Provided by the Organic Trade Association
Fertilizers and the Health of Aquatic Systems
Because organic agriculture respects the balance of microorganisms in
the soil, organic producers use composted manure and other natural materials, as well as
crop rotation, to help improve soil fertility, rather than synthetic fertilizers that can
result in an overabundance of nitrogen and phosphorous in the ground. As a result, organic
practices help protect ground water supplies and avoid runoff of chemicals that can cause
"dead zones" in larger bodies of water.
- "Organic farming can help reduce ground and surface water contamination, and can
safeguard drinking water supplies in certain areas, thus contributing to food safety
in a larger sense and sustainable agriculture."
Source: "Food Safety and Quality as Affected by Organic Farming," 22nd FAO Regional
Conference for Europe, Porto, Portugal, July 24-28, 2000, Agenda Item 10.1.
- Farm comparisons in Europe have shown nitrate leaching rates on organic farms are
40-57% lower per hectare and carbon dioxide emissions are 40-60% lower per hectare than
conventional systems, according to a comprehensive European-wide literature review.
Source: "Environmental and resource use impacts of organic farming in Europe," by
Stolze, Piorr, Haring and Dabbert, 2000.
On the other hand, current conventional practices have led to some measurable
problems:
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Nitrates in drinking water are statistically associated with an increased risk of
bladder cancer at levels lower than the U.S. EPA standard of 10 parts per million
(ppm), according to a University of Iowa Study of almost 22,000 women. Long-term
heavy use of nitrogen fertilizers in Iowa has resulted in nitrate concentrations
in excess of 5 ppm in 30-40 percent of the state's municipal water supplies, according
to a study published in Epidemiology. Peter Weyer of the University of Iowa's Center
for Health Effects of Environmental Contamination, and colleagues analyzed cancer
incidences in women participating in the Iowa Women's Health Study, and found that
women drinking water with average nitrate levels greater than 2.46 ppm were 2.83
times more likely to develop bladder cancer than women exposed to 0.36 ppm of
nitrates in water.
Source: Epidemiology, Vol. 11(3): 327-338, May 2001.
- The report "Waste Lands: The Threat of Toxic Fertilizer" noted that many commercial
fertilizers contain toxic metals. An analysis of 29 fertilizers found that each contained
22 different heavy metals. In 20 of the products, levels exceeded the limits set on wastes
sent to public landfills, with disturbing quantities of arsenic, lead, mercury, cadmium,
chromium, and dioxin, among others.
Source: "Waste Lands: The Threat of Toxic Fertilizer," U.S. Public Interest Research
Group, May 2001, available at www.pirg.org/toxics/reports/wastelands.
- A 2001 report has found that polluted runoff from farms and cities went largely unabated or
actually increased over the past 30 years. The report notes that many of the nation's
coastal environments exhibit symptoms of over-enrichment. Symptoms include algal blooms
(some of which may be toxic), loss of sea grasses and coral reefs, and serious oxygen
depletion. As a result, coastal regions see reduced production of valuable fisheries,
threats to biodiversity, and ecosystems less resilient to natural and human influences.
Source: "Marine Pollution in the United States: Significant Accomplishments, Future
Challenges," review led by Dr. Donald Boesch from the University of Maryland Center for
Environmental Science, Pew Oceans Commission, 2001.
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"The principal nutrient of concern in coastal waters is nitrogen. Our use of commercial
fertilizer and combustion of fossil fuels has had a dramatic effect on the global nitrogen
cycle. U.S. coastal ecosystems are receiving one hundred to four hundred percent more
nitrogen than natural systems would experience.Ninety percent of the nitrogen pollution
that contributes to the 'dead zone' in the Gulf of Mexico is discharged to tributaries
in the Mississippi and Ohio River watersheds from farms and cities located north of St.
Louis, MO."
Source: Testimony of the Honorable Eileen Claussen, president and chair of the board, Strategies for the Global Environment, and member, Pew Oceans Commission, before the Subcommittee on Fisheries Conservation, Wildlife and Oceans, House Committee on Resources, May 24, 2001.
- Nearly all crops grown in industrialized countries are exposed to more nitrogen than they can use. Too much nitrogen can throw the soil community out of balance, and also lead to algal blooms in water that suffocate other aquatic organisms. In fact, algal blooms and "dead zones" are now regular features of coastal life in many places around the world.
Source: "Toxic Fertility," by Danielle Nierenberg, WorldWatch, March/April 2001, pages 30-38.
- The increasing use of commercial fertilizers could be contributing to global warming by decreasing oxygen and raising levels of nitrous oxide in coastal waters, according to scientists at the National Institute of Oceanography in India. Their findings, published in the Nov. 16, 2000, issue of Nature, found nitrous oxide levels in the coastal Arabian Sea that are 100 times greater than normal levels.
Source: Nature, Nov. 16, 2000.
- Researchers at Iowa State University (ISU) are concerned over water quality in Iowa, particularly with the high levels of phosphorus due to the use of farm and lawn fertilizers. Phosophorus levels in Iowa are some of the highest in the world, according to John A. Downing, professor of aquatic ecology at ISU, noting that this contributes to eutrophication, or algae blooms.
Source: Iowa State University Extension press release, Sept. 21, 2001.
- Nitrogen delivery to the Gulf of Mexico could have been reduced 33 percent between 1960-1998 if the use of nitrogen-containing fertilizer in the Mississippi Basin had been cut by 12 percent, according to Gregory F. McIsaac, Mark B. David, George Z. Gertner, and Donald A. Goolsby.
Source: Brief Communications, Nov. 8, 2001, issue of Nature (pages 166-167).
Organic Trade Association, July 2002
© The Organic Cotton Company Inc. 2005