A note on the use of nitrate fertilizers in a high-risk geographical area for stomach cancer.

Chile being the only country in the world producing natural fertilizers (NaNO3 and KNO3), it uses very large quantities of them for agricultural purposes. Since in early 1970 Zaldívar first related the use of fertilizers to stomach cancer mortality, it is of key interest to know the amount of nitrogen fertilizers used, expressed in tons of N, by province, for the period from 1945 to 69. Of a total of 420,750 tons of N for the nation, 238,950 tons were used in the high-risk provinces for stomach cancer (Colchagua, Curicó, Talca, Maule, Linares, Nuble, Concepción, Bio-Bio, Arauco, Malleco, Cautín). On the other hand, in the low-risk provinces (Tarapacá, Antofagasta, Atacama, Magallanes) only 2,550 tons were used. In Chile, the use of fertilizers increased from 37,550 (1945-50) to 185,050 (1965-69) tons of N.