Influence of microplastics in the bioconcentration and depuration of organic pollutants in European eels

Despite high levels of organic pollutants (OPs) have been found in ecosystems considered as the habitats of European eels, there is scarce information about the bioconcentration and depuration kinetics of such OPs, and only few research has reported them in different eels’ tissues. In this research, the bioconcentration and depuration kinetics of a cocktail of 22 OPs in muscle, liver tissue and plasma of silver European eel were studied through a laboratory approach. Eels were distributed in three groups: control, exposed to OPs, and exposed to OPs and microplastics (MPs). The study was carried out for 58 days separated in two stages (i) exposure during days 0–28, and (ii) depuration during days 29–58. OPs in eels’ muscle and liver samples were extracted by QuEChERS and dispersive solid phase extraction (dSPE) whereas plasma was extracted by SPE. Then, extracts were analysed via UHPLC-MS/MS. OPs showed increasing concentrations in the three tissues (PFDA, PFOS, PFOA, chlorpyrifos, and terbuthylazine), or in some of them. PFASs’ bioconcentration followed the trend plasma > liver tissue > muscle. Two tendencies were observed in the depuration phase. One with OPs concentrations that tended to decrease (chlorpyrifos and terbuthylazine; in all tissues), another one, with concentration values that were similar or even tended to be higher than at the exposure phase (PFDA, PFOS, and PFOA; in all tissues). The presence of MPs seemed to affect the bioconcentration and depuration of OPs in eels’ tissues (increased kinetic bioconcentration factor BCFk). Pollutants are believed to be a key issue in understanding the reasons for the eels’ stock decrease and therefore, further research about PFASs, PPCPs and pesticides accumulation, depuration and toxicity on eels is imperative as this may be of great interest for human risk assessment of this widely consumed fish.