生活垃圾焚烧厂周边铅的分布规律研究与影响评估

Study on the distribution law of lead around the municipal solid waste incineration plant and its impact assessment

生活垃圾焚烧厂排放烟气中含有铅等污染物,经过大气扩散后通过沉降作用在土壤累积。以上海某生活垃圾焚烧厂作为研究对象,采用AERMOD模型探讨烟气中的铅在大气中的扩散分布规律,采用沉积模型研究铅的土壤沉积规律,并通过IEUBK模型评估了垃圾焚烧厂对周围儿童最大可产生的血铅浓度几何均数值。结果表明,生活垃圾焚烧厂排放烟气中铅的落地质量浓度最大值位于排放源的东南方向,距离排放源1338 m处,为0.017μg/m^3,远低于《环境空气质量标准》(GB 3095—2012)中的限值0.5μg/m^3。使用IEUBK模拟得到此暴露场景对周边儿童产生的血铅质量浓度几何均数值为6.63μg/L,低于开始产生不良影响的风险阈值100μg/L。进一步结合土壤污染累积模型计算得到,当生活垃圾焚烧厂运行30 a时,对周边土壤的最大铅累积量为7.6μg/kg,远小于《土壤环境质量建设用地土壤污染风险管控标准(试行)》(GB 36600—2018)筛选值800 mg/kg。将土壤铅暴露纳入评价范围后,儿童体内的血铅质量浓度几何均数值仍为6.63μg/L。

Contaminants such as lead are emitted during the municipal solid waste incineration(MSWI),and diffused through the atmosphere and accumulated in the soil through sedimentation.In this paper,a MSWI plant in Shanghai was used as the object of study.The AERMOD model was used to explore the distribution of lead in the atmosphere.The sedimentary model was used to study the depositional rule of lead in soil.The IEUBK model was used to assess the geometric mean value of the maximum blood lead concentration of the surrounding children.The results showed that the extreme concentration of lead in the flue gas emitted from the MSWI plant was located in the southeast direction of the emission source,1338 meters away from the emission source,and the concentration value was 0.017μg/m^3,it was far below the limits(0.5μg/m^3)in“Ambient air quality standard”(GB 3095-2012).It was found that the geometric mean value of blood lead concentration of surrounding children was 6.63μg/L simulated by IEUBK,below the risk threshold of 100μg/L.Further,the soil pollution accumulation model was combined,when the MSWI plant was operated for 30 years,the maximum lead accumulation to the surrounding soil was 7.6μg/kg,which was much smaller than the“Soil environmental quality risk control standard for soil contamination of development land(trial implementation)”(GB 36600-2018)screening value of 800 mg/kg.After the soil lead exposure was included in the evaluation,the geometric mean value of blood lead concentration in children was still 6.63μg/L.