Nitrogen from fertilizers and manures washed off farmland costs Americans $157 billion a year in damages to human health and the environment.
That is the stunning conclusion an international scientific team published Feb. 17 in the journal Environmental Research Letters. According to the study, the median cost of nitrogen pollution damages inflicted by fertilizing crops, burning fossil fuels, manufacturing industrial products and all other human-induced sources is $210 billion a year. Agriculture accounts for roughly 75 percent of the problem.
Within the agricultural sector, corn production uses the lion’s share of nitrogen fertilizer and manures and generates a lot of the nitrogen pollution. The authors calculate that the cost in human and environmental health problems caused by nitrogen pollution from agriculture is more than twice the $76.7 billion total value of corn produced for grain in the U.S. in 2011, when prices of corn and other agricultural commodities were high.
The researchers calculated that each kilogram of nitrogen used in the U.S. costs an average of $23.10 for increased incidence of respiratory disease and $16.10 for aggravating conditions that cause toxic algal blooms in waterways.
Last year, algal blooms left Toledo residents without drinking water for days. Earlier this year, the Des Moines Water Works utility sued three drainage districts in Iowa because nitrate pollution from farm fields forced it to spend nearly $1 million total to treat water in 2013, the most the utility had ever spent to handle unexpected nitrogen pollution.
Careful use of fertilizer and manures and conservation practices that prevent or treat polluted runoff from farm fields are proven techniques to protect waterways. The farm lobby has claimed for decades that Americans need to wait for farmers to volunteer to take action.
But farm-generated pollution is growing worse. The disastrous incidents that cost the citizens of Toledo and Des Moines time and money are not isolated cases. Drinking water supplies across the nation are threatened by agriculture pollution. Toxic algal blooms are becoming epidemic.
Farmers and landowners need to prevent fertilizer and manure from running into streams and groundwater. Many farmers are already voluntarily doing what needs to be done to keep water clean and safe, but their numbers are still too few to make an impact on farm-generated nitrogen pollution. States need to mandate sustainable use of fertilizer and manures now, since voluntary changes won’t keep surface water and groundwater safe.