NingXia Region(China) Drinking Water Problem
NingXia Region(China) Ground Water Quality
https://www.ncbi.nlm.nih.gov/pubmed/25990719
Radium in Drinking Water
http://pittsburgh.cbslocal.com/2018/01/11/radium-drinking-water-interactive-map/
USEPA 2015 Update: Drinking Water Contaminant Enforceable Standards
http://water.epa.gov/drink/contaminants/index.cfm
WHO 2011 Guidelines for Drinking-Water Quality
http://www.who.int/water_sanitation_health/publications/2011/dwq_guidelines/en/
USEPA Info. on Private Drinking Water Wells
http://water.epa.gov/drink/info/well/index.cfm