| Title | Mobility of heavy metals from polluted sediments of a semi-enclosed basin: in situ benthic chamber experiments in Taranto's Mar Piccolo (Ionian Sea, Southern Italy) |
| Abstract | In situ benthic flux experiments were conducted at two stations in the Mar Piccolo of Taranto (Italy), one of the most industrialised and contaminated coastal areas of the Mediterranean. Sediments of the two stations are notably different in their trace metal content, with a station closer to a Navy harbour showing higher mean concentrations of almost all investigated metals (Al, As, Cd, Cr, Cu, Fe, Hg, Mn, Ni, Pb, V and Zn). Conversely, both stations are characterised by significant Hg contamination, compared to the local baseline. Results of a sequential extraction scheme on surface sediments suggest a relatively scarce mobility of the examined metals (Zn > Ni > Cr > As > Cu > Pb). A Hg-specific extraction procedure showed that most of the element (93.1 %) occurs in a fraction comprising Hg bound to Fe/Mn oxi-hydroxides. Reduction of these oxides may affect Hg remobilisation and redistribution. Porewater profiles of dissolved trace metals were quite similar in the two sites, although significant differences could be observed for Al, Cu, Fe and Hg. The highest diffusive fluxes were observed for As, Fe and Mn. Mobility rates of several trace elements (Al, As, Cd, Cr, Cu, Fe, Hg, Mn, Ni, Pb, V and Zn) were directly measured at the sediment-water interface. Results from benthic in situ incubation experiments showed increasing dissolved metal concentrations with time, resulting in higher fluxes for Cu, Fe, Hg, V and Zn in the most contaminated site. Conversely, fluxes of Mn, Ni and Pb were comparable between the two stations. The estimated flux of Hg (97 mu g m(-2) day(-1)) was the highest observed among similar experiments conducted in other highly contaminated Mediterranean coastal environments. Benthic fluxes could be partially explained by considering rates of organic matter remineralisation, dissolution of Fe/Mn oxy-hydroxides and metal speciation in sediments. Seasonal and spatial variation of biogeochemical parameters can influence metal remobilisation in the Mar Piccolo area. In particular, metals could be promptly remobilised as a consequence of oxygen depletion, posing a serious concern for the widespread fishing and mussel farming activities in the area. |
| Source | Environmental science and pollution research international 23 (13), pp. 12582–12595 |
| Keywords | Heavy metalsSedimentsPorewaterBenthic fluxesSpeciation |
| Journal | Environmental science and pollution research international |
| Editor | Springer, Berlin, Germania |
| Year | 2016 |
| Type | Articolo in rivista |
| DOI | 10.1007/s11356-015-5281-1 |
| Authors | Emili, Andrea; Acquavita, Alessandro; Covelli, Stefano; Spada, Lucia; Di Leo, Antonella; Giandomenico, Santina; Cardellicchio, Nicola |
| Text | 398893 2016 10.1007/s11356 015 5281 1 ISI Web of Science WOS WOS 000378817300008 Scopus 2 s2.0 84940705084 Heavy metals Sediments Porewater Benthic fluxes Speciation Mobility of heavy metals from polluted sediments of a semi enclosed basin in situ benthic chamber experiments in Taranto s Mar Piccolo Ionian Sea, Southern Italy Emili, Andrea; Acquavita, Alessandro; Covelli, Stefano; Spada, Lucia; Di Leo, Antonella; Giandomenico, Santina; Cardellicchio, Nicola Univ Trieste; Univ Trieste; Environm Protect Agcy Friuli Venezia Giulia ARPA; CoNIS Ma Consorzio Nazl Interuniv Sci Mare; CNR In situ benthic flux experiments were conducted at two stations in the Mar Piccolo of Taranto Italy , one of the most industrialised and contaminated coastal areas of the Mediterranean. Sediments of the two stations are notably different in their trace metal content, with a station closer to a Navy harbour showing higher mean concentrations of almost all investigated metals Al, As, Cd, Cr, Cu, Fe, Hg, Mn, Ni, Pb, V and Zn . Conversely, both stations are characterised by significant Hg contamination, compared to the local baseline. Results of a sequential extraction scheme on surface sediments suggest a relatively scarce mobility of the examined metals Zn > Ni > Cr > As > Cu > Pb . A Hg specific extraction procedure showed that most of the element 93.1 % occurs in a fraction comprising Hg bound to Fe/Mn oxi hydroxides. Reduction of these oxides may affect Hg remobilisation and redistribution. Porewater profiles of dissolved trace metals were quite similar in the two sites, although significant differences could be observed for Al, Cu, Fe and Hg. The highest diffusive fluxes were observed for As, Fe and Mn. Mobility rates of several trace elements Al, As, Cd, Cr, Cu, Fe, Hg, Mn, Ni, Pb, V and Zn were directly measured at the sediment water interface. Results from benthic in situ incubation experiments showed increasing dissolved metal concentrations with time, resulting in higher fluxes for Cu, Fe, Hg, V and Zn in the most contaminated site. Conversely, fluxes of Mn, Ni and Pb were comparable between the two stations. The estimated flux of Hg 97 mu g m 2 day 1 was the highest observed among similar experiments conducted in other highly contaminated Mediterranean coastal environments. Benthic fluxes could be partially explained by considering rates of organic matter remineralisation, dissolution of Fe/Mn oxy hydroxides and metal speciation in sediments. Seasonal and spatial variation of biogeochemical parameters can influence metal remobilisation in the Mar Piccolo area. In particular, metals could be promptly remobilised as a consequence of oxygen depletion, posing a serious concern for the widespread fishing and mussel farming activities in the area. 23 Published version https //link.springer.com/article/10.1007/s11356 015 5281 1 Articolo in pdf 2016_Article_.pdf Articolo in rivista Springer 0944 1344 Environmental science and pollution research international Environmental science and pollution research international Environ. sci. pollut. res. int. Environmental science and pollution research international. Environmental science and pollution research international Print Environmental science and pollution research Print ESPR Print nicola.cardellicchio CARDELLICCHIO NICOLA antonella.dileo DI LEO ANTONELLA santina.giandomenico GIANDOMENICO SANTINA lucia.spada SPADA LUCIA |
