Occurrence, Loading, and Exposure of Atmospheric Particle-Bound POPs at the African and European Edges of the Western Mediterranean Sea

A comparative study for 62 toxic chemicals based on the simultaneous monthly collection of aerosol samples during 2015-2016 in two coastal cities at both the African (Bizerte, Tunisia) and European (Marseille, France) edges of the Western Mediterranean basin is presented. Legacy polychlorinated biphenyls (ΣPCBs) and polychlorinated dibenzo-p-dioxins and dibenzofurans (ΣPCDD/Fs) show generally higher median levels at the African edge (2.1 and 0.2 pg m, respectively) compared to the European coastal site (1.0 and 0.08 pg m, respectively). Contrarily, the >emerging> polybrominated diphenyl ethers' (ΣPBDEs) median concentrations were higher in Marseille (∼9.0 pg m) compared to Bizerte (∼6.0 pg m). Different past usages and current emission patterns were found at both edges of the Western Mediterranean, most probably linked to the respective different regulatory frameworks for toxic chemicals. Our results indicate that the total organic carbon (TOC) and/ or the elemental carbon (EC) contents in the atmospheric aerosol may have a stronger effect than the total suspended particle (TSP) content as a whole on the spatial-temporal variability and the long-range atmospheric transport potential of the studied POPs. A >jumping> of the PBDE local atmospheric stocks from the Northwestern European Mediterranean edge to the Northwestern African coast seems to be possible under favorable conditions at present. While a higher PBDE median loading is estimated for the Marseille area (∼550 ng m y) compared to Bizerte (∼400 ng m y), the median PCB and PCDD/F dry deposition fluxes were higher at the African site, resulting in a 3-fold higher toxic equivalent (TEQ) loading of dioxin-like pollutants (400 pg TEQ m y) compared to Marseille (∼140 pg TEQ m y), with potential implications for aquatic organisms. However, the inhalation exposure assessment points to a minimum risk for human health at both sites.This work was funded by the Labex OT-Med (no. ANR-11- LABX-0061)MEDPOP, funded by the French Government “Investissements d’Avenir” (ANR) through the A*MIDEX project (no ANR-11-IDEX-0001-02), and takes place in the MERMEX/MISTRALS program. It also received financial support from the IRD French−Tunisian International Joint Laboratory (LMI) “COSYS-Med,” the MIO-IRD Action Sud project “AEROBIZ,” and the PACA region project “Particule.” Catherine Guigue is acknowledged for her help on the sample preparation for the TOC/EC determinations. We thank Patrick Raimbault for the TOC analyses, Xavier Mari and Benjamin Guinot for the preparation of samples for EC determinations, and Genevieve Deviller (DERAC) for her contribution in the chemical risk assessment section. M I O authors acknowledge European Union for co-funding equipment and Oceanomedbuilding acquisition in the framework of ‘Fonds européens de développement régional ‘(FEDER Project n° 1166-39417 du 5 août 2011)Peer Reviewe