[Colloquium] Seminar Announcement: Biogeochemical Cycling of Man-Made Contaminants: The Mystery of Mercury - TODAY!

[Ninfa Mayorga]

Computation Institute Presentation

Speaker: David G. Streets, Senior Scientist, Decision and Information Services, Argonne National Laboratory
Date: September 29, 2011
Time: 1:00 PM - 2:00 PM
Location: The University of Chicago, Searle 240A, 5735 S. Ellis Ave., Argonne National Lab, TCS/Room 5C2 (5172)

Biogeochemical Cycling of Man-Made Contaminants: The Mystery of Mercury

Abstract:
Nature has always recycled mercury from its prison in the lithosphere, in the form of volcanic eruptions, erosion, and slow dissolution in oceans and rivers. But, about 5,000 years ago, man began digging into the Earth’s crust to extract gold, silver, copper, coal, and other materials—all of which came laced with mercury. The rate of release of mercury through human activities has now grown to be more than four times the natural release rate. The health damage caused by mercury is well-known, and its emissions are currently the topic of EPA and UNEP control proposals. At Argonne we are researching both historical and potential future global emissions of mercury from the earliest historical periods to 2050. Working with biogeochemical modelers at Harvard University, we are trying to understand how the released mercury has cycled over time through air, water, and land. Though we can roughly reproduce the kinds of levels of mercury measured in snow, ice cores, and lake sediments today, one big mystery remains. We find that releases of mercury to the atmosphere have increased in the past few decades; yet, measured mercury in the atmosphere at remote locations seems to have decreased at just about the same rate over the same period of time. The reason for this stark discrepancy is presently unknown. Clearly, there are unknown components of the mercury cycling scheme that remain to be discovered.

Information: This talk will be broadcast via the Access Grid at both locations - (Computation Institute) Searle/Room 240A and (Argonne) TCS Building 240/Room 5172