西北地区沙尘暴降尘部分特性的分析

Characteristic of Talldust in Sand-Storm in Northwest Area of China

目的研究中国西北地区主要的沙尘暴多发区降尘中的游离二氧化硅[SiO_2(F)]含量、分散度和可溶性化学成分,为预防风沙尘肺在该地区流行提供科学依据。方法2008年3—5月,在和田市、民勤县、中卫市和兰州市,于沙尘暴过后2～8 h内收集降尘并采集受试地区沙漠中的原沙。采用GB 5748—1985《作业场所空气中粉尘测定方法》规定的焦磷酸质量法、滤膜溶解涂片法分析降尘中的SiO_2(F)含量、分散度,采用离子色谱法测定降尘中的可溶性离子。结果原沙中SiO_2(F)含量51.76%～69.49%,沙尘暴降尘中SiO_2(F)的含量为17.36%～48.09%。降尘中可吸入尘(<10μm)比例为63.3%～84.1%。沙尘暴过后降尘可溶性化学成分中Cl^-浓度为220(和田市)～980μg/g(兰州市);SO_4^(2-)浓度为870(和田市)～5 400μg/g(兰州市);NO_3^-和NH_4^+浓度在沙漠边缘地区低于250μ/g/g,而兰州市浓度分别为1400和510μg/g。兰州市的降尘中Cl^-、SO_4^(2-)和NO_3^-度高于其他三地,差异有统计学意义(P<0.01)。结论沙尘暴尘为高SiO_2(F)含量、高分散度、潜在致肺纤维化危险性强的粉尘;具有导致沙尘暴多发区居民尘肺病流行的可能性。

Objective To survey free crystalline silica[SiO2（F）] content, particle size and water-soluble components concentration in the sand-dust storm dust, in order to prevent large-scale non-occupational silicosis （desert lung） prevalence in northwest desert area of China. Methods Atmospheric dust（falldust） were collected in Hetian, Minqin, Zhongwei and Lanzhou city when sand-dust storm befallen and free crystalline silica, particle size ratio and water-soluble components were analyzed according to GB 5748-- 1985. Results The rate of SiO2（F） component was over 50% in the original sand, the rate of SiO2（F） component was from 17.36% to 48.09% in the falldust of sand-dust storm, the falldust belongs to crystal dust. The inhaleble particle（particles with amedian diameter of 0.5-10μm） ratio was from 63.3% to 84.1%. The water-soluble components concentration increased as sand-dust storm moving. Cl, SO4^2- and NO3^- content was from 220 μg/g, 870μg/g and 230 μg/g of Hetian to 980 μg/g, 5 400 μg/g and 1 400 μg/g of Lanzhou（P〈0.01）. Conclusion The falldust of sand storm inhalation is a high-risk factor for the local peoples to be attacked by non-occupational pneumoconioses. The further studies should be carried out in epidemiological and toxicological fields.