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What's for Dinner? Corn Ethanol, Feedlot Pollution, and Food Safety

The debate over renewable energy is raging. The U.S. Congress recently passed a renewable fuels mandate which will effectively create an artificial market for at least 15 billion gallons of corn ethanol per year. Numerous studies have criticized ethanol's environmental footprint. From negligible greenhouse gas savings to increased ground level ozone, and dependency on high-input agriculture­corn ethanol's critics have painted a picture of a costly band-aid for our energy crisis.

None of this analysis examines the full cost of the corn ethanol boom, which actually creates more by-product than it does fuel. Ethanol from corn produces seven pounds of by-product for every gallon of ethanol. This by-product is already in our food. If you eat beef, chances are you have eaten cattle fattened on this ethanol waste.

Dried distillers grains with solubles (DDGS) are the leftovers after corn has been milled and fermented into ethanol. Cattle nutritionists recommend including ethanol by-products in cattle diets at 20%-40% maximum. The quantity of distillers grain available is dictated by government incentives for fuel refining, leaving the ethanol industry to engineer demand for its waste. Without the sale of these ethanol by-products, corn ethanol is vastly less profitable. Industry claims that co-production of distillers grain with ethanol is a win-win proposition. Cattle producers get economical, high-protein feed, and America gets renewable fuel. However, the market for distillers grain is limited, and their disposal, like any other industrial by product, comes with costs to the environment, the economy and public health.

The Problem with Ethanol By-Products

Concentrated phosphorus and nitrogen in cow dung

Feeding distillers grain to cattle increases the amount of nitrogen and phosphorus in their feces. Unfortunately, the ratio of phosphorous to nitrogen is so high in this cow dung that it is of little use as a fertilizer. Cows fed a diet that includes 40% distillers grain, have fecal material with 41% more phosphorous and 33% more nitrogen than cows fed conventional feedlot diets. More than 40 percent more land will be needed to treat the waste of cows consuming this by-product if it is disposed of by spreading it over fields. Even if the proper amount of land can be dedicated to treating wastes, water quality around feedlots will likely worsen. Eutrophication-the process by which streams with high-nutrient runoff clog with vegetation, reducing oxygen in the water, and killing fish and other aquatic organisms-is a proven result of large-scale cattle and dairy operations. More nitrogen and phosphorous cycling through these operations will intensify the deterioration of streams and rivers.

Increasing nitrogen cycling through feedlots also increases greenhouse gas emissions. Nitrous oxide, a greenhouse gas 296 times more potent than carbon dioxide, is a major toxic emission from large-scale agricultural operations. Nitrous oxide forms when bacteria naturally present in soils convert biologically available nitrogen to a gas bound with oxygen. In areas where nitrogen runoff is high, nitrous oxide emission is also high. Cows fed a diet of 40% distillers grain increase the amount of available nitrogen in their excrement by 33% percent. The amount of available nitrogen that forms greenhouse gases varies according to treatment methods applied to the waste. With over 200 billion pounds of by-product slated to be produced annually under Congressional ethanol targets, feedlots all over the nation will increase their nitrogen and phosphorus emissions dramatically.

Food safety: Sulfur, polio and E. coli

The market for ethanol by-products is limited due to sulfur residues. Sulfuric acid and other sulfur compounds used in the distilling process combine with naturally-occurring sulfur in corn to produce unhealthy and potentially lethal levels of sulfur in distillers grain. The sulfur levels in ethanol by-products vary between plants and even between batches at the same plant, making it difficult to label or control. Sulfur, in excess of 0.4% in cattle diets will cause polioencephalomalacia, a deadly form of polio that produces brain lesions. The fine nutritional testing necessary to feed a diet heavy in ethanol waste favors large feedlot operations that can afford to test their water supply and distillers grain for sulfur. Smaller ranchers are unlikely to be able to use ethanol waste to the same degree as feedlots, putting family cattle operations in direct competition with ethanol plants for feed corn.

