Distribution and enrichment of groundwater arsenic in shallow and deep aquifers of Yinchuan Plain, China

Yinchuan Plain of Ningxia autonomous region is one of high arsenic (As) groundwater areas with endemic arsenism in the Northwest of China (Yu et al. 2007); patients were found here in 1995. There have been more than 500 arsenic poisoning cases and patients have mild symptoms on the basis of an investigation by Tan et al. (2006).