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ARS Home » Plains Area » Fargo, North Dakota » Edward T. Schafer Agricultural Research Center » Food Animal Metabolism Research » Research » Publications at this Location » Publication #148928
Title: CALUX AND HIGH RESOLUTION GC/MS ANALYSIS OF DIOXIN-LIKE COMPOUNDS IN CHLOROPHENOXY PESTICIDE FORMULATIONS.

Author
item Huwe, Janice
item CLARK, GEORGE - XENOBIOTICS DETECTION SYS
item CHU, ANDREW - XENOBIOTICS DETECTION SYS
item GARRY, VINCENT - UNIV OF MINNESOTA

Submitted to: Organohalogen Compounds
Publication Type: Peer Reviewed Journal
Publication Acceptance Date: 1/1/2003
Publication Date: 1/1/2003
Citation: Huwe, J.K., Clark, G., Chu, A., Garry, V. 2003. Calux and high resolution gc/ms analysis of dioxin-like compounds in chlorophenoxy pesticide formulations. Organohalogen Compounds. 60:227-230.

Interpretive Summary: An epidemiology study of pesticide applicators in the Red River Valley of northwestern Minnesota has suggested a correlation between pesticide exposure, lowered testosterone levels, and an increased ratio of female to male offsping within an experiment cohort. Dioxins and dioxin-like compounds have been known to elicit these same biological effects and are known to be present in certain pesticides. We have, therefore, collected and analyzed eight 2,4-D type pesticide formulations commonly used in the Red River Valley area of MN. Three of these eight pesticides contained levels of toxic dioxins over 700 pg/g. It is speculated that the dioxins resulted from impurities in the chlorinated phenols used for production of the pesticides. In addition, these same pesticides were analyzed by a screening bioassay (CALUX) in order to determine whether a quick screening method could predict the extent of dioxin contamination in pesticide formulations. The CALUX responses were similar, but generally higher, than the traditional analytical results. Given the nature of the CALUX bioassay, it may provide a more convenient and accurate assessment of the potential biological activity of pesticide formulations.

Technical Abstract: Eight 2,4-D type pesticides commonly used in the Red River Valley of northwestern Minnesota were analyzed for dioxin-like compounds by both the cell-based CALUX screening bioassay and by high-resolution GC/MS. Comparison of the toxic equivalencies (TEQs) calculated for both methods showed that CALUX TEQs were similar to GC/MS TEQs but generally higher. Two pesticides (Bronate and Assure II) showed significant dioxin-like activity in the CALUX bioassay (800 and 1600 pg/g); however, little if any polychlorinated dioxins and furans (PCDD/Fs) were detected by GC/MS analysis. The active ingredients in these two pesticides or an impurity may be structurally similar enough to dioxins to activate the CALUX response pathway i.e. the cell's aryl hydrocarbon receptor. Each of the other six pesticides contained PCDD/Fs in varying amounts. GC/MS TEQs ranged from 0.3 to 2627 pg/g for the eight pesticides. Aside from the toxic 2,3,7,8-substituted PCDD/Fs, numerous other isomers of PCDD/Fs were also detected. The presence of PCDD/Fs in these pesticides is assumed to be due to impurities found in the starting chlorophenols.