Unmanageable Manure

From the Washington Post:

Nearly 40 years after the first Earth Day, this is irony: The United States has reduced the manmade pollutants that left its waterways dead, discolored and occasionally flammable. But now, it has managed to smother the same waters with the most natural stuff in the world.

Animal manure, a byproduct as old as agriculture, has become an unlikely modern pollution problem, scientists and environmentalists say. The country simply has more dung than it can handle: Crowded together at a new breed of megafarms, livestock produce three times as much waste as people, more than can be recycled as fertilizer for nearby fields.

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

And it washes down with the rain, helping to cause the 230 oxygen-deprived "dead zones" that have proliferated 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 ends of cows, pigs, chickens and turkeys.

Despite its impact, 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...

"We now know that we have more nutrient pollution from animals in the Chesapeake Bay watershed" than from human sewage, said J. Charles Fox, the EPA's new Chesapeake czar. "Nutrients" is the scientific word for the main pollutants found in manure, treated sewage, and runoff from fertilized lawns. They are the bay's chief evil, feeding unnatural algae blooms that cause dead zones...

The reasons for manure's rise as a pollutant have to do, environmentalists say, with a shift in agriculture and a soft spot in the law.

In recent decades, livestock raising has shifted to a smaller number of large farms. At these places, with thousands of hogs or hundreds of thousands of chickens, the old self-contained cycle of farming -- manure feeds the crops, then the crops feed the animals -- is overwhelmed by the large amount of waste.

The result in farming-heavy places has been too much manure and too little to do with it. In the air, that extra manure can dry into dust, forming a "brown fog." It can emit substances that contribute to climate change.

And it can give off a smell like a punch to the stomach. The way that modern megafarms produce it, Henning said, "Manure is no longer manure. Manure is a toxic waste now."

In the water, the chemicals in manure don't poison life, like pesticides or spilled oil. Instead, they create too much life, and the wrong kinds...

The chemicals in manure serve as fertilizer for unnatural algae blooms. They drain away oxygen as they decompose. Scientists say the number of suffocating dead zones -- oxygen-depleted areas where even worms and clams climb out of the mud, desperate to respire -- has grown from 16 in the 1950s to at least 230 today. The Chesapeake's is usually the country's third largest, after the Gulf of Mexico and Lake Erie...