Soil lead distribution characteristics and source identification in Hanyuan, upstream of Yangtze River, China

In order to ascertain the pollution status, chemical speciation, isotope compositions, and sources of soil lead in Hanyuan, upstream of Yangtze River in China was studied. The content of Pb in soil was determined by inductively coupled plasma mass spectrometry (ICP-MS), the speciation of soil Pb was analyzed by BCR, and lead isotope composition in the samples was determined by MC-ICP-MS. The results show that the average concentration of Pb in surface soils was 478.09 mg/kg, which is 15.94 times the background value of soil in Sichuan Province (30.00mg/kg). Pb in the soil of the living area was more in the form of extractable form (Pb extractable =62.38–84.31%), while Pb in the soil of mining area is more in the form of residue (Pb residue =57.35–60.12%). The natural end-member including bedrock and ore possessed 208 Pb/ 207 Pb ratios of 2.444 and 2.453 and 206 Pb/ 207 Pb ratios of 1.169 and 1.160, respectively. Anthropogenic end-members including car exhaust and cement plant fly ash possessed 208 Pb/ 207 Pb ratios of 2.486 and 2.501, and 206 Pb/ 207 Pb ratios of 1.184 and 1.197, respectively. The ratios of 208 Pb/ 207 Pb and 206 Pb/ 207 Pb for surface soil ranged from 2.448–2.491 and 1.154–1.193, respectively, which are close to the anthropogenic end-members, indicating human activities were the main source of Pb pollution.