is mainly from the catchment of the Yellow River.
• Pb in CSLB is a mixture of natural (from the watershed) and anthropogenic (from urban activities).
• Sewage discharging from CSLB didn't further extend to the middle and outer shelves.

The Pb concentration and Pb isotopes (204Pb, 206Pb, 207Pb, and 208Pb) in surface sediments from the Yellow River Estuary and nearby Bohai Sea have been determined to investigate the Pb sources in this area. Results showed that Pb in the Yellow River Estuary and northern Laizhou Bay (YRE-NL) sediments was mainly from the Yellow River catchment as a consequence of lithogenic sediments (from rock weathering) accumulation. However, Pb in the coastal area of southern Laizhou Bay (CSLB) sediments was from both natural and anthropogenic sources. Sewage discharged near the Mihe mouth of the CSLB did not extend further to the middle and outer shelves because of the current in Laizhou Bay. The total Pb concentration varied from 14.5 to 30.4 μg/g with an average concentration of 20.1 ± 4.2 μg/g. Thus, significant Pb pollution was not observed in the Yellow River Estuary and nearby Bohai Sea. However, Pb contamination in some sites was indicated by Pb isotope ratios.