Increasing rates of atmospheric mercury deposition in midcontinental North America
Swain EB, Engstrom DR, Brigham ME, Henning TA, Brezonk PL. 1992. Increasing rates of atmospheric mercury deposition in midcontinental North America. Science. 257(5071):784-787
Mercury contamination of remote lakes has been attributed to increasing depostion of atmospheric mercury, yet historic deposition rates and inputs from terrestrial sources are essentially unknown. Sediments of seven headwater lakes in Minnesota and Wisconsin were used to reconstruct regional modern and preindustrial deposition rates of mercury. Whole-basin mercury fluxes, determined from lake-wide arrays of dated cores, indicate that the annual deposition of atmospheric mercury has increased from 3.7 to 12.5 micrograms per square meter since 1850 and that 25 percent of atmospheric mercury deposition to the terrestrial catchment is exported to the lake. The deposition increase is similar among sites, implying regional or global sources for the mercury entering these lakes.
- Type
- Journal Article
- Authors
- Swain, E; Engstrom, D; Brigham, M; Henning, T; Brezonk, P
- Units
- ARD , ISRO
- Keywords
- AIRBIB, Deposition, headwater lakes, Mercury (Hg)