厦门港大气PM_2.5中重金属污染特征及健康风险评价

PM_2.5 samples at Haitian and Songyu container terminals in Xiamen Port were collected in summer and autumn/winter in 2020 and analyzed for 20 elements to investigate their temporal-spatial distribution features, sources, and health risk. The results showed that the levels of PM_2.5 were relatively low and did not show significant spatial and diurnal differences. Ca and Si were the main crustal elements, and Zn and Mn were the main heavy metals in PM_2.5. Compared with GB 3095-2012 guidelines, Cr(Ⅵ) was in the range of 27.4-28.6 times above the standard. Under the influence of monsoon and port throughput, the concentrations of some elements in summer were higher than those in autumn/winter. Significant diurnal variations were observed for Cu, Zn, SO₂, and NO₂ but not for V and Ni. Industrial sources were identified as the primary contributor (55.2%-59.4%), followed by traffic (28.7%-31.3%), ship emissions (7.1%-7.7%), and sea salt plus construction dust (4.8%-5.8%). The results of health risk assessment showed that heavy metals in PM_2.5in Xiamen Port had potential carcinogenic risk (ECR>1(10^-5) to people living near the port, and Cr(Ⅵ), V, and As together accounted for 97.3%-97.5% of the total risks; however, the non-carcinogenic risk was negligible (HI<1), and the major contributors were V, Mn, Ni, and As (89.6%-91.2%). The relative contributions of each contributor to ECR was in the order of traffic (47.2%-49.4%)>industrial (23.8%-24.2%)>ship emissions (16.9%-20.8%)>sea salt plus construction dust (5.7%-12.1%), and the relative contribution to HI was in the order of traffic (38.7%-42.3%)>industrial (24.5%-28.2%)>ship emissions (24.1%-27.2%)>sea salt plus construction dust (5.4%-9.6%).