Photochemical properties and toxicity of fluoroquinolone antibiotics impacted by complexation with metal ions in different pH solutions.

Acid-base dissociable antibiotic-metal complexes are known to be emerging contaminants in the aquatic environments. However, little information is available on the photochemical properties and toxicity of these complex forms. This study investigated the spectral properties of three fluoroquinolones (FQs) with and without metal ions Fe(III), Cu(II), and Al(III) in solutions under different pH conditions, as well as evaluated the changes in toxicity due to the complex with these metal ions using luminescent bacteria (vibrio fischeri). FQs showed a higher tendency to coordinate metal ions under alkaline conditions compared to neutral and acidic conditions, and the formation of complexes weakened the ultraviolet-absorbing ability of FQs. At pH = 7.0, Cu(II) quenched the fluorescence intensity of FQs. Moreover, their Fourier-transform infrared spectroscopy and X-ray photoelectron spectroscopy were explored, revealing that the coordination sites of Cu(II) in three FQs were situated in a bidentate manner through the oxygen atom of the deprotonated carboxyl group and cyclic carbonyl oxygen atom. This conclusion was further verified by the theory of molecular surface electrostatic potential. In addition, except for complexes of ciprofloxacin-metals, enhanced toxicity of FQs upon coordination with Fe(III) was observed, while reduced toxicity was found for coordination with Cu(II) and Al(III). These results are important for accurately evaluating the photochemical behavior and risk of these antibiotics in aquatic environments contaminated with metal ions.

Unveiling influences of metal-based nanomaterials on wheat growth and physiology: From benefits to detriments.

Metal-based nanomaterials (MNs) are widely used in agricultural production. However, our current understanding of the overall effects of MNs on crop health is insufficient. A global meta-analysis of 144 studies involving approximately 2000 paired observations was conducted to explore the impacts of MNs on wheat growth and physiology. Our analysis revealed that the MN type plays a key role in influencing wheat growth. Ag MNs had significant negative effects on wheat growth and physiology, whereas Fe, Ti, and Zn MNs significantly increased wheat biomass and photosynthesis. Our study also observed a clear dose-specific effect, with a decrease in wheat shoot biomass with increasing MN concentrations. Meanwhile, MNs with small sizes (<25 nm) have no significant impacts on wheat growth. Furthermore, both the root and foliar applications significantly improved wheat growth, with no considerable differences. Using a machine learning approach, we found that the MN type was the main driving factor affecting wheat shoot biomass, followed by MN dose and size. Overall, wheat growth and physiology can be negatively influenced by specific MNs, for which a high dose and small size should be avoided in practical applications. Therefore, our study can provide insights into the future design and safe use of MNs in agriculture and increase the public acceptance of nano-agriculture.

Metal-based nanomaterials in aquatic environments: What do we know so far about their ecotoxicity?

The wide range of applications of nanomaterials (NM) in different fields has led to both uncontrolled production and release into environmental compartments, such as aquatic systems, where final disposal occurs. Some efforts have been made to estimate their concentrations in environmental matrices; however, little is known about the actual effects of environmental NM concentrations on biota. The aims of the present review are to (i) expose the state of the art of the most applied NM and their actual concentrations regarding how much is being released to the aquatic environment and which are the predicted ones; (ii) analyze the current literature to elucidate if the aforementioned conditions were proven to cause deleterious effects on the associated organisms; and (iii) identify gaps in the knowledge regarding whether the actual NM concentrations are harmful to aquatic biota. These novel materials are expected to being released into the environment in the range of hundreds to thousands of tons per year, with Si- and Ti-based NM being the two most important. The estimated environmental NM concentrations are in the low range of ng to µg/L, except for Ti-based ones, which concentrations reach values on the order of mg/L. Empirical information regarding the ecotoxicity of environmental NM concentrations mainly focused on metal-based NM, however, it resulted poor and unbalanced in terms of materials and test species. Given its high predicted environmental concentration in comparison with the others, the ecotoxicity of Ti-based NM has been well assessed in algae and fish, while little is known regarding other NM types. While only a few marine species were addressed, the freshwater species Daphnia magna and Danio rerio accounted for the majority of studies on invertebrate and fish groups, respectively. Most of the reported responses are related to oxidative stress. Overall, we consider that invertebrate groups are the most vulnerable, with emphasis on microcrustaceans, as environmentally realistic metal-based NM concentration even caused mortality in some species. In the case of fish, we assumed that environmental concentrations of Ti-based NM represent a growing concern and threat; however, further studies should be carried out by employing other kinds of NM. Furthermore, more ecotoxicological information is needed in the case of carbon-based NM, as they are expected to considerably increase in terms of released amounts and applications in the near future.

