[Geography of the incidence of stomach cancer in relation to hardness of drinking water and water supply].

The incidence of gastric carcinoma was analysed in Zabrze in the years 1965-1975 taking into account the sex, age, place of birth (autochthonous and immigrated populations) and place of residence in different city districts in relation to drinking water hardness. A correlation was revealed between low incidence of the neoplasm and drinking water of high hardness grade (over 25 degrees u) with a relatively high content of mineral components.