Mercury distribution and speciation in historically contaminated soils of the Isonzo River Plain (NE Italy)

Environmental impact of potentially toxic elements on soils, sediments, waters, and air nearby an abandoned Hg-rich fahlore mine (Mt. Avanza, Carnic Alps, NE Italy)

“…These values were slightly higher than the estimated natural background of atmospheric GEM for the Northern Hemisphere (1.5–1.7 ng/m 3 , Sprovieri et al 2010 ) and not far from those recorded during a year-long monitoring at the remote site of Col Margherita, located ~75 km WSW from our study area in the North-Eastern Italian Alps (mean 3.14 ± 1.29 ng/m 3 ; Vardè et al 2022 ). Moreover, similar peak values of atmospheric GEM (up to 48.5 ng/m 3 ) were reported for the other Hg impacted coastal, lagoonal areas and alluvial plains of the Friuli Venezia Giulia region (Acquavita et al, 2022 ; Barago et al, 2020 ; Floreani et al, 2020 ), which suffered extended contamination due to the transport by the Isonzo River of Hg-enriched material from the Idrija cinnabar mine, located ~100 km upstream these locations (Acquavita et al 2022 ; Covelli et al 2001 , 2007 ). Overall, in the surroundings of the mining district, peaks of GEM concentrations higher than 15 ng/m 3 were observed above the abandoned waste rock piles and along the roads where Hg-rich material was used for construction of the various facilities (Fig.…”

Gaseous mercury evasion from bare and grass-covered soils contaminated by mining and ore roasting (Isonzo River alluvial plain, Northeastern Italy)

“…The southernmost coastal area of the plain adjacent to the mouth of the Isonzo River derives from hydraulic reclamation works carried out in past centuries to obtain cultivable areas from former lagoon and wetlands (Da Lio and Tosi, 2018;Marocco, 1989). Intense agriculture of prevalently maize and soybean occurs throughout the plain with the scarce presence of permanent meadows and a general increase in urbanisation and industrial settlements moving southwards (Acquavita et al, 2022;Contin et al, 2012;Salata et al, 2019). According to Rivas-Martínez et al (2011), the bioclimate of the study area is classifiable as temperate oceanic, with relatively mild temperatures throughout the year and frequent precipitation.…”

“…1) near the present course of the Isonzo River located between 40 and 70 km downstream the confluence with the Idrijca River. The sites were selected on the basis of existing information about Hg concentrations in soils (Acquavita et al, 2022): 3 were located in the High plain, in the municipalities of Savogna d'Isonzo (SVI and SAV) and Sagrado (SAG), and the remaining in the Low plain near the villages of Turriaco (TUR), San Canzian d'Isonzo (SCZ) and Fossalon di Grado (FOS). The soils of the latter two sites are classifiable as Gleyic Fluvic Cambisols according to the World Reference Base for Soil Resources (WRB, https://www.isric.…”

“…from soils characterised by the presence of native herbaceous vegetation cover and bare soil plots where grass was manually removed before sampling. Sampling points were chosen as close as possible to those previously used for the characterisation of Hg contamination of the Isonzo River plain (Acquavita et al, 2022). Flux measurements were performed by means of a Plexiglas non-steady state (NSS) flux chamber (60 × 20 × 25 cm) coupled with the Lumex analyser, which allows for the direct determination of Hg concentrations in the air in a wide dynamic range (2-30, 000 ng m − 3 ).…”

“…Leaching and erosion of contaminated soils and sediments, mostly during rain events, favour the mobilization and transport of Hg to the Isonzo River and then finally to the northern Adriatic Sea (Baptista-Salazar et al, 2017;Pavoni et al, 2021). Due to flooding events, Hg has been re-distributed over the entire alluvial plain of the Isonzo River, resulting in high concentrations in soils (up to 76 mg kg − 1 ) which progressively decrease as the distance from the river increases (Acquavita et al, 2022;Cerovac et al, 2018;Piani et al, 2013). Few studies have highlighted the occurrence of Hg 0 atmospheric concentrations which are slightly higher than the natural background, mostly in the coastal sector of the southernmost part of the plain (Barago et al, 2020;Floreani et al, 2020), but a direct evaluation of potential Hg 0 releases at the soil-air interface is still lacking.…”