The Marano and Grado Lagoon (Northern Adriatic Sea) has been affected by mercury (Hg) contamination coming from two sources, mining activity and discharges from a chlor-alkali plant (CAP). Sediments and water contamination have been previously well characterised, but little is known about the atmospheric compartment, where Hg is easily emitted and can persist for a long time as gaseous elemental mercury (GEM). In this work, atmospheric GEM levels and its spatial distribution over the lagoon were monitored at several sites by means of both continuous discrete instrumental measurements over several months and the determination of Hg bioaccumulated in lichens (Xanthoria parietina L.). Average GEM levels varied from 1.80 ± 0.74 to 3.04 ± 0.66 ng m−3, whereas Hg in lichens ranged between 0.06 to 0.40 mg kg−1. In both cases, the highest values were found downwind of the CAP, but excluding this point, spatial patterns of Hg in the atmosphere and lichens reflected the concentration of this metal in the sediments of the lagoon, showing a decrease moving westward. These results could indicate that the lagoon acts as a secondary source of Hg into the atmosphere: future work is needed to characterise the quantity of releases and depositions at different environments inside the lagoon.

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Mercury (Hg) is a global pollutant, being highly persistent in the atmosphere, in particular gaseous elemental mercury (GEM), which can easily be emitted and then transported over long distances. In the Gulf of Trieste (northern Adriatic Sea, Italy), contamination by Hg is well characterised but little is known regarding the concentrations, sources and fate of GEM in the atmosphere. In this work, discrete measurements of GEM were recorded from several sites at different times of the year. The database is consistent with temporal night-day variations monitored using a continuous real-time device. The meteorological conditions were collected as ancillary parameters. GEM levels varied from <LOD (2.0 ng m−3) to 48.5 ng m−3 (mean 2.7 ng m−3), with no significant differences found among sites. A clear daily pattern emerged, with maximum values reached just after sunset. Air temperature, relative humidity, wind speed and direction were identified as the main micrometeorological factors influencing both the spatial and temporal variation of GEM. Our results show that average atmospheric GEM values are higher than the natural background of the Northern Hemisphere and will be useful in future selection regarding the most suitable sites to monitor atmospheric Hg depositions and fluxes from soil and water.

When mines are decommissioned, tailings piles can act as sources of contamination for decades or even centuries. Tailings, which usually contain high concentrations of metals and trace elements, can be reprocessed for a secondary recovery of valuable elements with an innovative approach to a circular economy. This study offers new results for tailings ponds characterisation and chemical content prediction based on an integrated geophysical-geochemical approach. The study of the Raibl Pb-Zn tailings impoundment was done using bulk chemical analysis on borehole samples, Electrical Resistivity Tomography surveys, and Ground Penetrating Radar measurements. We found valuable and statistically significant correlations between the electrical resistivity of the mining impoundments and the metal distribution, thus providing a practical opportunity to characterise large volumes of metal-bearing tailings. In particular, these results can be useful to aid in the development of environmental monitoring programs for remediation purposes or to implement economic secondary recovery plans.