ANNOUNCEMENT: Workshop on Mercury Cycling in the Environment In Reply Refer To: Mail Stop 412 MEMORADNUM April 22, 1996 To: All U.S. Geological Survey (USGS) Employees From: David A. Rickert Chief, Office of Water Quality Subject: ANNOUNCEMENT: Workshop on Mercury Cycling in the Environment This memo announces a workshop on Mercury Cycling in the Environment, to be held in Lakewood, Colorado, July 8-10, 1996. The USGS is sponsoring the workshop in recognition that public concern for fish and wildlife and human health from mercury toxicity has increased substantially over the past 5 to 10 years. These concerns are manifested primarily from the issuance of fish consumption advisories in the majority of U.S. states, Canada, and several European countries due to high levels of mercury in game fish. Consumption advisories have been issued for systems as small as individual seepage lakes in Wisconsin (where a neighboring lake does not exhibit elevated levels in fish), to sub-regional areas as large as the Florida Everglades where a complete ban on game fish consumption is in effect. Although the precise causes for this contamination are poorly understood, it appears to result from both source and ecosystem-specific factors. Until recently, attempts to unravel this environmental contamination problem have been frustrated by both sampling and analytical barriers. For most aquatic ecosystems, atmospheric deposition is the primary source of mercury (although there are numerous instances of geologic and anthropogenic point-source contamination cases) and the resulting aqueous concentrations of total mercury are generally less than 10 nanograms/liters. The challenge to scientists is to explain the series of processes that lead to toxic or near-toxic levels of mercury in organisms near the top of the food chain (the bioaccumulation process), when aqueous concentrations and source-delivery rates are so low. To adequately understand this phenomenon an interdisciplinary approach is requisite. Due to recent great strides in sampling and analytical techniques, scientists can now routinely collect representative air, water, tissue, and sediment samples, and perform mercury species-specific analysis. The resultant data have provided new insights into the transport, cycling, and fate of mercury in systems as small as individual seepage lakes, to as large as Lake Michigan and oceanic-scale studies. In addition, new techniques that employ isotopic tracers have provided new insights about the specific processes at the root of this contamination problem: mercury methylation and demethylation. A draft agenda for the Workshop is attached. The workshop will be split into three major sections: · Mercury in the Environment: Presentations from scientists on a wide variety of topics that characterize the mercury contamination problem, summarize current knowledge of the important processes that control mercury cycling, and present case histories of mercury studies. · Data and Knowledge Gaps: Open forum discussion to identify the current scientific gaps in understanding the origin, causes, and effects of the widespread mercury contamination problem. · How can the Gaps Best Be Filled: Open forum discussion to prioritize needs for methods development, small scale process oriented studies, and large scale statistical/process oriented assessments. The Workshop will be held the week of July 8-10, 1996, at the Ramada Inn in Lakewood, Colorado. To aid our planning, please respond to Wayne Webb (wwebb@usgs.gov, 703-648-5810) by May 24th if you are coming to the Workshop. Also, the agenda is open to anyone who would like to present results of past or current mercury investigations. Please respond to David Krabbenhoft (dpkrabbe@usgs.gov, 608-276-3843) by May 24th if you would like to be a presenter [we are anticipating short, 15 minute, talks]. The agenda is a draft, please feel free to make comments to Wayne or Dave if you would like to see items added. MERCURY CYCLING IN THE ENVIRONMENT Draft Workshop Agenda Monday, 7/8/96, 1:00 - 5:00 pm Mercury in the Environment: The Problem · Human Health Concerns (Historical Record, Physicochemical Studies) · Mercury in Fish and Wildlife · Sources (Natural vs. Anthropogenic) · Atmospheric Transport, Reactions, and Deposition) · Recent Advances in Sampling and Analysis Tuesday, 7/9/96, 8:00 am - 12:00 pm Mercury in the Environment: Processes · Mercury Methylation and Demethylation Studies · Accumulation of Mercury in Sediment · Sediment/Water Exchange · The "Reservoir-Creation" Effect on Mercury · Interactions of Dissolved Organic Carbon and Mercury · Mercury fluxes to and from Terrestrial Soils Tuesday, 7/9/96, 1:00 pm - 5:00 pm Mercury in the Environment: Case Studies (To be identified) Wednesday, 7/10/96, 8:00 am - 12:00 pm Data and Knowledge Gaps (moderated open forum discussion) · Synthesis of Presentations · Open Forum Discussions on Information Gaps · Data syntheses · Source Characterization · Atmospheric Deposition · Human Health Impacts · Aquatic and Terrestrial Ecology · Geochemical Process Studies · Sampling and Analytical Needs How Can the Gaps Best Be Filled? Wednesday, 7/10/96, 1:00 - 5:00 pm How Can the Gaps Best be Filled (moderated open forum discussion) · Sampling and Analytical Developments (1:00 to 1:45) · Small-Scale, Process-Oriented Studies (1:45 to 2:30) · Regional/National Data Synthesis Needs (3:00 to 5:00) · Existing Geochemical Data · Pertinent GIS Coverages · Mercury Sources · Deposition Patterns · Bioaccumulation Patterns