Environmental variation of PCDD/Fs and dl-PCBs in two tropical Andean Colombian cities using passive samplers.

Passive air-sampling data of polychlorinated dibenzo-p-dioxins (PCDDs), polychlorinated dibenzofurans (PCDFs) and dioxin-like polychlorinated biphenyls (dl-PCBs) taken in Manizales (a medium-sized city) and Bogotá (a megacity), Colombia, were analyzed in order to identify potential sources of pollution and the possible influence of meteorological variables like temperature and precipitation. The results indicate important differences in levels of PCDD/Fs and dl-PCBs between Bogotá and Manizales, attributed to differences in site characteristics and potential local/regional sources. Higher PCDD/Fs concentrations were observed in Bogotá (373fg/m(3)) compared to those observed in Manizales, with mean levels ranging from 64fg/m(3) in a residential zone to 151fg/m(3) around a vehicular-influenced area. Higher dl-PCBs concentrations were observed in the industrial area of Manizales compared to those observed in Bogotá, with mean levels of 6668fg/m(3) and 4388fg/m(3) respectively. In terms of PCDD/Fs congener distribution, there was a predominance of octachlorodibenzodioxin (OCDD) followed by 1,2,3,4,6,7.8-heptachlorodibenzofuran (HpCDF) congeners, with both cities showing higher levels in zones of high vehicular activity. Industrial influence was most evident in dl-PCB levels. In comparison to the mean levels of dl-PCB congeners obtained in the vehicular zones of Bogotá and Manizales, the industrially influenced sampling stations showed higher concentrations of dl-PCB congeners. Passive sampling results suggested that congener concentration profiles are characteristic of their different emission sources, and can be used to distinguish between their industrial or vehicular origins.