Simultaneous immobilization of multiple heavy metal(loid)s in contaminated water and alkaline soil inoculated Fe/Mn oxidizing bacterium.

Two strains of Fe/Mn oxidizing bacteria tolerant to high concentrations of multiple heavy metal(loid)s and efficient decontamination for them were screened. The surface of the bio-Fe/Mn oxides produced by the oxidation of Fe(II) and Mn(II) by Pseudomonas taiwanensis (marked as P4) and Pseudomonas plecoglossicida (marked as G1) contains rich reactive oxygen functional groups, which play critical roles in the removal efficiency and immobilization of heavy metal(loid)s in co-contamination system. The isolated strains P4 and G1 can grow well in the following environments: pH 5-9, NaCl 0-4%, and temperature 20-30°C. The removal efficiencies of Fe, Pb, As, Zn, Cd, Cu, and Mn are effective after inoculation of the strains P4 and G1 in the simulated water system (the initial concentrations of heavy metal(loid) were 1 mg/L), approximately reaching 96%, 92%, 85%, 67%, 70%, 54% and 15%, respectively. The exchangeable and carbonate bound As, Cd, Pb and Cu are more inclined to convert to the Fe-Mn oxide bound fractions in P4 and G1 treated soil, thereby reducing the phytoavailability and bioaccessible of heavy metal(loid)s. This research provides alternatives method to treat water and soil containing high concentrations of multi-heavy metal(loid)s.

Assessment of internal exposure risk from metals pollution of occupational and non-occupational populations around a non-ferrous metal smelting plant.

Non-ferrous metal smelting poses significant risks to public health. Specifically, the copper smelting process releases arsenic, a semi-volatile metalloid, which poses an emerging exposure risk to both workers and nearby residents. To comprehensively understand the internal exposure risks of metal(loid)s from copper smelting, we explored eighteen metal(loid)s and arsenic metabolites in the urine of both occupational and non-occupational populations using inductively coupled plasma mass spectrometry with high-performance liquid chromatography and compared their health risks. Results showed that zinc and copper (485.38 and 14.00 µg/L), and arsenic, lead, cadmium, vanadium, tin and antimony (46.80, 6.82, 2.17, 0.40, 0.44 and 0.23 µg/L, respectively) in workers (n=179) were significantly higher compared to controls (n=168), while Zinc, tin and antimony (412.10, 0.51 and 0.15 µg/L, respectively) of residents were significantly higher than controls. Additionally, workers had a higher monomethyl arsenic percentage (MMA%), showing lower arsenic methylation capacity. Source appointment analysis identified arsenic, lead, cadmium, antimony, tin and thallium as co-exposure metal(loid)s from copper smelting, positively relating to the age of workers. The hazard index (HI) of workers exceeded 1.0, while residents and control were approximately at 1.0. Besides, all three populations had accumulated cancer risks exceeding 1.0 × 10-4, and arsenite (AsIII) was the main contributor to the variation of workers and residents. Furthermore, residents living closer to the smelting plant had higher health risks. This study reveals arsenic exposure metabolites and multiple metals as emerging contaminants for copper smelting exposure populations, providing valuable insights for pollution control in non-ferrous metal smelting.

Stability of As- and Mn-sludge after neutral mine water treatment using Fe(VI) vs electrocoagulation.