Sub-lethal effects of metals and pesticides on the freshwater dinoflagellate Palatinus apiculatus and environmental implications.

Microalgae are unicellular, photosynthetic organisms in aquatic environments and are sensitive to water quality and contaminants. While green algae and diatoms are widely used for toxicity assessments, there is a relatively limited amount of toxicity data available for freshwater dinoflagellates. Here, we evaluated the sub-lethal effects of the metals Cu, Cr, Ni, and Zn and the herbicides atrazine and S-metolachlor on the freshwater dinoflagellate Palatinus apiculatus. Based on the 72-h median effective concentration (EC50), P. apiculatus showed sensitive responses to metals in the order of Cu (0.052 mg L-1), Cr (0.085 mg L-1), Zn (0.098 mg L-1), and Ni (0.13 mg L-1). Among the tested herbicides, P. apiculatus was more sensitive to atrazine (0.0048 mg L-1) than S-metolachlor (0.062 mg L-1). In addition, we observed morphological alterations and significant increases in reactive oxygen species (ROS) production in cells exposed to 0.05 mg L-1 of Cu and 0.005 mg L-1 of atrazine. These indicated that metals and pesticides induced oxidative stress in cellular metabolic processes and consequently caused severe physiological damage to the cells. Our results provide baseline data on the toxic effects of typical environmental contaminants on freshwater dinoflagellate, suggesting that P. apiculatus could be used as a bioindicator in freshwater toxicity assessments. PRACTITIONER POINTS: The sub-lethal effects of metals and pesticides on the freshwater dinoflagellate Palatinus apiculatus were evaluated. Palatinus sensitively responded to metals and pesticides; of test chemicals, atrazine (0.0048 mg L-1 of EC50) was the most sensitive. Metals and pesticides induced oxidative stress and consequently caused severe physiological damage to the Palatinus cells. The freshwater dinoflagellate Palatinus can be used as a bioindicator in freshwater toxicity assessments.

Assessment of receptor-mediated activity (AhR and ERα), mutagenicity, and teratogenicity of metal shredder wastes in Wallonia, Belgium.

In this study, hazardous wastes including fluff, dust, and scrubbing sludge were sampled in 2019 from two metal shredding facilities located in Wallonia, Belgium. To assess the extent of the contamination, a global approach combining chemical and biological techniques was used, to better reflect the risks to health and the environment. The samples investigated induced significant in vitro aryl hydrocarbon receptor (AhR) agonistic bioactivities and estrogenic receptor (ERα) (ant)agonistic bioactivities in the respective CALUX (chemical activated luciferase gene expression) bioassays. The mutagenicity of the samples was investigated with the bacterial reverse gene mutation test using the Salmonella typhimurium TA98 and TA100 strains. Except for the sludge sample (site 3), all samples induced a mutagenic response in the TA98 strain (± S9 metabolic fraction) whereas in the TA100 strain (+ S9 metabolic fraction), only the sludge sample (site 2) showed a clear mutagenic effect. The in vivo toxicity/teratogenicity of the shredder wastes was further evaluated with zebrafish embryos. Except for the dust sample (site 2), all samples were found to be teratogenic as they returned teratogenic indexes (TIs) > 1. The high levels of contamination, the mutagenicity, and the teratogenicity of these shredder wastes raise significant concerns about their potential negative impacts on both human health and environment.

Construction of metal interpretable scoring system and identification of tungsten as a novel risk factor in COPD.

