Chronic arsenicism and cancer in Inner Mongolia — consequences of well-water arsenic levels greater than 50 μg/l

Abstract

Inner Mongolia is an autonomous region of China south of the Gobi desert and north and west of the great wall of China (Figure 5.1). Its capital was established as Huhhot in 1954. The Huhhot region lies in a triangular, segmented and sunken lake basin in Inner Mongolia, China, south of the Daqing (Great Green) Mountains and along the northern coast of the Yellow River (Figure 5.2). This region comprises approximately 4800km². The subterranean waters occur in a Q₄ earth stratum and have a naturally occurring high concentration of arsenic from the local rock. High levels of arsenic (mainly As⁺³) and of fluoride are found in the water, as are low levels of dissolved oxygen, sulfate, nitrate, and selenium, and traces of iron and manganese. The aquifers provide a reducing environment, rich in organic substances, in which arsenic easily moves and accumulates. The western Huhhot basin is an agricultural area, raising wheat, millet, corn, green beets, potatoes and sunflowers. Arsenical pesticides have not been used. No factories, mines or other industries discharge arsenic into the local air, water or soil. Examination of the surface soils, air, fish and crops have not found arsenic levels above the Chinese standards. The smoking habits in Huhhot resemble those of the general Chinese culture.