Lead (Pb) isotopes as a tracer of Pb origin in Yangtze River intertidal zone

In order to investigate the source of Pb within the Yangtze River intertidal zone, studying Pb isotope ratios is a likely approach because the ratios of these Pb isotopes can be used to identify the natural or anthropogenic origin of Pb. In this study, a total of 59 surface sediment samples (< 5 cm) were collected during 2004 and 2005 from 26 sites in the Yangtze River intertidal zone. We measured the total Pb concentrations and Pb isotopes (²⁰⁴Pb, ²⁰⁶Pb, ²⁰⁷Pb and ²⁰⁸Pb) and found that the total Pb concentrations varied from 18.3 to 44.1 mg kg^{- 1} with an average concentration of 27.3 mg kg^{- 1}. The observed Pb isotope ratios, excluding one station near Shanghai Pudong Airport which is significantly influenced by anthropogenic sources, varied from 18.459 to 18.750 for ²⁰⁶Pb/²⁰⁴Pb, 15.628 to 15.728 for ²⁰⁷Pb/²⁰⁴Pb, and 38.715 to 39.213 for ²⁰⁸Pb/²⁰⁴Pb. This study shows that Pb found within the Yangtze River intertidal zone sediments was mainly from the catchment in the Yangtze River watershed. Significant Pb pollution was not discerned in the Yangtze River intertidal zone. However, Pb contamination in some localized areas was suggested by Pb enrichment factor (EF).