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硝酸盐转变为亚硝酸盐再转变为亚硝胺,一般认为是致胃癌物质的前体。智利是世界上唯一有大量自然硝酸盐沉积,并长期将其做为肥料施用的国家。智利硝酸盐使用资料表明:不同地区胃癌死亡率与当地氮的总暴露量有高度的相关关系。1977年7月到1980年2月,智利进行了一次硝酸盐生态学研究,目的是想通过一些客观指标了解硝酸盐和亚硝酸盐是否与智利高低发区的胃癌死亡率有关。选用位于智利北端的A 市(Autofagasta,人口130000)和位于南端的P 市(Punta,Anenas,人口70000)为低发区;智利中部的C 市(Chilla’n,人口100000)和与其毗邻的L 市(Linanes,人口70000)为高发区。由专业现场调查员从四个城市在校儿童(11～13岁)中,抽样采取尿液和唾液标本,并从四个
Nitrate into nitrite and then into nitrosamines, is generally believed to be a precursor to gastric cancer substances. Chile is the only country in the world with large deposits of natural nitrates and its long-term use as a fertilizer. The use of nitrate in Chile shows that there is a high correlation between the mortality of gastric cancer in different regions and the total nitrogen exposure in the area. From July 1977 to February 1980, a study on nitrate ecology was conducted in Chile. The objective was to find out through objective indicators whether nitrate and nitrite were related to gastric cancer mortality in high and low-risk areas of Chile. Choose the lowland of A (Autofagasta, population 130,000) and Punta, Anenas (population 70000) located in the northern end of Chile; Chilla’n (population 100000) in central Chile and the L City (Linanes, population 70,000) as a high incidence area. A sample of urine and saliva samples were taken by professional field investigators from school children (11-13 years) in four cities and from four