Occurrence of Polychlorinated Dibenzo-p-dioxins and Dibenzofurans (PCDD/Fs), Polychlorinated Biphenyls (PCBs) and Polybrominated Diphenyl Ethers (PBDEs) in Lake Maggiore (Italy and Switzerland)

Abstract

Samples of air (gas and particulate phases), bulk deposition, aquatic settling material and sediments were collected in Lake Maggiore (LM) in order to determine their content of polychlorinated dibenzo-p-dioxins and dibenzofurans (PCDD/Fs), polychlorinated biphenyls (PCBs) and polybrominated diphenyl ethers (PBDEs). Air (gas and particulate phases) concentrations were 0.5 pg m-3, 80 pg m-3, 13 pg m-3 and 106 pg m-3 for sum PCDD/Fs, sum PCBs, sum dioxin like-PCBs (DL-PCBs) and sum PBDEs, respectively. Deposition fluxes ranged from 0.7 ng m-2 day-1 for sum PCDD/Fs to 32 ng m-2 day-1 for sum PCBs. Aquatic settling material presented concentrations of 0.4 ng g-1 dw for sum PCDD/Fs, 13 ng g-1 dw for sum PCB, 3.4 ng g-1 dw for sum DL-PCBs and 5.7 ng g-1 dw for sum PBDEs. Mean sediment samples concentration were 0.4 ng g-1 dw for sum PCDD/Fs, 11 ng g-1 dw for sum PCB, 3 ng g-1 dw for sum DL-PCBs and 5.1 ng g-1 dw for sum PBDEs. Similar PCDD/F and DL-PCB congener patterns in all the environmental compartments of LM point to an important, if not dominant, contribution of atmospheric deposition as source of these pollutants into LM. In contrast, BDE congener distribution was not similar in the different environmental compartments. BDE 47 dominated air samples and settling material, while BDE 209 was the predominant congener in the bulk deposition. Moreover, sediments showed two distinct PBDE congener profiles. Lower PBDE concentration sediment samples were dominated by congeners 47 and 99, while BDE 209 dominated in higher concentration samples. This suggests the influence of local sources as as well as atmospheric input of PBDE into LM.