Feedlots that use ethanol waste also threaten the food supply with E. coli outbreaks. A recent Kansas State University study shows that distillers grain promotes the growth of E. coli. The study's authors warn of "serious ramifications," predicting strong resistance to feeding ethanol waste. Cattle fed brewers grains, a similar product, are six times more likely to have E. coli in their feces than cattle fed real corn. E. coli outbreaks in factory farms are common. The use of ethanol by-products will doubly increase this phenomenon, both increasing the presence of E. coli and expanding the industrial model that makes our food system vulnerable to contamination in the first place.

The feedlot-refinery connection

Ethanol refineries and factory-style feedlots go hand in hand. For example, at an ethanol plant owned by E3 BioFuels corporation in Mead, Nebraska, manure from a 28,000-cow feedlot helps to power a 25 million gallon per year ethanol plant. In this system, the corn waste from the refinery makes up 40% of the cattle's diet. E3 plans to build larger ethanol plants with feedlots of 60,000-120,000 cattle. Such plants bring in a few jobs, but all of the added value of the ethanol stays with the refiner, while the community is left with despoiled water supplies, bad air quality, and all the other environmental problems associated with feedlots and refineries of that size. The pairing of feedlots and refineries makes sense from an industrial standpoint. Up to one third of the energy produced from ethanol is lost in the drying and shipping of its by-products. Pairing ethanol plants and feedlots eliminates drying and transportation costs. As more ethanol refineries are built around the country we can expect feedlots to follow, spoiling waterways and threatening food safety as they go.

Corporate consolidation and consumer choice

Corporate consolidation is occurring rapidly in the ethanol industry. Of the 119 ethanol plants operating in 2007, 49 of them were owned and operated by farmer cooperatives. But once ethanol refineries currently in construction come on line, farmers will only control 20% of the nation's ethanol (and distillers' grain) production capacity. Just as the refining business favors large corporations, the by-products industry will favor large corporate farms and feed lot operations. As ethanol drives corn prices up and the excess corn by-product becomes cheaper, factory feedlots and dairies are likely to edge out smaller operations that can't or don't want to use distillers grains. Consumers who prefer to avoid factory beef will have to buy from the small number of ranchers who sell to specialty markets.

Renessen-A case study in vertical corporate consolidation

Renessen Corporation has capitalized on the ethanol boom to consolidate market control over both our food and fuel systems. Renessen, a joint venture between agribusiness giants Cargill and Monsanto, has genetically engineered corn to make ethanol distillers grains for cattle feed more competitive within that limited market. Renessen's Mavera brand "high value corn with lysine" is the first commercially available crop genetically engineered for fuel. Mavera corn is stacked with transgenes for higher oil content, plus it creates its own pesticide in the stem like many other Monsanto varieties. What makes this corn unique is a gene that makes the corn produce lysine, an amino acid essential for protein and muscle production in mammals. Lysine is an expensive synthetic additive in feedlot diets. Renessen Corporation is betting a $450 million initial investment that this genetically-modified corn will help them corner the ethanol by-products market, giving them an upper hand in the ethanol industry. Its patented refining process also produces by-products for use in pig and poultry feed. Until now pigs, chickens and turkeys have been unable to successfully digest ethanol by-products as they have only one stomach compartment with which to digest the waste, compared to cattle's four. Renessen plans to extract another product from its waste stream-food grade corn oil.

Renessen's new pilot facility in Eddyville, Illinois only mills Mavera corn. This means that farmers in the area who want to sell to Renessen must both buy and sell to Renessen. Not only does Renessen stand to corner the market for ethanol by-products, but in doing so, could control a large share of the seed market as well.

Other uses for ethanol by-products

Recognizing that the market for ethanol by-products is limited, the industry has proposed several other uses. Mulch is one possible option, which raises the same concerns about damage to waterways from excess phosphorous and nitrogen. In addition, the pesticide Bt, a toxin engineered into many GM corn varieties, is still present in by-products. Plastic composites and industrial materials are other proposed ways to recycle ethanol waste. The energy consumption involved in making these by-products is not yet factored into ethanol's climate footprint.

Human food is perhaps the most disturbing proposed destination for refinery waste. As labeling laws stand right now, corn oil and corn flour made from ethanol waste could enter the commodity chain without labeling, so that unsuspecting consumers would never know if they are eating refinery by-product. Nor would they know how much sulfur, acids, or other processing residues were contained in the many foods that contain corn oil or corn flour.

