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The Adriatic Sea is an enclosed basin threatened by marine pollution due to its hydrographic features and anthropogenic pressure. Although zooplankton has been worldwide regarded as an immediate warning signal of contamination, limited information is available on the contamination of these organisms at the Adriatic level. Hence, this study provides comprehensive data on the presence and levels of multiple pollutants in zooplankton collected from 46 locations. With regards to legacy contaminants, both PCB and DDT levels have declined since the 1980s. Specifically, most samples were characterized by low DDT contamination (average of 3 ± 2.7 ng g− 1 dry weight) and only few of these accumulated levels of concern for what concerns PCB, pointing out possible hotspots of contamination in the central-eastern Adriatic Sea. As regards metal(loid)s, the Metal Pollution Index identified areas of concern in the north Adriatic Sea (Gulf of Venice) with high levels of Co, Cu, Hg, Cr and Pb; in the Central Adriatic Sea (Tremiti islands) with high levels of Co, Ni, Hg, Cr and Pb; in the Southern Adriatic Sea (Taranto and offshore Corfu), with high levels of most metal(loid)s, especially Cr, Ni and Zn. Certain metal(loid)s (e.g. Cd, Pb and Hg) have declined over time and most of them are lower than well-known contaminated worldwide marine ecosystems. Only Cu appears to be particularly high in the Mediterranean zooplankton. Overall, this work suggests a general improvement of the status of contamination of the Adriatic Sea. [Display omitted] • This study evaluated the contamination status of the Adriatic Sea using zooplankton. • PCB and DDT contamination appears to be declining over the past 50 years. • DDT levels are comparable to pristine and less impacted areas worldwide. • Data on trace elements pointed out some hotspots within the basin. • Most TE levels in zooplankton are lower than renowned worldwide contaminated areas. [ABSTRACT FROM AUTHOR]

Thermal desorption is a well-assessed technique to speciate mercury (Hg) in soils and sediments. However, the effects related to the different matrices are still not properly assessed. In this study, thermal desorption was applied to Hg-free calcite mixed with Hg standard and soils rich in carbonate and silicate minerals, as well as organic matter. Hg0, H g Cl 2 , H g O, α-HgS, β-HgS and organo-mercuric compounds were recognized, pointing out that the soil matrix operates notable differences in terms of breakdown temperatures of the Hg-compounds and suggesting that the mineralogical composition of soil has to be investigated before applying the thermal desorption technique. Furthermore, the presence of Hg0 was carefully evaluated since, as already observed, it forms Hg2+, which increases mercury mobility in the pedological cover with important consequences for those soils contaminated and located close to decommissioned or active mining areas and/or industrial sites (e.g. chloro-alkali industries). Experimental runs were thus carried out by using carbonate-, silicate- and organic-rich soils doped with liquid Hg. It was observed that Hg0 tends to be oxidized to form Hg+ and then Hg2+ as a function of soil matrix and reaction time. Surprisingly, the oxidation rate is rather fast, since after 42 days the initial content of Hg0 is halved, thus following an exponential decay. This implies that in Hg0-polluted areas, the fate of the resulting Hg2+ can be that to: i) be adsorbed by organic matter and/or Fe–Mn–Al oxides and/or ii) feed shallow aquifers. This study is a further step ahead to understand the behavior of Hg in contaminated soils from industrial and mining areas where liquid Hg is occurring in different soil matrices and may provide useful indications for remediation operations. [Display omitted] • Mercury speciation in different soil matrices by Lumex-Pyro 915+. • Desorption temperatures of Hg compounds are dependent on the Hg-bearing matrix. • Hg0 suffers oxidation processes to form more stable species Hg2+ in t 1/2 –42 days. • Results may have important implications during soil remediation activities. [ABSTRACT FROM AUTHOR]

Coastal ecosystems, such as coral reefs, are particularly vulnerable to mercury contamination due to direct contact with terrestrial sources. Here, we evaluated, for the first time, the concentration of mercury in coral reefs in the Southwestern Atlantic using the amphi-atlantic scleractinian coral Montastraea cavernosa. Sampling was realized over an extension of 200 km along different coral reefs. Our data show mercury values ranging from 0.01 to 0.27 mg kg−1 in the tissue and 0.001–0.06 mg kg−1 in the skeleton and higher values when compared to coral worldwide. The concentration of mercury in the tissue from Todos os Santos Bay was higher than in open sea regions but also higher compared to other coral reefs of the world, while the skeleton concentration did not indicate any differences when compared to the open sea regions. The data presented is of concern as we consider the importance of coral reefs and should be used in future environmental management planning. [Display omitted] • Hg in corals were reported for the first time in 200 km in Southwest Atlantic. • M. cavernosa presented higher Hg concentration then other species worldwide. • Tissue of M. cavernosa showed more Hg concentration than skeleton. • Concentrations of Hg from Todos os Santos Bay were higher than in open sea reefs. [ABSTRACT FROM AUTHOR]

The development of functionalized covalent organic frameworks (COFs) is crucial in expanding their potential for removing toxic heavy metals from drinking water. Here, a new sulfhydryl-modified heteroporous COF (COF DBD-BTA) was prepared using a "bottom-up" approach in which a direct amine-aldehyde dehydration condensation between 2,5-diamino-1,4-benzenedithiol dihydrochloride (DBD) and [1,1′-biphenyl]-3,3′,5,5′-tetracarbaldehyde (BTA) was occurred. The COF DBD-BTA featured a hexagonal kagome (kgm) structure and a sheet-like morphology. Notably, COF DBD-BTA contained densely S atoms that provided high-density Hg(II) adsorption sites for efficient and selective trace Hg(II) removal. COF DBD-BTA exhibited excellent performance in rapidly removing trace Hg(II) from 30 μg L−1 to 0.71 μg L−1 within 10 s, below the World Health Organization's allowable limit of 1 μg L−1. Additionally, COF DBD-BTA exhibited a high Hg (Ⅱ) removal level from water, achieving adsorption capacity of 687.38 mg g−1. Furthermore, the adsorbent exhibited a wide range of applicability for low concentration (6–500 μg L−1) Hg (Ⅱ), a simple and feasible regeneration method, and strong Hg(II) removal ability in real tap water systems. The excellent adsorption efficiency, outstanding recyclability, and one-step room temperature synthesis make S -rich COF DBD-BTA a promising candidate for eliminating Hg (Ⅱ) from drinking water. [Display omitted] • Bottom-up synthesis of a novel S -rich COFs with heteropore was achieved. • The adsorbent has Kagome lattices and high-density sulfhydryl chelating sites. • The adsorbent shows ultrafast trace Hg(II) uptake and large uptake capacity. • The adsorbent shows great Hg(II) removal potential from the actual water system. • The adsorbent shows good uptake performance for multiple coexisting trace HMs. [ABSTRACT FROM AUTHOR]

