Advanced Light Source: Quantitative Zinc Speciation in Soil
A scientific approach to cleaning up the environment requires basic chemical
information at the molecular level about contaminants. For example, a remediation
strategy depends not just on the concentration of the toxic metal but on
its mobility in soil and water and its ease of uptake by plants, animals,
and people, properties that depend on the chemical compounds containing
the metal. A team of French researchers working at the Advanced Light Source
(ALS) and the European Synchrotron Radiation Facility (ESRF) in Grenoble
has shown how to use complementary x-ray techniques to identify zinc-containing
compounds in contaminated French and Belgian soils located near smelters.
In particular, they combined spatially resolved (at the µm scale) x-ray
fluorescence (µ-XRF) and extended x-ray absorption fine structure (µ-EXAFS)
at the ALS and polarized EXAFS at the ESRF to make the key identification
of important zinc constituents and their structural forms (i.e., their speciation).