Nitrate levels at a Columbus water treatment facility increased overnight, according to city officials, who said the no-drink advisory for pregnant women and infants younger than 6 months has been continued.
The defensive expenditure model predicts that in the presence of an adverse event the demand for substitute goods will increase. In this case, we would expect the demand for bottled water to increase in reaction to the increased nitrate levels in Columbus drinking water. The demand increase should increase the price of bottled water.
We would also expect farmers to deny they have anything to do with nitrate levels in drinking water.
But that's a different theory.