Manure becomes pollutant as its volume becomes unmanageable

The Washington Post reported recently that the United States has significantly reduced human-sourced pollutants over the last 40 years that once left rivers and lakes dead, discolored and occasionally flammable, but now has "managed to smother the same waters with the most natural stuff in the world."

A March 1 feature story by David Fahrenthold pointed out that animal manure, a byproduct of the new breed of megafarms, has become an unlikely modern pollution problem, according to scientists and environmentalists. Livestock now produce three times as much waste as people, more than can be recycled for nearby fields.

That excess manure gives off air pollutants and "it is this country's fastest-growing large source of methane, a greenhouse gas."

What's more, it washes down stream then down river with rains, helping to cause the 230 oxygen-deprived "dead zones" that have spread along the U. S. coast. In the Chesapeake Bay, about one-fourth of the pollution that leads to dead zones can be traced to "the back end of cows, pigs, chickens and turkeys."

Contributing to the problem, manure has not been as strictly regulated as more familiar pollution problems, like human sewage, acid rain or industrial waste. "The Obama administration has made moves to change that but already has found itself facing off with farm interests, entangled in the contentious politics of poop."

The saga of manure "is already a gloomy counterpoint to the triumphs in fighting pollution since the first Earth Day in 1970. An air pollutant that causes acid rain has been cut by 56 percent. By one measure, the output from sewage plants got 45 percent cleaner."

But, according to Cornell University researchers, the amount of one key pollutant -- nitrogen -- entering the environment in manure has increased by at least 60 percent since the 1970s.

The Environmental Protection Agency has signalled an intent to tighten its grip on regulating manure. On Feb. 22, the agency announced that reducing manure-laden runoff was one of its six "national enforcement initiatives." New rules went into effect last December that will impose even tighter restrictions on large farms.