U.S. agriculture has been placed in a regulatory “bulls-eye” by the Environmental Protection Agency’s recent decision to revise its Total Maximum Daily Load (TMDL) rule. The agency’s decision, some observers say, is based on shoddy science.
EPA seeks to use the TMDL rule to regulate farms as sources of pollution. The agency estimates that 70 percent of water impairment in the United States is due to agriculture.
But according to Dr. Jefferson Edgens, an assistant professor at the University of Kentucky and an adjunct scholar with the Georgia Public Policy Foundation, significant questions remain about the true state of the nation’s water and whether agriculture is as significant a contributor to water pollution as EPA contends.
“The federal government has spent more than $541 billion on water pollution control since the Clean Water Act was enacted in 1972,” notes Edgens. “Yet the state of the nation’s water quality remains largely unknown.”
EPA claims don’t compute
Edgens explains that the pollution coming from “point” sources—such as the pipes associated with wastewater treatment and industrial processes—is monitored and reported. But there is little good information about non-point sources, such as runoff from farmland.
By law, states must report water quality conditions to Congress. The reported data is compiled in the National Water Quality Inventory, which provides a “snapshot” of water quality. The NWQI, warns Edgens, “really is only a snapshot, because most of the nation’s water has not been tested.”
In 1996, Edgens notes, the NWQI had tested only 19 percent of rivers and streams, 40 percent of lakes, ponds, and reservoirs, and 72 percent of estuaries. Analysts with the U.S. General Accounting Office recently testified before Congress that only six of the 50 states have compiled all the data needed to fully assess their water quality.
Of the waters that have been tested, less than 40 percent are classified as “impaired,” meaning the water does not support at least one of nine different uses specified by EPA, such as serving as a supply of drinking water.
EPA acknowledges its data may not be representative of general conditions in the nation’s water. “States . . . often focus on surveying [water bodies] with suspected pollution problems in order to direct scarce resources to areas that could pose the greatest risk,” the agency explains. The water quality assessments available today give undue weight to “hot spots” where known water impairment occurs.
With respect to agriculture’s contribution to water quality impairment, Edgens notes surface runoff is notoriously difficult to measure: “First, it’s diffuse and can originate from different sources: farms, driveways, rooftops, etc. Second, the primary surface runoff pollutants—phosphorous and nitrogen—occur naturally in the environment.
“Without sufficient monitoring,” Edgens concludes, “it’s difficult to tell whether these pollutants are coming from a farm or from another source.”
Nevertheless, says Edgens, simple mathematics can prove agricultural pollution is not as bad as EPA claims.
“Divide the number of stream miles EPA claims agriculture has impaired by the total number of U.S. stream miles,” advises Edgens. “Agriculture pollutes only 4.8 percent of total stream miles.
“Or divide the number of “agriculturally polluted” stream miles by just the total number of stream miles actually examined for pollution,” Edgens suggests. “By this measure, only 25 percent of stream miles are polluted by agriculture.”
Either way, says Edgens, the number of stream miles polluted by agriculture is far less than the 70 percent EPA claims.
Real monitoring is rare
EPA’s claim is even more suspect, Edgens says, because state estimates of water quality are typically made according to “best professional judgment” (using the best available information) and watershed maps. Little or no water quality monitoring takes place.
According to the latest NWQI, states that derived more than 50 percent of their water quality data through “best available judgment” methods reported that 46 percent of their stream miles have been “impaired” by agriculture. The figure is much lower in states that directly monitor water quality. In Michigan, for example, all stream miles are directly monitored . . . and only 13 percent of stream miles are determined to be “impaired” by agriculture.
“When EPA issues regulations based on shoddy science, agricultural communities will suffer very real, and very unjust, consequences,” warns Edgens. In its 1992 Census of Agriculture, the Economic Research Service estimated roughly 450,000 livestock operations run in the U.S. All of them could be subject to EPA’s new TMDL regulation.
Edgens says the system can be improved. “State and federal lawmakers should demand that regulatory decisions be based on sound science,” he says, “and that all scientific claims be examined by outside scientific experts.
“Without sound science, we’ll get costly and ineffective regulations,” he says. Farmers and consumers of agricultural products will foot the bill.
David W. Riggs Ph.D. is director of land and natural resource policy at the Competitive Enterprise Institute.