Agricultural Runoff Is Putting Babies and Viagra Users in Danger

Last week, officials in Columbus, Ohio, issued a troubling warning to a portion of the city's infants, pregnant women, and Viagra users: don't drink the water. The problem, Columbus's water division explained, was that the nearby Scioto River, which supplies one of the city's main water treatment plants, had become flushed with too-high levels of nitrates after heavy rains flooded the river with agricultural runoff from the area's corn, soy, and hog farms. This polluted water is a common byproduct of high-intensity farms that fertilize their crops with nitrogen-heavy chemical fertilizers—as well as animal farms whose furry creatures produce vast amounts of waste each day. It can make its way into drinking water in agricultural areas whose water treatment plants are ill-equipped to filter out excess nitrates, endangering the health of nearby populations.

Such is the case in Columbus, where citizens served by the Dublin Road water treatment plant remain under an advisory urging them to drink bottled water. The immune systems of pregnant women and infants are particularly ill-equipped to handle high levels of nitrates, which can bind to hemoglobin in rthe blood, causing suffocation due to methaemoglobinemia, or so-called "blue baby syndrome." As for Viagra users, they're susceptible to a sudden drop in blood pressure when consuming nitrates, as both the medicine and nitrates cause blood vessels to expand. Such a precipitous drop in blood pressure can lead to a heart attack.

Instances of blue baby syndrome can be typically be controlled by keeping nitrate levels in drinking water below 50 milligrams per liter, and in the US, the Environmental Protection Agency mandates that nitrate levels in tap water not exceed ten milligrams per liter. Though officials in Columbus stressed that the 11.7 milligrams of nitrates in the water processed by the Dublin Road facility barely exceeded EPA limits—"these levels are less than if you eat a hot dog," a poison control worker told the Columbus Dispatch—that's enough to cause some water analysts concern.

"I wouldn't drink water containing over ten milligrams of nitrate-nitrogen per liter," said Dr. Daniel Sobota, a former postdoctoral research associate with National Research Council who is currently a water quality analyst at the Oregon Department of Environmental Quality. According to Sobota—who spoke based on his professional research and not in any official capacity on the part of Oregon's DEQ—the problem of nitrogen pollution as a result of intensive agricultural production and fossil fuel combustion is one that is growing. Data compiled by the EPA shows that between 2000 and 2010, violations issued as a result of high nitrogen levels in drinking water more than doubled, from about 500 to nearly 1,100. As Sobota pointed out, global production of nitrogen has about doubled over the past century, a result of our increasing reliance on fossil fuel-produced fertilizers as well as increased emissions from burning fossil fuels. Besides affecting drinking water, that pollution leads to a whole host of environmental problems, including massive low-oxygen "dead zones," such as those in the Gulf of Mexico and the Chesapeake Bay, that cause devastation to fish and shellfish populations. Sobota said that agriculturally-intensive swaths of the US, such as the Midwest's corn and soy rotations, contribute to these problems.

"I don't think it's rocket science to say that agriculture is one of the largest sources of nitrogen in the US today," he said.

While there's been a lot of research on nitrogen pollution and its environmental toll, Sobota said, few reports have attempted to tie all the data together to form a larger picture of just how much our production of this pollutant is costing us. That issue is exactly what Sobota and his colleagues sought to address with their paper entitled "Cost of Nitrogen Release from Human Activities to the Environment in the United States," published in the scientific journal Environmental Research Letters earlier this year. By inventorying nitrogen sources across the US and calculating their annual emissions, Sobota and his team came up with a staggering dollar figure, estimating that the median cost of nitrogen pollution damages inflicted by fertilizing crops, burning fossil fuels, manufacturing industrial products and all other human-induced sources runs about $210 billion a year in harm to human health and the environment. Agriculture, which accounts for roughly three-quarters of this nitrogen production, could therefore be said to cost us $157 billion in nitrogen-related damages each year.

As Sobota explained, curbing agriculture's nitrogen pollution is a tricky proposition. With the global population skyrocketing and our need for reliable food sources as high as it has ever been, our reliance on harmful but effective chemical fertilizers grows in turn.

"We need to feed the population," Sobota said. "It's just a fundamental fact that this will lead to increased nitrogen loading."

On a personal level, Sobota said, there are a lot of choices that individuals can make to reduce their "nitrogen footprint." Because raising our food supply makes such heavy use of nitrogen, people could both eat less meat as well as waste fewer of the groceries they buy, Sobota said. They could also opt for mass transit whenever possible. At N-Print.org, you can calculate how much nitrogen your lifestyle uses per year.

Sobota said that by putting a dollar sign on our nitrogen use, as he and his colleagues did in their paper, he hoped to give people a better grasp on nitrogen pollution than that which is currently conveyed by more remote numbers on fish population or losses in biodiversity.

"If it's not affecting them immediately, it's harder to make sense of it," he said. "Hopefully, this is a way of moving the conversation forward."