Light Emitting Diodes (LEDs) have emerged as a tool with great potential in the field of phytoremediation, offering a novel approach to enhance the efficiency of plant-based remediation techniques. In this work investigated the influence of LEDs on the phytoremediation of arsenic (As) and mercury (Hg) by Ceratophyllum demersum L., propagated using tissue culture methods. In addition, the biochemical properties of the plants exposed to metal toxicity were examined. Phytoremediation experiments employed concentrations of As (0.01–1.0 mg/L) and Hg (0.002–0.2 mg/L), with application periods set at 1, 7, 14, and 21 days. In addition to white, red and blue LEDs, white fluorescent light was used for control purposes in the investigations. A positive correlation was observed between higher metal concentrations, extended exposure times, and increased metal accumulation in the plants. Red LED light yielded the highest level of heavy metal accumulation, while white fluorescent light resulted in the lowest accumulation level. Examination of the biochemical parameters of the plants, including photosynthetic pigment levels, protein quantities, and lipid peroxidation, revealed a pronouncedly enhanced performance in specimens subjected to red and blue LED illumination, surpassing outcomes observed in other light treatments. The findings of this study introduce innovative avenues for the effective utilization of red and blue LED lights in the realm of phytoremediation research. Thus, the interaction between LEDs, tissue culture, and the phytoremediation process could lead to synergistic effects that contribute to more effective and sustainable remediation strategies. [Display omitted] • LED lights are very effective for phytoremediation of As and Hg. • Heavy metal accumulation values of plants increase under Red and Blue LEDs. • Red LED application reduces the effects of heavy metal stress in plants. • Tissue culture is a great advantage for effective and sustainable phytoremediation. • A highly efficient remediation system can be created with LEDs and tissue culture. [ABSTRACT FROM AUTHOR]

Rare earth elements (REEs) are increasingly being studied mainly due to their economic importance and wide range of applications, but also for their rising environmental concentrations and potential environmental and ecotoxicological impacts. Among REEs, neodymium (Nd) is widely used in lasers, glass additives, and magnets. Currently, NdFeB-based permanent magnets are the most significant components of electronic devices and Nd is used because of its magnetic properties. In addition to REEs, part of the environmental pollution related to electrical and electronic equipment, fluorescent lamps and batteries also comes from mercury (Hg). Since both elements persist in ecosystems and are continuously accumulated by marine organisms, a promising approach for water decontamination has emerged. Through a process known as sorption, live marine macroalgae can be used, especially Ulva lactuca , to accumulate potential toxic elements from the water. Therefore, the present study aimed to evaluate the cellular toxicity of Nd and Hg in Mytilus galloprovincialis , comparing the biochemical effects induced by these elements in the presence or absence of the macroalgae U. lactuca. The results confirmed that Hg was more toxic to mussels than Nd, but also showed the good capability of U. lactuca in preventing the onset of cellular disturbance and homeostasis disruption in M. galloprovincialis by reducing bioavailable Hg levels. Overall, the biochemical parameters evaluated related to metabolism, antioxidant and biotransformation defences, redox balance, and cellular damage, showed that algae could prevent biological effects in mussels exposed to Hg compared to those exposed to Nd. This study contributes to the advancement of knowledge in this field, namely the understanding of the impacts of different elements on bivalves and the crucial role of algae in the protection of other aquatic organisms. [Display omitted] • The presence of Ulva lactuca reduced Hg accumulation by mussels. • The presence of Hg induced mitochondrial activity in mussels without algae. • Limited cellular damage in the Nd or Hg treatments. • Mussels co-exposed to Nd and algae showed activation of GPx and CbEs. • Mussels exposed to Hg with algae exhibited a greater redox imbalance. [ABSTRACT FROM AUTHOR]

Mediterranean marine biota suffers from various anthropogenic threats. Among them, pollutants such as mercury (Hg) represent important environmental issues that are exacerbated by bioaccumulation and bioamplification along food webs via its organic form, monomethylmercury (MMHg). To date, very little is known regarding the impact of mercury on Porifera and the few available studies have been exclusively focused on Demospongiae. This work studies the effect of MMHgCl at different biological levels of Oscarella lobularis (Porifera, Homoscleromorpha). Bioaccumulation assays show that MMHgCl significantly accumulated in sponge tissues after a 96-h exposure to 0.1 μg L−1. Toxicity assays (LC50 96h) show a sensibility that depends on life-stage (adult vs bud). Additionally, we show that the exposure to 1 μg L−1 MMHgCl negatively impacts the epithelial integrity and the regeneration process in buds, as shown by the loss of cell-cell contacts and the alteration of osculum morphogenesis. For the first time in a sponge, a whole set of genes classically involved in metal detoxification and in antioxidant response were identified. Significant changes in catalase, superoxide dismutase and nuclear factor (erythroid-derived 2)-like 2 expressions in exposed juveniles were measured. Such an integrative approach from the physiological to the molecular scales on a non-model organism expands our knowledge concerning sensitivity and toxicity mechanisms induced by MMHg in Porifera, raising new questions regarding the possible defences used by marine sponges. [Display omitted] • The sensitivity of the sponge Oscarella lobularis life cycle-dependent. • Three antioxidant genes are under-expressed after exposure to mercury. • Exposure to mercury induces strong defects on major epithelial features. [ABSTRACT FROM AUTHOR]

Mercury (Hg) stable isotope ratios supplemented by Hg solid speciation data were determined in soils in a former Fe–Hg mining/smelting area (Jedová hora, Czech Republic, Central Europe). The dominant Hg phase in the studied soils was found to be cinnabar (HgS). A secondary form of soil Hg(II) was represented by Hg weakly and strongly bound to mineral (micro)particles, as revealed by thermo-desorption analysis. These Hg species probably play a key role in local soil Hg processes and biogeochemical cycling. The Hg isotopic data generally showed small differences between HgS (−1.1 to −0.8‰; δ202Hg) and the soil samples (−1.4 to −0.9‰; δ202Hg), as well as limited isotopic variability within the two studied soil profiles. On the other hand, the detected negative δ202Hg shift (∼0.4‰) in organic horizons compared to mineral soils in the highly contaminated profile suggests the presence of secondary post-depositional Hg processes, such as sorption or redox changes. For the less contaminated profile, the observed Hg isotopic variation (∼0.3‰; δ202Hg) in the subsurface mineral soil compared to both overlying and underlying horizons is likely due to cyclic redox reactions associated with Hg isotopic fractionation. We assume that the adsorption of Hg(II) to secondary Fe(III)/Mn(III,IV)-oxides could be of major importance in such cases. [Display omitted] • Cinnabar and Hg(II) bound to mineral particles were the main Hg forms in soils. • Generally small δ202Hg variations in contaminated soil profiles. • Post-depositional soil processes (sorption, redox changes) cause Hg fractionation. • First determination of Hg isotopic ratios in Fe(III)-containing ore. [ABSTRACT FROM AUTHOR]

Mercury pollution poses a global health threat due to its high toxicity, especially in seafood where it accumulates through various pathways. Developing effective and affordable technologies for mercury removal from water is crucial. Adsorption stands out as a promising method, but creating low-cost materials with high selectivity and capacity for mercury adsorption is challenging. Here we show a sustainable method to synthesize low-cost sulfhydrylated cellulose with ethylene sulfide functionalities bonded glucose units. Thiol-functionalized cellulose exhibits exceptional adsorption capacity (1325 mg g−1) and selectivity for Hg(II) over other heavy metals (Co, Cu, Zn, Pb) and common cations (Ca++, Mg++) found in natural waters. It performs efficiently across a wide pH range and different aqueous matrices, including wastewater, and can be regenerated and reused multiple times without significant loss of performance. This approach offers a promising solution for addressing mercury contamination in water sources. [Display omitted] • Here we report a novel class of low-cost sulfhydrylated cellulose adsorbents. • Sulfhydrylated cellulose is synthesised by a simple and sustainable synthetic route. • Sulfhydrylated cellulose has a high selectivity and adsorption capacity for Hg(II). • It has a high Hg(II) removal efficiency even in wastewater. [ABSTRACT FROM AUTHOR]

