Nitrogen pollution's little-known environmental and human health threats

Seed Daily: Billions of people owe their lives to nitrogen fertilizers - a pillar of the fabled Green Revolution in agriculture that averted global famine in the 20th century - but few are aware that nitrogen pollution from fertilizers and other sources has become a major environmental problem that threatens human health and welfare in multiple ways.

"It's been said that nitrogen pollution is the biggest environmental disaster that nobody has heard of," Alan Townsend, Ph.D., observed at the 242nd National Meeting and Exposition of the American Chemical Society (ACS), being held here this week.

Townsend, an authority on how human activity has changed the natural cycling of nitrogen to create a friend-turned-foe dilemma, called for greater public awareness of nitrogen pollution and concerted global action to control it. He spoke at a symposium on the topic, which included almost a dozen reports (abstracts of each presentation appear below) by other experts.

"Awareness has grown, but nitrogen pollution remains such a little-recognized environmental problem because it lacks the visibility of other kinds of pollution," Townsend explained. "People can see an oil slick on the ocean, but hundreds of tons of nitrogen spill invisibly into the soil, water and air every day from farms, smokestacks and automobile tailpipes. But the impact is there - unhealthy air, unsafe drinking water, dead zones in the ocean, degraded ecosystems and implications for climate change. But people don't see the nitrogen spilling out, so it is difficult to connect the problems to their source."

Townsend described the scope and the intensification of the nitrogen pollution problem as "startling." He noted that nitrogen inputs to the terrestrial environment have doubled worldwide during the past century. This increase is due largely to the invention and widespread use of synthetic fertilizer, which has revolutionized agriculture and boosted the food supply....

A satellite image of the Black Sea (thank you, NASA) shows phytoplankton blooms partly due to fertilizer run-off from Europe