The electrocoagulation (ECG) and ferrate (Fe(VI))-based processes are increasingly acknowledged as efficient for the simultaneous removal of As and Mn from synthetic and real mine effluents. Prior to design of full-scale applications, more information on the physicochemical, mineralogical, and environmental characterization of the produced sludge is required. The main objective of this study was to characterize and evaluate the leaching potential of problematic elements in As- and Mn-rich sludge produced during ECG or Fe(VI) treatment of circumneutral surrogate mine water. To do so, PHREEQC modelling was carried out on the effluents, before and after ECG or Fe(VI) treatment, to calculate the saturation index of dissolved As, Fe, and Mn species. A physicochemical and mineralogical characterization of the sludge was also performed using powder X-ray diffraction (PXRD) and a scanning electron microscope equipped with an energy dispersive spectrometer (SEM-EDS). Then, a non-sequential selective extraction procedure (N-SEP) combined with a USGS field leaching test (FLT) were conducted to evaluate the environmental behaviour of the As- and Mn-rich sludge. Geochemical modelling indicated that the Fe(VI) and ECG processes favor the precipitation of Fe-(oxy)hydroxides (lepidocrocite, schwertmannite, ferrihydrite). Chemical characterization showed that the Fe(VI)-sludge contained higher As and Mn concentrations and lower Fe concentrations than the ECG-sludge (3.8% As, 5.3% Mn, and 34% Fe for the Fe(VI)-sludge vs 1.2% As, 0.77% Mn, and 52% Fe for the ECG-sludge). These findings can be explained by the smaller amount of sludge produced during the Fe(VI) treatment and the higher removal efficiency of this method, especially for Mn. The PXRD patterns suggested the formation of poorly crystalline Fe-(oxy)hydroxides (lepidocrocite or ßFeO(OH) in the ECG-sludge vs ferrihydrite in the Fe(VI)-sludge); however, no As- or Mn-bearing minerals were identified. Findings from N-SEP tests showed different speciation of As and Mn in the sludge, with a higher proportion of As bound to poorly crystalline Fe-(oxy)hydroxides in the Fe(VI) sludge than the ECG-sludge (97% and 71%, respectively), and higher proportion of Mn associated with the residuals in the Fe(VI)-sludge than the ECG-sludge (57% and 5.7%, respectively). Finally, FLT results indicated that very low concentrations of As (<0.05 mg/L) and Mn (<0.5 mg/L) were leached from the ECG- and Fe(VI)-sludge, with the Fe(VI) treatment resulting in slightly better As and Mn immobilization in the sludge relative to the ECG process. Nevertheless, both treatment processes were satisfactory in terms of efficient removal of As and Mn and their immobilization in the produced sludge.

Evaluation of the Adriatic Sea pollution using mesozooplankton as an environmental indicator.

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.

Vertical distribution patterns and ecological risk assessment of heavy metal(loid)s pollution in a sediment profile from Bohai Sea.

The sedimentary records of heavy metal(loid)s contamination and their potential risks from the Bohai Sea are still very lacking. In this study, a sediment profile B18 was collected in the Bohai Sea to explore the contamination status and vertical distributions of heavy metal(loid)s as well as their potential risks. The heavy metal(loid)s contents showed an upward increasing trend towards the surface, and the heavy metal(loid)s concentrations in the upper layer are significantly higher than those of the middle layer and bottom layer. Obvious enrichment of Sb, As, Pb and Cd was observed and the ecological risk assessment results also revealed potential ecological risks of As, Ni and Cd. Moreover, the vertical distributions of pollution status (PLI) and ecological risk (RI) all increased steadily towards the surface for sediment profile B18. Based on comprehensive analysis of the above results, the gradually increasing trend of heavy metal(loid)s contents, pollution status, and potential ecological risks could be linked to anthropogenic influence in recent years, and could be regarded as a potential geological fingerprint for anthropogenic influence over the past few decades. This study could provide important insights to the geochemical distributions, sources and potential risks of heavy metal(loid)s in Bohai Sea sedimentary records.

Toxic Metals and Metalloids in Food: Current Status, Health Risks, and Mitigation Strategies.

PURPOSE OF REVIEW: Exposure to toxic metals/metalloids, such as arsenic (As), cadmium (Cd), and lead (Pb), through food consumption is a global public health concern. This review examines the contamination status of these metals/metalloids in food, assesses dietary intake across different populations, and proposes strategies to reduce metal/metalloid exposures throughout the food chain. RECENT FINDINGS: For the general population, dietary intake of metals/metalloids is generally lower than health-based guidance values. However, for vulnerable populations, such as infants, children, and pregnant women, their dietary intake levels are close to or even higher than the guidance values. Among different food categories, seafood shows higher total As, but largely present as organic species. Rice accumulates higher As concentration than other cereals, with inorganic As (iAs) and dimethylarsinic acid (DMA) being the main As species. Methylated thioarsenate species, such as dimethylmonothioarsenate, have also been detected in rice. The distribution of iAs and DMA in rice shows geographical variation. Additionally, seafood and cocoa products generally contain more Cd than other food, but seafood consumption does not significantly increase in adverse health effects due to its high zinc and iron content. Compared to As and Cd, Pb concentrations in food are generally lower. To minimize the health risks of metal/metalloid exposure, several strategies are proposed. Food contamination with toxic metals/metalloids poses significant concerns for human health, particularly for vulnerable populations. This review provides scientific evidence and suggestions for policy makers to reduce human exposure of metals/metalloids via dietary intake.

