Development of Analytical Methods for Trace Environmental Contamination

The cleanup and restoration of sites that exhibit "legacy" environmental contamination continues to present unique challenges for the analytical chemist. For example, new environmental regulations may stipulate a detection limit at or below that normally achieved using traditional procedures and equipment that has been tested and approved by either state or federal environmental protection agencies. Further, some sites may exhibit contamination from species that do not appear on compilations such as the U. S. Environmental Protection Agency's Appendix IX. Such sites may have been used for the production of military-specific compounds such as chemical warfare agents. Additionally, there is a continued effort to reduce the volume of chemically-hazardous waste used to perform a given determination. Analytical methods that generate considerable volumes of waste solvent during the normal determination of an ultratrace-level contaminant are steadily going out of favor. Finally, there is the ever-increasing need to demonstrate that an analytical procedure actually does perform as claimed. Current practice demands that detection limits be calculated in some practical and meaningful fashion, that the analytical results be confirmed both for the identity and concentration of a given compound, and that the method actually perform as stated. All of those concerns may be addressed using a statistically-based protocol for evaluating new analytical procedures.

The Group has extensive experience in dealing with all of these concerns, based on our long-standing association with the U. S. Army Rocky Mountain Arsenal. New methods were developed and tested for part-per-billion or part-per-trillion concentrations of organochlorine, organonitrogen, or organophosphorus pesticides in ground water. Additional technologies were evaluated for the determination of chemical warfare agent by-products and degradation products of sarin (GB), sulfur mustard (HD), and Lewisite (L) in ground water, soil, and crushed concrete. The volume of chemically-hazardous waste produced per determination was reduced, particularly for ground water samples, using solid-phase extraction (low-volume waste) or solid-phase microextraction ("solventless" extractions). Each new method was ultimately evaluated using the rigorous statistical protocol mandated by the Rocky Mountain Arsenal. Most of our results have been published in the open literature, and may be found on our special website.

For more information, contact Bruce Tomkins.