高砷燃煤燃烧飞灰中砷粒径分布及健康风险评价

The Distribution of Arsenic Particle Size Distribution and Health Risk Assessment of High Arsenic Coal Combustion Fly Ash

摘要: 贵州省黔西南地区因使用高砷燃煤带来地方性砷中毒。近年来，对于地方性砷中毒的机制及健康风险研究已成为关注的热点。本文模拟高砷燃煤燃烧时产生的飞灰中砷的粒径分布及对人体致癌的风险。将高砷燃煤在扩散炉中进行燃烧，燃烧温度为600℃~1000℃，生成的飞灰粒径采用Andersen分级采样器进行采样，共分为8级(1.2~42.6 μm)。实验表明：飞灰中砷的含量随粒径的减小而增大。尤其是当燃煤飞灰粒径<10.7μm时，这种变化更为明显。飞灰中砷含量最小值为2280μg/g，最大值达到5812μg/g。粒径在3.4~16.3μm之间的飞灰质量占总飞灰质量的60.27%，其中砷的质量占飞灰中砷的总质量的61.3%，峰值出现在第五级(5.4~107μm)，为23.86%左右，呈单峰态分布。对飞灰中As的含量应用USEPA的方法，开展健康风险评价，结果表明，As通过皮肤接触和吸入这两种暴露途径进入人体的日均暴露量分别为ADDinh = 2566.1 mg/(kg∙d)和ADDdrem = 85.42 mg/(kg∙d)，存在严重致癌的风险。高砷燃煤飞灰中的As暴露于人体的健康风险评价鲜有报道，故本文的研究为定量描述流行病学提供依据。

Abstract: Local arsenic poisoning has been caused by high arsenic coal burning in the southwest of Guizhou province. In recent years, the research on the mechanism and health risk of endemic arsenic poisoning has become a hot topic. In this paper, analysis of the particle size distribution of arsenic is simulated in fly ash then the carcinogenic risk is calculated. High arsenic coal burned in diffusion furnace at the temperature between 600˚C and 1000˚C, and the fly ash particle size was sample classified using Andersen sampler, which is divided into 8 classes (1.2~42.6 microns). The experimental results show that the content of arsenic increases with the decrease of particle size. Especially when coal fly ash particle size <10.7μm, it showed more obvious change. The minimum value of arsenic content in the fly ash is of 2280μg/g, and a maximum of 5812μg/g. More than 60.27% of the total mass of fly ash showed particle size between 3.4~16.3μm, and 61.3% of the total mass peak appears in the fifth class (5.4~107μm), which accounts for 23.86%, is unimodal distribution. Health risk of fly ash was evaluated using the method of EPA, and daily exposure amount in two kinds of exposure path ways is calculated (inhalation and dermal exposure) ADDinh = 2566.1 mg/(kg∙d) and ADDdrem = 85.42 mg/(kg∙d), which showed a serious risk of cancer. The study in this paper provides a basis for quantitative description of epidemiology of arsenic while the As exposure assessment to human health is rarely reported.2280 mg/gµµ