电镀厂周边大气PM10中重金属季节性分布特征及生态风险评价

Seasonal Characteristics and Ecological Risk Assessment of Heavy Metals in PM_(10) Around Electroplating Plants

本研究以东莞市5个镇区的电镀厂为中心,在其周边共布设45个监测点位,通过系统采集2015年度春夏秋冬四个季节不同时段电镀厂周边大气PM_(10)颗粒物样品,应用ICP-MS分析样品中12种重金属的含量,并对季节分布特征及空间分布特征进行比较,评价其生态风险.以期为大气环境危害与风险评估及相关部门制定污染治理决策提供科学依据.结果表明,5个镇的PM_(10)浓度均小于我国《环境空气质量标准》(GB 3095-2012)中相应日均值二级标准限值,且呈现出冬季污染严重,夏季污染较轻的规律.PM_(10)中各金属的浓度总体表现为秋冬季偏高,且各镇PM_(10)中As、Cd、Cr均超过《环境空气质量标准》(GB 3095-2012)中年平均浓度限值,其中严重超标的是虎门镇、沙田镇和大岭山镇.富集因子法和地累积指数法分析表明,Cd、Sb、Hg、Co为极强污染,Pb、Zn为轻度污染到强污染,Ni、Cr、Mn和V属于未污染.研究区大气颗粒物PM_(10)中重金属的潜在生态风险指数RI远大于600,潜在的生态风险极强.

PM_（10） samples were collected from 45 sites around the electroplating factories in five towns in Dongguan at different times during all four seasons in 2015.The contents of 12 heavy metals（HMs） from the PM_（10） samples were analyzed by ICP-MS.The seasonal and spatial distribution characteristics and the ecological risk were analyzed to provide a scientific foundation for the relevant department to make decisions regarding the environmental hazard,risk assessment and,pollution control.The results showed that PM_（10） concentrations in the towns were lower than national standard level-Ⅱ,and the air pollution was heavier in winter than summer.The HM concentrations were higher in autumn and winter,and As,Cd,and Cr concentrations were higher than national standard（GB3095-2012）.The concentrations of HMs in Humen,Shatian,and Dalingshan were much higher.The results for the enrichment factor and the geoaccumulation index indicated that Cd,Sb,Hg,and Co were in the extreme degree of pollution category,Pb and Zn were in the slight to extreme degree of pollution category,and Ni,Cr,Mn,and V were described as uncontaminated.The average potential ecological risk assessment（RI） of the HMs from the PM_（10） samples was more than 600,which suggested an extremely serious ecological risk in the study area.