Traces of the past: assessing the impact of potentially toxic elements from an abandoned mine on groundwater and agricultural soil in San Luis Potosí, México.

The study was conducted in Cerritos, San Luis Potosí, México, near the Guaxcama mine, focused on environmental contamination (groundwater and agricultural soil) from antimony (Sb), arsenic (As), lead (Pb), cadmium (Cd), and mercury (Hg). In March 2022, 20 agricultural soil and 16 groundwater samples were collected near the historically cinnabar (HgS)- and arsenopyrite (FeAsS)-rich Guaxcama mine. Hydride generation atomic fluorescence spectrometry (HG-AFS) for As, cold vapor atomic fluorescence spectrometry (CV-AFS) for Hg, and inductively coupled plasma optical emission spectrometry (ICP-OES) for Cd, Pb, and Sb were used for the determinations of potentially toxic elements (PTEs). While concentrations of Cd, Hg, Pb, and Sb in groundwater were below detection limits, As levels exhibited a range from 40.9 ± 1.4 to 576.0 ± 1.0 µg/L, exceeding permissible limits for drinking water (10 µg/L). In agricultural soil, As was between 7.67 ± 0.16 and 24.1 ± 0.4 µg/g, Hg ranged from 0.203 ± 0.018 to 2.33 ± 0.19 µg/g, Cd from 2.53 ± 0.90 to 2.78 ± 0.01 µg/g, and Pb from 11.7 ± 1.2 to 34.3 ± 4.1 µg/g. Only one study area surpassed the Mexican As soil limit of 22 µg/g. Sequential extraction (four-step BCR procedure) indicated significant As bioavailability in soil (fractions 1 and 2) ranging from 3.66 to 10.36%, heightening the risk of crop transfer, in contrast to the low bioavailability of Hg, showing that fractions 1, 2, and 3 were below the limit of quantification (LOQ). Crucial physicochemical parameters in soil, including nitrate levels, pH, and organic matter, were pivotal in understanding contamination dynamics. Principal component analysis highlighted the influence of elements like Fe and Ca on phytoavailable As, while Pb and Cd likely originated from a common source. Ecological risk assessments underscored the significant impact of pollution, primarily due to the concentrations of Cd and Hg. Non-cancer and cancer risks to residents through As poisoning via contaminated water ingestion also were found. The hazard index (HI) values varied between 4.0 and 82.2 for adults and children. The total incremental lifetime cancer risk (TILCAR) values for adults ranged from 7.75E - 04 to 1.06E - 02, whereas for children, the values were from 2.47E - 04 to 3.17E - 03.

Dietary exposure to metals/metalloids and persistent organic pollutants in Spanish preschool and primary school children.

Diet is a primary source of pollutant exposure. Given children's vulnerability to their effects, this study assessed dietary intake of metals/metalloids and different persistent organic pollutants in children in Tarragona (Spain), compared it with the health-based guideline values (HBGV), and identified the main dietary sources. The analysis included 533 preschoolers and 443 primary school children from the EPINED and ECLIPSES studies. Dietary intake of cadmium (Cd), methylmercury (MeHg), lead (Pb), inorganic arsenic (inAs), polychlorinated dibenzo-p-dioxins and dibenzofurans (PCDD/Fs), dioxin-like polychlorinated biphenyls (DL-PCBs), and non-dioxin-like polychlorinated biphenyls (NDL-PCBs) was estimated using validated food frequency questionnaires and a database from the Catalan Agency for Food Safety. Preschoolers and primary school children exceeded the relevant reference value for InAs and DL-PCBs. Only preschoolers exceeded the limit for MeHg and PCDD/Fs. Cd, Pb, and NDL-PCBs intakes did not exceed the limits in either age group. Salted cereals/potatoes were the main source of InAs; fish for MeHg and DL-PCBs; and milk/yogurt for PCDD/Fs, followed by white fish in preschoolers and fatty fish in primary school children. The findings highlight that dietary exposure to some pollutants poses a significant risk to these children, emphasizing the need for public health policies to reduce pollutants in their diets.

