Pollution historical trends as recorded by sediments at selected sites of the Venice Lagoon.
Polychlorinated biphenyls (PCBs), dibenzo-p-dioxins (PCDDs), dibenzofurans (PCDFs) and hexaclorobenzene (HCB) were determined in three sediment cores of the Venice Lagoon: I1, from the San Giuliano Canal that is likely the main source of pollutants for the study area; E, representing the lagoon sediment of the zone of Campalto; and M3, typical of a salt marsh environment and mostly subject to atmospheric inputs. Maximum concentrations were found in core I1: 25-1858 ngI-TE kg(-1) (PCDD/Fs), 1.7-13 microg kg(-1) (HCB), and 107-717 microg kg(-1) (PCBs) are surficial and peak values, respectively. The lagoon sediment (E), is much less contaminated: 24-47 ngI-TE kg(-1) for PCDD/Fs, 2.3-3.6 microg kg(-1) for HCB, and 56-203 microg kg(-1) for PCBs, whereas M3 shows the lowest values: 1.6-6.0 ngI-TE kg(-1) for PCDD/Fs, 0.3-0.6 microg kg(-1) for HCB, and 7.1-39 microg kg(-1) for PCBs. In any case, the recent trend is toward a decrease of pollutant concentration. The chronology of cores E and M3 is based on both 210Pb and 137Cs activity-depth profiles. The maximum concentrations of PCDD/Fs, HCB, and PCBs correspond to the years 1949, 1980, and 1968, respectively. The homologue profiles of PCDD/Fs confirm that I1 has been subject to an industrial source while the other sites also recorded significant contributions, changing over time, of octachlorinated dioxin from combustion. A comparison of the pollutant inventories, all normalised to 210Pb inventories, suggests that the atmospheric contribution to the contamination of the area of Campalto is low: the upper limits range from 6% (PCDD/Fs) to 17% (HCB).
Consiglio Nazionale delle Ricerche, Istituto di Scienze Marine-Sezione di Geologia Marina, Via Gobetti, 101, 40129 Bologna, Italy. mauro.frignani@bo.ismar.cnr.it
Mauro
M
Frignani
Luca G
LG
Bellucci
Maurizio
M
Favotto
Sonia
S
Albertazzi
D001572:Benzofurans / Q000032:analysis*; D002910:Chronology as Topic; D002947:Cities; D004784:Environmental Monitoring; D004785:Environmental Pollutants / Q000032:analysis; D019015:Geologic Sediments / Q000737:chemistry*; D001556:Hexachlorocyclohexane / Q000032:analysis*; D007558:Italy; D011078:Polychlorinated Biphenyls / Q000032:analysis*; D000072317:Polychlorinated Dibenzodioxins / Q000031:analogs & derivatives* / Q000032:analysis; D012623:Seawater
D001572:Benzofurans; D004785:Environmental Pollutants; D000072317:Polychlorinated Dibenzodioxins; D001556:Hexachlorocyclohexane; C023614:dibenzofuran; D011078:Polychlorinated Biphenyls