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您的检索式：作者名="Stefano Covelli"
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| 1 | Evaluation of mercury biogeochemical cycling at the sediment–water interface in anthropogenically modified lagoon environments显示文摘The Marano and Grado Lagoon is well known for being contaminated by mercury(Hg) from the Idrija mine(Slovenia) and the decommissioned chlor-alkali plant of Torviscosa(Italy).Experimental activities were conducted in a local fish farm to understand Hg cycling at the sediment–water interface. Both diffusive and benthic fluxes were estimated in terms of chemical and physical features. Mercury concentration in sediments(up to 6.81 μg/g)showed a slight variability with depth, whereas the highest methylmercury(MeHg) values(up to 10 ng/g) were detected in the first centimetres. MeHg seems to be produced and stored in the 2–3 cm below the sediment–water interface, where sulphate reducing bacteria activity occurs and hypoxic–anoxic conditions become persistent for days. DMeHg in porewaters varied seasonally(from 0.1 and 17% of dissolved Hg(DHg)) with the highest concentrations in summer. DHg diffusive effluxes higher(up to 444 ng/m^2/day) than those reported in the open lagoon(~ 95 ng/m^2/day), whereas DMeHg showed influxes in the fish farm(up to-156 ng/m^2/day). The diurnal DHg and DMeHg benthic fluxes were found to be higher than the highest summer values previously reported for the natural lagoon environment. Bottom sediments, especially in anoxic conditions, seem to be a significant source of MeHg in the water column where it eventually accumulates. However, net fluxes considering the daily trend of DHg and DMeHg, indicated possible DMeHg degradation processes. Enhancing water dynamics in the fish farm could mitigate environmental conditions suitable for Hg methylation. | Elisa Petranich Stefano Covelli Alessandro Acquavita Jadran Faganeli Milena Horvat Marco Contin | 2018 | Journal of Environmental Sciences2018，30，6： | 4 |
| 2 | Mercuryspeciation in sediments affected by dumped miningresidues in the drainage area of the Idrija MercuryMine,Slovenia 显示文摘 | Biester Harald Gosar Meteja Covelli Stefano | 2000 | Environmental Science & Technology2000，34，16： | 1 |
| 3 | Suspended particulate mercury associated with tidal fluxes in a lagoon environment impacted by cinnabar mining activity(northern Adriatic Sea)显示文摘The Isonzo River has been demonstrated to be a continuing point source of mercury(Hg)in the Gulf of Trieste although the Idrija mine was last active in 1996. The present study aims to investigate the role of the suspended particulate matter(SPM) associated with tidal fluxes to disperse particulate Hg(PHg) into the Grado coastal lagoon system. PHg concentrations(avg. 3.11 ± 2.62 μg/g, d.w.), notwithstanding the ebb or flood tides, were significantly higher than the local sediment background(0.13 μg/g). The relative affinity of Hg for the particulate phase in surface waters was confirmed by higher average distribution coefficient(Kd) values(5.6–6.7). PHg contents showed the highest values in ebb tide conditions, thus suggesting their origin from the erosion of tidal flats and saltmarshes of the lagoon. When compared to river discharge, high PHg surface concentrations in flood tide are related to rainfall events occurring within the river basin. Results can be used to make an indicative assessment of the amount of Hg bound to SPM which is transported in and out of the lagoon basin following the action of tidal fluxes. A simple estimation provides a negative budget for the Grado lagoon sub-basin which loses between 0.14 and 1.16 kg of PHg during a tidal semi-cycle. This conclusion is in agreement with the evidence of morphological deterioration which has emerged from recent studies on the lagoon environment, and which testifies to a current sedimentary loss from the lagoon into the northern Adriatic Sea. | Alisè Turritto Alessandro Acquavita Annelore Bezzi Stefano Covelli Giorgio Fontolan Elisa Petranich Raffaella Piani Simone Pillon | 2018 | Journal of Environmental Sciences2018，30，6： | 1 |
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