Association of multiple urinary metals/metalloids with obesity defined by body fat percentage: A cross-sectional study among Guangxi Zhuang ethnic in China.

BACKGROUND: Previous studies confirmed a link between urinary metals/metalloids and obesity; however, the majority of these studies defined obesity using body mass index (BMI) or waist circumference (WC), and their results were not constantly consistent. Studies defining obesity based on body fat percentage (BFP) is less reported. METHODS: A total of 5405 participants aged 35-74 from Guangxi Zhuang ethnic group in China were included in the analysis. Inductively coupled plasma mass spectrometry (ICP-MS) was used to detect the concentrations of 22 metals/metalloids in urine. Using a binary logistic regression model, the impact of individual metal/metalloid on the risk of BFP/obesity was analyzed, and the LASSO regression model was employed to choose metals/metalloids independently related with BFP/obesity to construct a multiple-metal models. The quantile g-computation model was used to evaluate the combined impacts of metals/metalloids on BFP/obesity. RESULTS: In multiple-metal models, compared with the lowest quartile, the highest quartile of urinary concentrations of Mg, Cd, and Ti was significantly associated with a reduced risk of BFP/obesity (Mg: OR=0.66, 95 %CI: 0.51, 0.85; Cd: OR=0.63, 95 %CI: 0.49, 0.82; Ti: OR=0.73, 95 %CI: 0.57, 0.93). Conversely, the highest quartiles of urinary concentrations of Zn, V, and Sb was significantly associated with an increased risk of BFP/obesity (Zn: OR=1.75, 95 %CI: 1.39, 2.22; V: OR=1.63, 95 %CI: 1.25, 2.14; Sb: OR=1.38, 95 %CI: 1.06, 1.79). In quantile g-computation analysis, Mg, Cd, and Sn were the main contributors to negative effects, while Zn, V, and Sb were the main contributors to positive effect, although no significant relationship was observed between the multiple metal/metalloid mixtures and BFP/obesity. CONCLUSIONS: According to our study, urinary Mg, Cd, and Ti levels were negatively associated with BFP/obesity risk, and Zn, V, and Sb levels were positively associated with BFP/obesity risk. However, these associations need to be further verified by longitudinal studies, and the molecular mechanisms need to be further explored by animal and cell experiments.

Geochemical fingerprinting and statistical variation of 35 elements in produced water and rock material from offshore chalk reservoirs.

Trace metals and metalloids occur in small quantities in the subsurface water generated from oil wells, called produced water (PW). While these substances are present in low concentrations, PW volumes are sufficiently large that they are still a potential environmental concern. This study has focused on quantifying 71 trace metals and metalloids present in PW from Danish offshore oil production sites. These metals are often a challenge to measure and are globally underreported. By employing optimized sample treatment combined with ICP-OES and ICP-SFMS methods, the full elemental screening of PW samples collected from various offshore platforms has been carried out with high accuracy. Distinct geochemical signatures involving 35 elements have been discovered and they are associated with significant site-specific variations in the concentrations of key trace metals, including W, Ba, Mo, Cu, and Tl. Utilizing Principal Component Analysis (PCA), the study has effectively distinguished between PW samples from different fields, highlighting the relevance of certain trace metals and elemental ratios as potential geochemical markers. Geochemical analysis of the chalk rock material from the same production wells as the fluid samples has shown a correlation of key elements Tl, W, Cu, Mo, Ba, and As in the chalk with the produced water, potentially indicating the origin of the metals. The study has revealed a high compositional variability of PW and found that elements including Zn, Co, Hg, and Cs occur in concentrations of magnitude higher than previous estimates from reports. In addition, there is high variability in concentrations at different sampling times, underlining the need for environmental monitoring and developing more informed management strategies for the main offshore PW stream. The variability in concentrations in space and time leads to large uncertainties in environmental reporting based on a few samples. The detailed sampling campaign reported here for the first time highlights the need for much more frequent sampling, ideally continuous monitoring. The safety of produced water discharge to sea can be significantly underestimated by limited sampling. This paper provides the first field-specific and time varied screening of heavy metals in real produced water and shows the discrepancy in our understanding of the environmental impact of PW.

