生活垃圾收运过程中恶臭暴露的健康风险评估

通过现场采样检测,研究了生活垃圾收运链中氨、硫化物、萜烯化合物、芳香烃、醇类化合物、挥发性有机酸、醛酮类化合物等7类恶臭物质的组成特征;分析了收运链不同环节中恶臭污染物的分布特征及操作方式对其影响;依据恶臭污染物的分布特征,评估了生活垃圾转运场所职业暴露人员的致癌和非致癌风险,并对结果进行了不确定分析.结果表明,收运过程中,末端垃圾码头的恶臭污染物比前端的垃圾箱房高1个数量级以上,与生活垃圾在收运过程中降解程度逐渐提高相对应;不同类别恶臭污染物中,醇类化合物随收运链的延伸而稳定上升,挥发性有机酸(VFAs)和芳香烃化合物则呈阶跃增加,分别在集装箱码头和散装码头处达到峰值(分别为131, 711μg/m3).收运链前端,垃圾箱房的主要致臭化合物为醛酮类化合物;收运链末端,垃圾码头的主要致臭化合物为硫化物和挥发性有机酸.生活垃圾散装运输操作方式,对作业人员和周边人群可能造成较大健康影响.散装码头处恶臭污染导致的致癌和非致癌风险值最高,致癌风险值LCR总为2.64×10-5,超过生活垃圾收运链中的其它作业点,存在较大的健康风险;非致癌风险值HI总为3.01,集装箱码头处的HI总为1.22,超过了USEPA推荐的可接受范围,其余作业点的非致癌风险值HI总<1,在可接受的范围内.

Health risk assessment of exposure to odorous pollutants emitted from the transportation process of MSW

Seven categories of odorous pollutants released from the collection and transportation process of municipal solid waste (MSW), including ammonia, sulfur compounds, terpenes, aromatics, alcohols, volatile fatty acids (VFAs) and carbonyls, were quantified through different analytical methods. Based on the field data, the compounds mainly causing malodour were assessed and identified. The cancer and non-cancer risk of odor exposure in the circumstance were corrsesponingly estimated by the health risk model. The uncertainties of risk value were estimated by Monte Carlo simulation．The concentration of odorous pollutants in the transfer station was one order of magnitude higher than that in the dust bin, which was closedly associated with the degradation of MSW. The concentration of alcohols increased stably with the extension of transportation chain, whereas the concentrations of VFAs and aromatics increased with fluctuation, and peaked in the bulk transfer station and in the container transfer station (131μg/m3, 711μg/m3respectively). The major odorous compounds at the early stage of transportation were carbonyls, whereas at the end stage were sulfur compounds and VFAs.The adults’ total cancer risk from odor pollution in the bulk transfer station was 2.64×10-5, whereas the total non-cancer risk was 3.01in the bulk transfer sstation and 1.22in the container transfer station, which was closed to or exceeded the maximum acceptable risk levels recommended by US EPA. The risk values in the other transportation points were within the acceptable range.