RESUMEN
Chronic arsenicosis is a newly-emerged public-health issue in China and many other Asian countries. Over 200 million people are estimated to be at the risk of high arsenic exposure from drinking-water in the Asian region. To protect people from the hazards of chronic arsenic poisoning, the Chinese Government has been providing low-arsenic drinking-water to some seriously-affected rural areas, such as Inner Mongolia autonomous province. Results of follow-up studies showed that both the average values of arsenic, including inorganic arsenic (iAs), monomethylated arsenic, dimethylated arsenic and trimethylated arsenic, and 8-hydroxydeoxyguanine in urine, decreased significantly after drinking low-arsenic water for one year, and arsenic-specific skin lesions also improved to some extent. However, a five-year follow-up study showed no more significant improvement of skin lesions, while the potential risk of arsenic-induced cancers after cutting off high-arsenic exposure was still uncertain and indefinite. The susceptibility of children compared to adults to chronic arsenic exposure and the need to re-evaluate the appropriate standard of arsenic in drinking-water were also discussed in this paper.