Halogenated flame retardants in atmospheric particles from a North African coastal city (Bizerte, Tunisia): Pollution characteristics and human exposure

In the present study, atmospheric particle samples were collected between September 2015 and February 2016 from Bizerte city (Tunisia) to investigate the occurrence, potential sources and impacts of a range of flame retardants (FRs), including hexabromocyclododecane diastereoisomers (HBCDDs), new halogenated flame retardants (NHFRs), as well as methoxylated polybrominated diphenyl ethers (MeO-BDEs). Among 19 examined compounds, 9 congeners (α-HBCDD, β-HBCDD, γ-HBCDD, HBB, DBDPE, syn-DP, anti-DP, 2′-MeO-BDE-68 and 6-MeO-BDE-47) were detected in atmospheric particles at different levels and frequencies. Overall, the average concentration of NHFRs (1.53 pg m−3) was 1.5 and 51 folds higher than that of HBCDDs (1.04 pg m−3) and MeO-BDEs (0.03 pg m−3), respectively. By comparison with other areas of the world, NHFRs and HBCDDs in Bizerte were at medium pollution level, while MeO-BDEs were at lower levels. No significant correlations were found between NHFR, HBCDD and MeO-BDE concentrations, suggesting different sources related on one hand to the biogenic origin of MeO-BDE, and on the other hand to various types and utilisations of imported NHFR- and HBCDD-containing products, as Tunisia does not manufacture FRs. DP and HBCDD diastereoisomer profiles appeared to be divergent from their commercial products, pointing out that a complex degradation or stereoselective transformation processes occurring in ambient air around Bizerte city. The estimated daily human exposure dose (DED) to particle-bound HBCDDs, NHFRs and MeO-BDEs via outdoor air inhalation was generally at low levels. Hence, this study reports for the first time the occurrence and potential impact of HBCDDs, NHFRs and MeO-BDEs in atmospheric particles from North Africa. © 2020 Turkish National Committee for Air Pollution Research and Control

This study was supported by the Institut de Recherche pour le Développement (IRD), through the International Joint Laboratory (LMI) “COSYS-Med”, the Tunisian Ministry of Higher Education and Scientific Research, the PACA region “Particule” project, the IRD-MIO Action Sud “AEROBIZ” project and the Generalitat de Catalunya (Consolidated Research Group Water and Soil Quality Unit 2017). P. Raimbault (MIO) is acknowledged for OC and ON analyses. We are grateful to two anonymous Reviewers for their relevant comments on the manuscript.

Peer reviewed