Nutrient Pollution a Persistent Threat to Nation’s Water Quality

Photo courtesy Jeff Vanuga, USDA NRCS.

A number of recent studies have assessed the status and trends of nutrient pollution in the nation’s groundwater, streams, lakes, and estuaries and reviewed the effectiveness of government efforts to protect and restore these vital water resources. Much more needs to be done. Agriculture is a major contributor the nation’s polluted groundwater and waterways, and corn production (the source of most of today’s biofuels) uses more nitrogen than any other crop. Getting more producers to use best management practices to use less fertilizer more effectively would help.

On October 4, the Senate Committee on Environment and Public Works, Subcommittee on Water and Wildlife held a hearing to examine nutrient pollution in the nation’s groundwater and water ways and to review the status of current federal efforts to reduce nutrient pollution.The Subcommittee heard that nitrogen and phosphorous pollution is a major threat to clean water and to the human populations and aquatic ecosystems that depend upon clean water. There are many sources of nutrient pollution – both urban and rural. About half of the nation’s streams and 40 percent of lakes have high or medium concentrations of nutrients – little changed over the past 30 years. In addition, the nutrient contamination of coastal estuaries and ecosystems is getting worse, now affecting almost half of the coastal ecosystems in the United States.

The U.S. Department of Agriculture (USDA) reported that nutrient pollution would have been worse if voluntary USDA conservation programs and incentives had not been established years ago. The greatest success so far has been the reduction of soil loss. Conservation programs have achieved modest success controlling the loss of nitrogen and phosphorous at the surface, but they have achieved the least success in reducing the loss of nitrogen through subsurface groundwater. The main message of the hearing: Much remains to be done to restore healthy drinking water supplies, fisheries, beaches, and ecosystems. Panelists included representatives from the USDA, the Environmental Protection Agency, the U.S. Geological Survey, and the National Wildlife Federation.

Separately, on September 22, the USDA’s Economic Research Service released a new report entitled, “Nitrogen in Agricultural Systems: Implications for Conservation Policy” . The costs of nitrogen pollution can be high. The report estimates that it costs $4.8 billion per year to remove nitrates from drinking water supplies – and that is only one of the many costs to society. The report finds that widespread adoption of best management practices could reduce nitrogen pollution from agriculture, but that only about one-third of planted field crops today are planted using all of the best management practices which focus on the rate, timing, and method of application. The report reviews a variety of policies that might encourage greater use of best management practices.

EESI and the Water Environment Federation hosted a briefing June 9 “Managing Nutrients to Protect Water Quality: Innovative Approaches” which explored market-based approaches to reducing nitrogen pollution. In addition, EESI advocates expanding conservation programs and planting perennial energy crops in place of row crops on marginally productive and erodible lands. Conservation land and transitioning to energy crops could help buffer watersheds by slowing surface run-off, conserving soil and water, and soaking up excess nutrients from surface and groundwater.