A significant dose-response relation between ingested
arsenic and several
cancers has recently been reported in four townships of the endemic area of blackfoot disease, a unique
peripheral artery disease related to the chronic
arsenic exposure in southwestern Taiwan. This study was carried out to examine ecological correlations between
arsenic level of well water and mortality from various
malignant neoplasms in 314 precincts and townships of Taiwan. The
arsenic content in water of 83,656 wells was determined by a standard
mercuric bromide stain method from 1974 to 1976, while mortality rates of 21
malignant neoplasms among residents in study precincts and townships from 1972 to 1983 were standardized to the world population in 1976. A significant association with the
arsenic level in well water was observed for
cancers of the liver, nasal cavity, lung, skin, bladder and kidney in both males and females as well as for the
prostate cancer in males. These associations remained significant after adjusting for indices of urbanization and industrialization through multiple regression analyses. The multivariate-adjusted regression coefficient indicating an increase in age-adjusted mortality per 100,000 person-years for every 0.1 ppm increase in
arsenic level of well water was 6.8 and 2.0, 0.7 and 0.4, 5.3 and 5.3, 0.9 and 1.0, 3.9 and 4.2, as well as 1.1 and 1.7, respectively, in males and females for
cancers of the liver, nasal cavity, lung, skin, bladder and kidney. The multivariate-adjusted regression coefficient for the
prostate cancer was 0.5. These weighted regression coefficients were found to increase or remain unchanged in further analyses in which only 170 southwestern townships were included.