Seasonal variations in the atmospheric concentrations of polychlorinated biphenyls in Kuwait

The spatial and temporal variations in the atmospheric concentrations of PCBs were concomitantly measured at several sites over a twelve-month period in Kuwait to examine seasonal variability and urban-rural concentration gradients using two sampling methods. The annual mean (and range) of ∑PCB concentrations measured using high volume samplers was 10.8 (1.2-32) pg m^-3 at the remote site and 39.4 (1.1-128) pg m^-3 at the urban site. The median concentrations of ΣPCBs at the urban location (30.3 pg m^-3) was significantly higher (p < 0.001) than that measured at the remote location (8.6 pg m^-3) consistent with the view that urban centers are an important net source of these compounds to the environment. Passive sampler derived concentrations across the country showed a uniform distribution except at a few locations in the vicinity of suspected sources where elevated concentrations were measured. As with active sampling data, the concentrations measured using passive samplers were higher in urban areas (range, 4-78 pg/m³) compared to remote sites (range, 2.2-17 pg/m³). The concentrations measured at some urban sites correlated extremely well with mean temperature during the deployment period whereas temperature correlations with measured concentrations were negative at remote and semi-rural sites suggesting that air-surface exchange maybe a key driving mechanism of the current levels of PCBs in Kuwait.