生活垃圾焚烧厂周边住宅小区内二噁英类物质的暴露特征及健康风险评估

Exposure Characteristics and Health Risk Assessment of PCDD/Fs in Residential Areas around Domestic Waste Incineration Plant

以长江中下游地区某生活垃圾焚烧处理厂为监测对象,研究其主导上、下风向住宅小区内的环境空气、土壤和室内积尘等各环境介质中二噁英的浓度水平和分布特征。研究结果表明,该生活垃圾焚烧厂排放废气中的二噁英毒性当量浓度为0.007~0.064 ng·m^(-3),满足《生活垃圾焚烧污染控制标准》(GB 18485—2014)中规定的二噁英毒性当量限值0.1 ng·m^(-3)。4个住宅小区内环境空气、土壤和室内积尘中二噁英毒性当量浓度分别是0.12~0.19 pg·m^(-3)、1.1~4.8 ng·kg^(-1)和1.1~5.3 ng·kg^(-1),均处于较低水平。住宅小区内环境空气中二噁英的浓度呈现出秋冬季稍高于春夏季的现象,与废气中二噁英排放特征一致,下风向小区C和小区D环境介质中二噁英的浓度明显高于其他点位,说明本研究区域内的二噁英主要来源于该生活垃圾焚烧厂,在秋冬季要加强焚烧企业的管控力度。通过比较同一住宅小区、同一监测时段室内积尘和土壤监测数据发现,室内积尘对人体的暴露风险要大于土壤暴露风险。通过人群健康风险评估发现,儿童的呼吸暴露量是成人的4倍,儿童经口摄入土壤或室内积尘的日均暴露量是成人的10倍,儿童的暴露应该得到更高的重视。

The concentration level and distribution characteristics of polychlorinated dibenzo-p-dioxins and dibenzofurans(PCDD/Fs)in ambient air,soil,indoor dust and other environmental media in a residential area in the upper and lower winds of a domestic waste incineration plant in the middle and lower reaches of the Yangtze River were studied.The results show that the toxic equivalent quantity(TEQ)concentration of PCDD/Fs in the waste gas emitted by the incineration plant is 0.007~0.064 ng·m^(-3),which meets the limit requirement of 0.1 ng·m^(-3)stipulated in the Pollution Control Standard for Incineration of Domestic Waste(GB 18485—2014).The TEQ concentrations of PCDD/Fs in ambient air,soil and indoor dust in the four residential areas were 0.12~0.19 pg·m^(-3),1.1~4.8 ng·kg^(-1)and 1.1~5.3 ng·kg^(-1),respectively,which were all at low levels.PCDD/Fs concentration in the air of the residential district in autumn and winter is slightly higher than that of spring and summer,which is consistent with the emission characteristics of exhaust gas PCDD/Fs.The PCDD/Fs concentrations in lower wind area C and D environmental medium are significantly higher than the other points,which indicates the influence of PCDD/Fs in the research area mainly comes from the incinerators.In autumn and winter,the management and control of incineration enterprises should be strengthened.By comparing indoor dust and soil monitoring data in the same residential area and monitoring period,it is found that the exposure risk of indoor dust for human body is greater than that of soil exposure risk.Through the health risk assessment,it is found that the respiratory exposure of children is 4 times that of adults,and the daily exposure of children by oral intake of soil or indoor dust is 10 times that of adults.Therefore,more attention should be paid to children’s exposure.