福州市公交枢纽站地表灰尘重金属含量、来源及其健康风险评价

城市地表灰尘中的重金属已成为城市环境和人类健康最重要的威胁之一. 为评价地表灰尘重金属的污染水平,研究了福州市公交枢纽站地表灰尘中的重金属质量分数、来源及其可能产生的健康风险. 结果表明:福州市公交枢纽站地表灰尘中w(Cr)、w(Cu)、w(Zn)和w(Cd)分别是福州市城区土壤的2.74、4.21、4.01和4.68倍. 灰尘中重金属Co、Ni和Mn主要来源于城市土壤,Cd、Pb和Cu来源于交通运输过程,Cr来源于城市土壤和交通运输,Zn主要来源于交通运输、城市生活污染和工业活动等复合污染源. 不同暴露途径的重金属暴露剂量和非致癌风险大小排序为消化道>皮肤接触>呼吸吸入. 地表灰尘中重金属非致癌总风险为儿童高于成人. 致癌重金属的暴露风险为Cd>Ni>Cr. 城市公交枢纽站地表灰尘中重金属污染受交通运输影响较大. 

Concentrations, Sources and Health Risk Assessments of Heavy Metals in Ground Surface Dust from Urban Bus Terminals of Fuzhou City

Heavy metals in urban ground surface dust are one of the most serious threats affecting human health and urban environments. Concentrations, sources and health risk assessments of heavy metals in ground surface dust from bus terminals in Fuzhou City were studied to evaluate their pollution levels. The results showed that concentrations of Cr, Cu, Zn and Cd in ground surface dust were 2.74,4.21,4.01and 4.68times higher than those in the urban soil of Fuzhou City. Co, Ni and Mn in dust came from urban soils; Cd, Pb and Cu were possibly related to transportation process; Cr was mainly associated with urban soil and transportation process; Zn originated from compound pollutant sources including transportation process, urban domestic pollution and industrial activities. The exposure dose and non-cancer risk of heavy metals through exposure decreased as:ingestion>dermal absorption>inhalation. The non-cancer risk for children was higher than for adults. Meanwhile, the cancer risk of heavy metals declined in the order of Cd>Ni>Cr. Heavy metals in ground surface dust from urban bus terminals are mainly affected by transportation process.