Effect of co-exposure to multiple metals (Pb, Cd, Cr, Hg, Fe, Mn and Ni) and metalloid (As) on liver function in Swiss albino mice.

The study examined the cumulative toxic effect of multiple elements, As, Pb, Cd, Cr, Hg, Fe, Mn and Ni on the liver function and their association with inflammation and apoptosis. To explore the health consequence of simultaneous exposure to multiple metals and metalloid, male and female Swiss Albino mice were randomly divided into 14 groups and subjected to different doses [MPL (maximum permissible limit), 1×, 5×, 10×, 50× or 100×] of metal(loid)s mixture via drinking water for 8 weeks. Data showed that combined effect of multiple elements impaired the liver function. This was associated with significant decrease in the antioxidant enzymes and the elevation in lipid peroxidation for high exposure dose of 50× and 100× (p < 0.05). The metal(loid)s mixture exposure led to significant increase (p < 0.05) in cytokines, TNF-α, IL-6 and effector caspases (3 and 6) in exposure groups above 10× dose. Histopathological observation also revealed significant damage in the hepatic tissue on exposure to high dose. Dose dependent accumulation of respective elements (As, Cd, Cr, and Pb) in the liver was observed in each of the exposure groups. However, similar dose related increment was not observed for essential metals such as Ni, Fe and Mn. Differential accumulation of metals in the liver may be attributed to the effect of co-contaminant exposure, which could affect the divalent cation absorption due to antagonism and competitive transport process. Overall findings in this study manifest the complexity of possible joint effect of co-exposure to multiple metals and metalloid on the liver function.

Alginate-Bentonite Encapsulation of Extremophillic Bacterial Consortia Enhances Chenopodium quinoa Tolerance to Metal Stress.

This study explores the encapsulation in alginate/bentonite beads of two metal(loid)-resistant bacterial consortia (consortium A: Pseudomonas sp. and Bacillus sp.; consortium B: Pseudomonas sp. and Bacillus sp.) from the Atacama Desert (northern Chile) and Antarctica, and their influence on physiological traits of Chenopodium quinoa growing in metal(loid)-contaminated soils. The metal(loid) sorption capacity of the consortia was determined. Bacteria were encapsulated using ionic gelation and were inoculated in soil of C. quinoa. The morphological variables, photosynthetic pigments, and lipid peroxidation in plants were evaluated. Consortium A showed a significantly higher biosorption capacity than consortium B, especially for As and Cu. The highest viability of consortia was achieved with matrices A1 (3% alginate and 2% bentonite) and A3 (3% alginate, 2% bentonite and 2.5% LB medium) at a drying temperature of 25 °C and storage at 4 °C. After 12 months, the highest viability was detected using matrix A1 with a concentration of 106 CFU g-1. Further, a greenhouse experiment using these consortia in C. quinoa plants showed that, 90 days after inoculation, the morphological traits of both consortia improved. Chemical analysis of metal(loid) contents in the leaves indicated that consortium B reduced the absorption of Cu to 32.1 mg kg-1 and that of Mn to 171.9 mg kg-1. Encapsulation resulted in a significant increase in bacterial survival. This highlights the benefits of using encapsulated microbial consortia from extreme environments, stimulating the growth of C. quinoa, especially in soils with metal(loid) levels that can be a serious constraint for plant growth.

Towards harmonization of metal(loid)s analysis in conventional and compostable plastics: Comparison of acid digestion protocols in LDPE and PBAT/TPS blends.

