Ethanol Production Creates Water, Health Risks

Unless biofuel farmers adopt new agricultural methods, the growing demand for ethanol could strain water supplies in some areas and raise the risk of harm to the environment and human health, according to a new report from the National Research Council (NRC).

A committee of NRC members came to those conclusions after examining how the country's shift to more energy crops could affect water management and other issues.

One of the problems with growing corn for fuel instead of food is that water demands vary considerably from one part of the U.S. to another, the committee found. For example, replacing soybeans and cotton with corn cultivation would require more agricultural water than is used now in the northern and southern plains. On the other hand, corn farming generally uses up less water than those other crops in the Pacific and mountain regions of the country.

Corn also requires more fertilizers and pesticides per acre than soybeans, mixed-species grasslands and other crops, the report added. Such increased chemical use could worsen existing "dead zones" in places like the Gulf of Mexico, where fertilizer runoff seasonally drives algae blooms that take oxygen from the water and kill off marine life. And greater use of water-soluble nitrogen fertilizers could cause runoff to contaminate drinking water wells, rivers and streams.

"When not removed from water before consumption, high levels of nitrate and nitrite -- products of nitrogen fertilizers -- could have significant health impacts," the NRC said.

Furthermore, building more refineries to make ethanol would also place added strain on water supplies, the committee found. A biorefinery that pumps out 100 million gallons of ethanol a year would use about as much water as a city of 5,000 people. Depending on where such refineries are located, the result could be "intense challenges for local water supplies," the NRC said.

The committee said many of these challenges could be addressed by adopting new agricultural practices and techniques. Crops grown for fuel, for instance, might be irrigated with wastewater not suitable for food crops. Future fuel crops might also be genetically modified to require less water. The report added the problem of chemical-filled runoff might be solved by injecting fertilizer below the soil surface or using controlled-release fertilizers with water-insoluble coatings.

Other possible solutions might include growing more perennial crops like switchgrass, poplars, willows or other prairie plants that can be used for biofuel but hold soil and nutrients in place better than corn, the report said. And corn farming could be improved by leaving cornstalks and cobs in the field after harvesting to enrich the soil and reduce erosion.

Growing crops for ethanol has expanded recently as subsidies have encouraged production and interest grows in building U.S. energy dependence. Earlier this year, Pres. George W. Bush called for a goal of 35 billion gallons of home-grown ethanol per year by 2017 -- enough to replace about 15 percent of the liquid transportation fuels used in the country today.

National Research Council, "Increase in Ethanol Production from Corn Could Significantly Impact Water Quality and Availability if New Practices and Techniques are Not Employed." URL: (http://www8.nationalacademies.org/onpinews/newsitem.aspx?RecordID=12039)