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PESTICIDE EXPOSURE AND CHIRAL CHEMISTRY: THE PYRETHROID FAMILY
ULRICH, E. M. PESTICIDE EXPOSURE AND CHIRAL CHEMISTRY: THE PYRETHROID FAMILY. Chimica Oggi (Chemistry Today). TEKNOSCIENZE, Milano, Italy, 25(5):37-39, (2007).
The overall goal of this research program is to identify those chemicals, pathways, and activities that represent the highest potential exposures to children and to determine the factors that influence these exposures. The following objectives will address this goal: (1) Revise and refine the existing research plan for children's exposure measurements research. (2) Collect measurement data on children's exposures. (3) Provide analytical support to children's pesticide exposure research. (4) Develop analytical methods for pesticides in duplicate diet food samples. (5) Develop and apply analytical methods for other chemicals including but not limited to brominated diphenyl ethers, phthalates, perfluorinated chemicals. (6) Evaluate the impact of chiral chemistry on the risk to children and exposure assessment. (7) Provide support to the National Children's Study. (8) Perform data analyses to fill critical data gaps. (9) Conduct analyses of dietary samples and refine the dietary model for the dietary exposure algorithm.
Advances in chiral chromatography significantly advanced the ability to analyze individual enantiomers of chiral compounds. These techniques are being employed at the U.S. EPA for human exposure and ecological research studies. Enantiomer fractions (EFs) were measured for cispermethrin, a pyrethroid insecticide. Nonracemic EFs in some environmental samples indicate that some nantioselective biological degradation has occurred, either in the indoor environment or prior to translocation indoors. These results highlight the importance of chiral methods because some degradation pathways can change the distribution of enantiomers in the environment and may lead to differential exposure. The toxicity of enantiomers can also vary. When these two factors are combined, a differential risk to humans and other organisms may be revealed.