Pollution from Giant Livestock Farms Threatens Public Health
Waste lagoons and manure sprayfields — two widespread and environmentally hazardous technologies — are poorly regulated.
Giant livestock farms that are known as Concentrated Animal Feeding Operations or CAFOs house thousands of cows, chickens or pigs and produce staggering amounts of animal manure. The way these wastes are stored and used has profound effects on human health and the environment.
A giant factory farm in North Carolina; the brown rectangle at left is a waste lagoon.
On most factory farms, animals are crowded into relatively small areas; their manure and urine are funneled into massive waste lagoons. These cesspools often break, leak or overflow, sending dangerous microbes, nitrate pollution and drug-resistant bacteria into water supplies. Factory-farm lagoons also emit toxic gases such as ammonia, hydrogen sulfide and methane. What’s more, the farms often spray the manure onto land, ostensibly as fertilizer — these “sprayfields” bring still more of these harmful substances into our air and water.
Yet in spite of the huge amounts of animal wastes that factory farms produce, they have largely escaped pollution regulations; loopholes in the law and weak enforcement share the blame. NRDC has fought, and won, a number of courtroom battles over the years to force the federal government to deal with the problem of factory farms, but more protections are needed to adequately protect public health and the environment from CAFO pollution.
Threats to Human Health
People who live near or work at factory farms breathe in hundreds of gases, which are formed as manure decomposes. The stench can be unbearable, but worse still, the gases contain many harmful chemicals. For instance, one gas released by the lagoons, hydrogen sulfide, is dangerous even at low levels. Its effects — which are irreversible — range from sore throat to seizures, comas and even death. Other health effects associated with the gases from factory farms include headaches, shortness of breath, wheezing, excessive coughing and diarrhea.
Animal waste also contaminates drinking water supplies. For example, nitrates often seep from lagoons and sprayfields into groundwater. Drinking water contaminated with nitrates can increase the risk of blue baby syndrome, which can cause deaths in infants. High levels of nitrates in drinking water near hog factories have also been linked to spontaneous abortions. Several disease outbreaks related to drinking water have been traced to bacteria and viruses from waste.
On top of this, the widespread use of antibiotics also poses dangers. Large-scale animal factories often give animals antibiotics to promote growth, or to compensate for illness resulting from crowded conditions. These antibiotics are entering the environment and the food chain, contributing to the rise of antibiotic-resistant bacteria and making it harder to treat human diseases.
Threats to the Natural Environment
LAGOONS AND SPRAYFIELDS
Some people hear the word “lagoon” and picture blue water, surrounded by palm trees, perhaps, or with mountains in the background. A visit to a factory farm would quickly erase this beautiful image from their minds.
At factory farms, “lagoon” means an open-air pit filled with urine and manure. Lotsof urine and manure — some lagoons are larger than seven acres and contain as much as 20 to 45 million gallons of wastewater. The waste is collected with scrapers, flushing systems, or gravity flow gutters, and then stored in lagoons. Opportunities for disaster abound. The lagoons can leak or rupture, for instance, or they can be filled too high and overflow after a rain. But even if none of these problems occur, the lagoons still release gases. Their horrible stench and toxic chemicals harm workers and nearby residents.
Sprayfields are yet another threat. Manure is periodically pumped out of lagoons and sprayed on fields. Although manure can be an excellent fertilizer when it is applied at rates that crops can absorb, it must be safely — and sensibly — applied. But factory farms produce far more manure than their land requires, and they often overapply it to fields as a way to get rid of it, causing it to run off the fields and into rivers and streams. Farmers may also spray when it is rainy or windy, or with little regard for adjacent property. In addition, the act of spraying wastes increases evaporation and vaporization of pollutants.
The natural environment also suffers in many ways from factory-farming practices. Sometimes the damage is sudden and catastrophic, as when a ruptured lagoon causes a massive fish kill. At other times, it is cumulative — for example, when manure is repeatedly overapplied, it runs off the land and accumulates as nutrient pollution in waterways.
Either way, the effects are severe. For instance, water quality across the country is threatened by phosphorus and nitrogen, two nutrients present in animal wastes. In excessive amounts, nutrients often cause an explosion of algae that robs water of oxygen, killing aquatic life. One toxic microorganism, Pfiesteria piscicida, has been implicated in the death of more than one billion fish in coastal waters in North Carolina.
Manure can also contain traces of salt and heavy metals, which can end up in bodies of water and accumulate in the sediment, concentrating as they move up the food chain. And lagoons not only pollute groundwater; they also deplete it. Many factory farms use groundwater for cleaning, cooling and providing drinking water.
Better Alternatives Exist
Practical remedies to these problems do exist. But implementing them will require some important changes in factory farm practices and government oversight:
RELATED NRDC WEBPAGES:
How factory farm lagoons and sprayfields threaten environmental and public health.
Updates on animal agriculture issues and efforts to replace factory farms; good links
Information on Waterkeeper’s campaign against factory farms.
Lets you look at the amount of animal waste produced in your state and the trends over time; good links as well
News, reports and fact sheets from the Sierra Club’s campaign
Information on Clean Water Act permitting and factory farms