The sustainable utilization of resources motivate us to create eco-friendly processes for synthesizing novel carbon nanomaterials from waste biomass by minimizing chemical usage and reducing energy demands. By keeping sustainability as a prime focus in the present work, we have made the effective management of Parthenium weeds by converting them into carbon-based nanomaterial through hydrothermal treatment followed by heating in a tube furnace under the nitrogen atmosphere. The XPS studies confirm the natural presence of nitrogen and oxygen-containing functional groups in the biomass-derived carbon. The nanostructure has adopted a layered two-dimensional structure, clearly indicated through HRTEM images. Further, the nanomaterials are analyzed for their ability towards the electrochemical detection of mercury, with a detection limit of 6.17 μM, while the limit of quantification and sensitivity was found to be 18.7 μM and 0.4723 μM μA−1 cm−2, respectively. The obtained two-dimensional architecture has increased the surface area, while the nitrogen and oxygen functional groups act as an active site for sensing the mercury ions. This study will open a new door for developing metal-free catalysts through a green and sustainable approach by recycling and utilization of waste biomass. [Display omitted] • Parthenium hysterophorus , a hazardous weed poisonous to humans and animals. • Novel method for synthesizing carbon material from weed leaf extract is proposed. • As-synthesized material is utilized for the electrochemical sensing of Hg+2 ions. • This study attained a sustainable approach for utilizing hazardous weed. [ABSTRACT FROM AUTHOR]

Mercury (Hg) is a global environmental concern that affects both humans and ecosystem. The comprehensive understanding of sources and dynamics is crucial for facilitating targeted and effective control strategies. Herein, a robust approach integrating Multivariate Statistics, Geostatistics, and Positive Matrix Factorization (PMF) was employed to quantitatively elucidate the distribution and sources of Hg in agricultural lands. Results indicated elevated Hg concentrations in the land with 74.46% of soils, including 84.85% of topsoil, 69.70% of subsoil, and 67.31% of deepsoil, exceeding risk screening value. Geoaccumulation Index of Hg in soil surpassed level Ⅱ with more than 50% of Hg in the residual fraction regardless of the layer or location. The levels of Hg in surface water for irrigation exhibited a negative correlation with the distance from the mine and a positive correlation with that in sediment (R 2 >0.78, p < 0.01), suggesting the downstream migration and remobilization from sediment. Source apportion revealed that human activities as primary contributors despite high variability across locations and soil layers. Contributions to downstream soil Hg from Natural Background (NB), Primary Ore Mining (OM), Agricultural Practices (AP), and Wastewater Irrigation (WI) were 15.5%, 83.1%, 1.3%, and 0.1%, respectively. A reliable approach for source apportionment of Hg in soil was suggested, demonstrating potential applicability in the risk management of Hg-contaminated sites. Upstream Topsoil (ALUT), Upstream Subsoil (ALUS), Upstream Deepsoil (ALUD), similarly in the downstream Topsoil (ALDT), subsoil (ALDS), and Deepsoil (ALDD). [Display omitted] • High Hg levels were found in water, sediment, and soil near mining areas. • Geostatistics, multivariate statistics, and PMF formed an integrated framework. • Surface water Hg correlated with sediment indicating cross-media migration. • Mining dust and wastewater irrigation were major contributors to soil Hg. • Source contribution varied largely depending on location and soil layers. [ABSTRACT FROM AUTHOR]

In this paper, we present a novel fluorescent material based on the herbal tea of Lavandula multifida (Lm). The fluorescence properties of Lm aqueous extract were analyzed under various excitation wavelengths in the range of 290–450 nm. The Lm herbal infusion was found to be highly fluorescent, with an emission maximum at 450 nm under excitation at 390 nm. Consequently, it was exploited to develop a fluorescence method for detecting metal ions. Results obtained upon the addition of Hg2+, Na+, K+, Ca2+, Mg2+, Pb2+, Cd2+, Cu2+, Ni2+, Bi3+, Mn2+, Fe3+ and Co2+ ions showed that the fluorescence intensity of the Lm aqueous extract decreased strongly with the presence of mercury ions. A solid-state fluorescent sensor, based on Lm embedded into a Nafion membrane and deposited on a transparent polyethylene terephthalate (PET) sheet, has also been developed for the effective detection of Hg2+ ions. The Lm -Nafion-PET sensor exhibited good stability, high repeatability, and reproducibility. Furthermore, the Lm -Nafion/PET sensor demonstrated remarkable sensitivity to Hg2+ in sea water, with a limit of detection of 0.25 fM. To our knowledge, this is the first study which reports Lavandu la multifida plant for making a novel eco-friendly fluorescent solid-state sensor for the detection of mercury ions at femto-molar concentrations in seawater. [Display omitted] • A novel fluorescent material based on the herbal tea of Lavandula multifida (Lm) is presented. • A Lm- Nafion on polyethylene terephthalate (PET) fluorescent probe sensor has been developed. • Highly sensitive and selective sensing of Hg2+ was achieved. • Exceptional low detection limit (LOD) of 0.25 fM for Hg2+ ions in seawater was reported. [ABSTRACT FROM AUTHOR]

The Amazon region abounds in precious mineral resources including gold, copper, iron, and coltan. Artisanal and small-scale gold mining (ASGM) poses a severe risk in this area due to considerable mercury release into the surrounding ecosystems. Nonetheless, the impact of mercury on both the overall microbiota and the microbial populations involved in mercury transformation is not well understood. In this study we evaluated microbial diversity in samples of soil, sediment and water potentially associated with mercury contamination in two localities (Taraira and Tarapacá) in the Colombian Amazon Forest. To this end, we characterized the bacterial community structure and mercury-related functions in samples from sites with a chronic history of mercury contamination which today have different levels of total mercury content. We also determined mercury bioavailability and mobility in the samples with the highest THg and MeHg levels (up to 43.34 and 0.049 mg kg−1, respectively, in Taraira). Our analysis of mercury speciation showed that the immobile form of mercury predominated in soils and sediments, probably rendering it unavailable to microorganisms. Despite its long-term presence, mercury did not appear to alter the microbial community structure or composition, which was primarily shaped by environmental and physicochemical factors. However, an increase in the relative abundance of mer A genes was detected in polluted sediments from Taraira. Several Hg-responsive taxa in soil and sediments were detected in sites with high levels of THg, including members of the Proteobacteria, Acidobacteria, Actinobacteria , Firmicutes and Chloroflexi phyla. The results suggest that mercury contamination at the two locations sampled may select mercury-adapted bacteria carrying the merA gene that could be used in bioremediation processes for the region. [Display omitted] • In long-polluted sites bacterial communities are more affected by environmental variables than by Hg. • MerA was more abundant in Taraira sediments in line with higher mercury levels. • The Hg-immobile form was dominant, probably limiting microorganism access. • Proteobacteria , Acidobacteria , Actinobacteria , Firmicutes, and Chloroflexi dominated in high Hg sites. [ABSTRACT FROM AUTHOR]

