| Popis: |
Polychlorinated biphenyls (PCBs) and polychlorinated dibenzo-p-dioxins and dibenzofurans (PCDD/Fs) belong to a large group of persistent organic pollutants. PCBs are commercial products while PCDD/Fs are undesirable by-products of industrial processes which include chlorine (chemical, paper industry) and waste incineration. Once emitted, they spread over all abiotic and biotic compartments of environment. In this study we summarise our findings of PCB and PCDD/F levels in ambient air samples collected in Zagreb between 1997 and 2001. From October to December 1997, samples were collected at two sampling points: Jakuševec (10 samples) and Ksaver (14 samples) and analysed for presence of six PCB indicator congeners (PCB-28, PCB-52, PCB-101, PCB-138, PCB-153, PCB-180). The highest level found at both locations was that of PCB-28. The levels of six indicator PCBs were measured again together with 14 more PCB congeners at Ksaver and Jakuševec between June 1999 and February 2001. PCB concentration ranges in air samples collected in 1997 and 2001 overlap. The comparison of respective periods in 1997 and 1999 shows a slight decrease at Ksaver. The levels of PCDD/Fs were determined in 29 samples collected in May-June 1997, January-April 1998, November 1999, and January-March 2000 at five different locations in Zagreb. The calculated I-TEQ values were 9-47 fg/m^3 for samples collected in May/June 1997, 17-308 fg/m^3 for samples collected in January/April 1998, 21-29 fg/m^3 for samples collected in November 1999, and 15-90 fg/m^3 for samples collected in January-March 2000. |
