Vegetarian Guide

Vegetarians and the Environment

How Factory Farming Pollutes Water and Soil

  • This excessive use of water can create stresses for already depleted water sources in some communities where factory farms locate. It is also lowering the levels in aquifers -- the Ogallala aquifer, which is the largest aquifer in the United States and supplies water from Texas up to South Dakota, is not recharging itself as fast as water is being extracted. It's been estimated that the over 174,000 square miles of water will be used up in the next 50 years due to unsustainable practices, including those from factory farms.2
  • Factory dairy farms create large amounts of liquid and solid waste. One 1,200 pound dairy cow alone produces the same amount of waste as 23 humans.3 That means a dairy farm with 10,000 cattle will produce the same amount of manure waste as a city of 230,000 humans.
  • The EPA reports that the waste generated by hogs, chicken, and cattle has polluted over 35,000 miles of river and has contaminated groundwater in 17 states (out of the 22 states reporting animal waste figures).4
  • The EPA estimate that agriculture pollution "degrade[d] aquatic life or interfere[d] with public use of 173,629 river miles (i.e. 25% of all river miles surveyed) and contribute[d] to 70% of all water quality problems identified in rivers and streams."5
  • According to a study performed by researchers from the Department of Economics at the University of Essex, the annual cost of environmental damage caused by industrial farming in the U.S. is $34.7 billion.6
  • The vast amounts of waste produced by mega dairies can overwhelm the ability of local soils and crops to absorb the nutrients, resulting in runoff and ground and surface water contamination. Runoff from factory dairy farms can flow from silage, stockpiled manures, barns, and accidental and intentional releases. Runoff from manure on frozen ground can result in significant levels of fecal coliform. In two watersheds in Virginia, over 80% of fecal streptococci were from domestic livestock.7
  • Dairy waste is often mixed with water and flushed into large open holes called lagoons. Studies show that groundwater quality can be endangered near factory farms due to leakage and seepage from lagoons which are large holes that store and minimally treat the waste after it is flushed and mixed with water. Results from a preliminary study from seven dairy feedlots over six years point to significant contamination from lagoons. Elevated levels of nitrate, ammonia, chloride, nitrogen and total dissolved solids were discovered in nearby monitoring wells. The study concluded that the mean concentration for all contaminants increased as dairy herds increased.8
  • Waste lagoons, even with clay liners, allow contaminants to leach into the ground below the lagoon. At the maximum allowable rate a three-acre lagoon could legally leak more than a million gallons a year.9 Seepage from manure holding basins and lagoons can have a serious impact on ground water quality, especially from nitrate and ammonium. Even lined basins and lagoons, though properly constructed, can be a hazard when constructed in coarse textured soils or sandy porous limestone.10
  • Animal waste from factory farms contains nitrogen and phosphorus compounds called nutrients that can flow into groundwater and wells, making water unsafe for drinking. Runoff can also contain harmful pathogens that can cause human disease and death.11 Too much phosphorus is extremely toxic to fish; at lower levels, both will over-enrich water and create an excess of algae. These algae can kill fish and marine life. Too much manure in water also leads to oxygen depletion. This can suffocate fish, or suffocate the food fish eat, thus starving the fish.
  • Too many nutrients have also led to the emergence of Pfiesteria piscicida, a microorganism that has killed millions of fish by attaching to their bodies and eating away their flesh. Fish from North Carolina up through the Delaware Bay have been caught or found with huge, gaping holes and sores on their body. Human exposure to Pfiesteria can cause memory loss, confusion, headache, skin rash, burning, eye irritation, upper respiratory irritation, muscle cramps and gastrointestinal symptoms.12 Anyone can become infected with Pfiesteria by coming in contact with infected water or fish.
  • As nitrogen from lagoons changes to gas and escapes into the air, it changes into ammonia. North Carolina alone emits at least 186 tons of ammonia into the air each day. About half of the ammonia created rises as a gas and generally falls as rain or fog to the forests, fields or open water within 50 miles. The rest is transformed into small dry particles which can travel over 250 miles away. Traces of pure urine have actually been found in rainwater.13
  • Studies from an independent scientific organization show a link between higher contaminations of well water near factory farms. Water from wells used by low income residents in the Lower Yakima Valley, Washington have been tested this past year by the Valley Institute for Research and Education (VIRE). The study reveals a direct correlation between the location of large confined dairy operations and the pollution of private wells with E. Coli and high nitrate concentrations.14
  • Studies now show that pathogen loading of a concentrated operation such as a dairy is significantly higher than that of rangeland fed cattle. Pathogens such as fecal coliform, E. coli, girardia lambia, and cryptosporidium exist in dairy manure, which can result in human illness if manure discharges or runoff occurs. Four outbreaks of cryptosporidium have been linked to non-point agricultural pollution.15
  • Dr. Stephen D. Arnold, from New Mexico State University provides data on the impact of dairies in a recent preliminary study measuring dairy feedlot contributions to groundwater contamination. Results from this study that analyzed groundwater quality data from seven dairy feedlots over a six-year period point to significant contamination problems. This study found elevated levels of nitrate, ammonia chloride, nitrogen, and total dissolved solids. The mean concentrations for all contaminants tended to increase as the size of the dairy herds increased.
  • Heavy metals are added to livestock feed. For example, zinc and copper are added to hog and poultry feed to prevent disease and aid digestion. Cadmium and selenium are also used because they’ve been found to promote growth in low doses. Animals can only absorb 5-15% of the metals they ingest so the majority is excreted in manure, which absorbs into the soil but also runs off into the water.16 Plants can absorb some of the metals, but a significant quantity builds up in the soil. This can stunt plant growth and can also poison grazing animals, which tend to ingest soil when grazing.17 This sort of heavy metal pollution is almost irreversible.
  • Another preliminary study has recently been conducted to evaluate the health impact of dairy farms on surrounding rural communities in Southern New Mexico. In addition to groundwater contamination, other health concerns for rural populations surrounding dairy farms include odor, flies, and dust.
  • The results of the Southern New Mexico study identified an association between living close to a dairy and a higher reported rate of diarrhea and asthma in children during the preceding three months. Several new studies have been released in the past few years regarding residents who live in the vicinity of hog factories. The preliminary results of this mimic the findings in research which demonstrates that residents are experiencing health problems due to intensive livestock operations.
  • Flies can be a significant agents or mechanical carriers of disease and control of fly populations on dairies is difficult. The normal travel range of flies is one to two miles. Flies can spread a host of diseases dangerous to man, including salmonella, diarrhea, gastroenteritis, amoebic dysentery, and conjunctivitis.18 Flies have recently been linked as a vector for cryptosporidium parvum. Two studies used infected bovine feces to yield these results. The studies suggest that if infected flies land on food, cryptosporidosis could also be a significant food borne infection.19
  • Manure from factory farms can also degrade soil quality; since heavy metals are added to animal feed in order to promote growth, manure can contain trace amounts of metals such as arsenic, copper, selenium, and zinc. The high concentration of manure in factory farm lagoons enable heavy metals to accumulate in the surrounding environment, contaminating soil, poisoning wildlife, and polluting groundwater.20


