中文摘要：

采集了2012年11月至2013年1月期间厦门市大气降尘样品,用改进的BCR四步连续提取法分析了12种重金属元素（Ba、Ti、Co、Cr、Cu、Fe、Mn、Zn、Ni、Pb、Sr、V）的含量、赋存形态和生物有效性.结果显示,重金属元素四态含量之和均值（mg·kg-1）顺序为：Fe（43733）〉Zn（4495）〉Ti（2728）〉Ba（747）〉Mn（723）〉Cu（444.4）〉Sr（176）〉Cr（171）〉Pb（160）〉Ni（40.4）〉V（27.6）〉Co（11.2）;Zn和Cu含量分别为我国土壤环境质量标准第二类标准限值（250和100 mg·kg-1）的18倍和4.4倍;除Fe、Ti、Ba、Cr和V外,大气降尘中其他元素生物有效态含量占有相当的比例（32.2%—88.6%）.Zn、Sr主要以弱酸溶态存在,Pb主要以可还原态存在,Cu主要以可氧化态存在,其余元素主要以残渣态存在.大气降尘中重金属的平均生物有效性系数顺序为：Sr（0.87）〉Zn（0.85）〉Cu（0.80）〉Pb（0.67）〉Mn（0.50）〉Co（0.47）〉Ni（0.39）〉Ba（0.19）≈Cr（0.19）〉V（0.12）〉Fe（0.08）〉Ti（0.01）,Ti、Fe、V、Cr和Ba为生物不可利用元素,Ni、Co、Mn和Pb为潜在生物可利用元素,Cu、Zn和Sr为生物可利用元素.

英文摘要：

The atmospheric dustfall samples were collected from November 2012 to January 2013 in different functional areas of Xiamen,China. A modified BCR four-step sequential extraction procedure was used to obtain the speciation and bioavailability of Ba,Ti,Co,Cr,Cu,Fe,Mn,Zn,Ni,Pb,Sr and V. The results showed that the average sum content of the four fractions of heavy metals（mg·kg-1） was in the order of Fe（43733）〉Zn（4495）〉Ti（2728）〉Ba（747）〉Mn（723）〉Cu（444.4） 〉Sr（176） 〉Cr（171） 〉Pb（160） 〉Ni（40.4） 〉V（27.6） 〉Co（11.2）,of which Zn and Cu were respectively 18 and 4.4 times of the second class standard limits（250 and 100 mg·kg-1）.Except Fe,Ti,Ba,Cr and V,the other elements presented considerable bioavailable contents with the range of 32. 2%—88. 6% to the total four fractions. Zn and Sr mainly existed in the acid extractable,Pb mainly existed in the reducible fraction, Cu mainly existed in the oxidizablefraction,while the other elements were mainly present in the residual fraction. The average ratio of extractable content to total content of the twelve elements was in the order of Sr（0.87） 〉Zn（0.85） 〉Cu（0.80） 〉Pb（0.67） 〉Mn（0.50） 〉Co（0.47） 〉Ni（0.39） 〉Ba（0.19） ≈ Cr（0.19） 〉V（0.12） 〉Fe（0.08） 〉Ti（0.01）. Ti,Fe,V,Cr and Ba were classified as non-bioavailable elements,whereas Ni,Co,Mn and Pb were remarked as potential bioavailable elements,and Cu,Zn and Sr were regarded as bioavailable elements.