Lecture Abstracts
"Interfaces, Heavy Metals, Microbes, and Plants:
Shedding New Light on Environmental Science at the Molecular Level"
Wednesday, December 1, 2004 - 4:30pm - 125 Riley Robb
This talk will focus on recent applications of synchrotron radiation-based methods to environmental processes and problems, particularly those occurring at environmental interfaces. Following a brief introduction to synchrotron radiation (SR), SR sources, and some of the SR methods now being used to examine complex environmental samples, we will examine a number of case studies aimed at addressing specific environmental processes and problems, including heavy metal sorption processes at mineral/aqueous solution and plant/solution interfaces, the role of microorganisms in heavy metal transformations, the effect of biofilm and natural organic matter coatings on mineral surfaces in heavy metal sequestration, Pb contamination at Leadville, CO, Zn contamination in soils in northern France, Cr and U contamination problems in the vadose zone at Hanford, Washington, and As contamination problems in Bangladesh.
"From Subduction to Mercury in Tuna: Hg Mining and
Contamination in the California Coast Range, USA"
Tuesday,
November 30, 2004 - 4:30pm - Department of
Earth and
Atmospheric Sciences, Seminar Series, 2146 Snee Hall
This presentation will explore mercury as a significant environmental contaminant, particularly in the San Francisco Bay area and California Coast Range, as a result of mercury mining in the Coast Range and placer gold mining activities in the Sierra Nevada foothills, where elemental mercury was used to amalgamate gold. Following a review of the magnitude of the problem and the associated health effects, the geology of the two major mercury deposits in North America (New Almaden, CA and New Idria, CA) will be reviewed via an "armchair" field trip to these deposits, including a discussion of acid mine drainage at the New Idria Mine and a sidebar on microbial oxidation of pyrite, which is one of the main processes producing acidic mine waters. We will then examine the various pathways that mercury takes in its journey from these deposits to surface waters such as drinking water reservoirs and San Francisco Bay. Details of the mineralogy and geochemistry of mercury will be highlighted, as will the transport mechanisms of mercury, its molecular level speciation, sorption processes, and transformations into potentially bioavailable forms. This presentation will conclude with a study of atmospheric emissions of mercury, which is based on measurements made at various mining sites in the western U.S. and correlated with mercury mineralogy at these sites.
"Applications of Hard and Soft X-ray Spectroscopy, Scattering,
and Imaging Methods to Model Environmental Systems: A Reductionist
Approach to Complex Environmental Processes""
Thursday,
December 2, 2004 - 12:00pm - G10 Biotechnology
Synchrotron radiation methods are being used to provide unique information on the chemical forms of common environmental contaminants in complex natural and laboratory systems at the molecular level. Such information is essential for defining the processes by which contaminants are transformed to more (or less) toxic forms by microbial organisms, plants, and mineral surfaces in polluted soils and aquatic systems. A reductionist approach is necessary in order to provide fundamental understanding of chemical processes in complex environmental systems. This lecture will focus on recent applications of various synchrotron radiation methods to complex environmental materials and processes, including photoemission studies of the interaction of water with metal oxide surfaces, XAFS studies of the structure of water, XAFS and x-ray scattering studies of the structure of aqueous metal complexes, grazing incidence XAFS studies of metal ion adsorption at metal oxide-aqueous solution interfaces, crystal truncation rod diffraction studies of the hydrated surfaces of metal oxides, x-ray standing wave studies of the effect of microbial biofilms on the chemical reactivity of common metal oxide surfaces, and scanning transmission x-ray microscopy studies of biocolloids.
2008 Run
Nov 19th - Dec 22nd
