Document Detail


Bioaccumulation and biotransformation of chiral triazole fungicides in rainbow trout (Oncorhynchus mykiss).
MedLine Citation:
PMID:  17118468     Owner:  NLM     Status:  MEDLINE    
Abstract/OtherAbstract:
There are very little data on the bioaccumulation and biotransformation of current-use pesticides (CUPs) despite the fact that such data are critical in assessing their fate and potential toxic effects in aquatic organisms. To help address this issue, juvenile rainbow trout (Oncorhynchus mykiss) were exposed to dietary concentrations of a mixture of chiral triazole fungicides (bromuconazole, cyproconazole, metconazole, myclobutanil, penconazole, propiconazole, tebuconazole, tetraconazole, and triadimefon) and a chiral legacy pesticide [alpha-hexachlorocyclohexane (alpha-HCH)] to study the bioaccumulation and biotransformation of these CUPs. Fish accumulated all triazoles rapidly during the 8 day uptake phase, and was followed by rapid elimination, which was estimated by taking accelerated sampling times during the 16 day depuration period. Half-lives (t1/2s) and times to 95% elimination (t95s) ranged from 1.0 to 2.5 and 4.5 to 11.0 days, respectively. Chiral analysis suggested no significant selectivity in biotransformation for most of the compounds based on statistically unaltered enantiomer fractions (EFs) in the fish compared to food values; exceptions were a change in EF of myclobutanil and changes in diastereomer fractions (DFs) of propiconazole and cyproconazole. No biotransformation was observed for alpha-HCH based on consistent EFs in the fish throughout the experiment and a t1/2 (15.8 days) that fell within the 95% confidence interval of a log K(ow)-log t1/2 relationship developed for assessing biotransformation of organic contaminants. This relationship did show that biotransformation accounted for the majority (ranging from 59.9 to 90.4%) of the elimination for all triazoles, and that triazole compounds with oxygen and hydroxyl functional groups were more easily biotransformed. This research indicated that chiral analysis may potentially miss biotransformation of CUPs and other potential non-persistent organic contaminants and shows the utility of the log K(ow)-log t1/2 relationship as a mechanistic tool for quantifying biotransformation. Based on the rapid biotransformation of the triazoles, future research should focus on formation of metabolites and their fate and possible effects in the environment.
Authors:
Brad J Konwick; Arthur W Garrison; Jimmy K Avants; Aaron T Fisk
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Publication Detail:
Type:  Comparative Study; Journal Article; Research Support, Non-U.S. Gov't; Research Support, U.S. Gov't, Non-P.H.S.     Date:  2006-10-21
Journal Detail:
Title:  Aquatic toxicology (Amsterdam, Netherlands)     Volume:  80     ISSN:  0166-445X     ISO Abbreviation:  Aquat. Toxicol.     Publication Date:  2006 Dec 
Date Detail:
Created Date:  2006-12-18     Completed Date:  2007-02-22     Revised Date:  -    
Medline Journal Info:
Nlm Unique ID:  8500246     Medline TA:  Aquat Toxicol     Country:  Netherlands    
Other Details:
Languages:  eng     Pagination:  372-81     Citation Subset:  IM    
Affiliation:
Warnell School of Forestry and Natural Resources, University of Georgia, Athens, GA 30602, United States. konwickb@warnell.uga.edu
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MeSH Terms
Descriptor/Qualifier:
Animals
Biotransformation
Fungicides, Industrial / analysis,  pharmacokinetics*
Half-Life
Lindane / analysis,  toxicity
Oncorhynchus mykiss / metabolism*
Triazoles / analysis,  pharmacokinetics*
Water Pollutants, Chemical / analysis,  pharmacokinetics*
Chemical
Reg. No./Substance:
0/Fungicides, Industrial; 0/Triazoles; 0/Water Pollutants, Chemical; 319-84-6/alpha-hexachlorocyclohexane; 58-89-9/Lindane

From MEDLINE®/PubMed®, a database of the U.S. National Library of Medicine


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