Renewable vs. Sustainable

Ethanol by-products have already made their way into our food system, but are not yet recognized as an environmental or public health threat. The 2007 renewable fuel standards are consolidating corporate control of food and fuel while creating significant public costs for rural communities and the environment. Ethanol has no climate benefits when the complete cycle of production is analyzed. As ethanol production ramps up, feedlots will have greater difficulty disposing of their waste resulting in even more greenhouse gas emissions. Because ethanol by-products are difficult to transport, feedlots are likely to congregate around ethanol refineries. This model of factory farms with feedlots has synergies, but is in no way sustainable for the environment or the people who live nearby. The use of ethanol by-products as cattle feed does not in any way eliminate competition for corn between food and fuel. To the contrary, it threatens the food supply with increased E. coli outbreaks and the proliferation of unsanitary factory feedlots.

Idyllic television ads to the contrary, the ethanol boom will not help the U.S. transition to a green future. And it will not save family farms or revitalize rural economies. Instead, it will allow a few corporations to consolidate control over our food and fuel systems, turning more land into factory farms. The issue of disposal of distillers grains is only one aspect of this so-called sustainable, fuel source. In the ethanol boom, from field to refinery and gas tank, to feedlots and our dinner tables, the big winners will be large corporations, not small farmers, not unsuspecting consumers, and certainly not our environment.

Baker, Allen and Steven Zahniser. 2006. "Ethanol Reshapes the Corn Market, "USDA Economic Research Service. AmberWaves. 4 (2) April 2006.
Iowa General Assembly. 2007 Committee Briefings, Animal Feeding of Distiller's Grains Study Committee. September 13, 2007
Powers, Wendy. Dan Loy, Allen Trenkle, and Rachael Martin. 2006. "Use of Distiller's Grains in Feedlot Diets: Impact on Phosphorous Excretion" Iowa Beef Center, Iowa State University Extension. ibid. |
Crutzen, P.J., A.R. Mosier, K.A. Smith, and W. Winiwarter. 2007. "Nitrous oxide release from agro-biofuel production negates global warming reduction by replacing fossil fuels" Atmospheric Chemistry and Physics. Discuss. 7 11191-11205.
Powers, Wendy et al 2006
McElroy, Anduin Kirkbride. 2007. "Sulfur content should be considered." Distiller's Grain Quarterly. BB International, 4th Quarter 2007
Niles, GA, S. Morgan, WC Edwards, and D Lalman. 2002 "Effects of dietary sulfur concentrations on the incidence and pathology of polioencephalomalicia in weaned beef calves" Veterinary and Human Toxicology 44 (2): 70-72
McAllister, MM, DH Gould, MF Raisbeck, BA Cummings, GH Loneragan. 1997. "Evaluation of ruminal sulfide concentrations and seasonal outbreaks of polioencephalomalacia in beef cattle in a feedlot" Journal of the American Veterinary Medical Association. 211 (10): 1275
Institute for Local Self Reliance. 2007. "Nebraska Ethanol Plant Taps Cow Power Next Door." New Rules Project News. Institute for Local Self Reliance. Washington, D.C. July, 18, 2007. ibid.
Hazan, Hamza 2007. "Overview of U.S. Ethanol Market," Food First Fact Sheet. Institute for Food and Development Policy. Oakland, California.
Rosi-Marshall, E.J., J.L. Tank, T.V. Royer, M.R. Whiles, M. Evans-White, C. Chambers, N.A. Griffiths, J.Pokelesek, and M.L. Stephen. 2007. "Toxins in transgenic crop byproducts may affect headwater stream ecosystems." Proceedings of the National Academy of Sciences 104 (41).
Searchinger et al. 2008. "Use of U.S. Croplands for Biofuels Increases Greenhouse Gases Through Emissions from Land Use Change." Science. 319 (1238).

All content ©2008 Food First/Institute for Food and Development Policy 398 60th Street, Oakland, CA 94618 USA. Tel: (510) 654-4400, Fax: (510) 654-4551.


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