The analysis of metal-containing additives in plastic materials via acid digestion protocols has attracted growing interest to address potential environmental implications. However, the lack of protocol harmonization hinders data comparability within the literature. Here, six acid digestion protocols were employed to determine the metal(loid) content in plastics: these included three different acid mixtures (HNO3 combined with H2SO4, HCl or H2O2) for microwave-assisted digestion, with or without an additional room-temperature digestion step with H2O2. Each protocol was first validated for seven metal(loid)s (As, Cd, Cr, Pb, Sb, Sn and Zn) using a low-density polyethylene (LDPE) certified reference material (ERM®-EC681m). Then, validated protocols were applied on end-use materials, including conventional (i.e. LDPE) and compostable (i.e. PBAT/TPS) plastics. The combination of H2SO4 and HNO3 with a further digestion step with H2O2 was the most suitable protocol: it successfully passed validation thresholds for all metal(loid)s (recoveries in the range 98.6 - 101.0 %) and yielded the highest concentrations in end-use materials. All other protocols resulted in a less efficient digestion of the sample matrix, leading to lower recoveries and the formation of solid residues. Notably, end-use plastics showed a great variability in metal(loid) concentrations, likely due to their additive-rich composition, in contrast to the minimal content of acid-soluble additives of the reference material. This study represents an initial step towards the harmonization of acid digestion protocols and highlights new challenges in accurately analyzing end-use plastic materials, due to their complex additive composition.

Appraisal of contamination, hydrogeochemistry, and Monte Carlo simulation of health risks of groundwater in a lithium-rich ore area.

This study incorporated hydrogeochemical facies, the entropy-weighted water quality index (EWQI), multivariate statistics, and probabilistic human exposure assessment to investigate hydrogeochemistry, analyze groundwater quality, and estimate potential risks to human health in a lithium-rich ore area (Jadar River basin, Serbia). The findings designated the Ca·Mg-HCO3 hydrogeochemical type as the predominant type of groundwater, in which rock weathering and evaporation control the major ion chemistry. Due to the weathering of a lithium-rich mineral (Jadarite), the lithium content in the groundwater was very high, up to 567 mg/L, with a median value of 4.3 mg/L. According to the calculated EWQI, 86.4% of the samples belong to poor and extremely poor quality water for drinking. Geospatial mapping of the studied area uncovered several hotspots of severely contaminated groundwater. The risk assessment results show that groundwater contaminants pose significant non-carcinogenic and carcinogenic human health risks to residents, with most samples exceeding the allowable limits for the hazard index (HI) and the incremental lifetime cancer risk (ILCR). The ingestion exposure pathway has been identified as a critical contaminant route. Monte Carlo risk simulation made apparent that the likelihood of developing cancerous diseases is very high for both age groups. Sensitivity analysis highlighted ingestion rate and human body weight as the two most influential exposure factors on the variability of health risk assessment outcomes.

Exposure to Lead (Pb) influences the outcomes of male-male competition during precopulatory intrasexual selection.

Male-male competition is a component of Darwin's theory of precopulatory intrasexual selection, where males compete for access to resources important for reproduction and successful males pass on traits that endow greater competitive ability to their offspring, thereby exaggerating the trait(s) over evolutionary time. Metals, such as lead (Pb) often occur in urban mangrove forests, where shore crabs reside, and being neurotoxic may cause sub-lethal effects on behaviour. In this study, we asked whether exposure to Pb influences the outcomes of male-male competition in the Semaphore crab, Heloecius cordiformis, thereby altering outcomes of intrasexual selection. Crabs were exposed to an environmentally relevant, and a behaviourally relevant, concentration of lead (i.e. Pb, 10 µg/L and 100 µg/L respectively) under laboratory conditions for 96 h and subsequently allowed to compete for burrow ownership in experimental arenas. Exposed crabs (100 µg/L) were less successful than control crabs in chela size-matched paired competitive interactions, spent less time in burrows and predominantly lost burrow ownership. Further, exposure to Pb contamination (both 10 µg/L and 100 µg/L) negated the chela size advantage in size-asymmetric competitive interactions. This contaminant-induced loss of size-related competitive advantage may result in relaxation in selection pressure on body size and smaller male carapace widths and especially male chela lengths in contaminated locations. Assessment of a range of locations in the wild found a consistent pattern of metal-associated size declines in more contaminated locations for males, but not for females.

Colloid mobilization and transport in response to freeze-thaw cycles: Insights into the heavy metal(loid)s migration at a smelting site.

