344-2 Chromium Chemical Speciation In Pedogenic Iron Nodules From Santa Cruz, California.



Wednesday, October 19, 2011: 8:30 AM
Henry Gonzalez Convention Center, Room 212B, Concourse Level

Yuji Arai, Dept of Entomology Soils Plant Sciences, Clemson University, Clemson, SC, Marjorie Schulz, USGS, Menlo Park, CA and Samuel Webb, SSRL/SLAC, Menlo Park, CA
Drinking water contamination of hexavalent chromium(Cr) in several U.S. major cities was recently brought to our attention by California Environmental working group. While the current remediation methods and water treatment systems can be re-visited to improve the water quality, there are numerous indigenous Cr contamination sources that continue to pose threats to human and ecological health in the U.S. In this study, we investigated the chemical speciation and spatial distribution of Cr in Fe nodules and its relation to Fe mineralogy at a marine terrace soil chronosequence northwest of Santa Cruz, California. Iron nodules (0.5 to 25 mm) are abundant in the terraces at depths < 1m, and nodules are naturally high in Cr due to weathering of ultramafic rocks particularly rich in serpentine. The results of synchrotron based X-ray microprobe/XRD and X-ray absorption spectroscopy analysis will be discussed.
See more from this Division: S02 Soil Chemistry
See more from this Session: Advanced Analytical Methods for Understanding the Chemistry of Elements In Soils: I