Numerous studies have highlighted the correlation between metal intake and deteriorated pulmonary function, emphasizing its pivotal role in the progression of Chronic Obstructive Pulmonary Disease (COPD). However, the efficacy of traditional models is often compromised due to overfitting and high bias in datasets with low-level exposure, rendering them ineffective in delineating the contemporary risk trends associated with pulmonary diseases. To address these limitations, we embarked on developing advanced, interpretable models, crucial for elucidating the intricate mechanisms of metal toxicity and enriching the domain knowledge embedded in toxicity models. In this endeavor, we scrutinized extensive, long-term metal exposure datasets from NHANES to explore the interplay between metal and pulmonary functionality. Employing a variety of machine-learning approaches, we opted for the "Mixer of Experts" model for its proficiency in identifying a myriad of toxicological trends and sensitivities. We conceptualized and illustrated the TSAP (Toxicity Score at Population-level), a metal interpretable scoring system offering performance nearly equivalent to the amalgamation of standard interpretable methods addressing the "black box" conundrum. This streamlined, bifurcated procedural analysis proved instrumental in discerning established risk factors, thereby uncovering Tungsten as a novel contributor to COPD risk. SYNOPSIS: TSAP achieved satisfied performance with transparent interpretability, suggesting tungsten intake need further action for COPD prevention.

Mediation analysis for TNF-α as a mediator between multiple metal exposure and kidney function.

The association between metal mixtures and kidney function has been reported. However, reports on the mechanism of metal toxicity were limited. Oxidative stress was reported as a possible cause. This study aimed to determine the association between of kidney function and metals, such as arsenic (As), cadmium (Cd), cobalt (Co), copper (Cu), lead (Pb), selenium (Se), and zinc (Zn), and to explore the possible mediating role of tumor necrosis factor alpha (TNF-α) between metal toxicity and kidney function. In this study, we recruited 421 adults from a health examination. The concentration of blood metals was analyzed using inductively coupled plasma mass spectrometry. We used linear regression models to assess the association between metals and TNF-α. Then, mediation analysis was applied to investigate the relationship between metal exposure, TNF-α, and kidney function. In univariate linear regression, blood As, Cd, Co, Cu, Pb, and Zn levels significantly increased TNF-α and decreased kidney function. Higher blood As and Pb levels significantly increased TNF-α in multivariable linear regressions after adjusting for covariates. We found that blood levels of As (coefficients = -0.021, p = 0.011), Pb (coefficients = -0.060, p < 0.001), and Zn (coefficients = -0.230, p < 0.001) showed a significant negative association with eGFR in the multiple-metal model. Furthermore, mediation analysis showed that TNF-α mediated 41.7 %, 38.8 %, and 20.8 % of blood Cd, As and Pb, respectively. Among the essential elements, TNF-α mediated 24.5 %, 21.5 % and 19.9 % in the effects of blood Co, Cu, and Zn on kidney function, respectively. TNF-α, acting as a mediator, accounted for 20.1 % of the contribution between the WQS score of metal mixtures and the eGFR (p < 0.001). This study suggested that TNF-α may be a persuasive pathway mediating the association between metals and kidney function. Inflammation and kidney injury could be the underlying mechanisms of metal exposure. However, there is still a need to clarify the biochemical mechanism in follow-up studies.

Polyamines: Rising stars against metal and metalloid toxicity.

Globally, metal/metalloid(s) soil contamination is a persistent issue that affects the atmosphere, soil, water and plant health in today's industrialised world. However, an overabundance of these transition ions promotes the excessive buildup of reactive oxygen species (ROS) and ion imbalance, which harms agricultural productivity. Plants employ several strategies to overcome their negative effects, including hyperaccumulation, tolerance, exclusion, and chelation with organic molecules. Polyamines (PAs) are the organic compounds that act as chelating agents and modulate various physiological, biochemical, and molecular processes under metal/metalloid(s) stress. Their catabolic products, including H2O2 and gamma amino butyric acid (GABA), are also crucial signalling molecules in abiotic stress situations, particularly under metal/metalloid(s) stress. In this review, we explained how PAs regulate genes and enzymes, particularly under metal/metalloid(s) stress with a specific focus on arsenic (As), boron (B), cadmium (Cd), chromium (Cr), and zinc (Zn). The PAs regulate various plant stress responses by crosstalking with other plant hormones, upregulating phytochelatin, and metallothionein synthesis, modulating stomatal closure and antioxidant capacity. This review presents valuable insights into how PAs use a variety of tactics to reduce the harmful effects of metal/metalloid(s) through multifaceted strategies.

