File talk:Arsenic contamination areas.jpg

Missing USA information

See the USA graphic of arsenic contamination of groundwater from the Center for Public Integrity posted in article at Michigan's arsenic problem is among the worst in the nation. Here's why. Wikipedia needs an updated map to reflect the more extensive situation in the USA reflected in the CPI graphic. -- Paleorthid (トーク)

The Michigan region (subject of the article with the graphic) is interesting in terms of groundwater As in that the most egregious arsenic contamination is being tied to anaerobic failure of soil resulting from improper (excessive loading of BOD) land treatment of high strength wastewater. this article says "The accumulation of juice wastes sprayed over more than 40 years on fields behin [sic?] the plant caused a condition in the soil that releases naturally occurring iron, manganese and arsenic particles into groundwater, according to the MDEQ. Monitoring wells near the former spray fields have shown levels of these heavy metals above current federal limits. There is a plume of heavy metals and contaminants that has tainted more than 20 wells east of the plant."

That "...condition in the soil..." is a reduced chemistry (see en:redox), the significance being that in wetlands, in the soil bottom of water storage lagoons, in en:cesspits, all common features worldwide, ionic forms of reduced iron, manganese and arsenic are soluble in water, allowing these metals to migrate with water, and to concentrate in groundwater. Although the article refers to allegations and an unresolved lawsuit, the science is settled: en:arsenic contamination of groundwater, like iron contamination of groundwater is connected to redox chemistry. My understanding of the science that I have as a soil scientist working with land application of wastewater is accurately stated by this 2009 article accurately states: "The spraying of the large amount of juice waste robs the soil of oxygen and causes natural-occurring metals in the soil, including arsenic, to collect in amounts that can be hazardous in drinking water." -- Paleorthid (トーク) 18:30, 17 February 2019 (UTC)