DES MOINES, Iowa (AP) - A study shows Iowa leads the nation in the amount of human and animal waste it produces.
Christopher Jones is a scientist at the University of Iowa. The Des Moines Register reports that Jones' study shows the state of 3.2 million people and total livestock population of nearly 110 million produces as much manure as a human population of 168 million.
His study indicates pigs are responsible for driving the state to the top of the rankings. Jones writes in a blog on the university's website that Iowa is home to at least 23 million pigs.
In another study, Jones found that growth in the state's livestock population has led to a doubling of nitrate levels in two western watersheds near the largest concentrations of pigs and cattle.
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