厦门港大气PM_(2.5)中重金属污染特征及健康风险评价

Characterization and Health Risk Assessment of Heavy Metals in PM_(2.5) in Xiamen Port

于2020年夏季和秋冬季在厦门港海天码头和嵩屿码头进行大气PM_(2.5)的采集,并对20种元素污染特征、来源及健康影响进行了分析.结果表明,厦门港大气PM_(2.5)浓度较低,且两个站点的PM_(2.5)浓度并无显著性差异,也不存在明显的昼夜差异.地壳元素中以Ca和Si的含量最高,而痕量元素中以Zn和Mn的含量为最高.与标准值相比,重金属元素中只有Cr(Ⅵ)出现超标.受风向和吞吐量季节性变化的影响,部分元素浓度在夏季高于秋冬季.Cu、Zn、SO_(2)和NO_(2)有较一致的明显昼夜变化,但来自重油燃烧排放的V和Ni并无明显昼夜差异.PMF源解析确定码头PM_(2.5)的4个污染因子为工业源、船舶排放、交通源和海盐+建筑尘混合源,其中工业源对PM_(2.5)浓度的贡献率最大(55.2%~59.4%),远高于船舶排放的贡献率(7.1%~7.7%).健康风险评估显示,厦门港大气PM_(2.5)中重金属对人群具有潜在的致癌风险(>1×10^(-5)),其中Cr(Ⅵ)、V和As的累计贡献率为97.3%~97.5%;非致癌风险的危害指数<1,其中V、Mn、Ni和As的累计贡献率为89.6%~91.2%.4种污染因子对重金属致癌风险的贡献率顺序为:交通源(47.2%~49.4%)>工业源(23.8%~24.2%)>船舶排放(16.9~20.8%)>海盐+建筑尘(5.7%~12.1%),而对非致癌风险的贡献率顺序为:交通源(38.7%~42.3%)>工业源(24.5%~28.2%)>船舶排放(24.1%~27.2%)>海盐+建筑尘(5.4%~9.6%).

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,SO_(2),and NO_(2) 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_(2.5) in 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%).