ANTHROPOGENIC INFLUENCES ON THE GLOBAL MERCURY CYCLE - A MODEL-BASED ANALYSIS

A model of the global Hg cycle is presented and applied to analyze mod em Hg budgets and historical changes in deposition. Our modeling sugge sts that mixing into the ocean interior is a significant sink of Hg an d likely has limited any anthropogenically-caused increase in surface ocean Hg concentrations to about 50% above natural levels rather than 200% as has recently been argued. Additionally, both the increase in a ir pollutants during the industrial era and their recent decrease in N orth America likely have affected atmospheric Hg scavenging and the re sulting records of Hg deposition rates in lake and bog sediments.