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Atmospheric Deposition of Pesticides to Chesapeake Bay Estuaries
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Project Title: Atmospheric Deposition of Currently Used Pesticides to the St. Jones River Reserve and Upper Delmarva Peninsula Atmosphere
Research Locations: Delaware Bay, DE
Last Update: April 8, 2004
The Delmarva Peninsula, a region within the Chesapeake Bay watershed, is a highly agricultural area dominated by corn and soybean farming. Because of the heavy use of chemicals on these farms, the peninsula’s streams and tributaries are particularly vulnerable to agricultural runoff. However, runoff is not the only threat to coastal water quality. Research has shown that a significant amount of pesticide from regional farms is carried to estuaries through the atmosphere as well. Yet very little is known about atmospheric transport of pollutants or its role in water quality degradation. This project is taking some of the first steps towards understanding these processes. Researchers are expanding on an existing air and precipitation monitoring network to include the detection of pesticides, and testing a new atmospheric deposition model that will help predict deposition of agricultural pollutants.
Approach
Pesticides from the atmosphere can be delivered to the coastal environment in two ways: as particles in air, or as concentrate in rainwater. Researchers collected weekly air and precipitation samples from
3 sites over a two year period, and determined the pesticide concentrations in both transport forms. They then used this data to calculate the rates of deposition, determine the trends in deposition loads and
identify the regions that contribute the highest amounts of contaminants.
Methods
Researchers adapted a commercial funnel-type rainwater collector to include a sensor-activated lid that
opens when it rains. Rainwater enters the funnel and is pulled through a glass fiber filter and an
extraction cartridge. Air samples were collected using a commercial high-volume air sampler with a glass fiber filter and polyurethane foam.
Results
Investigators found various pesticides, including herbicides, insecticides and fungicides, in samples retrieved from each site. Preliminary results reveal that herbicide amounts peaked during the spring in
correspondence with corn and soy crop spraying. Insecticide and fungicide concentrations appear to increase during the summer months corresponding with vegetable spraying. Researchers are continuing to develop a model which will determine the contribution of pesticides from various regions.
Managing Local Atmospheric Deposition
Results from this project will provide much-needed information on the contribution of the atmosphere to pesticide loading in the Delaware Bay watershed. Local and state agencies can incorporate the methods used on this project to better understand and monitor this type of contaminant input.
Informing Other Coastal Decisionmakers
Managers, scientists and coastal decision makers from around the country will benefit from understanding more about the total pesticide “budget” entering their watersheds, and how the atmosphere contributes to it. To make their methods and results available to a wider audience, investigators plan to present their findings to scientists, regulators, municipal officials, and coastal managers, at the Delaware Bay Reserve in 2004.
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Project Coordinator
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Dr. Alba Torrents (301) 405-1979 |
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Start -End Date:
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09/01/2001 - 09/01/2004
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NERR Reserve(s):
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Delaware Bay, DE
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For more information: |
Dolores Jalbert Leonard |