In the present research, extraction of silica (SiO 2) from rice husk (RH) was optimized and silica nanoparticles (SNPs) was produced using it and functionalized by chitosan (CS) functional groups to obtain CS functionalized SNPs (SNPs–CS) bionanocomposite for the first time. The physical and chemical characteristics of the produced materials were examined using structural analyses. The results of structural analyses confirmed the fine structure of the produced materials. The SNPs–CS bionanocomposite was applied to effectively remove Hg2+ ions from aqueous solutions as an environmentally–friendly bionanoadsorbent and optimization and modeling of the adsorption conditions was explored using designed experiments by Design–Expert software with central composite design (CCD) and response surface methodology (RSM). Optimum adsorption conditions were obtained as solution pH of 6, SNPs–CS dosage of 0.1 g L−1 and Hg2+ ions concentration of 100 mg L−1 by removal efficiency of 85% and desirability function of 0.876. The results of adsorption kinetic showed a better fit of the pseudo–second–order model with experimental data, indicating the chemisorption of the adsorption process. The better fit of the Langmuir model with experimental data was confirmed by the results of adsorption isotherms, demonstrating monolayer adsorption on the homogeneous surface. The adsorption thermodynamic results illustrated the exothermicity and spontaneity of the adsorption reaction. The results of SNPs–CS recovery depicted its excellent recovery ability of removal efficiency with more than 90% after five consecutive adsorption and desorption cycles, which proved high potential of the produced bionanocomposite for industrial applications. [Display omitted] • Highly pure amorphous silica (SiO 2) extraction from rice husk (RH) agricultural waste was optimized. • Highly ordered structure silica nanoparticles (SNPs) was synthesized using extracted SiO 2 from RH. • SNPs was functionalized using chitosan (CS) functional groups to obtain SNPs–CS bionanocomposite. • SNPs–CS bionanocomposite was applied as bionanoadsorbent to effectively remove Hg2+ ions from aqueous solutions. • SNPs–CS bionanoadsorbent high adsorption capacity and reusability proved its high potential for environmental applications. [ABSTRACT FROM AUTHOR]

This study explores the accumulation of total mercury (THg) in deep-sea sediments and demersal megafauna of the ultra-oligotrophic Southeastern Mediterranean Sea (SEMS) across bathymetric gradients in the range 35–1900 m, sampled in seven cruises during 2013, 2017–2021, and 2023. Measurements of THg were conducted in surficial (0.0–0.5 cm) and subsurface (9.0–10 cm) sediments, demersal sharks, demersal teleost fish, and benthic crustaceans. Sedimentary organic carbon and biota δ13C and δ15N values were determined to explore possible foraging habitats and dietary sources of THg. The results exhibit an increasing trend of THg in surficial sediments with increasing bottom depth, while in the subsurface, pre-industrial sediments, THg remains lower, slightly increasing with depth. Having no major terrestrial point sources in this area, this increasing trend of THg in surficial sediments across bathymetric gradients is controlled by atmospheric mercury deposition, scavenged by the biological pump, and by lateral transport of particulate Hg in winnowed fine particles from the shelf. Similarly, the THg in benthic crustaceans and demersal fish ranged between 0.02 and 2.71 μg g−1 wet weight (0.06 and 10.8 μg g−1 dry weight) and increased with muscle δ13C as a function of distance offshore, while presenting a low THg-δ15N bio-magnification power. Our results suggest that foraging habitats, longevity, and species-specific depth distribution control their muscle THg bioaccumulation. Despite this complexity, the pooling of THg in megafauna into specific deep zones reflected the trend of increasing anthropogenic THg across bathymetric gradients. Furthermore, many of the biota measurements exceeded safe consumption thresholds for Hg and therefore, should be considered carefully in the development and regulation of deep-sea trawling in this region. [Display omitted] • Total mercury accumulation was studied across Mediterranean bathymetric gradients. • Anthropogenic enrichment was observed in deep-sea sediments and megafauna. • Foraging habitats and longevity control muscle THg enrichment in oligotrophic basins. • Biota measurements exceeded safe consumption thresholds for Hg. [ABSTRACT FROM AUTHOR]

Recent ecotoxicological studies have indicated mercury (Hg) contamination in aquatic ecosystems in the Amazon Basin. Although Hg contamination can be associated with small-scale gold mining, the soils of the Amazon region have naturally high Hg concentrations, and can be transported to aquatic ecosystems via deforestation and mining activities. Biomagnification of Hg can pose risks to the local human population; therefore, its concentration in fish tissues must be monitored consistently. Fast and sensitive Hg determination is required for continuously monitoring ecosystems impacted by mineral exploration. The direct mercury analyzer (DMA-80) is widely used for determining total Hg levels in tissue samples; it is fast and cost-effective, without requiring sample preparation. Here, we determined the sensitivity and specificity of Hg detection accomplished using DMA-80, and whether these results are reliable compared to those obtained using Inductively Coupled Plasma Mass Spectrometer (ICP-MS), which is the gold standard. We obtained 106 paired dried samples of muscle tissue from fish species occupying different trophic levels in the Lower Amazon region, and analyzed them using both equipment (DMA-80 and ICP-MS). The results obtained using DMA-80 had an overall Hg mean of 1.90 ± 0.18 mg/kg which was higher (p < 0.05) than the mean of those obtained using ICP-MS (1.55 ± 0.13 mg/kg). Linear regression analysis comparing the Hg levels obtained using both devices was within the 95% prediction interval, and a high coefficient of correlation showed agreement between the devices (r = 0.979; 0.069 to 0.986, 95% CI). Bland-Altman analysis showed that DMA-80 had a positive bias of 6.5% in relation to ICP-MS, which is more evident in samples with high Hg concentrations. DMA-80 was efficient in determining whether the Hg levels exceeded the maximum allowed levels required by the European Union, USA, and Brazil, showing a specificity and sensitivity of above 95%. [Display omitted] • Anthropogenic activities may increase Hg contamination in aquatic ecosystems. • We compared a Direct Mercury Analyzer (DMA) and ICP-MS for [Hg] in paired fish muscle. • DMA had a positive bias of 6.5% against ICP-MS. • Hg concentration were highly correlated (r = 0.979). • DMA had high (>95%) sensitivity and specificity to detect contaminated fish samples. [ABSTRACT FROM AUTHOR]

Mercury (Hg) and vitamin A (VitA) are two environmental factors with potential health impacts, especially during pregnancy and early childhood. Fish and seafood may present elevated levels of methylmercury (MeHg), the major Hg derivative, and VitA. This study aimed to evaluate the transgenerational effects of exposure to MeHg and/or VitA on epigenetic and toxicological parameters in a Wistar rat model. Our findings revealed persistent toxicological effects in generations F1 and F2 following low/mild doses of MeHg and/or VitA exposure during dams' (F0) gestation and breastfeeding. Toxicological effects observed in F2 included chronic DNA damage, bone marrow toxicity, altered microglial content, reduced neuronal signal, and diminished male longevity. Sex-specific patterns were also observed. Co-exposure to MeHg and VitA showed both synergistic and antagonistic effects. Additionally, the study demonstrated that MeHg and VitA affected histone methylation and caused consistent effects in F2. While MeHg exposure has been associated with transgenerational inheritance effects in other organisms, this study provides the first evidence of transgenerational inheritance of MeHg and VitA-induced toxicological effects in rodents. Although the exact mechanism is not yet fully understood, these findings suggest that MeHg and VitA may perpetuate their impacts across generations. The study highlights the need for remedial policies and interventions to mitigate the potential health problems faced by future generations exposed to MeHg or VitA. Further research is warranted to investigate the transgenerational effects beyond F2 and determine the matrilineal or patrilineal inheritance patterns., Competing Interests: Declaration of competing interest The authors declare that they have no known competing financial interests or personal relationships that could have appeared to influence the work reported in this paper., (Copyright © 2024 Elsevier Ltd. All rights reserved.)

