Passive-sampler derived air concentrations of persistent organic pollutants on a north-south transect in Chile

Passive air samplers consisting of polyurethane foam (PDF) disks, were deployed in six locations in Chile along a north-south transect to investigate gas-phase concentrations of polychlorinated biphenyls (PCBs), organochlorine pesticides (OCPs), and polybrominated diphenyl ethers (PBDEs). The study provides new information on air concentrations of these persistent organic pollutants (POPs) which is lacking in this region. It also provides insight into potential sources and long-range transport (LRT). The samplers were deployed for a 2-month period in five remote sites and one site in the city of Concepción. Mean concentrations (pg m^-3) for ΣPCB were 4.7 ± 2.7 at remote sites and 53 ± 13 in Concepción. PCB levels at remote sites were related to proximity to urban source regions and/or air back trajectories. With the exception of endosulfan I, mean concentrations (pg m^-3) of OCPs at background sites were consistently low: 5.4 ± 1.4 for α-HCH, 7.0 ± 1.1 for γ-HCH, 2.5 ± 0.5 for TC, 2.5 ± 0.6 for CC, 1.9 ± 1.2 for dieldrin, and less than 3.5 for toxaphene. Endosulfan I showed a decreasing concentration gradient from 99 to 3.5 pg m^-3 from the north to south of Chile. Concentrations of OCPs in the Concepción City were generally 10-20 times higher than at the background sites suggesting continued usage and/or re-emission from past use. For instance, at remote sites, the α/γ ratio (0.76) was typical of background air, while the ratio in Concepción (0.12) was consistent with fresh use of γ-HCH. Levels of ΣPBDEs were below the detection limit of 6 pg m^-3 at all sites.