Nitrate fertilizers as environmental pollutants: positive correlation between nitrates (NaNO3 and KNO3) used per unit area and stomach cancer mortality rates.

Since a significant positive correlation between nitrate fertilizer exposure and stomach cancer mortality has been found, a study of nitrate fertilizer pollution in arable land in terms of amount of nitrates used per unit area (kg/ha) and stomach cancer death rates was carried out. The regression of death rates for stomach cancer, standardized for age, on the nitrates used per unit area, by province (N = 25), exhibited a significant association between the 2 variables (p less than 0.004). When industrialized provinceds (N = 3) were not considered, a highly significant association was found (F = 16.47; d.f. = 1, 20; p less than 0.0006). The correlation coefficient was + 0.672.