Among the radioactive pollutants 210Po is the most substantial one in terms of seafood safety due to its efficient accumulation in marine animals and high irradiation of its alpha emission. Mercury is a highly toxic metal for both marine organisms and human beings. Biomagnification of MeHg (methylmercury) through marine food chains has made Hg concern of ecotoxicology and seafood safety. In the current study, the bioaccumulation of 210Po and THg (total mercury) were determined in 20 mollusc species, including 8 bivalves, 7 gastropods and 5 cephalopods collected from the island of Gökçeada in the north-eastern Aegean Sea. The highest accumulation of 210Po and Hg was seen in bivalves and cephalopods, respectively. Elevated Hg concentrations in all body parts (arms, mantle and viscera) were observed in octopus' species. The results of this study suggests that filter feeder bivalves and gastropods have a capacity to concentrate 210Po in their bodies, whereas predator gastropods and cephalopods have a capacity to concentrate Hg in their bodies. 7.0 kg (3.2–14.2) bivalve flesh intake is adequate due to 210Po ingestion in the studied region to reach 1 mSv which is the annual committed effective dose. Octopus consumption of 705 g in a week alone is needed to reach Provisional Tolerable Weekly Intake (PTWI) of mercury, 5 μg kg−1 body weight. Due to very low non-fish seafood consumption in Turkey there is no risk of Hg intake and alpha radiation of 210Po above the limit values through mollusc consumption. • Po-210 activities and Hg concentrations were measured in molluscs. • Bivalve molluscs more efficiently accumulated 210Po compared to gastropod and cephalopod molluscs. • Filter feeder molluscs exhibited elevated 210Po activities while predator molluscs had high capacity to concentrate Hg. • Consumption of bivalve molluscs may cause increased internal radiation dose in the studied region due to 210Po intake. • Elevated Hg concentrations were observed in edible parts (mantle and arms) of cephalopods. [ABSTRACT FROM AUTHOR]

Mercury (Hg), a significant toxic metal for nephrotoxicity, can be found in food (vegetable and seafood) and drinking water by contamination. Oxidative stress is involved in inorganic Hg-induced nephrotoxicity, but the Sirtuin1 (Sirt1)/Nrf2/OH-1 pathway and sodium (Na)/calcium (Ca) ions actions in mercuric chloride (HgCl 2)-induced nephrotoxicity remains unclear to date. In this study, Kunming mice were treated HgCl 2 (5 mg/kg) for 24 h to evaluate potential mechanism. Here, along with Sirt1 activation, pale kidney, hisologic conditions, typical apoptotic changes and TUNEL positive nuclei were observed under acute HgCl 2 exposure. Specifically, although HgCl 2 increased the expression of Nrf2, Keap1, OH-1 and NQO1, the mRNA levels of GSS, GCLC and GCLM showed no significant alterations in mice kidney. Moreover, mice exposed to HgCl 2 decreased the concentrations of Mg, K, P, Mn, Fe, Zn, and elevated Na, Ca, Cu and Se in kidney. It was also observed that HgCl 2 suppressed the ATPases (Na+-K+-ATPase, Ca2+-ATPase, Mg2+-ATPase and Ca2+-Mg2+-ATPase) activities and decreased the mRNA levels of Atp1a1, Atp1a2 in the kidney. Further study showed that HgCl 2 elevated Na+ concentrations by markedly increased the mRNA levels of Na+ transporter. The present study revealed that HgCl 2 induced Sirt1/Nrf2/OH-1 pathway activation while did not inhibit apoptosis in kidney of mice. Additionally, HgCl 2 regulates Na+ concentrations, which might create secondary disorders in absorption and excretion of other ions. Altogether we assume that Sirt1/Nrf2/Na+/Ca2+ pathway might be a potential therapeutic target for treating acute HgCl 2 induced nephrotoxicity. Image 1 • HgCl 2 caused Na+ overload through increased sodium transporter. • HgCl 2 induced Nrf2/HO-1 pathway while did not alter GCLC and GCLM mRNA levels. • HgCl 2 increased the expression of Sirt1 in kidney of mice. • HgCl 2 triggered apoptosis via ionic disorder, inactivation of ATPases activities. [ABSTRACT FROM AUTHOR]

Development of an in situ passive sampler for mercury (Hg), and its toxic form, methylmercury (MeHg), using simple polymer films, was explored for the potential to make an efficient and environmentally relevant monitoring tool for this widespread aquatic pollutant. The sulfur-containing polymers polysulfone (PS), and polyphenylene sulfide (PPS), were found to accumulate both MeHg and inorganic Hg (iHg), whereas polyethylene (PE) sorbed iHg but not MeHg, and polyoxymethylene (POM) and polyethersulfone (PES) films had low affinity for both Hg species. Uptake rates of Hg species into polymers were linear over two weeks, and dissolved organic matter at natural levels had no effect on partitioning of MeHg or iHg to the polymers. Sorption of MeHg to PS and PPS from three estuarine sediments correlated with uptake into diffusive gel-type samplers over time, and in PPS, with accumulation by the estuarine amphipod, Leptocheirus plumulosus. These polymers had lower MeHg adsorption rates, but are simpler to assemble, than diffusive gel-type samplers. Higher contaminant concentrations in polymer and gel-type samplers corresponded with porewater concentrations across sediments, suggesting they sample the dissolved MeHg pool, whereas MeHg levels in amphipods were more elevated with higher bulk sediment MeHg, which may reflect feeding strategy. While polymers with higher affinity for MeHg and iHg are needed for some environmental applications, this work suggests a simple sampling approach has potential for time-integrated, environmentally-meaningful MeHg monitoring in contaminated sediments. Image 1 • Plastics adsorb mercury and methylmercury at a constant rate. • Sulfur containing polymers have a high affinity for mercury species. • Methylmercury levels in passive samplers correspond with porewater concentrations. [ABSTRACT FROM AUTHOR]

The diffusive gradients in thin films technique (DGT) was used for the determination of bioavailable mercury in urban soils, and results were compared to the mercury accumulation by Pisum sativum L. (pea) parts (leaf, root, stem, blossom, legume, and green seed). The total mercury concentration in soil samples was ranged between 0.084 and 0.326 mg kg−1. The soil solutions contained 0.15%–0.20% of mercury present in soils. In the soil solution, 2.21%–3.45% of mercury was available for DGT units. The highest mercury content was determined in the leaf and root of the pea plant, and the lowest in the consumable part of the pea plant (green seed). Mercury concentration in the parts of the pea plant increased over time, alongside the growth of the plant. The effect of acid precipitation on mercury bioavailability was statistically non-significant (p = 0.53). Significant and positive correlations were found between mercury flux into DGT unit, and mercury flux into the root (r = 0.989), leaf (r = 0.985), and stem (r = 0.904) of the pea plant. The obtained results suggest that the DGT method could be used for description of the uptake of mercury by pea plant parts in non-contaminated and slightly contaminated soils. Image 108 • The mercury bioavailability to Pisum sativum L. in urban soils was observed. • The highest mercury content was determined in leaves and roots of pea plant. • The consumable parts did not exceed the maximum permissible level of mercury. • The DGT technique was tested for predicting mercury bioaccumulation. [ABSTRACT FROM AUTHOR]

