Fitzgerald, W. F., Dept. Marine Sciences, Univers, Groton, CT, USA, william.fitzgerald@uconn.edu
Hammerschmidt, C. R., Dept. Earth & Environmental Sciences, Wright State University, Dayton, OH, USA, chad.hammerschmidt@wright.edu
Engstrom, D. R., St Croix Watershed Research Station, Science Museum of Minnesota, Marine on St Croix, MN, USA, dre@umn.edu
Lamborg, C. H., Marine Chemistry & Geochemistry, Woods Hole Oceanographic Institution, Woods Hole, MA, USA, clamborg@whoi.edu
Balcom, P. H., Dept. Marine Sciences, University of Connecticut, Groton, CT, USA, prentiss.balcom@uconn.edu
Reddy, C. M., Marine Chemistry & Geochemistry, Woods Hole Oceanographic Institution, Woods Hole, MA, USA, creddy@whoi.edu

MODERN AND HISTORIC MERCURY DEPOSITION: INSIGHTS FROM DATED LAKE SEDIMENTS AND A VARVED ESTUARINE CORE

Contemporary and historical Hg depositional information is important for understanding the biogeochemical cycling of Hg and assessing impact associated with human-related Hg emissions on its natural cycle. Dated lake sediments have been the primary source of secular data for reconstructing Hg accumulation / depositional patterns associated with preindustrial periods to the modern era. These lacustrine natural archives are particularly well suited for examining the global/regional nature of atmospheric Hg dispersion, deposition, and anthropogenic interferences. Here we present an evaluation of the impact from pollutant Hg on local to global scales. The accumulation ratio or “anthropic global increase”, relative to preindustrial levels, is remarkably uniform at 3±1 based on 182 cores and 90 lakes from remote locations. Localized enhancements are evident in urban areas (i.e., Minneapolis/St. Paul, MN) with peaks in the 1960-1970 period. New and detailed historical data for Hg accumulation in a well studied, scrupulously dated, varved core from the Pettaquamscutt Estuary, RI (northeast US) will be presented. The significance of these new findings will be explored relative to other temporal reconstructions of Hg deposition.

Oral presentation

Presentation is given by student: No
Session #:187
Date: 03-07-2008
Time: 08:00