上海市崇明岛农业土壤中二噁英的现状研究及来源分析

Current Situation and Source Apportionment of Dioxin Compounds in Agricultural Soil of Chongming Island,Shanghai

为了解上海市崇明岛农用土壤中二噁英类化合物(PCDD/Fs)现状水平及其来源,于2021年6-7月采集上海市崇明岛31个农业土壤样品,采用同位素稀释法测定样品中17种2,3,7,8-PCDD/Fs的含量,并且对其现状水平、异构体特征以及来源进行初步分析。结果表明,31个土壤样品中均检出PCDD/Fs,质量分数为88.14~356.55 pg/g,对应毒性当量为0.64~2.20 pg I-TEQ/g,统计频率分析发现呈右侧拖尾的偏态分布,中位数为1.05 pg I-TEQ/g。经过比较,崇明岛农用土壤属于典型的背景土壤,土壤中二噁英类物质的污染属于较低水平。利用主成分分析(PCA)和正定矩阵因子分解法(PMF)对可能的来源进行分析,结果显示上海市崇明岛农业土壤中PCDD/Fs的主要来源为五氯酚(PCP)、水稻秸秆烟(RSS)和交通源(TS),占比分别为61.6%,23.2%和15.2%。结合采样地理位置推断,上海市崇明岛农业土壤中PCDD/Fs可能受到来自崇明岛自身农耕以及交通等因素的影响。

In order to obtain the current level and the sources of the dioxins compounds in soil samples from Chongming Island,31 agricultural soil samples were collected in Chongming Island,Shanghai during June and July 2021,to analyze the 17 kinds of 2,3,7,8-substituted polychlorinated dibenzo-p-dioxins and polychlorinated dibenzofurans(PCDD/Fs)by isotope dilution method.A preliminary analysis was conducted on the PCDD/Fs current levels,congener profiles,as well as the possible pollution sources.The results showed that the concentrations of PCDD/Fs ranged from 88.14 to 356.55 pg/g,the corresponding toxicity equivalent(TEQ)concentrations ranged from 0.64 to 2.20 pg I-TEQ/g,statistical frequency analysis showed a positive skewed distribution with a median of 1.05 pg I-TEQ/g.By comparison with other researches,the PCDD/Fs contamination level of agricultural soil in Chongming Island was at a low level,indicating the agricultural soil in Chongming Island was typical background soil.The possible sources were analyzed by the principal component analysis(PCA)and the positive matrix factorization(PMF).The results showed that the main sources of PCDD/Fs in agricultural soil in Chongming area of Shanghai were pentachlorophenol(PCP),rice straw smoke(RSS)and traffic sources(TS),accounting for 61.6%,23.2%and 15.2%in average,respectively.Combined with the geographical sampling location,PCDD/Fs in agricultural soil in Chongming area of Shanghai may be affected by its own agriculture and traffic factors.