This example is from work by other authors performed at the ALS in LBNL.

To determine the availability of chemical elements in soils, it is critical that the chemical speciation and reaction mechanisms of elements be understood. In this study we examine the distribution of trace elements and mineral associations in soil samples using synchrotron based X-ray fluorescence microprobe and determine the oxidation state and local atomic structure using X-ray absorption spectroscopy. In particular, this study focuses on the trace elements arsenic and selenium, and their associations with the iron minerals jarosite and goethite. The findings of this research will provide a better understanding of trace element cycling in a natural, unaltered, soil environment.