Background and objective: China's Xuan Wei County in Yunnan Province have the world's highest incidence of lung cancer in nonsmoking women-20 times higher than the rest of China. Previous studies showed, this high lung cancer incidence may be associated with the silica particles embedded in the production combustion from the C1 coal. The aim of this study is to separate the silica particles from production combustion from the C1 bituminous coal in Xuan Wei County of Yunnan Province, and study in vitro toxicity of naturally occurring silica particles on BEAS-2B.
Methods: ①Separating the silica particles from combustion products of C1 bituminous coal by physical method, observing the morphology by Scanning Electron Microscope, analysis elements by SEM-EDX, observed the single particle morphology by Transmission Electron Microscope, analyed its particle size distribution by Laser particle size analyzer, the surface area of silica particles were determined by BET nitrogen adsorption analysis; ②Cell viability of the experimental group (silica; naturally occurring), control group (silica; industrial produced and crystalline silica) was detected by assay used the 3-(4,5-dimethylthiazol-2-yl)-2,5-diphenyltetrazolium bromide (MTT) method, and the reactive oxygen species (ROS), lactate dehydrogenase (LDH) were determined after 24 h-72 h exposed to these particles.
Results: ①The physical method can separate silica particles from production combustion from the C1 bituminous coal, which have different size, and from 30 nm to 120 nm particles accounted for 86.8%, different morphology, irregular surface area and containing trace of aluminum, calcium and iron and other elements; ②Under the same concentration, the experiment group have higher toxicity on BEAS-2B than control groups.
Conclusions: Physical method can separate silica particles from production combustion from the C1 bituminous coal and not change the original morphology and containing trace; ②Naturally occurring silica nanoparticles have irregular morphology, surface area, and containing complex trace elements may has greater toxicity than the silica nanoparticle of industrial produced and crystalline silica.
背景与目的: 中国云南省宣威地区是世界非吸烟女性肺癌发病率最高的地区之一，其发病率是中国其他地方的20倍，前期研究认为，这种高肺癌发病率可能与当地出产和使用的烟煤燃烧产物中含有的二氧化硅颗粒物有关。本研究将从宣威地区出产的烟煤（C1烟煤）燃烧产物中分离二氧化硅颗粒物并进行表征，同时研究这种自然产出的二氧化硅颗粒物对正常人支气管上皮细胞（BEAS-2B）的体外毒性。
方法: ① 物理法从C1烟煤燃烧后的底灰中分离二氧化硅颗粒物，扫描电镜（scanning electron microscope, SEM）观察分离出的颗粒物形态，能谱分析显微组分的依存关系，透射电镜（transmission electron microscope, TEM）观察单颗粒形貌，激光粒度分析仪分析其颗粒物粒径分布，BET氮吸附比表面积仪测定颗粒物表面积；②应用3-(4, 5-dimethylthiazol-2-yl)-2, 5-diphenyltetrazolium bromide（MTT）比色法检测分离出的二氧化硅处理组（实验组）、工业生产的纳米二氧化硅处理组和结晶型二氧化硅处理组（对照组）的细胞成活率变化，测定经刺激24 h-72 h后细胞内活性氧化酶（ROS）和乳酸脱氢酶（LDH）含量变化。
结果: ① 我们从C1烟煤燃烧后的底灰中分离出二氧化硅颗粒物，这些颗粒物粒径大小不一，30 nm到120 nm的颗粒物占86.8%，形态各异，表面不光滑，赋存有铝、钙和铁等元素；②相同浓度下，与工业生产的纳米二氧化硅和结晶型二氧化硅相比，自然产出的纳米二氧化硅对BEAS-2B有更高的体外毒性。
结论: ① 物理法能从C1烟煤底灰中分离出天然的纳米二氧化硅颗粒物，且不改变原有的形貌特征和显微组分的依存关系；②天然产出的纳米二氧化硅因形貌不规则、高比表面积和复杂的化学组分可能比工业生产的纳米二氧化硅和结晶型二氧化硅具有更高的细胞毒性。