地氟病区农田土壤中全氟化合物的组成及污染特征研究

Study on the composition and pollution characteristics of perfluorinated compounds in the farmland soil in an endemic fluorosis area

为探究中国西南地氟病区农田土壤中全氟化合物(PFCs)的污染状况,对四川省泸州市古蔺县65个农田土壤样品中PFCs的组成及其与土壤性质参数(pH、有机质、总氟和水溶性氟)的相关性进行了研究。结果表明:古蔺县农田土壤以中性为主,有机质质量分数为2.62%~14.01%,平均值为7.78%。土壤氟含量分析结果显示,该地区土壤氟污染较为严重,总氟和水溶性氟平均值分别为985、7.15 mg/kg,土壤高氟含量一方面来源于较高的土壤背景值,同时也与施用含氟量高的磷肥有关。在21种目标PFCs中,仅有8种PFCs被检出,其中全氟己酸(PFHxA)是该地区检出率最高的PFCs(85%),而全氟癸酸(PFDA)是平均质量浓度最高的PFCs(1.039 ng/g)。土壤样品中总PFCs(∑PFCs)为0.026~3.642 ng/g,主要来源为大气沉降、生活垃圾和农业活动。所有土壤样品中,∑PFCs占土壤总氟含量的比例均不超过0.52%,且∑PFCs与总氟之间无显著相关关系,∑PFCs对总氟的贡献有限。

In order to investigate the pollution status of perfluorinated compounds(PFCs)in the farmland soils of endemic fluorosis areas in Southwest China,the composition of PFCs in 65 farmland soil samples from Gulin County,Luzhou City,Sichuan Province,and their correlation with soil property parameters(i.e.pH,organic matter,total fluorine and water-soluble fluorine)were studied.The results showed that the farmland soil pH in Gulin County was mainly neutral,and the content of organic matter was in range of 2.62%-14.01%,with an average value of 7.78%.The average concentration of total fluorine and water-soluble fluorine were 985 and 7.15 mg/kg,respectively,indicating serious soil fluorine pollution in this area.The high concentration of fluorine in soils was not only due to the high soil background value,but also related to the application of phosphorus fertilizer containing high concentration of fluorine.Among the 21 target PFCs,only 8 PFCs were detected,in which PFHxA had the highest detection rate(85%)and PFDA had the highest average concentration(1.039 ng/g).The∑PFCs in all soil samples ranged from 0.026 ng/g to 3.642 ng/g,the main source was atmospheric deposition,domestic waste and agricultural activities.In all soil samples,the proportion of∑PFCs in total fluoride concentration was less than 0.52%,and the correlation between∑PFCs and total fluoride was not significant,indicating that the contribution of∑PFCs to total fluoride was limited.