Drinking water Technology, Eawag, developed a method by which hazard maps could be produced for geogenic toxic substances in groundwater. This provides an efficient way of determining which wells should be tested. Parameters for drinking water quality typically fall within three categories: Physical and chemical parameters include heavy metals, trace organic compounds, total suspended solids (TSS), and turbidity. Microbiological parameters include Coliform bacteria, "E. coli", and specific pathogenic species of bacteria (such as cholera-causing "Vibrio cholerae"), viruses, and protozoan parasites. Chemical parameters tend to pose more of a chronic health risk through buildup of heavy metals although some components like nitrates/nitrites and
Tianji Coal Chemical Industry Group chemical spill Tianji Coal Chemical Industry Group chemical spill The Tianji Coal Chemical Industry Group chemical spill was a severe chemical spill that occurred in Shanxi Province, China during 2012–2013. More than 39 tons of anilines (toxic chemicals widely used as precursors in the manufacture of pigment, herbicides and other chemicals) leaked from a loose drainage valve at a plant owned by Tianji Coal Chemical Industry Group in the Shanxi city of Changzhi. This chemical spill contaminated the Zhuozhang River which is the source of drinking water for more than one million people, and so caused a water crisis in the downstream