Arsenic contamination of groundwater and prevalence of arsenical dermatosis in the Hetao plain area, Inner Mongolia, China

An investigation was carried out on arsenic contamination of groundwater an d prevalence of arsenical dermatosis in the Hetao plain of Inner Mongolia A utonomous Region, China. Based on the screening of water samples from 96 ra ndomly selected wells in this Region, two areas (Wuyuan and Alashan) were c hosen as highly contaminated areas because arsenic in the water samples was higher than 50 mug/l. Arsenic was measured using an arsenic silver diethyl dithiocarbamate method for 326 water samples from all the wells in these a reas. The results show arsenic contaminated groundwater from tubule-type we lls of depths about 15-30 m was serious compared with open-type wells where depth is about 3-5 m. In the Wuyuan area, 96.2% of water samples from tubu le-type wells contained arsenic above 50 mug/l and 69.3% in Alashan area; t he highest value was 1354 mug/l and 1088 mug/l, respectively. In these two areas, a health survey was carried out for arsenical dermatosis. The result s show the prevalence of arsenical dermatosis in the Wuyuan area was 44.8%, higher than 37.1% prevalence of arsenical dermatosis in the Alashan area. The prevalence of arsenical dermatosis was highest in the over 40-year-old age group. There was no sex difference in the prevalence. Further investiga tion is needed to clarify the actual situation of arsenic pollution of grou ndwater in Inner Mongolia, China in order to reduce the adverse health effe ct among residents exposed to arsenic.