Lead contamination and transfer in urban environmental compartments analyzed by lead levels and isotopic compositions

Lead levels and isotopic compositions in atmospheric particles (TSP and PM_2.5), street dust and surface soil collected from Nanjing, a mega city in China, were analyzed to investigate the contamination and the transfer of lead in urban environmental compartments. The lead contents in TSP and PM_2.5 are significantly higher than them in the surface soil and street dust (p < 0.05). The enrichment factor using the mass ratio of lead to the major crustal elements (Al, Sr, Ti and Fe) indicates significant lead enrichment in atmospheric particles. The plots of ²⁰⁶Pb/ ²⁰⁷Pb vs.²⁰⁸Pb/²⁰⁶Pb and ²⁰⁶Pb/ ²⁰⁷Pb vs. 1/Pb imply that the street dust and atmospheric particles (TSP and PM_2.5) have very similar lead sources. Coal emissions and smelting activities may be the important lead sources for street dust and atmospheric particles (TSP and PM_2.5), while the deposition of airborne lead is an important lead source for urban surface soil.