When it comes to solving the fossil fuel crisis, it seems like every silver lining comes accompanied by a dark cloud.
Both water quality and the availability of water could be threatened by sharply increasing crops such as corn for ethanol, according to a National Research Council report released Wednesday.
President Bush's stated goal is to increase biofuel production about six times, to 35 billion gallons, by 2017.
"That would mean a lot more fertilizers and pesticides" running into rivers and flowing into the oceans, said Jerald Schnoor, who chaired the panel of experts that prepared the report.
The experts noted that more fertilizer and pesticides are used on corn than any other crop. Switching to more corn crops could send more nitrogen into the water system.
"When not removed from water before consumption, high levels of nitrate and nitrite — products of nitrogen fertilizers — could have significant health impacts," the National Research Council noted in a statement issued with the report.
Nitrogen in stream flows is also the major cause of "dead zones" in coastal waters, where a lack of oxygen chokes off marine life, the experts said.
The report did note that ways to reduce nutrient pollution exist, such as injecting fertilizer below the soil surface and using special controlled-release fertilizers.
The committee added that erosion, which contributes to fertilizer runoff, might be reduced if perennial crops — like switchgrass and poplars — were used instead of row crops like corn.
"From a water quality perspective, it is vitally important to pursue policies that prevent an increase in total loadings of nutrients, pesticides, and sediments to waterways," the experts stated.
Lots of water needed
In terms of water use, the experts stated that "there are likely to be significant regional and local impacts where water resources are already stressed."
Schnoor noted that water availability depends on where the crops are grown. If it is an area needing irrigation, it takes 2,000 gallons of water for every bushel of corn: "That's a high amount of water."
And that's in addition to the secondary issue of how much water is needed by the biorefineries that produce the ethanol, said Schnoor, a professor of environmental engineering and co-director of the Center for Global and Regional Environmental Research at the University of Iowa.
"A biorefinery that produces 100 million gallons of ethanol a year would use the equivalent of the water supply for a town of about 5,000 people," the National Research Council said. "Biorefineries could generate intense challenges for local water supplies, depending on where the facilities are located."
The report suggests the possibility of irrigating crops for biofuel with wastewater that would not be suitable for food crops.
The experts also noted that biorefineries are starting to use less water via recycling and new conversion methods.
Cellulose solution?
What is needed is a breakthrough in technology so that ethanol can be produced from cellulose such as grass, wood and sawdust, Schnoor said. "If we could do that it would be much better environmentally."
While Brazil is having success producing fuels from sugarcane, "we don't have much tropical land in the United States," Schnoor observed.
Also, he noted, Brazil uses waste from the cane to fuel its ethanol factories, while the U.S. uses natural gas or other fuels.
Supplies are already stressed in some areas of the country, including a large region where water is drawn from the underground Ogallala aquifer, which extends from west Texas up into South Dakota and Wyoming.
The study was sponsored by the McKnight Foundation, Energy Foundation, National Science Foundation, U.S. Environmental Protection Agency and National Research Council Day Fund.
The National Research Council is an arm of the National Academy of Sciences, an independent organization chartered by Congress to provide science, technology and health policy advice.