Environmental Effects of Factory Farming

In the United States an estimated 10 billion farm animals are born, raised and slaughtered each year for food in the factory farming system.  All these animals produce a big problem for factory farm owners: manure.  To give you an idea of how immensely large this problem is, take the pork industry for example.  A typical 200 lb pig produces approximately 13 lbs of manure a day.  With 100 million pigs in factory farms in the U.S., that amounts to 650,000 tons of manure produced PER DAY in the pork industry alone!

The EPA has estimated that all confined animals generate 3 times more raw waste than is generated by humans in the U.S.

Where does all this waste end up?

On a typical farm, the balance of nature is kept in check by recycling the animal waste and using it as fertilizer.  The manure is spread onto fields to fertilize the crops and it is absorbed into the ground at a sustainable rate.  In a factory farm system, this balance cannot be maintained due to the vast amount of animals in a small confined area.  Typical methods of dealing with the overabundance of animal waste include storing it liquefied form in open-air holding pits, known as lagoons and spraying the waste over nearby land.

Land and Water Pollution

When your factory farm produces tons of waste each week, what do you do with it all?  Unlike human waste, livestock manure does not undergo processing for sanitation.  Typically, it’s mixed with water to form a liquid and held in manure lagoons and then sprayed onto nearby land.   Lagoons are sealed and protected with earthen embankments to protect from leaks and spills, but the system is not perfect.  Leaks can cause the liquefied waste to seep into groundwater and overflows caused by excessive rain or storms can send the waste flowing to nearby lakes and rivers.   One study conducted by North Carolina State University in 1995 estimated that as many as 55% of the manure lagoons on hog farms in that state were leaking.

Manure lagoons at an Indiana CAFO. Photo by Peter McBride. Photo Credit: ELPCenter on Flickr

On August 10th, 2005, the earthen walls of the manure lagoon collapsed and 3 million gallons of liquid cow waste poured into the Black River and polluted an area one-fourth the size of the Exxon Valdez oil spill. New York state environmental officials estimate that the spill killed upwards of 200,000 to 250,000 fish.

Manure pits have also been known to claim the lives of farm workers.  Between 1992 and 1997 at least twelve workers died due to asphyxiation by manure gases and drowning while trapped in manure lagoons.

According to the EPA, the agricultural sector is “the leading contributor to identified water quality impairments in the nation’s rivers and streams, lakes, ponds, and reservoirs.”

Since livestock manure is not treated like human waste, all the feed additives and antibiotics that have been fed to the animals is released into the environment as well.  Roughly 29 million pounds of antibiotics – about 80 percent of the nation’s antibiotics use in total – are added to animal feed every year to speed livestock growth. These antibiotics are released into the environment along with animal waste and contribute to the rise of drug resistant bacteria.

The EPA reports that the waste generated by animal agriculture has polluted over 35,000 miles of river in 22 states.

Air pollution

In 2004, the EPA estimated that 20% of all man-made methane production resulted from livestock digestion, primarily cows.  On factory farms and feedlots, cows are fed low quality grain-based feed that their bodies were not designed to digest; causing chronic indigestion that contributes to high methane emissions.

Pigs behind barsThe process of breaking down organic compounds in manure can also contribute to air pollution.  Manure lagoons emit hydrogen sulfide, which can cause symptoms such as nausea, headaches, vomiting and severe diarrhea.  Exposure to extreme amounts of hydrogen sulfide can bring on life-threatening pulmonary edema, or fluid accumulation in the lungs.   The National Institute for Occupational Safety and Health (NIOSH) has deemed hydrogen sulfide to be “a leading cause of sudden death in the workplace”.

Factory farms are also a leading producer of ammonia, which causes respiratory health problems even at very low levels.  Ammonia is formed by decomposing manure and in manure lagoons, it is found in extremely high amounts which affect factory farm workers and the surrounding communities.

What can you do?

There is clearly a lack of balance between factory farms and the environment.  High concentrations of animals combined with the copious amount of waste the produce is quickly becoming a threat to the environment.  Here’s how you can help:


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