Health Issues Associated With Factory Farms
"Concentrated Animal Feeding Operations: Public Health and Community Impacts"
Iowa's Center for Agricultural Safety and Health Institute for Agriculture and Trade Policy Respiratory and Other Illnesses
More than 25 studies of CAFO workers show that 25-30% of workers report serious respiratory problems (5,8), some of which are due to toxins (e.g., endotoxin, glucans) from inhaled microbes. CAFO air emissions may also be a public health hazard. Iowans living within a two-mile radius of a 4,000-hog unit reported more respiratory and other symptoms than did people not living near a CAFO. North Carolina residents near a 6,000-feeder pig unit reported more symptoms (respiratory, diarrhea, headaches, burning eyes) than did residents in a non-livestock area. Utah residents near a large hog unit had more respiratory and diarrheal illnesses than did people in comparison areas and Utah as a whole.
Neurological and Mood Problems
The brain and nervous system help regulate human sensory and thought processes, moods, and behavior. Air emissions from hog CAFOs include hydrogen sulfide (H2S), an irritant and toxin to this system. Workers exposed to 5 parts per million (ppm) or more of H2S are likely to have accelerated deterioration of neurobehavioral function. Low levels of H2S may be more harmful than previously thought. People exposed to .1-1 ppm of H2S at home revealed neurobehavioral dysfunction, including abnormal balance and grip strength, and delays in verbal recall. Generally, H2S odors only become noticeable and detectable at slightly lower levels of .025-.1 ppm. H2S monitoring at a medium-sized CAFO in Minnesota revealed regular emissions high enough to cause nausea, headaches, and diminished quality of life among neighbors. Neighbors of a North Carolina hog CAFO reported more confusion, tension, depression, and fatigue than did others not exposed.
Numerous CAFO wastes contribute to odor pollution, which, even at low concentrations, can cause gastrointestinal, stress-related, and respiratory symptoms, including by interacting with the brain and organ systems. Compared to people in areas of dairies or no livestock, neighbors of swine CAFOs were less often able to go outside or open windows in nice weather.
Water contamination from CAFOs, from nitrogen, phosphorus, microbes, and antibiotics, may increase with concentration of livestock and liquid manure storage and spreading. Contamination risk may decrease with less livestock concentration, proper waste management, and well-planned CAFO siting that considers regional water quality and avoids sandy soils, shallow groundwater, and flood plains. Manure contains high levels of nitrogen (N) and phosphorus (P). N is: 1) emitted to air as ammonia vapor, 2) incorporated into soil where plants absorb it, and 3) transported into water where microorganisms metabolize it. Microbial breakdown of N in manure forms nitrates, which contaminate many private wells in some rural areas. Elevated nitrates in drinking water can cause blue baby syndrome, which harms infants by reducing the oxygen carried by blood. Nitrates may combine with amino acids in the human gut to form nitrosamines, suspected carcinogens. N emitted to air can precipitate, leading to contaminated surface water, decline of native plants, and overgrowth of undesirable species. P from manure often exceeds ecological capacity and may reduce oxygen in water, enhancing growth of algae and the organism Pfiesteria piscida. These problems can diminish the usability of waterways, including for recreation, and impair human health and quality of life. Animal waste may carry infectious organisms including Campylobacter, Escherichia coli (E coli), and Salmonella, significant causes of food-borne illness in humans. E coli bacteria have been carried downstream by surface runoff and can survive semi-arid conditions. Tetracyclineresistant genes have been found in lagoons and groundwater underlying swine CAFOs. 25-75% of antimicrobials given to CAFO livestock pass unchanged into manure waste and may contaminate soil and water.
CAFOs' widespread use of antimicrobials in animal feed contributes to increasing bacterial resistance, which is transmitted to humans typically, but not only, via contaminated food. Most of these antimicrobials are identical or nearly so to drugs used in human medicine. More and more humans are infected with bacteria that respond poorly or not at all to treatment with those same antimicrobials or closely related drugs. An estimated 70% of antimicrobials used in the US are fed to livestock, in the absence of disease, to promote growth and compensate for the stress and health risks of confinement.
As large-scale CAFOs concentrate in an area, rural communities often experience related declines in local business purchases, physical infrastructure, and population. Sales values of real estate and homes tend to decline with proximity to CAFOs. Decreases in neighborliness, social cohesion, and democratic values are documented. CAFOs in North Carolina and Mississippi are often sited in poor and African American rural communities, causing disproportionate adverse health and socioeconomic impacts. Many farmers and rural residents are concerned that large-scale, vertically-integrated CAFOs are undermining the socioeconomic structures supporting family farms and rural communities. They question the government policies related to tax incentives, cheap grain, subsidization of manure management, and non-competitive markets that favor vertically-integrated CAFOs over family farm producers. Sustainable alternatives in livestock production, processing, marketing, and related public policies are being developed in many states and nations.
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