Search

The Gulf of Trieste (Northern Adriatic Sea, Italy) is the coastal area of the Mediterranean Sea most highly contaminated by mercury (Hg) due to fluvial inputs from the Isonzo/Soča River system, draining over 500 years' worth of cinnabar extraction activity from the Idrija mining district (Western Slovenia). The aim of this research is to investigate the concentration of Hg in hair samples taken from the general population of the Friuli Venezia Giulia (FVG) Region coastal area, as a marker of chronic exposure to Hg. Three hundred and one individuals - 119 males and 182 females - were recruited by convenience sampling in Trieste in September 2021. An amount of approximately 100 mg of hair was collected from the occipital scalp of each participant to measure the respective Hg concentrations (expressed as mg/kg). Moreover, participants completed a self-report questionnaire collecting extensive socio-demographic and life-style information. A multiple linear regression analysis was employed to investigate factors associated with increased levels of Hg concentration in hair. A mean Hg concentration in hair of 1.63 mg/kg was found, slightly above the 1.0 mg/kg threshold recommended by the WHO for pregnant women and children, although still well below the no observed adverse effects level (NOAEL) of 10 mg/kg. Among respondents, 55.6% showed a Hg concentration in hair > 1 mg/kg, 22.9% > 2 mg/kg, and 2 participants exhibited Hg levels > 10 mg/kg. The adjusted mean hair Hg level increased in those subjects who reported a preference for shellfish/crayfish/mollusks (RC = 0.35; 95%CI: 0.16; 0.55), whereas it decreased in those who reported a preference for frozen fish (RC = -0.23; 95%CI: - 0.39; - 0.06). Though a risk alert for Hg exposure for coastal residents from FVG is deemed unnecessary at this time, it is recommended that pregnant women limit their ingestion of locally caught fish to < 4 servings/month., (© 2022. The Author(s).)

Health and safety of occupations entailing extensive skin contact with cinnabar-enriched sand in beaches of Friuli-Venezia Giulia (FVG) Region (North-eastern Italy) have been questioned for possible skin absorption of mercury (Hg). One hundred mg hair was collected from the occipital scalp of 50 male workers of Grado beach and 121 males from FVG general population. Factors associated with hair Hg content were investigated by multivariable logistic (considering Hg levels >1 vs ≤1 mg/kg) and log-transformed linear regression. The median hair concentration of Hg in male beach workers was 0.70 (IQR = 0.42; 1.34) mg/kg, lower than FVG general population's [1.29 (IQR = 0.87-2.06) mg/kg (p < 0.001)]. In both regression models the hair Hg increased with fish consumption, both among beach workers of Grado and FVG general population. The mean Hg levels in beach workers of Grado fell within an acceptable range, not requiring restrictions of their occupational activities., Competing Interests: Declaration of competing interest None to declare., (Copyright © 2022 Elsevier Ltd. All rights reserved.)

The sediments in the Gulf of Trieste (northern Adriatic Sea, Italy) are contaminated by mercury (Hg) due to historic mining which took place in Idrija (Slovenia). Despite many studies having been done regarding Hg, no information is available on the potential impact of dredging required along the main channel approaching the Port of Monfalcone. Sixteen surface sediment samples were collected along the channel to determine both total Hg concentration and chemical species using the thermo-desorption (TD) technique. Six samples were also chosen to apply a selective sequential extraction (SSE). The TD technique showed the maximum Hg release approximately at 260 and 335°C, corresponding to metacinnabar (β-HgS) and cinnabar (α-HgS), respectively. The SSE demonstrated that Hg was mainly associated with poorly soluble or insoluble compounds (98.7%). A resuspension event over a limited period of time can be considered of negligible impact to the water column due to the scarce Hg mobility from sediments.

