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SEPARATION OF ENANTIOMERS OF ENVIRONMENTAL POLLUTANTS
Citation:
Garrison, A W. SEPARATION OF ENANTIOMERS OF ENVIRONMENTAL POLLUTANTS. Presented at 221st American Chemical Society National Meeting, San Diego, CA, April 1-5, 2001.
Impact/Purpose:
Extend existing model technologies to accommodate the full range of transport, fate and food chain contamination pathways, and their biogeographical variants, present in agricultural landscapes and watersheds. Assemble the range of datasets needed to execute risk assessments with appropriate geographic specificity in support of pesticide safety evaluations. Develop software integration technologies, user interfaces, and reporting capabilities for direct application to the EPA risk assessment paradigm in a statistical and probabilistic decision framework.
Description:
Chiral environmental pollutants exist as sets of 2 (or more) enantiorners - mirror image isomers that are identical in all physical and chemical properties except when reacting with other chiral entities such as enzymes and other chiral molecules. This exception give rise to differences in microbiological transformation rates and toxicities of the enantiomers. It is, therefore, important
to understand the relative biotransformation rates of enantiomers so as to predict their persistence and occurrences in the environment, and to study their relative toxicities. Coupling this persistence and toxicity data should allow more accurate risk assessment of pesticides and other pollutants. In order to study the occurrence, fate and toxicity of enantiomers, it is necessary to use separation techniques based on chiral chemistry. We have developed and adapted such techniques to high pressure liquid chromatography, gas chromatography and capillary electrophoresis instrumentation. Examples will be shown of the separation of the enantiomers of organophosphorus, organochlorine, imidazolinone, phenoxyacid and other classes of pesticides, as well as of PCBs and other environmental pollutants. In addition, applications of these separation techniques to determine the environmental occurrences of enantiomers and the enantioselectivity of microbial transformation of chiral pollutants will be illustrated.