Joseph Scudlark

The trace element composition of precipitation has been used to examine the atmospheric emission sources which contribute to the composition of wet deposition on Delmarva. Meteorological and multivariate statistical receptor models, including air mass back-trajectory analysis, Principal Component Analysis, and the Chemical Mass Balance Method, were employed to reveal these sources.These models were applied independently and in composite form to two data bases; (1) the long-term (1982-1989) continual record at Lewes, Delaware, and (2) intensive sampling at Lewes, Delaware and Beltsville, Maryland which involved synoptic aerosol and precipitation sampling conducted in cooperation with the University of Maryland. Particular emphasis was placed on discriminating emissions related to electric power generation, and on contrasting the differences between aerosol and precipitation-based receptor modeling.

A method is described for the accurate determination of trace metals in precipitation, which has been successfully utilized for ten years at diverse rural and remote locations. The accurate determination of trace metals in precipitation at the nanomolar level (generally 3 or more orders of magnitude less than major ion constituents), requires the use of specific materials and exacting cleaning, handling, preservation and collection procedures. The total atmospheric wet deposition of trace metals is apportioned between dissolved and particulate phases, which varies spatially and temporally for each metal. The application of proper collection and analysis techniques insures quantification of the total (dissolved plus particulate) concentration.

ABSTRACT The primary objective of this study was to compare the fluvial versus atmospheric importance oftrace element fluxes to the Delaware Inland Bays. The dissolved fluvial loading of selected trace metals was determined based on seasonal sampling (1992-95) of the major streams. Atmospheric wet metal deposi­ tion was gauged based on long-term (1982-present) continuous collections at a nearby site. Atmospheric dry deposition was modeled based on measured aerosol concentrations and assumed bi-model deposition velocities. Atmospheric dry flux appears to be more significant for crustal elements (AI, Fe, and Mn), while wet flux is more important for non-crustal trace elements (Cd, Cr, Cu, Pb and Zn). Overall, atmospheric deposition provides at least 5% (Mn) to 30% (Zn) of the total loading to the Inland Bays, with direct flux to the surface waters comprising about half ofthe total aeolian input. The Inland Bays watershed serves as a reservoir for atmospherically deposited AI, Cr, Cu and In. An examination of basin yields (kg/m1) for the major tributaries reveals the accelerated weathering ofuniquely bog iron deposits in two marshy tributaries, while another exhibits exceptionally large export of anthropogenic metals Cd, Cr, Cu and Pb.

ABSTRACT The purpose of the study was to determine atmospheric loadings of selected trace elements and organic compounds directly into the Chesapeake Bay. The work represents the first year of the Chesapeake Bay Atmospheric Deposition Study. A one-year study (6/90-7/91) was conducted to estimate the deposition of atmospheric contaminants to the Maryland portion of the Chesapeake Bay. The studied contaminants included the trace elements (Aluminum, Arsenic, Cadmium, Chromium, Copper, Iron, Manganese, Nickel, Lead, Selenium, and Zinc) polychlorinated biphenyl (PCBs) congeners, and polycyclic aromatic hydrocarbons (PAHs).

... Jennifer A. Volk a , 1 , E-mail The Corresponding Author , Joseph R. Scudlark a , E-mail The Corresponding Author , Karen B. Savidge a , A. Scott Andres b , E-mail The Corresponding Author , Robert J. Stenger c , E ... (1977), Glibert and Loder (1977), and Solorzano and Sharp ...