| The atmospheric deposition and sources of mercury and other trace elements (Al, As, Ba, Ca, Cd, Co, Cr, Cu, Fe, K, Mg, Mn, Na, Ni, Pb, Rb, Sb, Se, Sr. Ti, V and Zn) to northern New York were investigated in this study. This research, which had many interrelated parts, is presented in four distinct sections in this thesis: (1) estimation of the atmospheric Hg loadings to Lake Ontario, (2) identification of possible source regions for wet deposition of Hg, (3) investigation of the characteristics of trace elements in precipitation, and (4) development and evaluation of two direct measurement techniques for Hg dry deposition.; In the first section, a total deposition model describing wet deposition, air-water exchange and dry particle deposition was developed to estimate atmospheric Hg loadings to Lake Ontario. Data from monitoring sites at Sterling NY, Pt Petre Ontario and from three cruises on Lake Ontario aboard the R/V Lake Guardian were used. Assuming that 10% of Lake Ontario surface area was influenced by urban areas, the atmospheric Hg loadings of wet deposition, net air-water exchange of Hg0, RGM dry deposition, and Hg(p) dry deposition to Lake Ontario were about 170, -110, 68, and 20 kg yr-1 , respectively, resulting in a net Hg loading of 150 kg yr -1. The net Hg loadings were very sensitive to the urban-rural concentration ratios, the amount of the lake assumed to be influenced by urban areas, wind speed and DGM concentration.; In the next section, analyses of event-based wet deposition samples collected to investigate the characteristics of trace elements in precipitation measured in Potsdam, NY were examined. The concentrations and wet deposition fluxes of trace elements varied over one to four, and one to three orders of magnitude in terms of range, respectively. The annual volume weighted mean (VWM) concentration and wet deposition fluxes of Hg were 5.5 ng L-1, 5.9 mug m-2, respectively. The seasonal variations in the VWM concentrations were not consistent for all elements. The wet deposition fluxes of sixteen trace elements were largest in spring (Mg, Al, Ca, Mn, Fe, Cu, Sr, Cd, Sb, Ba and Pb) and summer (Ti, V, Se, Rb and Hg) in which the highest precipitation amounts were measured. (Abstract shortened by UMI.)... |
