Trophic transfer of Ag-110m in the turbot Scophthalmus maximus through natural prey and compounded feed

摘要

Industrial incidents can result in radionuclide release in the environment, among which Ag-110m. Indeed, under particular circumstances, non-negligible amounts of Ag-110m have been measured in the marine environment (as observed in Fukushima Dai-ichi incident). This element can therefore be accumulated by aquatic organisms through different pathways including the trophic transfer. The present study aimed at examining the variation of Ag-110m assimilation efficiency (AE) by turbots, Scophthalmus maximus, when exposed through different feeds. Pulse-chase feeding experiments were carried out in mesocosms, using radiolabelled feeds (natural prey and commercial pellets). Depuration kinetics of Ag-110m over 21 days were generally fitted by a two-component exponential model; the ingested radioelement was poorly assimilated by turbots regardless of the food item that was used (AE always <3%). Concentration and subcellular distribution of Ag-110m in prey did not seem to influence its assimilation by turbot. These results suggest that physiological mechanisms could occur in fish that would prevent the transfer of Ag-110m from gut lumen to internal organs (e.g. Ag-110m neutralization in the lumen of the stomach, detoxification mechanisms occurring in the gut). (C) 2015 Elsevier Ltd. All rights reserved.