Study On Toxicological Effects Of Desert Dust And Desert Lung Syndrome Of Dweller In Northwest Area Of China

Objectives:1.Sand dust pollution,which caused by sandstorms and floating dust weather,is important environmental problems in northwest China.The health impact on sand dust has been attracted wide attention. The short-term health problems has been researched in many current studies,but the literature on long-term chronic effects,particularly lung damage induced by sand dust,is infrequent.Hetian city of Xinjiang Province and Minqin County of Gansu Province are the birthplace of dust storms in Northwest China.In order to explore risk of pneumoconiosis induced by the desert dust,the free silica content,dispersity and soluble chemical constituents in sand dust were analysesed;And the toxicity of pulmonary macrophage and lung fibroblasts in vitro experiments induced by desert dust were studied.2.In order to preliminary understand hazardous of desert lung syndrome,the suspected tuberculosis patients in these area of sandstorm-damage was screened.Methods:Desert dust and Atmospheric dust(falldust) were collected in Hitian city,Minqin county,Zhongwei city,Lanzhou city when sand-dust storm befallen.Free crystalline silica,particle size ratio and water-soluble componets were analyzed according to GB5748—1985.AMs were cultured by different concentrations of desert dust and SiO₂ respectively. AMs of the control group were cultured by normal DMEM culture medium.After 24 hours exposure,collect cells the supernatant of culture media and measure MDA content,GSH-Px activity,LDH activity and TGF-β1 content.Rat PFBs were cultured with collected culture media of Ams.After 24 hours exposure,cells the supematant of culture media were collected.Survival rate and hydroxyproline of PFBs were measured. 2.According to the diagnostic criteria of pneumoconiosis(GB5906-1997), 777 cases who are suspected tuberculosis patients in Yumen CDC in 2005～2007 were analyzed by X-ray diagnosis and classification.Results:1.Experimental result of toxicology.(1)The rate of SiO₂(F) component was over 50%in 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 componets concentration increased as sand-dust storme moving.Cl^-, SO4_<sup>2+and NO₃^-content was from 220μg/g,870μg/g and 230/μg/g of Hetian to 980μg/g,5400μg/g and 1400μg/g of Lanzhou(P＜0.01).(2) Compared with the control group,survival rate of Ams was significant lower in 400,800,1600μg/ml desert dust groups of Hetian and 100,200,400,800,1600μg/ml groups of Minqin(P＜0.05).(3)Compared with the control group,the content of MDA,GSH-Px activity and TGF-β1 content in 200 and 400μg/ml desert dust groups of HeTian and MinQin was significant higher(P＜0.05),while the activity of LDH in 100,200 and 400μg/ml groups of desert dust and SiO₂ group was significant higher(P＜0.01).(4)Compared with the control group,with the increasing concentration of Ams cells the supernatant of culture media of desert dust of Minqin and Hetian,survival rate and droxyproline of PFBs was significant higher in 400μg/ml desert dust(P＜0.01).2.Results of desert lung syndrome survey:Desert lung syndrome is 107 cases from 2005 to 2007 suspected tuberculosis patients,the combined rate is over 10%.The average age is 59.4 years old,male is 53 cases and female is 64 cases.In 107 cases of Desert lung syndrome,â… andâ… ⁺ Phase is 52 cases,â…¡andâ…¡⁺,â…¢Phase is 3 cases.The prevalence of desert lung syndrome combined tuberculosis is 72.9%.X-ray findings indicate:p,q cpacities is higher proportion than others,which is 70.3%.Irregular s,t and u cpacities is less proportion.Conclusion:There is high free silica content,high dispersity in sandstorms dust,which may lead to pulmonary fibrosis.The potential hazard of sandstorm will increase because the sandstorm dust can bring a number of air pollutants with floating and migration of sandstorm increase potentially harmful.Desert dust of HeTian and MinQin appears toxicity to Ams,enhances Lipid Peroxidation and releases Fibrosis factor TGF-β₁.PFBs and collagen is creased when desert dust concentration is higher.The prevalence rate of desert lung syndrome combined tuberculosis is higher in the origin of sandstorm and we infer to there is higher prevalence rate of desert lung syndrome,which is related to tuberculosis.