2328Pollution characteristics, source identification and potential ecological risk of 50 elements in atmospheric particulate matter during winter in Qingdao

This study provided the pollution level, source identification and ecological risk assessments of multi-elements in total suspended particulate matter (TSP) during wintertime in Qingdao. Total suspended particulate matter (TSP) samples were collected from November 2016 to February 2017 to determine 50 elements. The enrichment factor (EF), positive matrix factorization (PMF) model and trajectory model were used to analyse the pollution sources of the elements. The results showed that Ca, Al, Fe, Na, K, Mg and Zn were the main elements in the samples, accounting for 95.8% of the total mass concentration of all the elements, while the lanthanides accounted for 0.11%. The ratios of La/Ce, La/Sm and La/V indicated that La was enriched in the samples. The average concentrations of the 50 elements all increased significantly on haze days. EF and I geo analysis showed that the influence of human activities heavily enriched harmful metal elements such as Cd, Zn, Bi, Pb, Hg, As and Cu. On haze days, the EF values of 35 elements were higher than those on non-haze days. The PMF model showed that elements in the TSP mainly came from fossil fuel combustion and traffic sources (40.7%), soil dust sources (20.3%), chemical and smelting sources (16.1%), marine sources (12.8%) and coal combustion sources (10.1%). The air mass from western Shandong province had high concentrations of Hg, Co, Cd, Ba, Pb and lanthanides, which were affected by chemical and fossil fuel combustion. Atmospheric particulate matter showed a high potential ecological risk in winter, which was affected by the high concentration of Cd, Hg, Cu, As and Pb.