西北干旱区电子垃圾拆解处置区典型有机物污染环境效应及人群暴露风险

With the adjustment of layout of national energy distribution and the focus ponit of environment pollution control area, and as well as the improvement of norms and environment protection requirements for disposal of waste, electronic and solid waste disposal industry have been moving gradually to the inland areas of Northwest China. This project is going to investigate the contaminations, dry depositions, characteristics of distribution in atmospheric particles and gas-particle partitioning, spatial and seasonal differences of PCBs and PBDEs of electronic waste dismantling and disposal in arid regions in Northwest China by collecting the air, and soil samples, and to clarify their environmental fate and behavior and possible influence to surrounding environments by combining HYSPLIT-MESODIFF transport and dispersion model; Based on the observation data, the main route of human exposure to PCBs and PBDEs contamination was explored, and cancer risk due to human exposure to PCBs and PBDEs was also assessed. The conduction of this project is to provide considerable insight for environment, ecosystem, health risk evaluation and protection strategies associated with electronic waste disposal industry moving towards Northwest regions in China.

随着国家能源布局和环境污染治理重点区域的调整，以及对于电子垃圾处置的规范和环保要求的不断提高，电子垃圾和固体废弃物处理产业已逐渐向我国西北内陆地区迁移。本项目拟以两类典型POPs：PCBs和PBDEs为目标化合物，以西北干旱区具有较大规模的甘肃皋兰电子垃圾拆解和处置地为研究区域，拟通过对其大气和土壤进行为期一年的观测研究，阐明PCBs和PBDEs在大气、土壤中的污染特征、时空分布差异、大气干沉积通量、粒径分布和气-粒分配特征，结合HYSPLIT-MESODIFF迁移扩散模型揭示其在研究区环境中的归趋行为及其可能对周围环境所造成的影响；基于观测数据，探究研究区人群PCBs和PBDEs的主要环境暴露途径，初步评估人群由于PCBs和PBDEs环境暴露所造成的癌症风险。本项目的开展可为我国电子垃圾处理产业西移相关的环境、生态、健康风险评估和保护，以及污染防控提供基础科学数据和对策。

含PCBs和PBDEs的产品在生产、使用和处置过程中，会造成PCBs和PBDEs的释放；PCBs还会以副产物的形式排放如环境。西北作为我国产业转移的承接地，对PCBs和PBDEs的污染研究较少。本项目以甘肃省皋兰电子垃圾拆解厂所在的工业园和周围环境为对象，结合污染观测和模型模拟，阐明研究区PCBs和PBDEs污染特征和环境归趋，评估居民的暴露风险。拆解车间内PCBs和PBDEs大气浓度高于拆解车间外，由于该厂拆解以人工拆解和机械破碎为主，致使污染程度整体较低。拆解厂周围环境PCBs大气浓度110.2-429.9pg/m3，干沉降通量13.8-158.8ng/(m2•d)，工业园区污染较高；PBDEs大气浓度59.1-163.8pg/m3，干沉降通量5.0-12.2ng/(m2•d)，城区污染较高。环境PCBs大气浓度较拆解车间高，而PBDEs则相对较低，且与拆解车间外浓度接近。土壤PCBs浓度3.7-19.2ng/g，拆解厂周围污染较高；PBDEs浓度1.6-2.8ng/g，各区域PBDEs浓度接近。非取暖季PCBs大气浓度和干沉降通量上升，而PBDEs呈现下降；PBCs和PBDEs在取暖季主要分布于PM10；PCBs以四氯和五氯联苯为主，PBDEs以十溴联苯醚为主，四氯联苯含量在取暖季呈现上升。研究区PCBs和PBDEs主要聚集于土壤中，其清除通道以大气平流输出为主，随大气迁移的PCBs和PBDEs会造成研究区城区和兰州市的污染。职业工人PCBs暴露风险低于拆解厂周围人群，而PBDEs的暴露风险则高于周围人群，但二者风险整体较低；呼吸暴露是研究区人群主要暴露途径。研究区PCBs可能源于燃烧和工业热过程的无意排放，PBDEs可能以室内排放为主；拆解厂对周围环境的污染贡献相对较低。