Magazine article Endangered Species Bulletin

CAFOs Feed a Growing Problem

Magazine article Endangered Species Bulletin

CAFOs Feed a Growing Problem

Article excerpt

Some CAFOs are in locations that may result in take of species and habitats protected by the Endangered Species Act. In California, an 11 million gallon (42 million liter) spill of liquid waste from a large poultry farm damaged a wetland vernal pool system in the Arena Plains Unit of Merced National Wildlife Refuge, killing endangered vernal pool fairy shrimp (Branchinecta lynchi) and vernal pool tadpole shrimp (Lepidurus pochardi). This resulted in a large fine, some of which went for acquisition of prime habitat for the refuge as compensation for damages to natural resources.

While eating their favorite hamburgers, chicken, or pork chops, people seldom stop to think about where these foods originate. If they do, a small family farm may come to mind. But that traditional picture is changing with the trend towards large, corporate agricultural operations.

The number of livestock animals concentrated in large concentrated animal feeding operations, or CAFOs, has increased dramatically in the last decade. During a 10-year period in California, the number of swine CAFOs decreased by 50 percent but the number of animals per operation rose 200 percent. Such CAFOs often house thousands of animals: in Texas, for example, nearly half of the permitted beef cattle CAFOs hold more than 16,000 animals. Because CAFOs are often clustered, local watersheds can be overloaded with nutrients, and possibly other contaminants, from discharges and run-off. Waste from animal feeding operations is degrading water quality and air quality in many areas of the country, from California to the Carolinas. The impacts from CAFOs may be both long-term and catastrophic.

Chronic, excessive discharge of nutrients over a long period of time leads to algal blooms, which lower dissolved oxygen levels in streams and lakes. These oxygen depleted waters are more suitable for species that are tolerant of poor water quality, less suitable for most sport fish or sensitive species, and usually result in lower species diversity.

Elevated levels of organic nutrients may favor proliferation of the microbe Pfisteria, which can kill fish and may even threaten human health. Excessive input of nutrients and anaerobic bottom sediments may also provide vectors for animal diseases such as Salmonella, Staphylococcus, Streptococcus, avian botulism (Clostridium botulinum), and avian cholera (Pasteurella multocida), microorganisms that can kill large numbers of waterfowl. Bacteria and other disease-causing organisms from CAFOs could also pose a health risk for people and wildlife, including direct or indirect adverse impacts on migratory bird populations. Ground water can also be polluted by excess nitrates and other contaminants that leach through the soil over time.

Accumulations of heavy metals and other contaminants may cause chronic problems affecting the health and reproduction of many aquatic and avian species, and contribute to water quality impairment and harm to aquatic organisms in local waterways. Some of the heavy metals in feed additives, such as zinc, copper, arsenic, nickel, manganese, and selenium, will end up in animal wastes and be concentrated in holding ponds and/or spread on fields as fertilizers. Concentrations of selenium (a trace mineral necessary in low levels. but toxic in high levels) in surface waters of some CAFO waste storage pits or lagoons exceed safe levels for aquatic life by tenfold. Runoff or uncontrolled releases from CAFOs can transport selenium to natural water bodies, where it can increase in concentration as it makes its way up the food chain and may reach toxic levels in fish and other aquatic organisms. …

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