Modeling Long-Term Patterns of Speciated Mercury Concentrations in Maryland Using CALPUFF

John Sherwell
Maryland Power Plant Research Program (PPRP), 580 Taylor Ave.,
Tawes State Office Building, Annapolis, MD, 21401

Tom Wickstrom, Anand Yegnan, Mark Garrison
ERM, 350 Eagleview Blvd., Exton, PA 19341

Mark Castro, Chris Moore
University of Maryland Center for Environmental Science,
301 Braddock Rd., Frostburg, MD 21532


The Maryland Department of Natural Resources, Power Plant Research Program (PPRP) has provided support for the enhancement of a monitoring site at the Piney Reservoir in western Maryland by adding instrumentation (Tekran) that measures ambient speciated mercury on a continuous basis. Since the Piney site is part of several monitoring networks, a comprehensive set of concentration, deposition, and meteorological parameters are measured there. Nearly two years of continuous, speciated mercury concentrations are now available from the Piney site - elemental (HG0), reactive (Hg2+) and particulate (HgP). These data display seasonal, diurnal, and other patterns of mercury concentrations (including occasional large peaks of Hg2+) that can contribute to an understanding of the relative importance of local, regional, and global sources of mercury. PPRP has developed a modified version of the CALPUFF Lagrangian model to estimate mercury concentrations and deposition in Maryland. CALPUFF is capable of creating detailed source contribution matrices of mercury concentrations and deposition. While the CALPUFF model has demonstrated reasonably good performance when compared to weekly mercury deposition network (MDN) measurements, it has yet to be comprehensively evaluated with continuous concentrations. Success in predicting mercury concentrations is a necessary ingredient for estimating dry deposition, which may play an extremely important (but less-understood) role in mercury loading to watersheds and waterbodies due to atmospheric input. PPRP is taking the first step in this evaluation by comparing model predicted patterns with patterns measured at Piney. To develop the model predictions, a 10-year meteorological data set is used to examine the frequency and persistence of certain patterns. This poster will compare the model predictions over a ten-year period to measurements taken at Piney to provide insights into model performance related to speciated concentrations.