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Abstract: Mercury (Hg) settlements in the Mediterranean Sea determine a potential toxicological relevance of seafood intakes for coastal populations. To assess this possibility, fish, molluscs, and crustaceans of commercial size of 69 different species were sampled and analyzed for total mercury (HgTOT) from georeferenced areas and evaluated for their compliance with the European Union Maximum Residue Limits of 0.5 and 1.0mg/kgwet weight (ww). Accounting for the weekly estimated seafood intake in the Italian coastal population (mean 469–626g/person/week) it was then possible to recover threshold contamination values in seafood. Under a Tolerable Weekly Intake of 1.3μg/kg/bw/week, a threshold seafood contamination <0.10mg/kgww has been derived for sensitive groups. A suitable algorithm based on the parallel MeHg and HgTOT analysis on the most consumed species, helped to refine the uncertainties related to the conservative assumption in seafood all the HgTOT present is in form of MeHg. This work aims to improve the link between the risk management and risk assessment strategies, with the identification of those fish and seafood species, that, when regularly consumed, could determine or prevent potential HgTOT/MeHg overintakes in sensitive groups. [Copyright &y& Elsevier]

An 8-week feeding trial was undertaken with Cyprinus carpio to determine the effects of two commercial Se diets (HSe 1.0mgkg−1 and LSe 0.25mgkg−1) on growth, accumulation and antioxidant response in juveniles at time 0, 30 and 60 days. HSe carp had higher mean weight (W) values than LSe group at 60 days and the Fulton condition factor (K) indicated good fish health for both diet groups. Among the investigated HSe tissues, kidney and liver were mainly involved in Se accumulation, whereas the Se level in muscle indicated a very low Se contamination risk for human health. Selenium accumulation levels in HSe tissues followed this order: kidney>liver>muscle. Although growth was not impaired, biochemical antioxidant indicators in liver and kidney evidenced an oxidative stress condition in HSe juveniles. Furthermore, selenium supplementation levels, higher than the one employed in this study, might worsen the antioxidant status of carp. [Copyright &y& Elsevier]

To date, the occurrence of rare earth elements (REEs) in freshwater ecosystems has garnered limited attention in the scientific literature. Furthermore, a dearth of data exists regarding their potential bioaccumulation in freshwater fish. To fill this knowledge gap, we studied REEs concentrations in water, sediment, and fish specimens collected along the Po River (northwest Italy) and calculated biota-sediment accumulation (BSAF) and bioconcentration (BCF) factors, while taking into account fish feeding behavior and trophic level effects on the overall content of total REEs (ƩREEs). The fish communities were composed of native and non-native species. Remarkably low concentrations of REEs (<0.0003 mg/L) were detected in the water samples, indicating REEs insolubility. In contrast, sediment samples were found to be a good sink for REEs, with a higher mean ƩREEs recorded for the samples from the Moncalieri station (70.93 mg/kg). Notably, no significant differences in ƩREEs concentration were observed in the muscle tissue of fish samples from the three stations. The highest mean ƩREEs was recorded in the samples from the Murazzi station (0.027 mg/kg). The BSAF was very low, consistently below the unit, indicating an absence of bioaccumulation in fish muscle from sediment. In contrast, the BCF was high for several REEs, mainly for Sc and Y. While feeding ecology did not appear to affect REEs accumulation in muscle, there was a significant negative relationship between the trophic level and ΣREEs, indicating a trophic dilution of REEs from predator (Silurus glanis) to planktivorous (Alburnus arborella) fish. This study provides baseline concentrations, trophic transfers, and patterns of REEs in a river system. Further studies are needed to understand the transfer of REEs to other biotic components of lotic ecosystems. [Display omitted] • Sediment samples were found to be a good sink for REEs. • Bioconcentration factor values were high for several REEs, mainly for Sc and Y. • Feeding ecology had no influence on the REEs content in fish. • An inverse relationship between trophic levels of fish and REEs content was found. [ABSTRACT FROM AUTHOR]

Transition metals are cofactors for a wide range of vital enzymes and are directly or indirectly involved in the response against reactive oxygen species (ROS), which can damage cellular components. Their altered homeostasis has been studied in neurodegenerative disorders such as Alzheimer's disease (AD), Parkinson's disease (PD) and amyotrophic lateral sclerosis (ALS), but no data are available on rarer conditions. We aimed at studying the role of essential trace elements in ataxia telangiectasia (A-T), a rare form of pediatric autosomal recessive cerebellar ataxia with altered antioxidant response. We found an increased level of copper (Cu, p = 0.0002) and a reduced level of zinc (Zn, p = 0.0002) in the blood of patients (n. 16) compared to controls, using inductively coupled plasma mass spectrometry (ICP-MS). Other trace elements involved in the oxidative stress response, such as manganese (Mn) and selenium (Se), were unaltered. Cu/Zn-dependent superoxide dismutase (SOD1) was shown to have a 30% reduction in gene expression and 40% reduction in enzyme activity upon analysis of lymphoblastoid cell lines of patients (Student's t -test, p = 0.0075). We also found a 30% reduction of Mn-SOD (SOD2; Student's t -test, p = 0.02), probably due to a feedback regulatory loop between the two enzymes. The expression of antioxidant enzymes, such as erythrocyte glutathione peroxidase ( GPX1 ), and SOD2 was unaltered, whereas catalase ( CAT ) was increased in A-T cells, both at the mRNA level and in terms of enzyme activity (~ 25%). Enhanced CAT expression can be attributed to the high ROS status, which induces CAT transcription. These results suggest that alterations in essential trace elements and their related enzymes may play a role in the pathogenesis of A-T, although we cannot conclude if altered homeostasis is a direct effect of A-T mutated genes ( ATM ). Altered homeostasis of trace elements may be more prevalent in neurodegenerative diseases than previously thought, and it may represent both a biomarker and a generic therapeutic target for different disorders with the common theme of altered antioxidant enzyme responses associated with an unbalance of metals. [ABSTRACT FROM AUTHOR]

Highlights: [•] Local seafood supply relevant for MeHg intake in Mediterranean coastal population. [•] Seafood consumption questionnaire broken into 42 seafood species administered to 278 adults. [•] 30% of 18–45years vulnerable women (N =98) exceeds the TWI for MeHg (1.3μg/kg bw). [•] The choice of consumed species appears as the main determinant in over-exposure. [•] The empowerment about a more responsible choice of seafood is envisaged. [Copyright &y& Elsevier]