Spatial and temporal variations in the atmospheric concentrations of "Stockholm Convention" organochlorine pesticides in Kuwait.

The study reports fortnightly atmospheric concentrations of organochlorine pesticides concomitantly measured at an urban, "industrial" and a remote location over a twelve month period in Kuwait to examine seasonal variability and urban-rural concentration gradients. The average±SD (and range) of the ΣOC concentrations measured throughout the study period in decreasing order were urban, 505±305 (range, 33-1352) pgm, remote, 204±124 (4.5-556) pgm, and "industrial" 155±103 (8.8-533) pgm. The concentrations of most OCs measured in this study, except for DDT and its metabolites, were higher at urban locations relative to their concentrations at remote location, in line with the literature on POPs regarding urban conurbations being sources of industrial chemicals. The most abundant pesticides measured throughout this study were dieldrin, pentachlorobenzene, hexachlorobenzene, ΣDDTs, ΣHCHs, and oxychlordane. Hexachlorobenzene concentrations were generally higher than those of pentachlorobenzene and are both strongly negatively correlated with temperature (p<0.05) at all sampling locations. Mean summertime concentrations were higher for hexachlorocyclohexanes, chlordanes, dieldrin, and DDT isomers, except for pp-DDT. This may suggest that concentrations of these compounds may be driven by temperature.