1. Weida, William J. “A citizens Guide to the Regional Economic and Environmental Effects of Large Concentrated Dairy Operations,” GRACE Factory Farm Project November, 19, 2000.

2. Halverson, Marlene. "The Price We Pay For Corporate Hogs." Institute for Agriculture and Trade Policy, March 2001 (Second Printing), p. 51.

3. United States Environmental Protection Agency.
Environmental Protection Agency and Department of Agriculture. “Draft Unified National Strategy for Animal Feeding Operation,” EPA and USDA. September 11, 1998.

4. Congressional Legislative Information (OCIR). "Legislative Hearings and Testimony: Statement of Michael Cook before the subcommittee on livestock, dairy, and poultry and the subcommittee on forestry, resource conservation, and research of the committee on agriculture U.S. House of Representatives." May 13, 1998.

5. Norberg-Hodge, Helena , Todd Merrifield, and Steven Gorelick. Bringing the Food Economy Home: Local Alternatives to Global Agribusiness. Bloomfield, CT: Kumarian Press, Inc. 2002.

6. Weida, William J. “A citizens Guide to the Regional Economic and Environmental Effects of Large Concentrated Dairy Operations,” GRACE Factory Farm Project November, 19, 2000. p.36.

7. Arnold, Stephen D. and Edward Meister, PhDs. “Dairy Feedlot Contributions to Groundwater Contamination,” Environmental Health, September 1999. Abstract, p.16.

8. Weida, William J. “A citizens Guide to the Regional Economic and Environmental Effects of Large Concentrated Dairy Operations,” GRACE Factory Farm Project November, 19, 2000p. p.36.

9. Ibid.

10. Ibid.

11. Ibid., p 26.

12. Buck, Eugene H., Claudia Copeland, and Jeffery A. Zinn. “Pfiesteria and Related Algal Blooms: Natural Resource and Human Health Concerns,” Congressional Research Service (CRS). December 1997.

13. Halverson, Marlene. The Price We Pay For Corporate Hogs. Institute for Agriculture and Trade Policy, March 2001 (Second Printing).

14. Press Release CARE, January 13, 2003 Helen Reddout CARE Charles Tebbut Western Environmental Law Center.

15. Weida, William J. “A Citizens Guide to the Regional Economic and Environmental Effects of Large Concentrated Dairy Operations,” GRACE Factory Farm Project November, 19, 2000, p. 33.

16. Steinfeld, Henning. “Livestock-Environment Interactions in Industrial Production Systems.” Proceedings of the International Conference on Livestock and the Environment. Food and Agriculture Organization. June 1997.

17. Halverson, Marlene. The Price We Pay For Corporate Hogs . Institute for Agriculture and Trade Policy, March 2001 (Second Printing), p 48.

18. Arnold, Stephen PhD. “Dairy Herds and Rural Communities in Southern New Mexico.” Environmental Health, July-August 1999, p.11.

19. Hyde, Barbare. “Flies Implicated as vector for Cryptosporidium,” Press Release: American Society for Microbilolgy November 2, 2000.

20. Marks, Robbin. "Cesspools of Shame: How Factory Farm Lagoons and Sprayfields Threaten Environmental and Public Health." Natural Resource Defense Council (NRDC). July 2001.


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