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Environ Sci Technol

Title:		"Changing chemical composition of precipitation in Wilmington, North Carolina, U.S.A.: implications for the Continental U.S.A"
Author(s):		Willey JD; Kieber RJ; Avery GB;
Address:		"Department of Chemistry and Biochemistry and Marine Science Program, University of North Carolina Wilmington, Wilmington, North Carolina 28403-5932, USA. willeyj@uncw.edu"
Journal Title:		Environ Sci Technol
Year:		2006
Volume:		40
Issue:		18
Page Number:		5675 - 5680
DOI:		10.1021/es060638w
ISSN/ISBN:		0013-936X (Print) 0013-936X (Linking)
Abstract:		"The H+(aq) concentration in Wilmington, NC, precipitation has decreased by approximately 50% during the preceding two decades, similar to trends seen nationwide. The decrease in acidity is important because solution pH plays a key role in atmospheric reactions, and because the change is so large. This study presents the first long-range study of dissolved organic carbon (DOC) levels in precipitation which demonstrates that DOC concentrations have decreased by approximately half in Wilmington, NC, precipitation. The concentrations of H+(aq) and DOC are highly correlated primarily because small organic acids contribute to both DOC and H+(aq) in precipitation. Ammonium ion concentrations in precipitation have increased due to increased agricultural activities, and this also affects precipitation pH. The reduction of SO2 emissions in 1995 imposed by the Clean Air Act Amendment, better control of emissions of volatile organic compounds, and the increase in ammonia emissions all contribute to the decreasing H+(aq) in precipitation nationwide. These compositional changes in precipitation have many environmental implications, such as decreased acid deposition to lakes, changing speciation for trace metals in precipitation, increased ammonium deposition to coastal waters, and decreased DOC transport to the open ocean"
Keywords:		Acid Rain Carbon/*chemistry Chlorides/chemistry Hydrogen-Ion Concentration North Carolina Organic Chemicals/chemistry Quaternary Ammonium Compounds/chemistry Rain/*chemistry;
Notes:		"MedlineWilley, Joan D Kieber, Robert J Avery, G Brooks Jr eng Research Support, U.S. Gov't, Non-P.H.S. 2006/09/30 Environ Sci Technol. 2006 Sep 15; 40(18):5675-80. doi: 10.1021/es060638w"