ANALYSIS OF POLYCHLORINATED-BIPHENYLS, ORGANOCHLORINE PESTICIDES AND CHLOROPHENOLS IN RAIN AND SNOW

Polychlorinated biphenyls (PCBs), organochlorine pesticides and chloro phenols were measured in samples of rain and snow collected at urban a nd suburban/semi-rural locations in the Zagreb City area, Croatia. PCB s and organochlorine pesticides were extracted with hexane from filter ed aqueous samples and from particulate matter isolated by filtration. Chlorophenols were accumulated from rain and snow water by C-18 rever sed-phase adsorption. All samples were analysed by capillary gas chrom atography using an electron-capture detector. Polychlorinated dibenzod ioxins (PCDDs) and dibenzofurans (PCDFs) in rain and snow water were c hecked by gas chromatographic-mass spectrometric analysis of combined hexane extracts. PCBs were detected in all water (<1-203 ng l(-1)) and particle (40-4155 ng g(-1)) samples. The only organochlorine pesticid e present in all rain and snow water (1-36 ng l(-1)) and in particle ( 7-512 ng g(-1)) samples was gamma-hexachlorocyclohexane as a consequen ce of the regular local usage of lindane. A positive correlation was f ound between its concentration in the water phase and the average air temperature during the sampling period. Compounds of the DDT-type, tra ce amounts of which were detected in only two rain water samples, were determined in most particle samples. The DDE:DDT median concentration ratio in particles was lower than unity and indicated a recent input of DDT into the atmosphere. The incidence and concentrations of di-, t ri-, tetra- and pentachlorophenols were higher in snow (single compoun d concentration 11-527 ng l(-1)) than in rain (single compound concent ration 2-171 ng l(-1)), A quadratic decrease in chlorophenol concentra tions in snow and rain with increasing air temperature was observed. T race amounts of PCDDs and PCDFs were detected in both rain and snow wa ter samples and the highest concentrations were measured for octa-CDD (2 pg l(-1) in snow and 6 pg I-1 in rain).