Smelting sites often exhibit significant heavy metal(loid)s (HMs) contamination in the soil and groundwater, which are inevitably subjected to environmental disturbances. However, there is limited information available regarding the migration behaviors of HMs in a disturbed scenario. Thus, this work explored the migration of HMs-bearing colloids in response to freeze-thaw treatments by laboratory simulation and pore-scale study. Ultrafiltration results of soil effluents revealed that 61.5 %, 47.6 %, 68.0 %, and 59.2 % of Zn, Cd, Pb, and As were present in colloidal phase, and co-transported during treatments. Nanoparticle tracking analysis (NTA) further confirmed that freeze-thaw cycles were conducive to the generation of colloidal particles and showed the heteroagglomeration among different particles. Pore-network model (PNM) was used to quantify the soil macropore characteristics (macropore diameter, macropore number, coordination number, and Euler value) after treatments. It is evident that freeze-thaw cycles induced the formation of larger macropores while simultaneously enhancing macropore connectivity, thereby establishing an optimal pathway for colloid migration. These findings underscored the importance of environmental disturbances as a trigger for the release and migration of HMs in the smelting site, offering valuable insights for controlling HMs pollution. ENVIRONMENTAL IMPLICATION: The contaminated site has been subjected to prolonged environmental disturbances, causing the exacerbation of pollutants leaching and frequent occurrences of unstable pollution situations. This work explored the migration of HMs-bearing colloids in response to freeze-thaw treatments by laboratory simulation and pore-scale study. The distinct effects of freeze-thaw treatment on colloidal particle number concentration and macropore characteristics may explain the generation and migration of colloid-associated HMs driven by environmental disturbances. This work revealed the underlying mechanisms driving the redistribution of HMs under freeze-thaw cycles, offering valuable insights for risk assessment of soil and groundwater associated with HMs migration.

The Bioaccumulations of Metal(loid)s in the Tissues of Invasive Carassius gibelio (Bloch, 1782) Fish from the Kizilirmak River (Türkiye) and Health Risk Assessment.

The present research was an examination of the concentration levels of 10 metal(loid)s that had accumulated in the muscle, gills, and liver tissues of Carassius gibelio (Prussian carp) fish. The fish species, used as samples in the study, were obtained from the part of the river in Gülsehir (Türkiye). Besides, possible health risks to consumers were specified based on the daily estimated intake (EDI) of metal(loid)s in adults. Additionally, considering the inhabitants' frequency of fish consumption in the area, target hazard quotient (THQ), hazard index (HI), carcinogenic risk (CR), and maximum safe consumption quantity (MSCQ) values were assessed. All of the examined metal(loid)s in the research were determined in all of the tissues of the fish. Also, Fe and Zn had the highest levels in the tissues, and Pb had the lowest level. There were statistically significant differences of Fe, Co, Cu, Zn, As, Cd, and Pb among the tissues (p < 0.05). It was determined that the gender of the fish did not affect the accumulation of the metal(loid)s in the tissues. According to the research results, no significant statistical difference was found between the accumulation of the metal(loid)s (except Ni) and the size of the fish (length and weight) (p > 0.05). The estimated daily intake levels of the metal(loid)s accumulating in the eatable muscle of the samples were calculated to be lower than the reference dose limit. Besides, the THQ and the HI values lower than 1 were found. Carcinogenic risk values related to inorganic As were below 10-6. This result specifies that consumption of the fish poses no carcinogenic risks to consumers' health. It was concluded that less than 70 g of C. gibelio daily consumption would not harm consumers' health.

Trace elements and heavy metal(loid)s triggering ecological risks in a heavily polluted river-reservoir system of central Mexico: Probabilistic approaches.

