Occurrence of polychlorinated dibenzo-p-dioxins and dibenzofurans (PCDD/Fs), polychlorinated biphenyls (PCBs) and polybrominated diphenyl ethers (PBDEs) in Lake Maggiore (Italy and Switzerland)
Résumé
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 m3 and 106 pg m-3 for SPCDD/Fs, SPCBs,
S dioxin-like PCBs (DL-PCBs) and SPBDEs, respectively. Deposition fluxes ranged from 0.7 ng
m-2 d-1 for SPCDD/Fs to 32 ng m-2 d-1 for SPCBs. Aquatic settling material presented
concentrations of 0.4 ng g-1 dry weight (dw) for SPCDD/Fs, 13 ng g-1 dw for SPCB, 3.4 ng g-1
dw for SDL-PCBs and 5.7 ng g-1 dw for SPBDEs. Mean sediment concentrations were 0.4 ng
g-1 dw for SPCDD/Fs, 11 ng g-1 dw for SPCB, 3 ng g-1 dw for SDL-PCBs and 5.1 ng g-1 dw
for SPBDEs. 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, PBDE congener distribution was
not similar in the different environmental compartments. BDE 47 dominated air and settling
material, while BDE 209 was the predominant congener in the bulk atmospheric deposition.
Moreover, sediments showed two distinct PBDE congener profiles. Lower PBDE concentrated
sediments were dominated by congeners 47 and 99, while BDE 209 dominated in higher PBDE
concentrated samples. This suggests the influence of local sources as well as atmospheric input of
PBDEs into LM.