Atmospheric particle-bound organophosphate ester flame retardants and plasticizers in a North African Mediterranean coastal city (Bizerte, Tunisia)

Abstract

Organophosphate ester (OPE) flame retardants and plasticizers have been detected at generally high frequencies (70–98%) for the first time in the atmosphere over the NW African coastal Mediterranean. Results from sixty air samples (total suspended particles, TSP) collected between March 2015 and January 2016 in an urban coastal site (Bizerte, Tunisia) revealed ∑9OPE concentrations of ~100–1060 pg m−3 (470 pg m−3, median) with TCPPs, EHDPP and TiBP exhibiting the higher median concentrations (~110, 100 and 85 pg m−3, respectively). Spring generally exhibited the lowest concentrations, probably linked to the influence of local meteorological conditions and air mass trajectories to a lesser extent. Non-chlorinated OPEs generally predominated, in contrast to the most common reported situation in marine environments (i.e. higher abundance of chlorinated OPEs) pointing to the relevance of local OPE sources in the study area. TiBP levels were generally higher than those reported for other marine/coastal environments suggesting this OPE as a good tracer of local sources in Bizerte. Contrarily, the atmospheric levels of other abundant OPEs in the area (e.g. TCPP) seem to be in the range and/or lower than those reported for remote marine environments. These findings point to the interplay of different factors with solar irradiance (potentially enhancing atmospheric photochemical oxidation reactions) and meteorological conditions in the study area likely compensating potential local sources of some OPEs. Not all OPEs presented the same seasonality in terms of atmospheric concentrations and pattern. The estimated atmospheric dry deposition fluxes (∑9OPEs) were 18–180 ng m−2 d−1. Up to ~9 kg y−1 of OPEs (~1 kg y−1 of new organic anthropogenic phosphorus coming from OPEs) can be loaded to the shallow and enclosed Bizerte lagoon (~130 km2), considered as the most important aquaculture area in Tunisia, with yet unknown implications for the environmental exposure and impacts in the ecosystem functioning.