Previous studies of mercury (Hg) in pregnant women in the area of La Paz, Baja California Sur (BCS), Mexico found a proportion of individuals had concentrations of total Hg ([THg]) above some thresholds of concern set by health agencies. The [THg] were associated with fish and seafood consumption as well as other factors; although it was unclear which marine diet items could potentially be contributing to the concentrations observed. We examined [THg] and monomethylmercury concentration ([MeHg+]) in the archived hair of 70 pregnant women from BCS as well as in diet items including fish, shellfish, and staple items (rice, beans, corn, and flour). We measured stable isotopes of carbon and nitrogen and employed a Bayesian stable isotope mixing model to investigate the proportion of fish and seafood in the isotopic profiles of archived hair samples. Concentrations of Hg species were low in staple foods and ranged from below detection limit to 5.71 parts per billion (ppb) wet weight. In hair, geometric mean [THg] was 658 ppb and [MeHg+] was 395 ppb, which were lower than previous reports. Percent MeHg+ was positively correlated with higher δ15N values. The largest carbon contributors to the diet of the study participants were corn and rice, and our analysis of fish contribution to diet varyingly agreed with the self-reported fish consumption. This report highlights the ability to discriminate potential sources of Hg from a diverse diet and the limitations of dietary recall studies. • [THg] in hair (pregnant women) was lower than previous reports, and [THg] in fish were low compared to thresholds. • Stable isotope mixing models reveal limitations in dietary recall studies and the value of chemical analyses. • Percent methylmercury was positively associated with δ15 N values. [ABSTRACT FROM AUTHOR]

Speciation and isotopic analyses of mercury (Hg) detected at high concentration (11–107 mg total Hg/kg) in the hair samples of Pakistani subjects were carried out to analyze whether the source of Hg was the skin cream or the soap they used. Liquid chromatography-ICP mass spectrometric speciation analysis revealed that the Hg in the hair was primarily inorganic. This result supported our assumption that skin care products were the source of the high concentration of Hg in hair, which was based on the statistical association found in our previous study because it is known that inorganic Hg compounds are added to some skin care products sold in some countries. Stable isotope ratios of the Hg in the hair samples of 6 subjects and 3 skin cream samples, which were reported to be used by the subjects, were measured by multi-collector ICP mass spectrometry after acid digestion. A comparison of the isotopic compositions of Hg in hair and skin cream in two subjects revealed that the composition in both samples matched in one subject, hence confirming that the products were the source of high Hg concentration in hair. However, the isotopic compositions of Hg in hair and skin cream did not match in the other subject demonstrating the presence of other exposure source(s). • Speciation and isotope ratios of mercury detected high concentration in hair were analyzed. • Mercury in the hair samples was mostly inorganic and methymercury was negligible. • High level of Hg was detected in some of the skin lightning creams the subjects used. • Isotopic ratios of hair and skin creams were consistent in one subject but not in the other. [ABSTRACT FROM AUTHOR]

Organic amendments (OA) have been applied in many mercury (Hg)-polluted paddy soils to meet increasing food demands with scarce land resources. However, little is known on the effects of different OAs on Hg dissolution and the composition of dissolved organic matter (DOM) in soil pore waters, both of which may be associated with Hg mobility. Consequently, DOM composition and Hg release levels were investigated in soil pore waters after applying food waste compost (FC), fulvic acids (FA) and humic acids (HA) to Hg-polluted paddy soils. FA and HA treatments promoted increased abundances of humic- and fulvic-like substances in pore water DOM while FC amendment increased soluble microbial by-products. FA amendment and high levels of both HA and FC amendments greatly promoted Hg dissolution in pore waters that could be attributed to the complexation of Hg with different DOM components. However, among all DOM components, only UVA fulvic and visible humic-like substances were positively correlated with Hg release levels and total organic carbon. These results indicate that discrepant DOM compositions are induced by different OA. Further, these differences may be associated with differential Hg dissolution in pore waters. Consequently, FA amendment and high level of FC or HA amendments should be limited to reduce potential Hg release into pore waters. Image 1 • Organic amendments (OA) affected dissolved organic matter (DOM) composition. • Fulvic acid amendment mostly promoted Hg dissolution in pore water. • Not all DOM fractions were correlated with release of Hg and total organic carbon. • DOM compositional change induced by OA may be associated with Hg dissolution. [ABSTRACT FROM AUTHOR]

Amorphous molybdenum sulphide materials are attracting more attention in heterogeneous catalysis, gas adsorption and water remediation fields. Herein, a new type of amorphous molybdenum sulphide composite (poly(diallyldimethylammonium-MoS 4), shorten as PDADMA-MoS 4) was synthesized via a facile precipitation reaction. Metal adsorption tests of prepared PDADMA-MoS 4 composite shows that Hg2+ and Pb2+ concentrations in solution can decrease from 10 ppm to <0.5 ppb level much lower than the drinking water requirement (<2 ppb) in 10 min. The metal adsorption isotherms suggest that maximum metal-uptake capacities are 1460.0 mg/g for Hg (pH = 5) and 433.7 mg/g for Hg (pH = 1), indicating that this sorbent works over a wide pH range (1.0–7.0) to effectively remove Hg from aqueous solution. More importantly, at very low pH = 1, this sorbent material exhibits extraordinarily high selectivity of Hg over Pb and Cu (separation factors β H g / C u = 4.5 × 10 4 and β H g / P b = 3.6 × 10 4 ). The excellent Hg capacity and selectivity at low pH region (pH < 2) has shed light on the new generation of adsorbent materials for acidic wastewater treatment. Image 1 • Amorphous molybdenum sulphide composite for heavy metal removal. • One-step synthesis of novel adsorbent under mild conditions. • Large metal adsorption capacity for Hg (1460.0 mg/g) and Pb (765.9 mg/g) at pH = 5. • High adsorption capacity and selectivity for Hg at highly acidic pH = 1. • Fast adsorption kinetics for Hg and Pb. [ABSTRACT FROM AUTHOR]

Mercury (Hg), cadmium (Cd), lead (Pb), selenium (Se) and arsenic (As) concentrations in internal tissues of 72 striped dolphins (Stenella coeruleoalba) from Murcia Region (Mediterranean coastline) have been investigated for the first time. Hg showed the highest concentration, followed by Se, Cd, As and Pb. In general, the levels of metal found in this study were similar to those described in similar studies in the Mediterranean Sea. However, in some adult specimens, Hg liver concentrations were related with toxic effects in cetacean. A significant correlation was observed with age, likewise between Se and Hg and Cd in tissues, which agree with detoxify effect attributed to Se through inert complex formation. Molar ratio Hg:Se in liver was close to 1:1 in some specimens, which would indicate overload of the Hg-Se detoxify function and compromised health. These results could contribute to a better knowledge of the distribution of these persistent pollutants in the Mediterranean Sea. • First study about trace metals on stranded cetacean in Western Mediterranean, Murcia coatline. Spain. • Hg, Cd, Pb, As and Se were detected in internal tissues from striped dolphins from the Murcia Region. • Hg liver levels in some adults of striped dolphins (Stenella coeruleoalba) are related with toxic effects in cetacean. • Ratio Hg:Se in liver from some adults specimens suggest overload of the Hg-Se detoxify function and compromised health. [ABSTRACT FROM AUTHOR]

