Nitrogen, phosphorus from fertilizers and pet waste polluting urban water

April 05, 2017

New research from the University of Minnesota points to lawn fertilizers and pet waste as the dominant sources of nitrogen and phosphorus pollutants in seven sub-watersheds of the Mississippi River in Saint Paul, Minnesota.

The study -- published in the Proceedings of the National Academy of Sciences -- is the first to compare the urban watershed budgets of nitrogen and phosphorus. And the results can be applied to urban watersheds around the world impaired by excess nutrients.

The research team -- led by Sarah Hobbie, Distinguished McKnight University Professor in the Department of Ecology, Evolution & Behavior and an Institute on the Environment Fellow -- discovered households are the main sources of nutrient pollutants in the Twin Cities urban watershed. Household nitrogen fertilizer use in particular is more than 10 times greater than commercial fertilizer use by golf courses, college campuses and other non-residential locations, and pet waste is the leading source of phosphorus to these watersheds.

Urban watersheds are highly "leaky" with regard to nutrient pollution because of their dense networks of streets and storm drains, which are designed to readily move water off the landscape to avoid flooding. As a result, most of the phosphorus entering urban watersheds ends up being carried away by stormwater that drains into surface waters and thus contributes to pollution and eutrophication. Nitrogen tends to disperse through more diverse pathways -- about one-fifth is transported via stormwater into surface water while much of the rest ends up either being released into the atmosphere or moving through soil into groundwater.

This makes managing urban watersheds a challenge. "Urban waters -- lakes, streams, rivers, coastal waters -- continue to be impaired by nutrient pollution, especially phosphorus, despite long-running efforts to clean them up," said Hobbie. "Not only is this a concern for water resource managers tasked with cleaning up urban pollution, but also urban and downstream residents who depend on clean water for drinking water, recreation and aesthetic value."

Given that dense urban neighborhoods don't have a lot of space for nutrient-capturing features such as rain gardens and ponds, the researchers point to alternate solutions such as focusing on reducing excessive nitrogen fertilizer use and keeping phosphorus out of streets and gutters in the first place, for instance by controlling erosion and increasing street sweeping efforts, and picking up dog waste as soon as possible to limit the release of phosphorus.
-end-
The University of Minnesota Institute on the Environment is leading the way toward a future in which people and the environment prosper together. For more information, visit environment.umn.edu.

University of Minnesota

Related Nitrogen Articles from Brightsurf:

Chemistry: How nitrogen is transferred by a catalyst
Catalysts with a metal-nitrogen bond can transfer nitrogen to organic molecules.

Illinois research links soil nitrogen levels to corn yield and nitrogen losses
What exactly is the relationship between soil nitrogen, corn yield, and nitrogen loss?

Reducing nitrogen with boron and beer
The industrial conversion of nitrogen to ammonium provides fertiliser for agriculture.

New nitrogen products are in the air
A nifty move with nitrogen has brought the world one step closer to creating a range of useful products -- from dyes to pharmaceuticals -- out of thin air.

'Black nitrogen'
In the periodic table of elements there is one golden rule for carbon, oxygen, and other light elements.

A deep dive into better understanding nitrogen impacts
This special issue presents a selection of 13 papers that advance our understanding of cascading consequences of reactive nitrogen species along their emission, transport, deposition, and the impacts in the atmosphere.

How does an increase in nitrogen application affect grasslands?
The 'PaNDiv' experiment, established by researchers of the University of Bern on a 3000 m2 field site, is the largest biodiversity-ecosystem functioning experiment in Switzerland and aims to better understand how increases in nitrogen affect grasslands.

Reducing reliance on nitrogen fertilizers with biological nitrogen fixation
Crop yields have increased substantially over the past decades, occurring alongside the increasing use of nitrogen fertilizer.

Flushing nitrogen from seawater-based toilets
With about half the world's population living close to the coast, using seawater to flush toilets could be possible with a salt-tolerant bacterium.

We must wake up to devastating impact of nitrogen, say scientists
More than 150 top international scientists are calling on the world to take urgent action on nitrogen pollution, to tackle the widespread harm it is causing to humans, wildlife and the planet.

Read More: Nitrogen News and Nitrogen Current Events
Brightsurf.com is a participant in the Amazon Services LLC Associates Program, an affiliate advertising program designed to provide a means for sites to earn advertising fees by advertising and linking to Amazon.com.