Butyltin compound (BTC) contamination was evaluated in two north Adriatic marinas, San Rocco (Italy) and Lucija (Slovenia). BTC sedimentary concentrations (121 ± 46 and 352 ± 30 ng Sn g -1 in San Rocco and Lucija, respectively) evidenced the past use of antifouling paints, confirmed by the reduced tributyltin content (~ 46%) with respect to the sum of BTC. Elemental and organic carbon isotopic (δ 13 C) analyses of bulk sediments and its lipid and humic substances were performed in order to evaluate their role in BTC partitioning and preservation. The δ 13 C of sedimentary bulk and refractory organic matter suggested that diagenetic processes could play a role in the preservation or release of pollutants. No contamination was found in water collected from the benthic chamber and thus, fluxes at the sediment-water interface were not assessed, except for MBT efflux at Lucija (28.9 ng Sn m -2 day -1 ). Nevertheless, BTC concentrations in porewaters (up to 75 ng Sn l -1 ) and rather low sediment-porewater partitioning coefficients (K d ) with respect to the data reported in the literature would suggest a potential risk of the reintroduction of BTC into the water column at both sites: at Lucija, sedimentary contamination is high despite the greater Log K d , whilst at San Rocco, the low BTC concentration is associated with a reduced sediment affinity.

Dissolved gaseous mercury (DGM) production was examined in relation to ultraviolet radiation within a marine aquaculture site in the contaminated Marano and Grado Lagoon (Italy). The measured rates of DGM production relative to time elapsed (17.06 and 20.68 pg h -1 , respectively) were substantially (6-20 times) higher than what has been observed in other marine Hg studies. We measured similar levels of DGM relative to dissolved total mercury (THg D ) (0.84%-8.91%) at these sites in comparison to uncontaminated marine sites, however relative to other moderately-contaminated marine sites in Portugal the % DGM/THg D was high. These results suggest a substantial capacity for Hg volatilization from these highly contaminated lagoons to the atmosphere due to photoreduction mechanisms.

Metabolism and carbon, oxygen, and nutrient fluxes (DIC, DOC, DO 2 , NO 2 - , NO 3 - , NH 4 + , PO 4 3- and SiO 4 4- ) were studied during three surveys at two sites (VN1 and VN3) located at a fish farm at the Marano and Grado Lagoon (northern Adriatic Sea), using an in situ benthic chamber. Field experiments were conducted in July and October 2015 and March 2016 at a depth of approximately 2 m along the main channels of the fish farm. Water samples were collected by a scuba diver every 2 h in order to investigate daily fluxes of solutes across the sediment-water interface (SWI). Regarding the solid phase, C org /N tot and C org /P org molar ratios suggested an autochthonous marine origin of the organic matter and a minor preservation of P in the sediments, respectively; high values of sulphur (S tot ) were also encountered (0.8-2%). The conditions at VN3 were mostly anoxic with high NH 4 + levels (30-1027 μM) and the absence of NO 3 - . Substantial daily patterns of all solutes occurred especially in autumn and winter. On the contrary, fluxes at VN1 were less pronounced. Usually, inverse correlations appeared between dissolved O 2 and DIC trends, but in our system this was observed only at VN3 in autumn and accomplished by a parallel increase in NH 4 + , PO 4 3- and SiO 4 4- during intense nutrient regeneration. These results are significantly different than those reported for open lagoon environments, where nutrient regeneration at the SWI and in surface sediments is the primary source of nutrients available for assimilation processes, especially during the warmer period of the year when the natural nutrient input by fresh water inflows is limited. Due to the importance of this site for aquaculture, biodiversity and ecosystem services, useful suggestions have been provided from this study in order to improve the quality of this unique aquatic system., (Copyright © 2018 Elsevier B.V. All rights reserved.)

One of the main environmental issues affecting coastal marine environments is the accumulation of contaminants in sediments and their potential mobility. In situ benthic chamber experiments were conducted at two tourist ports (marinas) located in the Gulf of Trieste, one in Slovenia and one in Italy. The aim was to understand if and where recycling at the sediment-water interface (SWI) may affect metal(loid)s. Short sediment cores were also collected near the chamber to investigate the solid (sediments) and dissolved phases (porewaters). Both diffusive and benthic fluxes were estimated to elucidate the release of metal(loid)s at the SWI. Total element concentrations and their labile fractions were determined in sediments to quantify their potential mobility. The total element contents were found to be two orders of magnitude higher in the Italian marina than in the Slovenian one, especially for Hg (up to 1000 mg kg -1 ), whereas the labile fraction was scarce or null. The opposite occurred in the Slovenian marina. Metal(loid)s in porewaters showed a clear diagenetic sequence and a close dependence upon the suboxic/anoxic conditions of sediments. The results suggest that although the sediments of the Italian marina exhibit the highest total metal(loid) concentration, these elements are scarcely remobilisable. Conversely, in the Slovenian marina, sediments seem to be comparatively more prone to release metal(loid)s at the SWI.