Metal ions overloading and cell death.

Cell death maintains cell morphology and homeostasis during development by removing damaged or obsolete cells. The concentration of metal ions whithin cells is regulated by various intracellular transporters and repositories to maintain dynamic balance. External or internal stimuli might increase the concentration of metal ions, which results in ions overloading. Abnormal accumulation of large amounts of metal ions can lead to disruption of various signaling in the cell, which in turn can produce toxic effects and lead to the occurrence of different types of cell deaths. In order to further study the occurrence and development of metal ions overloading induced cell death, this paper reviewed the regulation of Ca2+, Fe3+, Cu2+ and Zn2+ metal ions, and the internal mechanism of cell death induced by overloading. Furthermore, we found that different metal ions possess a synergistic and competitive relationship in the regulation of cell death. And the enhanced level of oxidative stress was present in all the processes of cell death due to metal ions overloading, which possibly due to the combination of factors. Therefore, this review offers a theoretical foundation for the investigation of the toxic effects of metal ions, and presents innovative insights for targeted regulation and therapeutic intervention. HIGHLIGHTS: • Metal ions overloading disrupts homeostasis, which in turn affects the regulation of cell death. • Metal ions overloading can cause cell death via reactive oxygen species (ROS). • Different metal ions have synergistic and competitive relationships for regulating cell death.

The impact of settleable atmospheric particulate on the energy metabolism, biochemical processes, and behavior of a sentinel mangrove crab.

We use the sentinel mangrove crab, Minuca rapax, as a model to investigate the effects of metallic settleable particulate matter (SePM) on wetland. Multiple levels of energetic responses, including (i) metabolic rate and energy budget, (ii) oxidative stress, and (iii) behavioral response by righting time, were assessed as well as the metal and metalloid content in crabs exposed to 0, 0.1 and 1 g.L-1 of SePM, under emerged and submerged conditions over five days, simulating the rigors of the intertidal habitat. Al, Fe, Mn, Cr, and Y exhibited a concentration-dependent increase. Metal concentrations were higher in submerged crabs due to the continuous ingestion of SePM and direct exposure through gills. Exposure concentration up to 1 g.L-1 decreased metabolic rate and enzymatic activities, reduced assimilation efficiency and energy for maintenance, and induces a slower response to righting time, probably by metal effects on nervous system and energy deficits. In conclusion, SePM exposure affects the redox status and physiology of M. rapax depending on he submersion regime and SePM concentration. The disruption to the energy budget and the lethargic behavior in M. rapax exposed to SePM implies potential ecological alterations in the mangrove ecosystem with unknown consequences for the local population.

Potential biomarkers of metal toxicity in deep-sea invertebrates - A critical review of the omics data.

Deep-sea mining (DSM) activities are expected to release potentially toxic metal mixtures through the generation of sediment plumes to the marine environment. This may disrupt the normal functioning of biological mechanisms, adversely affecting deep-sea invertebrate organisms. It is thus essential to understand the ecotoxicological effects from these toxic elements in deep-sea organisms and the omics approaches applied to ecotoxicology are seen as promising tools. Here, we provide an overview of the principal biological modifications identified in deep-sea invertebrates when exposed to metals and critically evaluate the current knowledge and discuss which potential biomarkers may be useful after metal exposure. Most of the 50 omics studies on deep-sea invertebrates revised are comparative transcriptomes (n = 41). Forty-three potential biomarker candidates are highlighted from immune system, 46 from cellular metabolism and 29 from oxidative stress. The processes mostly affected by metal toxicity in deep-sea invertebrates are related to innate immune defense; sulfur, chitin, and catabolic metabolism; antioxidation; and detoxification. We acknowledge the current limitations and future perspectives for their uses and emphasize the need to invest in further ecotoxicological studies using the omics approaches.

Strong synergistic and antagonistic effects of quinones and metal ions in oxidative potential (OP) determination by ascorbic acid (AA) assays.

