广州不同环境空气PM_(2.5)中金属元素污染特征与风险评价

Pollution Characteristics and Risk Assessment of Metals in Ambient PM_(2.5) in Guangzhou

根据2015年广州城区磨碟沙、内陆郊区天湖和近海郊区万顷沙不同环境空气PM_(2.5)中金属元素(Pb、Cd、Cr、Ni、As等23种)监测数据,分析其污染特征与富集程度,并评估潜在生态风险和健康风险,为大气污染风险防控提供支持。结果显示:广州大气PM_(2.5)中金属K、Na、Fe、Ca、Al和Zn含量相对较高。总元素浓度总体呈冬季最高、夏季最低的特征,且随PM_(2.5)污染加重而升高,但总元素在PM_(2.5)中的占比下降。Cd、Se、Zn、Cu、Mo、Pb和Na富集严重(富集因子>100),体现了人类活动的重要影响,磨碟沙城区站富集因子通常高于另2个站点。广州大气总金属元素潜在生态危害程度为“很强”,Cd贡献为主,Pb、Cu和As元素贡献分别在天湖、磨碟沙和万顷沙位列第二。As、Cr和Mn是大气金属元素健康风险的主要贡献者;磨碟沙的总致癌效应风险高于万顷沙和天湖,但万顷沙的总非致癌效应风险最高。

Based on 1-year observation in 2015 at the urban site(Modiesha,MDS),inland regional site(Tianhu,TH),and offshore regional site(Wanqingsha,WQS)in Guangzhou,chemical properties and enrichment factors were investigated for 23 metals,including Pb,Cd,Cr,Ni,As,etc.The potential ecological and health risks for the typical metals were evaluated to provide support for air pollution risk prevention and control.The results showed that the contents of K,Na,Fe,Ca,Al,and Zn in PM_(2.5) in Guangzhou were relatively high.Generally,the total metals showed highest mass concentration in winter and lowest in summer,and they increased with increasing PM_(2.5) concentrations,while the ratio of total metals to PM_(2.5) decreased.The enrichment factors of Cd,Se,Zn,Cu,Mo,Pb,and Na were higher than 100,indicating significant effect of human activity.The enrichment factors were usually the highest at MDS urban site.The ecological risk of total metals was high in Guangzhou.Cd was the major contributor,followed by Pb,Cu and As at TH,MDS and WQS,respectively.As,Cr and Mn were the main contributors to the health risk.The carcinogenic effect of metals in PM_(2.5) at MDS was higher than WQS and TH,while the non-carcinogenic effect at WQS was the highest.