大姚县青石棉污染的危害及预防与控制

Hazard,prevention and control of crocidolite contamination in Dayao county

目的 探讨环境中低浓度接触石棉对居民健康的影响及石棉相关疾病的预防。方法 采用横断面调查、回顾队列调查和动物实验等方法。结果 大姚县居民胸膜斑检出率为 10 .7% ,在 40岁以上人群中高达 19.8% ,并相继发现 83例地方性石棉肺。 1977～ 1983年期间肺癌的SMR为6 .6 3,RR为 7.2 3;间皮瘤死亡率为 8.5 /10万人年。 1987～ 1995年肺癌死亡率为 5 3.2 6 /10万人年 ,RR为 2 .14,明显高于对照组 (肺癌死亡率为 2 4.88/10万人年 ) ,P <0 .0 5 ;队列中有 7例间皮瘤 ,死亡率为17.75 /10万人年 ,对照组未发现间皮瘤。动物实验结果表明 ,绿茶和亚硒酸钠能有效降低大鼠肺癌和间皮瘤诱发率。经过 10多年的努力 ,大姚县综合治理已初见成效 ,青石棉污染得到明显控制 ,生态环境有了较大的改善。结论 居民在环境中接触低浓度青石棉可引起恶性肿瘤 。

Objective To explore the effects of exposure to low concentration of crocidolite in the environment on the health of residents and the prevention of asbestos related diseases.Methods A cross sectional and a retrospective cohort study and animal experiment were carried out.Results The incidence of pleural plaques was 10.7% in the whole study group(2 175) and 19.8% among those over 40 years of age (1 165) .In addition,83 patients with asbestosis were found among residents who had been exposed to crocidolite in environment.In 1977～1983 the standard mortality ratio( SMR ) for lung cancer was 6.63 and RR was 7.23,significantly different from that in the control group.The annual mortality rate was 8.5/10 5 person years for mesothelioma.In 1987～1995 the mortality from lung cancer was 53.26/10 5 person years. RR was 2.14( P <0.05) from lung cancer.There were 7 deaths due to mesothelioma in cohort and mortality was 17.75/10 5 person years.No mesothelioma was observed in the control group.The animal experiment showed that green tea and sodium selenite could efficiently reduce the incidence of lung cancer and pleural mesothelioma on rats.At present comprehensive measures of prevention and control have shown initial effectiveness in Dayao county.The contamination with crocidolite was prominently controlled and ecological environment was improved. Conclusion The mortality of lung cancer and mesothelioma may significantly increase among residents exposed to low concentration of crocidolite.