北京市东南郊灌区土壤和农产品酞酸酯污染风险评估

为明确北京市东南郊典型灌区土壤和作物酞酸酯PAEs含量和污染水平,2015年利用气象色谱-质谱仪检测了该灌区31个表层土壤样品和38个作物样品的6种优控PAEs含量.研究结果表明灌区表层土壤PAEs质量分数为1.8～12.2 mg/kg,均值5.1 mg/kg.与国内外相比,该研究中土壤PAEs含量处于较高水平.土壤中邻苯二甲酸正二丁酯(DnBP)和邻苯二甲酸二(2-乙基己基)酯(DEHP)含量均值分别占PAEs总量的60.4％和35.9％.土壤样品邻苯二甲酸二甲酯(DMP)和DnBP含量均超美国土壤PAEs控制标准,但总体上未超过美国土壤PAEs治理标准.冬小麦籽粒、夏玉米籽粒和果蔬可食用部位PAEs质量分数分别为2.34～3.66、1.76～3.15和2.26～3.76 mg/kg;与其他研究成果相比,该研究区农产品PAEs含量处于中等水平.不同污灌历史年限区域土壤和粮食作物籽粒PAEs含量均没有显著差异.冬小麦籽粒、夏玉米籽粒和果蔬中DEHP和DnBP含量分别占总量的50.3％和30.5％、45.1％和50.2％、47.16％～63.3％和31.96％～46.36％.农产品PAEs总量及各组分含量均低于欧洲的建议标准值.粮食作物籽粒中PAEs和DnBP含量与土壤中相应含量呈显著正相关,Pearson相关系数(r)分别为0.74～0.87和0.91～0.92.该研究中农作物对PAEs的迁移系数为0.24～1.65.儿童和成人PAEs致癌风险分别为1.34×10-5和3.87x10-5,非致癌指数分别为9.44x 10-1和3.83×10-1,均在可接受范围内;通过口-作物暴露对PAEs 2种风险贡献均最大,DEHP对人体2种风险贡献最大.

Assessment of contamination risk of PAEs in soils and crops of irrigation district located at southeastern suburbs of Beijing

In order to find out the concentration of phthalate acid esters (PAEs) and its pollution characteristics in topsoil and agricultural products in irrigation district at the Southeastern Suburb of B eijing,six kinds of PAEs in 31 topsoil samples and 3 8 crops samples in the irrigation district were detected by gas chromatography-mass spectrometry (GC-MS) in 2015.Results showed that the total concentration of six PAE compounds (∑PAEs) in topsoil ranged from 1.8 mg/kg to 12.2 mg/kg,with the average concentration of 5.1 mg/kg.There was no significant (P＞0.05) difference for PAEs in soil among the different sewage irrigation history.Concentration of PAEs in topsoil in this study was relatively higher compared to those reported for other places in literature.The content of di-butyl phthalate (DnBP) and di-(2-ethylhexyl) phthalate (DEHP) in top soils contributed 60.4％ and 35.9％ to total PAEs,respectively.According to soil allowable concentration of phthalic acid esters compounds in USA,the concentration of dimethyl phthalate (DMP) and DnBP in all soil samples exceeded the control limits,indicating that the topsoil in this district was contaminated by PAEs,but the concentrations of all PAEs compounds were lower than the cleanup objective.The total concentration of PAEs in winter wheat (Triticum aestivum) grain,summer maize (Zea mays) grain,and edible part of vegetables and fruit were 2.34-3.66 mg/kg,1.76-3.15 mg/kg,and 2.26-3.76 mg/kg,respectively.No significant (P＞0.05) difference was observed for PAEs in cereals grain among different sewage irrigation history.Concentrations of PAEs in agricultural products in this study were in the middle level compared to the results of other studies.The content of DnBP and DEHP in winter wheat grain contributed 30.5％ and 50.3％ to the total PAEs,respectively.The content of DnBP and DEHP in summer maize grain contributed 50.2％ and 45.1％ to the total PAEs,respectively.The content of DnBP and DEHP in vegetable and fruit contributed 31.96％-46.36％ and 47.16％-63.3％ to the total PAEs,respectively.The concentrations of the total PAEs and each PAE compound in agricultural products were less than the suggested targets in Europe,implying low health risk.The concentrations of PAEs and DnBP in cereal grain showed a significantly (P＜0.05) positive correlation with those in soils,with Pearson coefficients (r) of 0.74-0.87 and 0.91-0.92,respectively.The bioaccumulation factors of PAEs in wheat grain,maize grain,and vegetables and fruit were 0.74-0.82,0.28-0.90,and 0.24-1.65,respectively.The carcinogenic risk of child and adult caused by PAEs were 1.34× 10-5 and 3.87× 10-5,respectively.The non-carcinogenic hazard index of PAHs for child and adult were 9.44× 10-1 and 3.83 × 10-1,respectively.All of them were lower than the threshold values.Dietary intake is the major route of human exposure,which accounts for 99.81％-99.96％ of the total carcinogenic risk and 99.85％-99.95％ of the total non-carcinogenic hazard index,respectively.The carcinogenic risk and non-carcinogenic hazard index caused by DEHP in this study were relative higher,which accounted for 99.91％-99.94％ of the total carcinogenic risk and 84.15％-84.37％ of the total non-carcinogenic hazard index,respectively.