Urban vs Rural - 4

[timelets]

It used to be — due to large-scale factory production — that cities were unhealthy, while the countryside had clean air and water. No more:

One in seven Americans drink from private wells, according to the U.S. Geological Survey. Nitrate concentrations rose significantly in 21% of regions where USGS researchers tested groundwater from 2002 through 2012, compared with the 13 prior years. The greatest increases were in agricultural areas. More recent sampling shows the pattern is continuing, at a potentially greater rate.
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Runoff from fields is largely exempt from federal regulation. Many water utilities in the Midwest are struggling to pay for flushing farm runoff from their systems, say scientists and utility managers. Close to 500 public water systems in the U.S. exceeded federal nitrate limits in 2016, according to Environmental Protection Agency data.
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Larger dairies produce more milk at a greater scale. Cows today are bigger than in the past, so they eat—and excrete—more. Milk production per cow more than doubled between 1970 and 2017, according to the USDA. Farmers are growing less alfalfa to feed their animals and more corn, which requires more nitrogen fertilizer.

https://www.wsj.com/articles/farms-more-productive-than-ever-are-poisoning-drinking-water-in-rural-america-11547826031

I have a hypothesis about the impact of infrastructure costs related to the services economy, but I don't know how to prove it yet.