黄石市大气降尘中重金属污染及其化学形态特征研究

Research on Pollution and Speciation Characteristics of Heavy Metals in Atmospheric Dustfall of Huangshi

2012年5月在黄石市采集了17个大气降尘样品,利用修正的BCR连续提取技术,借助火焰-原子吸收光谱仪分析了7种重金属元素各形态的含量。结果显示,Cu、Pb、Cd、Zn、Mn、Fe、Co总量的平均值分别为1 674.19 mg/kg、949.30 mg/kg、41.35 mg/kg、2 122.53 mg/kg、986.78 mg/kg、28 028.89 mg/kg和465.95 mg/kg,降尘重金属污染严重,其中以Cu、Pb、Zn和Cd最为突出。重金属形态特征及生物有效性与环境风险分析结果表明,降尘中Fe和Co主要以残渣态形式存在,Cd主要以弱酸态形式存在,Cu、Pb、Zn和Mn主要以弱酸态和可还原态形式存在,其中Cd、Pb、Zn、Cu、Mn、Co有50%以上可能发生迁移,易被生物利用,对环境有较高风险。

Seventeen atmospheric dustfall samples were collected from Huangshi during May 2012.The speciation characteristics of heavy metals（Cu、Pb、Cd、Zn、Mn、Fe、Co）in atmospheric dustfall were extracted by the modified BCR sequential extraction procedure .The concentrations of heavy metals have been analyzed with flame atomic ab-sorption spectrometry.The results showed that mean concentrations of Cu、Pb、Cd、Zn、Mn、Fe、Co in atmospheric dustfall were 1 674.19 mg/kg,949.30 mg/kg,41.35 mg/kg,2 122.53 mg/kg,986.78 mg/kg,28 028.89 mg/kg, 465.95 mg/kg,respectively.The heavy metal pollution of dustfall in Huangshi City was serious ,especially Cu、Pb、Zn and Cd.The results of speciation characteristics analysis indicated that Fe and Co were dominated by residue fraction,Cd mainly existed in acetic acid extractable part,Cu、Pb、Zn and Mn were rich in acetic acid extractable＆amp;nbsp;part and reducible part.There were stronger transformation（＆gt;50%）and higher environmental risk of Cd、Pb、Zn、Cu and Mn.