John Wiley & Sons, Ltd.

Trophic dynamics of hexabromocyclododecane diastereomers and enantiomers in fish in a laboratory feeding study

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The in laboratory trophic transfer of hexabromocyclododecanes (HBCDs) was studied using predatory (oscar) fish and a prey species (tiger barb) exposed to a technical HBCD. Gut absorption, dynamic changes of diastereomer pattern and enantiomer fractions (EFs), and potential metabolism of HBCDs were examined. Compared to β‐ or γ‐HBCD, α‐HBCD showed lower absorption efficiency in oscar gut. A predominance of γ‐HBCD was observed in the tiger barb after 5 days HBCD‐exposed and oscar feeding on the tiger barb for 16 days. After 20 days of depuration, 41.1% γ‐HBCD and 42.7% β‐HBCD disappeared, and α‐HBCD exceeded the initial amount. The transformation from γ‐HBCD predominance in the food to α‐HBCD predominance in the oscar was mainly attributed to the isomerization of γ‐HBCD (at least 3%, up to 22.7%) to α‐HBCD. Selective enrichment of the (+) α‐ and (−) β‐enantiomers and no enantioselective enrichment of γ‐HBCD were observed in the tiger barbs. No enantioselective uptake of the 3 diasteromers was found in the oscar gut. The EFs of α‐ and γ‐diastereomers were significantly higher but that of β‐diastereomer were significantly lower in the oscars than in the tiger barbs, indicating enantioselective metabolism of the 3 diastereomers. Two HBCD monohydroxylated metabolites were detected in the two fish species, but their composition patterns were different, indicating a species‐specific metabolism of HBCD in the studied fish species. Environ Toxicol Chem © 2013 SETAC

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