A key challenge in oxidative potential (OP) assays is to accurately assess the cumulative impact of redox-active aerosol species rather than only their individual effects. This study investigates the OP of single and combined mixtures of 1,2-naphthoquinone (1,2-NQ), 1,4-naphthoquinone (1,4-NQ), 9,10-phenanthrenequinone (9,10-PQ), 1,4-benzoquinone (1,4-BQ), Cu, Fe, Mn, and Zn in standard ascorbic acid (OPAA) and the synthetic respiratory tract lining fluid (OPRTLF) assays. In both OPAA and OPRTLF, binary mixtures showed additive and synergistic effects in the presence of 1,2-NQ. The mixture of Cu and Zn showed substantial synergisms in both assays, while the mixtures in the absence of 1,2-NQ primarily induced antagonistic effects. For the first time, we propose linear equations to improve the prediction of OP values by considering the impacts of synergistic and antagonistic effects. Under this approach, we observed that the potential effects caused by binary mixtures in ambient particulate matter (PM) samples could account for up to 68 % of the PM-OP values in Fez, Morocco (OPmAA: 0.34 nmol min-1 µg-1 and OPmRTLF: 0.18 nmol min-1 µg-1). The present study improves the understanding of effects of chemical interaction of potentially toxic substances that are important in the understanding of PM-induced oxidative stress in the human body.

Ex Vivo Evaluation of the Function of Hematopoietic Stem Cells in Toxicology of Metals.

A variety of metals, e.g., lead (Pb), cadmium (Cd), and lithium (Li), are in the environment and are toxic to humans. Hematopoietic stem cells (HSCs) reside at the apex of hematopoiesis and are capable of generating all kinds of blood cells and self-renew to maintain the HSC pool. HSCs are sensitive to environmental stimuli. Metals may influence the function of HSCs by directly acting on HSCs or indirectly by affecting the surrounding microenvironment for HSCs in the bone marrow (BM) or niche, including cellular and extracellular components. Investigating the impact of direct and/or indirect actions of metals on HSCs contributes to the understanding of immunological and hematopoietic toxicology of metals. Treatment of HSCs with metals ex vivo, and the ensuing HSC transplantation assays, are useful for evaluating the impacts of the direct actions of metals on the function of HSCs. Investigating the mechanisms involved, given the rarity of HSCs, methods that require large numbers of cells are not suitable for signal screening; however, flow cytometry is a useful tool for signal screening HSCs. After targeting signaling pathways, interventions ex vivo and HSCs transplantation are required to confirm the roles of the signaling pathways in regulating the function of HSCs exposed to metals. Here, we describe protocols to evaluate the mechanisms of direct and indirect action of metals on HSCs. © 2024 Wiley Periodicals LLC. Basic Protocol 1: Identify the impact of a metal on the competence of HSCs Basic Protocol 2: Identify the impact of a metal on the lineage bias of HSC differentiation Basic Protocol 3: Screen the potential signaling molecules in HSCs during metal exposure Alternate Protocol 1: Ex vivo treatment with a metal on purified HSCs Alternate Protocol 2: Ex vivo intervention of the signaling pathway regulating the function of HSCs during metal exposure.

Exposure to a mixture of metal(loid)s and sleep quality in pregnant women during early pregnancy: A cross-sectional study.

Biological characteristics of pregnant women during early pregnancy make them susceptible to both poor sleep quality and metal/metalloid exposure. However, the effects of metal(loid) exposure on sleep quality in pregnant women remain unknown and unexplored. We aimed to examine the relationship between exposure to a mixture of metal(loid)s and pregnant women's sleep quality during early pregnancy. We recruited 493 pregnant women in the first trimester from prenatal clinics in Jinan, Shandong Province, China, and collected their spot urine samples. All urine specimens were assessed for eight metal(loid)s: arsenic (As), cadmium (Cd), iron (Fe), zinc (Zn), molybdenum (Mo), lead (Pb), selenium (Se), and mercury (Hg). We used the Pittsburgh Sleep Quality Index (PSQI) to assess sleep quality. Linear regression, logistic regression, generalized additive models (GAMs), quantile g-computation, and Bayesian kernel machine regression (BKMR) were applied to investigate the relationships between metal(loid) exposure and sleep quality. The results from single metal(loid) models, quantile g-computation models, and BKMR models consistently suggested that Fe was positively related to women's sleep quality. Moreover, in the quantile g-computation models, As was the most critical contributor to the negative effects of the metal(loid) mixture on sleep quality. In addition, we found significant As by Fe interaction for scores of PSQI and habitual sleep efficiency, Pb by Fe interaction for PSQI and sleep latency, and Hg by Fe interaction for PSQI, suggesting the interactive effects of As and Fe, Pb and Fe, Hg and Fe on sleep quality and specific sleep components. Our study provided the first-hand evidence of the effects of metal(loid) exposure on pregnant women's sleep quality. The underlying mechanisms need to be explored in the future.

