用HRGC/HRMS测定开放式生活垃圾焚烧残余物及周边土壤中的PCDDs/PCDFs

Determining PCDDs/PCDFs in Combustion-residue of An Open-burning Municipal Waste Site and Its Peripheral Soil with Isotope Dilution HRGC/HRMS Technique

以广东省东南沿海某开放式生活垃圾焚烧场为研究对象,用高分辨气相色谱/高分辨质谱同位素稀释法测定了垃圾焚烧场底灰、焚烧残余物及周边土壤中的多氯代二苯并对二噁英和多氯代二苯并呋喃(PCDDs/PCDFs)。结果表明,PCDDs/PCDFs的总浓度为161～4670ng·kg-1,毒性当量为1.10～45.8ngWHO1998-TEQ·kg-1,其中采自垃圾焚烧场的3个样品浓度为30～45ngWHO1998-TEQ·kg-1,剩余的土壤样品中有3个样品其浓度为4～35ngWHO1998-TEQ·kg-1,其余的2个样品浓度<4ngWHO1998-TEQ·kg-1。对比加拿大的土壤指导性标准,75%的测定样品浓度高于该标准,即土壤背景浓度,有25%的样品低于此背景浓度。将垃圾焚烧场焚烧残余物作为土壤改良剂造成受施土壤的PCDDs/PCDFs污染严重,需引起有关部门的高度重视。

An open-burning municipal waste site located in the southeast coast of Guangdong Province was taken as the subject for this study, and the technique of isotope dilution featuring high resolution gas chromatogram/high resolution mass spectrogram（HRGC/HRMS） was used to determine the concentrations of polychlorinated dibenzo-p-dioxins and polychlorinated dibenzofurans（PCDDs/PCDFs） in the bottom ash and combustion-residue of the waste incineration site and in the peripheral soil. As shown by the analytical results, the total concentration of PCDDs/PCDFs was 161-4 670 ng· kg^-1, which corresponded to a toxic equivalent of 1.10~45.8 ng1998-TEQ·kg^-1. The concentration for three samples collected from the waste incineration site ranged between 30-45 ng1998-TEQ·kg^-1 In regard to the peripheral soil samples, three samples concentrations 4~35 ng 1998-TEQ·kg^-1, while the remaining two samples concentrations were lower than 4 ng 1998-TEQ·kg^-1. Based on the Canadian guideline for soil quality, 75% of the samples tested in our study concentrations were greater than the soil background concentrations defined in the Canadian guideline, while only 25% of the samples tested in our study concentrations were lower than the soil background concentrations defined in the Canadian guideline. Therefore, using of the combustion residue of a waste site as soil modifier would result in serious pollution of PCDDs/PCDFs in soil, which we believe should solicit attention from the related authorities.