深圳市表层土中氟化物组成及分布

Composition and distribution of the fluoride compounds in topsoil samples of Shenzhen

为探究深圳市表层土中氟化物的组成及其与土壤性质参数（有机碳和p H值）的相关关系,应用氟离子选择电极法测定了深圳市表层土中总氟（TF）、可萃取有机氟（EOF）的含量,用固相萃取分离富集与高效液相色谱串联质谱的方法分析了深圳市表层土中全氟化合物（PFCs）的残留水平.结果表明,深圳市表层土中氟化物主要以无机态存在,呈TF〉〉EOF〉〉IF（可鉴别F,即以氟计量的总PFCs）的分布规律;EOF仅占TF的0.04%,IF占EOF的0.32%,显示近99.7%的EOF仍属未知.深圳市表层土中PFOA、PFOS分别占∑PFCs的43%（18%~100%）和20%（n.d.~44%）,是表层土中主要的PFCs污染物,就空间分布而言,∑PFCs呈西高东低的趋势.表层土中EOF和∑PFCs含量受土壤性质参数的影响,p H值与EOF（P〈0.05）、∑PFCs（P〈0.01）含量呈负相关,有机碳则与EOF、∑PFCs呈正相关（P〈0.01）.

In order to explore the composition of fluoride compounds and their relationship with soil parameters,23 topsoil samples were collected from Shenzhen. The total contant of fluorine（TF） and extractable organic fluorine（EOF） were measured using fluoride ion selective electrode,and the residue level of 13 perfluorinated compounds（PFCs） were analyzed using high performance liquid chromatography-tandem mass spectrometry combined with solid phase extraction enrichment. The results indicated that the fluoride mainly existed in the form of inorganic fluoride,and its distribution followed the order of TFEOF IF（Identified Fluorine） in topsoil samples. EOF only accounted for 0.04% of TF,and IF accounted for 0.32% of EOF,indicating that nearly 99.7% of the EOF was unknown. Perfluorooctanoic acid and perfluorooctane sulfonate were the major PFCs residue species,accounting for 43%（18%~100%） and 20%（n.d.~44%） of ∑PFCs,which were higher in the west than in the east of Shenzhen. Soil parameters could affect the levels of EOF and ΣPFCs,which negatively correlated with p H,and positively correlated with topsoil organic carbon.