Arsenic, fluoride and iodine in groundwater of China

- Groundwater As, F and I in north China are still of public health concern.
- Organic-rich sediment and sluggish flow lead to reducing, high As soda water.
- Evapotranspiration further enriches F, and possibly As in discharge zones.
- Iodine is derived from I-rich organic matter in marine strata.
- To assess risk, sediment provenance and the role of irrigation need further study.

Arsenicosis and fluorosis, two endemic diseases known to result from exposure to their elevated concentrations in groundwater of north China used by many rural households for drinking, have been major public health concerns for several decades. Over the last decade, a large number of investigations have been carried out to delineate the spatial distribution and to characterize the chemical compositions of high As and F groundwaters with a focus on several inland basins in north China. Findings from these studies, including improved understanding of the hydrogeological and geochemical factors resulting in their enrichments, have been applied to guide development of clean and safe groundwater in these endemic disease areas. Survey efforts have led to the recognition of iodine in groundwater as an emerging public health concern. This paper reviews the new understandings gained through these studies, including those published in this special issue, and points out the direction for future research that will shed light on safe guarding a long-term supply of low As and F groundwater in these water scarce semi-arid and arid inland basins of north China.