Gastrointestinal absorption, dynamic tissue-specific accumulation, and isomer composition of dechlorane plus and related analogs in common carp by dietary exposure

•Anti-isomers showed higher absorption but lower assimilation efficiencies than syn-isomers in common carp.•Linear uptake curves but non-first-order kinetic depuration curves were observed for DP.•Dynamic tissue distribution with raising proportion in muscle and decreasing proportion in liver was observed.•The isomer composition of DP exhibited tissue specificity and dynamic changes over time.

Dechlorane plus (DP) is a high-productive volume substance which had been identified as ubiquitous pollutant and has been widely detected in biota. In the present study, common carp (Cyprinus carpio) was exposed to known amounts of commercial DP-25 under laboratory conditions. The gastrointestinal absorption and tissue-specific bioaccumulation of DP and its dechlorinated analogs in common carp were investigated. The higher absorption efficiencies but lower assimilation efficiencies of anti-isomers indicated stereoselective metabolism of anti-isomers in fish. Linear uptake curves were seen in serum and muscle, but the depuration curves for all the four tissues (muscle, serum, liver and gonad) did not follow the first-order kinetics. The liver exhibited a high affinity for anti-isomers during the experiment. Other tissues, such as serum, muscle, and gonad, showed a selective accumulation of syn-DP in the early stages of the experiment, particularly the serum. However, the deviation of fanti between different tissues disappeared at late stages of the experiment, and the fanti values in all tissues were close to that in commercial mixtures. Our results suggest that the bioaccumulation of DP is a complex and multi-factorial process.