Effects of blood metal(loid) concentrations on genomic damages in sharks.

The use of effect biomarkers has contributed to the understanding of the sublethal effects of contaminants on different organisms. However, the analysis of genotoxic markers as an indicator of organism and environmental health in sharks is underexplored. Thus, the present study investigated the relationship between the genomic damage frequency in erythrocytes and metal(loid) concentrations in whole blood of three shark species (Galeocerdo cuvier, Negaprion brevirostris and Ginglymostoma cirratum), taking into account climatic seasonality. The results showed that G. cuvier, an apex predator, presented the highest total erythrocyte genomic damage frequencies together with the highest mean whole blood concentrations of Al, Cd, Cr, Fe, Mn, Ni, Pb and Zn. The shark N. brevirostris also presented high levels of metal(loid), indicating a greater susceptibility to these contaminants in species that preferentially feed on fish. In contrast, G. cirratum, a mesopredator, presented the lowest erythrocyte damage frequencies and whole blood metal(loid) concentrations. The presence of micronuclei was the most responsive biomarker, and Al, As and Zn had an important effect on the genomic damage frequencies for all species evaluated. Zn concentration influenced the binucleated cells frequencies and Al concentration had an effect on the total damage and micronuclei frequencies in G. cuvier and N. brevirostris. Binucleated cells and blebbed nuclei frequencies were affected by As concentration, especially in G. cirratum, while showing a strong and positive correlation with most of the metals analyzed. Nonetheless, baseline levels of metal(loid) blood concentrations and erythrocyte genomic damage frequencies in sharks have not yet been established. Therefore, minimum risk levels of blood contaminants concentrations on the health of these animals have also not been determined. However, the high genomic instability observed in sharks is of concern considering the current health status of these animals, as well as the quality of the environment studied.

Interaction and coexistence characteristics of dissolved organic matter and toxic metals with per- and polyfluoroalkyl substances in landfill leachate.

Landfill leachate-containing per- and polyfluoroalkyl substances (PFAS) is both an important 'sink' and a 'source' of secondary pollution, posing serious threaten to surrounding environments. To date, the pollution characteristics of PFAS in landfill leachate, and the coexistence and interaction between PFAS and other leachate contaminants, such as dissolved organic matter (DOM) and toxic metals remains unclear. Herein, our results showed that 17 target PFAS, with concentrations ranged from 1804 to 43309 ng/L, were detected in landfill leachates. The main PFAS were short-chain and even-chain substances represented by perfluorobutanoic acid (PFBA) and perfluorobutane sulfonic acid (PFBS). Leachate derived DOM is mainly composed of protein-like and humic-like substance, among which the total contribution of protein-like substance is as high as 73.7%. Correlation analysis results showed that the distribution of PFAS was strongly correlated with the substituted functional groups (e.g., carboxyl and hydroxyl) on the aromatic ring of humic-like substance (C2 and E253/E203) and autochthonous metabolism by microbial activities (FI). Furthermore, Mn element showed a significantly strong correlation with PFAS. Both organic and inorganic substances positively correlated with toxic metals. Our findings are helpful to understand the environmental fate of PFAS, and contribute to decision-making regarding DOM, toxic metals, and PFAS management in landfill.

Transcriptomic evaluation of metals detected in placenta.