The contamination of trace elements and heavy metal(loid)s in water bodies has emerged as a global environmental concern due to their high toxicity at low concentrations to both biota and humans. This study aimed to evaluate the ecological risk associated with the occurrence and spatial distribution of Mn, Fe, Co, Cd, Ni, Zn, Sb, As, Tl, Cu, Pb, U, and V in the heavily polluted waters of an important river-reservoir system (Atoyac River Basin) in central Mexico, using two-level tired probabilistic approaches: Risk Quotient based on Species Sensitivity Distribution (RQSSD) and Joint Probability Curves (JPCs). The concentrations of these elements varied widely, ranging from 0.055 µg L-1 to 9200 µg L-1 and from 0.056 µg L-1 to 660 µg L-1, in both total and dissolved fractions, respectively. Although geogenic and anthropogenic sources contribute to the presence of these elements in waters, the discharge of untreated or poorly treated industrial wastewater is the main source of contamination. In this regard, the RQSSD results indicated high ecological risk for Mn, Fe, Co, Ni, Zn, and Sb, and medium or low ecological risk for As, Tl, U, and V at almost all sampling sites. The highest RQSSD values were found downstream of a large industrial corridor for Co, Zn, Tl, Pb, and V, with Tl, Pb, and V escalating to higher risk levels, highlighting the negative impact of industrial contamination on biota. The JPC results for these elements are consistent with the RQSSD approach, indicating an ecological risk to species from Mn, Fe, Co, Ni, Zn, and Sb in waters of the Atoyac River Basin. Therefore, the results of this study offer a thorough assessment of pollution risk, providing valuable insights for legislators on managing and mitigating exposure.

Distribution and drivers of co-hosts of antibiotic and metal(loid) resistance genes in the fresh-brackish-saline groundwater.

Groundwater is an essential source of drinking water and agricultural irrigation water, and its protection has become a global goal for public health. However, knowledge about heavy metal(loid) resistance genes (MRGs) in groundwater and the potential co-selection of antibiotic resistance genes (ARGs) have seldom been developed. Here, during the wet and dry seasons, we collected 66 groundwater samples (total dissolved solids = 93.9-9530 mg/L) adjacent to Baiyangdian Lake in Northern China, which presented the few metal(loid) and antibiotic contamination. We identified 160 MRGs whose composition exhibited significant seasonal variation, and dissolved metal(loid)s (particularly Ba) played a determinative role in promoting the MRGs proliferation though with relatively low concentrations, suggesting the relatively vulnerable groundwater ecosystems. Moreover, 27.4% of MRG-carrying metagenome-assembled genomes (MAGs) simultaneously carried ARGs, with the most frequently detected MRG types of Cu, Hg, and As, and ARG types of multidrug and bacitracin. Physicochemical variables, variables related to total dissolved solids, metal(loid)s, and antibiotics synthetically shaped the variation of MRG-ARG hosts in groundwater. We found that the increase of MRG-ARG hosts was critically responsible for the spread of MRGs and ARGs in groundwater. Our findings revealed the widespread co-occurrence of MRGs and ARGs in few-contaminated groundwater and highlighted the crucial roles of salinity in their propagation and transmission.

Effects of mining activities and municipal wastewaters on element accumulation and integrated biomarker responses of the European chub (Squalius cephalus).

This study aimed to determine concentrations of 29 elements in the gills and liver as well as biomarker response in gills, liver, and blood of European chub from Pek River (exposed to long-term mining activities), and to compare these findings with individuals from Ibar River (influenced by emission of treated municipal wastewater) and Kruscica reservoir (source of drinking water) using inductively-coupled plasma optical emission spectrometry (ICP-OES). The metal pollution index (MPI) was also calculated. Supporting analyses for the detection of the municipal wastewater presence at investigated localities included analyses of microbiological indicators (total coliforms and Escherichia coli) of faecal pollution. We have assessed biomarker responses from molecular to organism level using the condition index, comet assay, micronucleus test, oxidative stress parameters, histopathological alterations, and fluorescence spectroscopy parameters. Multibiomarker analysis was summarized by Integrated Biomarker Response v2 (IBRv2). Among these locations, Kruscica exhibited the lowest, whereas the Pek River displayed the highest values for both categories of indicator bacteria. Due to the porphyry copper ores mining, individuals from Pek River had several times higher Cu concentrations in both gills and liver compared to the other localities which was confirmed by biomarker responses and IBRv2 value. On the contrary, fish from Kruscica reservoir were the least affected by elemental pollution which is also confirmed by low MPI and IBRv2 values. Responses of biomarkers correspond to the elemental accumulation in the liver and gills of the Ibar River are positioned between the Pek River and Kruscica reservoir. Of all the biomarkers analyzed in this study, the condition index was the least sensitive. The results of this study showed that fluorescence spectroscopy may be a method for fast screening of structural changes in gills caused by the pollution burden.