Toxic metals/metalloid contaminations of estuarine sediments due to compromised tributaries arouse significant interest in studying bacterial community that triggers natural attenuation processes. Geo-accumulation index (I geo), contamination factor (CF), pollution load index (PLI), and Hakanson potential ecological risk index (RI) as a sum of risk factors (Er) were used to quantify toxic metal/metalloid-pollution status of Lagos Lagoon (2W) and 'Iya-Alaro' tributary (4W) sediments in comparison with pristine 'Lekki Conservation Centre' sediment (L1-B). Bacteriology of the ecosystems was based on culture-independent analyses using pyrosequencing. 2W and 4W were extremely contaminated with mercury (I geo > 7), whereas, cadmium contamination was only observed in 4W. The two ecosystems were polluted with toxic metal based on PLI, where mercury (Er = 2900 and 1900 for 4W and 2W, respectively) posed very high ecological risks. Molecular fingerprinting revealed that Proteobacteria, Firmicutes, and Acidobacteria predominately contributed the 20 most abundant genera in the two ecosystems. The 240 and 310 species present in 2W and 4W, respectively, but absent in L1-B, thrive under the metal concentrations in the polluted hydrosphere. Whereas, the 58,000 species missing in 2W and 4W but found in L1-B would serve as indicators for systems impacted with metal eco-toxicity. Despite toxic metal pollution of the ecosystems understudied, bacterial communities play vital roles in self-recovery processes occurring in the hydrosphere. Image 1 • Two ecosystems in Lagos, Nigeria were polluted with Cd and Hg from human activities. • Mercury posed very high ecological risks on the estuary (2W) and its tributary (4W). • Proteobacteria, Firmicuites, and Acidobacteria predominated both ecosystems. • 755 OTUs in tributary but absent in estuary shape metal (loid)s' bioremediation. • 2938 OTUs missing in 4W but found in 2W indicated natural attenuation in 2W Hydrosphere heavily polluted with toxic metals alters the bacterial communities with increase in composition of tolerant phylotypes that shape natural attenuation in the ecosystems. [ABSTRACT FROM AUTHOR]

In this study, a novel adsorbent thiol functionalized magnetic carbon nanotubes (CNTs-SH@Fe 3 O 4) was synthesized to overcome somewhat existing difficulties during the Hg(II) adsorption process, including low efficiency and selectivity, narrow feasible pH range and difficult to separate and reuse. The Hg(II) adsorption performance of CNTs-SH@Fe 3 O 4 was evaluated using batch experiment and its physiochemical properties were investigated by characterization techniques. The batch experiment results showed that the prepared CNTs-SH@Fe 3 O 4 maintained high Hg(II) adsorption efficiency (>98%) over wide pH range from 3 to 11. The selective adsorption of Hg(II) by CNTs-SH@Fe 3 O 4 was achieved with the coexistence of Cu(II), Mg(II) or Zn(II) ions, in which adsorbate matrix Hg(II) removal efficiency of 81.39%, 89.36% and 95.52% was obtained, respectively. CNTs-SH@Fe 3 O 4 kept high Hg(II) removal efficiency (>80%) and good magnetic property (Ms value > 21 emg g−1) after five cycles of adsorption/regeneration. The Hg(II) adsorption kinetics could be better described by pseudo-second-order kinetic model. Freundlich model showed higher correlation coefficient in adsorption isotherms study, and the calculated maximum adsorption capacity was 172.4 mg g−1. Thermodynamic study suggested that the adsorption process was exothermic in nature. Surface adsorption, complex adsorption and reduction adsorption were all contributed to the removal of Hg(II) using CNTs-SH@Fe 3 O 4. • CNTs-SH@Fe 3 O 4 was synthesized and employed for Hg(II) adsorption. • CNTs-SH@Fe 3 O 4 showed excellent Hg(II) removal efficiency in wide pH range from 3 to 11. • CNTs-SH@Fe 3 O 4 showed high selectivity toward Hg(II) in binary ion matrices. • CNTs-SH@Fe 3 O 4 kept good Hg(II) removal and magnetic property after 5 cycles of regeneration. [ABSTRACT FROM AUTHOR]

Abstract The distributions of primary amino acids, MeHg and IHg in body tissues of two commonly farm-raised fish species (common carp: Cyprinus carpio ; grass carp: Ctenopharyngodon idellus) in Guizhou Province, SW China, were investigated to understand the effects of primary amino acids on MeHg and IHg metabolism in farm-raised fish. The primary amino acids were classified into four groups: (1) essential and polar amino acids; (2) essential and non-polar amino acids; (3) non-essential and polar amino acids; and (4) non-essential and non-polar amino acids. For both fish species, groups (1, 2 and 3) were enriched in muscle and kidney, whereas group (4) was enriched in scale. The two fish species showed low MeHg concentrations (grass carp: 0.5–3.9 ng/g; common carp:1.0–7.4 ng/g) and low MeHg proportions (grass carp: 2–45%; common carp: 6–37%) in their tissues, which are mainly due to the simple food web structures and the fast growth of the farm-raised fish. Positive correlations (r = 0.342 to 0.472; p < 0.01; n = 78) were observed between MeHg and several primary amino acids (cysteine, threonine, phenylalanine, leucine, valine, glutamate serine and tyrosine) in fish tissues, which may be driven by the formation of MeHg-Cys complexes within fish body. However, no significant correlations were observed between IHg and any primary amino acids, indicating the metabolic processes of IHg and MeHg are different. This study advances our understanding that cysteine and its related/derived amino acids may be an important driving force for MeHg distribution and translocation in fish. Graphical abstract Image 107220 Highlights • Methylmercury is rich in protein-rich fish tissues. • Cysteine and its related/derived amino acids have a high biological association with methylmercury. • The formation of MeHg-Cys complexes can be an important driving force for methylmercury distribution in fish bodies. Capsule Cysteine and its related/derived amino acids may be an important driving force for MeHg distribution and translocation in fish. [ABSTRACT FROM AUTHOR]

Abstract The northwestern Pacific Ocean including the Sea of Japan and the Sea of Okhotsk is one of the least studied regions in terms of mercury behavior and distribution in the sea-atmosphere system. In August and September 2017, we determined gaseous elemental mercury (Hg(0)) in the surface air over this water areas along a 12,000 km cruise. Concentrations varied from 1.07 to 2.74 ng m−3, with an average value of 1,68 ± 0.23 ng m−3 (N = 1853). The average concentrations for the Sea of Japan, the Sea of Okhotsk and the Kuril-Kamchatka sector of the Pacific Ocean were 1.61 ng m−3, 1.71 ng m−3 and 1.61 ng m−3, respectively. The maximum concentrations were observed in the Sea of Okhotsk during periods when air masses arrived from the southern and central Kuril Islands. We believe that the reason for that was volcanic activity. The minimum concentrations were registered in air masses arriving from the northeastern Russia and from open sea areas. In the Sea of Okhotsk we measured Hg(0) concentrations near the cyclone eye and did not register any increase due to increased turbulence. This fact contradicts the previously expressed hypothesis that a strong turbulence above the sea surface causes enhanced Hg(0) concentrations in the air. Apparently there are additional or completely different influencing factors which could provide such increase. Also we found that the diurnal Hg(0) cycle in the Sea of Japan was the opposite of the diurnal Hg(0) cycle in the Sea of Okhotsk. Highlights • Hg(0) increased with the arrival of air masses from the Kuril Islands. • The lowest concentrations were observed in air masses from the northeast Russia. • Air masses from open sea areas were also characterized by low concentrations. • Hg(0) concentrations did not increase during strong turbulence. • The daily Hg(0) cycles were different in different water areas. [ABSTRACT FROM AUTHOR]