This research aims to assess the concentration of metals in human and canine placentas from the same geographic area and to investigate how these metal levels influence gene expression within the placenta. Placentas of 25 dogs and 60 women who had recently given birth residing in Ankara, Turkey were collected and subjected to metal analysis using ICP-OES. Placentas with detectable metal levels underwent further examination including Next Generation Sequencing, transcriptional analysis, single nucleotide polymorphism investigation, and extensive scrutiny across various groups. For women, placentas with concurrent detection of aluminum (Al), lead (Pb), and cadmium (Cd) underwent transcriptomic analysis based on metal analysis results. However, the metal load in dog placentas was insufficient for comparison. Paired-end sequencing with 100-base pair read lengths was conducted using the DNBseq platform. Sequencing quality control was evaluated using FastQC, fastq screen, and MultiQC. RNA-sequencing data is publicly available via PRJNA936158. Comparative analyses were performed between samples with detected metals and "golden" samples devoid of these metals, revealing significant gene lists and read counts. Normalization of read counts was based on estimated size factors. Principal Component Analysis (PCA) was applied to all genes using rlog-transformed count data. Results indicate that metal exposure significantly influences placental gene expression, impacting various biological processes and pathways, notably those related to protein synthesis, immune responses, and cellular structure. Upregulation of immune-related pathways and alterations in protein synthesis machinery suggest potential defense mechanisms against metal toxicity. Nonetheless, these changes may adversely affect placental function and fetal health, emphasizing the importance of monitoring and mitigating environmental exposure to metals during pregnancy.

Toxic effects of trace metal(loid) mixtures on aquatic organisms.

The co-occurrence of metal (loid)s in realistic aquatic environments necessitates the evaluation of their combined effects. However, the generality of the additive effect hypothesis is contentious, particularly due to metal(loid)-metal(loid) interactions. The absence of systematic evaluation approaches restricts our ability to draw overall conclusions and make reliable predictions. In this study, we reviewed 1473 effect sizes from 38 publications, and classified all responses into seven main categories (from molecular to individual levels) according to their toxicological significance. Our meta-analysis revealed that metal(loid) mixtures had significant effects on aquatic organisms (33 %, 95 % CI 28 %-39 %, P < 0.05), along with significant response heterogeneity (Qt = 690,319.62, P < 0.0001; I2 = 99.95 %). Concurrently, we developed a Random Forest machine learning model to predict adverse effects and identify key variables. These two methods demonstrated that the toxicity of metal(loid) mixtures is primarily linked to the choice of toxicity endpoints, and the characteristics of metal(loid) mixtures. Our findings underscore the potential of combining meta-analysis with machine learning, a more systematic approach, to enhance the understanding and prediction of the adverse effects of metal(loid) mixtures, and they offer guidance for risk assessment and policy-making in complex environmental scenarios.

Potential risks of accumulated microplastics in shells and soft tissues of cultured hard clams (Meretrix taiwanica) and associated metals.

Microplastics (MPs) pose risks to both aquatic ecosystems and human health. This study investigated MPs in the shells and soft tissues of hard clams (Meretrix taiwanica) cultured in the inland waters of Taiwan. This study further developed two novel risk indices for assessing the potential ecological and health consequences of MPs. Moreover, the metal concentrations in the clam's soft tissues and the associated consumption health risks were investigated. Clamshells contained significant amounts of MPs with an average abundance of 16.6 ± 6.9 MPs/ind., which was higher than in the soft tissues (2.7 ± 1.7 MPs/ind.). The distribution and sizes of MPs in shells and soft tissues were similar, primarily small-sized (<2 mm, >99 %), blue (>65 %), and fibrous (>99 %). Dominant MP polymer types included rayon (83.5 %), polyethylene terephthalate (11.8 %), and polyacrylonitrile (3.6 %). The proposed MP potential ecological risk index indicates a higher potential ecological MP risk in soft tissues (302-423) than in shells (270-278) of the clams. The MP potential hazard risk index showed that the risk of exposure to MP through shellfish consumption decreased with age. The total hazard index (THI) value suggested negligible health hazards from metal exposure through shellfish consumption. Moreover, there was no significant correlation between MPs and metal concentrations in soft tissues, suggesting that metals bound to MPs contribute minimally to the total accumulated metals in clam's soft tissues. This study confirms the presence of MPs in clam shells and provides a novel tool to assess the potential ecological and health risks associated with MPs in shellfish.