Spatial and temporal variations of halogenated flame retardants and organophosphate esters in landfill air: Potential linkages with gull exposure

Landfills represent important sources of local emissions of organic contaminants, including halogenated (HFR) and organophosphate ester (OPE) flame retardants used in a large variety of consumer products. Gulls foraging in landfills may be exposed to elevated atmospheric concentrations of HFRs and OPEs that may vary spatially and temporally within a landfill site, thus modulating their exposure. The objective of the present study was to investigate the spatial and temporal variability of HFR and OPE concentrations in air samples collected from a major landfill in the Montreal area (QC, Canada) that is frequently visited by gulls for foraging. Miniature stationary passive air samplers (PASs) and high-volume active air samplers (AASs) were deployed in six different areas within this landfill site for 34 days to collect HFRs and OPEs in air. During the same period, wild-caught ring-billed gulls (Larus delawarensis) were equipped on their back with a similar miniature PAS that was deployed in the landfill along with a GPS datalogger to monitor their movements for ten days. Elevated concentrations of certain OPEs (e.g., tris(2-chloroethyl) phosphate and tris(2-chloroisopropyl) phosphate) and brominated diphenyl ether (BDE)-209 were measured in stationary PASs and AASs, although they were homogenously distributed within this landfill site. Temporal variability was observed for concentrations of BDE-209, -99 and -47 measured in AASs as well as tributyl phosphate during the 34-day deployment period. Moreover, air concentrations of BDE-209, -207 and -206 and selected OPEs (tris(1,3-dichloro-2-propyl) phosphate and tris(methylphenyl) phosphate) determined using AASs were positively correlated with ambient air temperatures. Gulls that visited a landfill at least once exhibited significantly greater concentrations of BDE-47 measured in PASs they carried on their back, suggesting that landfill air may represent a source of exposure to PBDEs for these birds, and potentially other urban-adapted wildlife using these sites for foraging.