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Air Deposition of Pollutants to Casco Bay: Field Monitoring and Estimation Protocols
Catherine Clayton-Richardson 1, Patrick A. Ryan 2, Hilary Hafner 2, Diane Gould 3
Jeri Weiss 3, Andy Johnson 1, Ellen Doering 1, Beverly Bayley-Smith 4
1 Maine Department of Environmental Protection (MEDEP), SS#17, Augusta, Maine
2 Sonoma Technology, Inc., Petaluma, California
3 US EPA, Boston, Massachusetts
4 Casco Bay Estuary Project, Portland, Maine
A monitoring site was established on the shore of Casco Bay at Wolfe's Neck in Freeport, ME in 1998 in order to assess the magnitude and impact of atmospheric deposition to the Casco Bay ecosystem. The sampling equipment installed at the site (1998-present) includes an IMPROVE (Interagency Monitoring of Protected Visual Environments) aerosol collection system, an NADP (National Atmospheric Deposition Program) precipitation collector, an MDN (Mercury Deposition Network) mercury precipitation sampler, and (1998-1999) a PAH (polycyclic aromatic hydrocarbon) wet and dry deposition sampler. The Casco Bay Study demonstrates that atmospheric deposition of both mercury and nitrogen is a current and very significant source of pollution to Casco Bay.
The Study has also developed an air deposition loading estimation protocol which may be used by other community-based programs to quickly estimate the magnitude of air deposition of pollutants where field monitoring may not be practical. The loading estimates developed for Casco Bay by applying the protocol compare favorably with the field monitoring data, suggesting that the estimation protocol is a useful tool.
Keywords: atmospheric deposition, NADP, MDN, IMPROVE, estimation, nitrogen, mercury