Pitt prof monitors high nitrates in rainfall

Nitrates, small molecules consisting of just one nitrogen and three oxygen atoms each, can… Nitrates, small molecules consisting of just one nitrogen and three oxygen atoms each, can have devastating effects on the environment.

Assistant professor of geology and planetary sciences Emily Elliott would know – she’s spent the last three years studying nitrate levels in the United States.

Her research has been based on water samples collected at 33 sites located in Ohio, West Virginia, Pennsylvania and other states northeast of Maine.

“In this study, we were just looking at rainfall from 2000,” Elliott said. “It was the first long-term study of its kind. We were looking for seasonal and spatial variations.”

These variations are the root of many of the nation’s environmental problems.

“Nitrate is one of the key components of acid rain,” Elliott said. “It can decrease biodiversity. Nitrate also, when it comes down in rainwater, can cause eutrophication, which is an excess of nutrients. What happens is, algae blooms. It then dies and decomposes and uses up all the oxygen in the water. This is how we get ‘dead zones.'”

These problems, however, aren’t isolated to areas with dead zones. They affect people all over the United States.

“This area of the country gets some of the highest levels in the U.S., mostly because of its coal-fire power-plants,” Elliott said. “We found a strong correlation, between 400 and 600 kilometers, that it was traveling. We estimate that nitrates can stay in the air up to a week.”

Nitrates may be naturally present in the environment, but not at the levels Elliott and her colleagues recorded. Elliott attributes some of the excess nitrates to stationary sources – things like power plants and cars – that emit nitrogen as a gas.

The nitrogen then falls to the earth in the form of nitrates, which are found in acid rain and snow.

Elliott’s research focused on the effects of nitrates on rural areas because that’s where most of the National Atmospheric Deposition Program’s collection sites were located.

“Most of our sites were in rural areas, which led us to believe nitrogen deposition in urban areas could be much higher than we originally thought,” she said.

Elliott hopes to start a collection site in Pittsburgh to see exactly how large the disparity is.

“The way cities are built you have direct runoff into sewers or culverts,” she said. “That would accelerate the transfer of nitrates into rivers and streams.”

Elliott pitched her testing method to the EPA because it is especially effective at monitoring the level of emissions that come from power plants and tracing nitrogen deposition.

“It really points out that we have a hole in our monitoring framework in this country,” she said. “I have given presentations to the EPA. I think it’s a kind of logistics and money issue. We were thinking if you repeated the study in about five years, you could really start to quantify the results.”

Elliott is also hoping to extend her research by taking on partners in the electricity and utility industries.

“We’ve had a hard time getting smoke stack samples,” Elliott said.

These samples would help determine exactly how many of the excess nitrates are coming from power plants and, thus, make it easier to prevent them from entering the air.

“Industries certainly have the power to reduce the amount of emissions, but that can be quite costly,” she said.

The question is, do the benefits outweigh the costs? Nitrates can harm not only the environment, but humans’ health as well. “Elevated nitrate in drinking water can cause a disease called methemoglobinemia – a blood disorder primarily affecting infants under six months of age,” the Michigan Department of Environmental Quality wrote in a pamphlet.

“Methemoglobinemia reduces the ability of the red blood cells to carry oxygen. The acutely poisoned person will have a blue discoloration of the skin due to the reduction of oxygen in the blood.”