Diving into Nutrients: How much is too much?
By Sean Sheldrake
There’s a nutrient “problem”?
Did you know nutrient pollution, primarily in the form of too much nitrogen and phosphorus, is one of the nation’s most widespread, costly and challenging environmental problems? Some 16,000 waterways are impaired, and 78 percent of assessed coastal waters suffer from nutrient pollution, affecting water used for drinking, fishing, swimming and other recreational purposes. These impacts also threaten tourism, home and property values and public health.
Nitrogen and phosphorous are food for some plants, like algae, and too much can spark a large algal bloom that can end up consuming all the dissolved oxygen in a waterway, causing fish to be starved for that critical gasp of O2. Fish die-offs are common with extreme nutrient problems.
Where does it come from?
Excessive nitrogen and phosphorus are often the result of human activities. Primary sources include agriculture (manure, excess fertilizer and soil erosion), inadequately treated wastewater, stormwater runoff, air pollution from burning fossil fuels and—us! Huh? Whenever we do things around the house that add nitrogen and phosphorus to the local watershed we are part of the problem. That can include not cleaning up after your dog, using too much fertilizer on the lawn or garden, or washing your car on the driveway (most soaps contain nutrients).
How can I help?
The good news is that since we are all part of the problem, we can all be part of the solution.
Bag the dog waste, apply fertilizer according to the label (or better yet, switch to using some backyard compost!) and park your car on the lawn instead of the driveway when you wash it, or go to a carwash. We can really make a dent in the problem.
How about a little science to help out?
But it’s not all up to individuals alone. EPA scientists are working on solutions, too.
EPA divers help deploy and retrieve scientific instruments, such as Acoustic Doppler Current Profilers (ADCPs), to help study nutrient pollution. For example, in one project in Puget Sound we deployed ADCPs to collect information on water flow, a critical first step that EPA computer modelers use to calculate the level of nutrients a water body can tolerate. Ensuring the proper placement for data collection is paramount for data quality.
Getting into the water can be a challenge though! Divers may have to upgrade to protective equipment and do a decontamination wash after the dive to ensure the safety of each diver getting in the water to collect data.
Read more about the latest in EPA scientific diving at facebook.com/EPADivers.
About the Author: Sean Sheldrake is part of the Seattle EPA Dive unit and is also a project manager working on the Portland Harbor cleanup in Oregon. He serves on the EPA diving safety board, responsible for setting EPA diving policy requirements.
Join us for a Twitter Chat to Learn More!
Got questions? Want to learn more? Join us for a Twitter chat this Thursday (July 18, 2013) at 2 pm ET on nutrient pollution and harmful algal blooms. Use #waterchat to ask a question or participate. Not on Twitter but have a question? Please add it to the comments section below.
Editor's Note: The opinions expressed here are those of the author. They do not reflect EPA policy, endorsement, or action.
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