Selenium and Mercury Interactions in Apex Predators from the Gulf of Trieste (Northern Adriatic Sea)

Bioaccumulation of organotin compounds in the marbled electric ray (Torpedo marmorata) in the northern Adriatic Sea

Organotin compounds (OTC), tri-, di- and monobutyl tin, were determined in the tissues of marbled electric ray (Torpedo marmorata) in the Adriatic Sea. Marbled electric ray specimens were provided by local fishermen from three localities in the northern Adriatic: area close to the shipyard in Seča, the natural protected area Strunjan Nature Reserve and along the west Istrian coast. To assess the concentration of OTC in the environment, sediment samples were also analysed. After an adequate extraction of OTC from both matrices, their concentrations were determined by GC-ICP-MS. The results indicate that the accumulation of TBT (tributyltin) and DBT (dibutyltin) in the marbled electric ray is related to the possible pollution sources, since their total concentrations were significantly higher (p < 0.001) in the area close to the shipyard (up to 69 μg Sn kg-1, w.w.) in comparison to the other two areas less affected by direct pollution (up to 7 μg Sn kg-1, w.w.). TBT concentrations ranged from 2 to 42 μg Sn kg-1, w.w., DBT concentrations were in the range from 2 to 22 μg Sn kg-1, w.w., and MBT concentrations were mostly below the detection limit with the highest up to 4 μg Sn kg-1, w.w. The proportion of the three determined congener concentrations in sediment samples indicate a temporally older pollution with these compounds, with prevailing DBT and MBT concentrations up to 30 μg Sn kg-1, w.w., and much lower TBT concentrations up to 7 μg Sn kg-1, w.w. According to our results, marbled electric ray could be considered as an ideal bioindicator of environmental pollution due to its ecological characteristics.

Concentration of mercury in human hair and associated factors in residents of the Gulf of Trieste (North-Eastern Italy)

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.

SCIENTIFIC SUBSTANTIATION OF TECHNOLOGY OF PASTA BASED ON FRESHWATER MUSSELS ENRICHED WITH SELENIUM

The possibility of using dietary selenium-protein additive "Neoselen" for enrichment of pastes based on mussels with organic selenium has been investigated. The formulation of the pastes involved the use of the soft body of the freshwater mmussels of the genus Anodonta. The influence of the introduction of different percentage of the additive "Neoselen" on the organoleptic properties of the developed pastes based on freshwater mussels was investigated. It is found that the addition of additive "Neoselen" even more than 5% does not impair the taste and color of the developed pastes. Moisture content, moisture retention, fat-holding capacity and active acidity of the developed pastes were investigated. The moisture-holding and fat-holding capacity of the developed paste is determined. The difference in the consistency of pastes based on freshwater mussels with different percentage of unpowered additives was investigated by determining the values of plastic viscosity and modulus of elasticity. The regularities of the influence of the additive "Neoselen" on the general chemical and mineral composition of pastes based on freshwater mussels have been established. It is established that the addition of 1%, 3% or 5% in the paste of additive "Neoselen" can enrich it by 7.8, 23.4 and 39 mkg of selenium, respectively. Studies have shown that in the composition of both the control and experimental samples of pastes in the amount of protein, minerals and water content. With the increase of the content of the additive "Neoselen" in the formulation of pastes, the content of protein and minerals increases. The complex of qualitative characteristics of the developed pastes is investigated. The regularities of the influence of the component composition on the organoleptic and physicochemical and functional-technological characteristics of the minced systems based on freshwater mussels and the additive "Neoselen" have been established. It is established that the optimal doses of the use of additive "Neoselen" in the formulation of pastes ranges from 3-5%.

Mercury and selenium in the grass goby Zosterisessor ophiocephalus (Pisces: Gobiidae) from a mercury contaminated Mediterranean lagoon

Mercury (Hg) and its bioaccumulation are important in evaluating the health risk through fish consumption. In the Marano and Grado Lagoon a historical contamination originating from both mining and industrial sources is present. In this study the Hg levels in the grass goby and the protective effect of selenium (Se) were determined as a function of size, sex, sampling sites and season. Mercury often exceeded the limit for commercialisation, whereas Se was mostly constant being homeostatically regulated. The mean Se/Hg molar ratio showed about 40% of data >1.0 and the HBV_Se index was on average equal to 0.0. Thus, grass goby of this area is not a Se source food indicated for pregnant and/or breastfeeding women, but its occasional consumption would appear to have no contraindications if integrated with other Se rich foods: the ingestion of about 10 fish fillets per week can be safely consumed by adults.