Abstract Foraging aggregations of east Pacific green sea turtles (Chelonia mydas) inhabit the Seal Beach National Wildlife Refuge (SBNWR) and San Diego Bay (SDB), two habitats in southern California, USA, located near urbanized areas. Both juvenile and adult green turtles forage in these areas and exhibit high site fidelity, which potentially exposes green turtles to anthropogenic contaminants. We assessed 21 trace metals (TM) bioaccumulated in green turtle scute and red blood cell (RBC) samples collected from SBNWR (n = 16 turtles) and SDB (n = 20 turtles) using acid digestion and inductively coupled plasma mass spectrometry. Principal component analyses of TM composition indicate that SBNWR and SDB turtles have location-specific contaminant signatures, characterized by differences in cadmium and selenium concentrations: SBNWR turtles had significantly more cadmium and selenium in RBC and more selenium in scute samples, than SDB turtles. Cadmium and selenium concentrations in RBC had a strong positive relationship, regardless of location. SBNWR turtles had higher selenium in RBCs than previously measured in other green turtle populations globally. Due to different retention times in blood vs. scute, these results suggest that SBNWR turtles have high long- and short-term selenium exposure. Turtles from SBNWR and SDB had higher trace metal concentrations than documented in green turtle populations that inhabit non-urbanized areas, supporting the hypothesis that coastal cities can increase trace metal exposure to local green turtles. Our study finds evidence that green turtle TM concentrations can differ between urbanized habitats and that long-term monitoring of these green turtles may be necessary. Highlights • Green sea turtles are known to inhabit polluted urban coastal areas. • Results indicate that turtles accumulate location-specific contaminant signatures. • Green sea turtles from Seal Beach had high levels of cadmium and selenium. • Seal Beach green turtle selenium in red blood cells is among highest measured. • Green turtle selenium levels related to cadmium levels in red blood cells. [ABSTRACT FROM AUTHOR]

Abstract Particulate organic matter (POM), composed of fine root fragments and other organic debris, is an important fraction of soil organic matter which can affect the fate of nanoparticles and influence their performance in nanoparticle-based remediation technologies due to aggregation. Effects of POM are not well studied compared with those of dissolved organic matter. In this research, POM was extracted from black soil by sieving, and heteroaggregation of selenium nanoparticles (SeNPs) with POM and consequences for elemental mercury (Hg0) immobilization were investigated. It was found that low concentrations of more negatively charged POM (0–60 mg L−1) inhibited homoaggregation as well as heteroaggregation with SeNPs which had a lower negative charge through electrostatic repulsion. In the presence of high concentrations of POM (80–100 mg L−1), SeNPs were more likely to attach to POM with more Hg0 remaining in the POM since a larger concentration of nanoparticles would lead to more effective collisions. However, Hg0 immobilization efficiency using SeNPs was not significantly influenced by the addition of POM. This work is helpful to further understand the nanoparticle's behaviour in the environment and consequences for toxic metal remediation. Graphical abstract Image 102269 Highlights • POM can affect the fate of SeNPs in the environment. • POM (0–60 mg L−1) inhibited its homoaggregation and heteroaggregation with SeNPs. • Hg0 immobilization efficiency by SeNPs was not inhibited in the presence of POM. [ABSTRACT FROM AUTHOR]

Abstract Understanding the sorption kinetics of Hg2+ is the key to predicting its reactivity in soils which is indispensable for environmental risk assessment. The temporal change in the solubility of 196Hg2+ spikes (6 mg kg−1) added to a range of soils with different properties was investigated and modelled. The sorption of 196Hg2+ displayed a biphasic pattern with a rapid initial (short-term) phase followed by a slower (time-dependent) one. The overall reaction rate constants ranged from 0.003 to 4.9 h−1 and were significantly correlated (r = 0.94) to soil organic carbon (SOC). Elovich and Spherical Diffusion expressions compellingly fitted the observed 196Hg2+ sorption kinetics highlighting their flexibility to describe reactions occurring over multiple phases and wide timeframes. A parameterized Elovich model from soil variables indicated that the short-term sorption is solely controlled by SOC while the time-dependent sorption appeared independent of SOC and decreased at higher pH values and Al(OH) 3 and MnO 2 concentrations. This is consistent with a rapid chemical reaction of Hg2+ with soil organic matter (SOM) which is followed by a noticeably slower phase likely occurring through physical pathways e.g. pore diffusion of Hg2+ into spherical soil aggregates and progressive incorporation of soluble organic-Hg into solid phase. The model lines predicted that in soils with >4% SOC, Hg2+ is removed from soil solution over seconds to minutes; however, in soils with <2% SOC and higher pH values, Hg2+ may remain soluble for months and beyond with a considerable associated risk of re-emission or migration to the surrounding environments. Graphical abstract Image 1 Highlights • Sorption of 196Hg2+ in soil occurred over two distinct phases. • Elovich and spherical diffusion models best fitted the experimental data. • Sorption of Hg2+ can be predicted from soil variables by an optimized Elovich expression. • Instantaneous sorption of Hg2+ is controlled by soil organic carbon. • Hg2+ may remain soluble for months in alkaline soils. [ABSTRACT FROM AUTHOR]

Abstract Metals attributed to pollution may increase their concentrations above the geological background and pose toxic challenges towards humans and biota. We analysed sixteen Kelp Gull eggs and eggshells for 30 metallic elements from the Swartkops Estuary (SE), an important recreational, industrial, and ecological asset for Port Elizabeth, the region, and South Africa. Mean concentrations for eggshell and egg content for Hg was 0.02 and 0.4 mg/kg dm, Cr was 4 and 18 mg/kg dm (the highest yet recorded for any gull or tern egg), for Zn 2.1 and 62 mg/kg dm, for Sr 880 and 12 mg/kg dm, for V 170 and 1.3 mg/kg dm, and for Co 1.7 and 0.002 mg/kg dm, respectively. Zinc, Se, and Hg, increased on a dry-mass basis from sediment via small fish to gull egg content, indicating bioaccumulation. No effect on eggshell thickness was seen. We also determined that eggshell concentrations cannot be used as a proxy for egg content concentrations. Mercury, Cr, V, Co, and Zn were elements we identified as potentially problematic that require source identification and mitigation. Further research into other high-trophic animals such as herons, egrets, cormorants, and otters in the SE system is proposed. Graphical abstract Image 1 Highlights • First southern hemisphere report of elements in Kelp Gull eggshells & contents. • Kelp Gull eggs collected from Swartkops Estuary, South Africa, and analysed. • Eggshell concentration and composition cannot be used as proxy for egg contents. • Co, Sr, Cr, Hg, and Zn in contents were identified as potentially problematic. [ABSTRACT FROM AUTHOR]