Sunday, August 23: 4:30 p.m., Room: 207 Hynes CC

Calcium Carbonate Mineralization Plays Role in Maintaining Ecosystem Balance in South Florida: Anthony R. Hoch, a USGS scientist, will discuss how the rate of calcium carbonate (calcite) mineralization in the Florida Everglades is affected by naturally occurring dissolved organic matter. The mineralization of calcite plays an important role in the regulation of the Everglades' water chemistry, and may affect the mobility and fate of mercury, a highly toxic metal. This study is part of a larger, inter-disciplinary effort by the USGS to provide sound scientific information to the public and natural resources managers who make decisions about the reestablishment and maintenance of the South Florida ecosystem.

Monday, August 24: 8:55 a.m., Room: 208 Hynes CC

Uranium Used to Trace Contamination of Ground Water Near Coal Fly Ash Storage Facilities: One of the industrial by-products of coal burning is a solid residue called "fly ash". This mixture of silicate glass and mineral matter is commonly destined for disposal in constructed pits, ponds, and landfills, or in abandoned mines and quarries. The primary environmental concern associated with these disposal sites is the potential for ground water contamination. Uranium is one of the more soluble and dispersible of a group of toxic trace constituents present in fly ash. Locally elevated, but not hazardous, concentrations of dissolved uranium near fly ash disposal sites may therefore indicate leakage and pathways of contaminated water from the sites. Addition of uranium to water supplies is a concern in view of the Environmental Protection Agency's (EPA) plans to add a drinking water standard for uranium by the year 2000. Join Robert A. Zielinski of Denver, Colorado, for an overview of a 2-year USGS
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Contact: Marion Fisher
mmfisher@usgs.gov
703-648-4583
United States Geological Survey
21-Aug-1998