Presence of other congeners did not influence the dynamic of PCB mobilisation.

<p>At day 11, differentiated rat adipocytes, which were previously contaminated with either individual PCB congeners or with a cocktail of PCBs, underwent a lipolytic process. The cellular levels of PCBs before the lipolytic process were quantified and set at 100%. During 12-hour period of lipolysis, the contents of PCB congeners within adipocytes and in the extracellular medium were assessed every 3 hours. The results for PCB-28 (A), PCB-118 (B) and PCB-153 (C) were expressed by the percentage of initial amounts of each congener. Within a condition of contamination, proportions of one PCB congener in the medium were obtained by adding the quantities released during the periods of 3 hours (e.g. proportion of one congener at 6 hours corresponds to the sum of this congener released between 0 and 3 hours and between 3 and 6 hours). At each given time of lipolytic treatment, no differences were noted between the proportions of each PCB (i.e. PCB-28, -118 and -153) in both conditions of contamination (i.e. congeners alone or in cocktail), either in the cells or in the lipolytic medium (0.122<<i>p</i><0.916). Only the percentage of PCB-153 in the lipolytic medium was lower when taken alone as compared to the condition in cocktail after 3 hours of lipolysis (<i>p</i> = 0.046). Data represent the means of (<i>i</i>) three independent experiments ± SEM for conditions with one PCB congener alone, (<i>ii</i>) five independent experiments ± SEM for conditions with the cocktail of PCBs.</p

Efficient accumulation of PCBs in adipocytes during a 12-hour period.

<p>Quantities of PCBs accumulated in differentiated rat adipocytes, expressed in nmol per unit of cellular protein and per unit of neutral lipids (NLs), after a dose of PCBs was added during 12 hours in the culture medium. Quantities of NLs, expressed in µmol per unit of cellular protein are also presented. Data represent the means of (<i>i</i>) three independent experiments ± SEM for conditions with one PCB congener alone, (<i>ii</i>) five independent experiments ± SEM for conditions with the cocktail of PCBs. There was no significant difference of PCB and NL concentrations between the three PCB congeners, whatever the kind of contamination, alone or in cocktail (<i>p</i>>0.05).</p><p>Efficient accumulation of PCBs in adipocytes during a 12-hour period.</p

Lipolytic treatment decreased cellular neutral lipids and increased extracellular fatty acids and glycerol.

<p>At day 11, differentiated rat adipocytes, which were previously contaminated with PCBs, were incubated with a lipolytic medium supplemented with 1 µM isoproterenol. We renewed the lipolytic medium every 3 hours for 12 hours. Cellular neutral lipids (corresponding to µmol of fatty acids in cellular neutral lipids) were expressed per mg of total cell protein (A). A significant decrease of cellular lipid contents was noted throughout the lipolytic process for the conditions with PCB-28 (<i>p</i> = 0.005) and the cocktail of PCBs (<i>p</i> = 0.029). The decrease was slighter for the conditions with PCB-118 (<i>p</i> = 0.298) and PCB-153 (<i>p</i> = 0.097). Total extracellular free fatty acids (B) and total extracellular glycerol (C) were expressed per ml of medium. Quantities of total free fatty acids and glycerol in the medium were obtained by adding the quantities released during the periods of 3 hours (e.g. total free fatty acids at 6 hours correspond to the sum of total free fatty acids released between 0 and 3 hours and between 3 and 6 hours). A significant increase of total free FAs and total glycerol was observed over the 12-hour lipolytic treatment (<i>p</i><0.001 for all conditions). Data represent the means of (<i>i</i>) three independent experiments ± SEM for conditions with one PCB congener alone, (<i>ii</i>) five independent experiments ± SEM for conditions with the cocktail of PCBs.</p

Lipolytic treatment decontaminated the adipocytes, inducing an accumulation of PCB congeners in the extracellular medium.

<p>At day 11, contaminated adipocytes underwent a lipolytic process. The PCB contents as well as the proportions of PCBs released in the extracellular medium were assessed every 3 hours. For each PCB congener, all results were expressed in percentage of the amounts initially present in the cells. Proportions of one PCB congener in the medium were obtained by adding the amounts released during periods of 3 hours (e.g. proportion of one congener at 6 hours corresponds to the sum of this congener released between 0 and 3 hours and between 3 and 6 hours). An important drop of cell PCB proportions was observed during the first 6 hours of lipolysis (<i>p</i><0.001) and was followed by a more moderate decrease of the cell PCB percentages during the last 6 hours (<i>p</i><0.001). In parallel, an important increase of PCBs was noted in the extracellular medium during the first half of lipolysis (<i>p</i><0.001) and was followed by a slower accumulation during the second half of lipolysis (0.001<<i>p</i><0.006). Data represent the means of five independent experiments ± SEM.</p

Chemicals and materials.

Procellariiform seabirds are known to have high rates of plastic ingestion. We investigated the bioaccessibility of plastic-associated chemicals [plastic additives and sorbed persistent organic pollutants (POPs)] leached from plastic over time using an in vitro Procellariiform gastric model. High-density polyethylene (HDPE) and polyvinyl chloride (PVC), commonly ingested by Procellariiform seabirds, were manufactured with one additive [decabrominated diphenyl ether (PBDE-209) or bisphenol S (BPS)]. HDPE and PVC added with PBDE-209 were additionally incubated in salt water with 2,4,4’-trichloro-1,1’-biphenyl (PCB-28) and 2,2’,3,4,4’,5’-hexachlorobiphenyl (PCB-138) to simulate sorption of POPs on plastic in the marine environment. Our results indicate that the type of plastic (nature of polymer and additive), presence of food (i.e., lipids and proteins) and gastric secretions (i.e., pepsin) influence the leaching of chemicals in a seabird. In addition, 100% of the sorbed POPs were leached from the plastic within 100 hours, while only 2–5% of the additives were leached from the matrix within 100 hours, suggesting that the remaining 95% of the additives could continue to be leached. Overall, our study illustrates how plastic type, diet and plastic retention time can influence a Procellariform’s exposure risk to plastic-associated chemicals.</div

Fatty acid metabolism (nmol per g of fish per day), deduced by the whole body fatty acid balance method, of rainbow trout reared at 15°C or 19°C on a control diet (FO) or a linseed oil diet (LO).

<p>Fatty acid metabolism (nmol per g of fish per day), deduced by the whole body fatty acid balance method, of rainbow trout reared at 15°C or 19°C on a control diet (FO) or a linseed oil diet (LO).</p

Fatty acid composition (mg/g of dry matter) of the control diet (FO) and the linseed oil diet (LO).

<p>Fatty acid composition (mg/g of dry matter) of the control diet (FO) and the linseed oil diet (LO).</p

Example of wax ester found in the oil of calanus finmarchicus.

Example of wax ester found in the oil of calanus finmarchicus.</p

Comprehensive overview of the influence of the polymer type and digestive conditions on the leaching of PBDE-209, PCBs and BPS.

Comprehensive overview of the influence of the polymer type and digestive conditions on the leaching of PBDE-209, PCBs and BPS.</p

Concentration of BPS released from HDPE (1) and PVC (2) in each phase of the salmon or calanus gastric fluid over time.

Concentration of BPS released from HDPE (1) and PVC (2) in each phase of the salmon or calanus gastric fluid over time.</p