Metal Mixtures Research Articles

Reduction of haemoglobin is related to metal mixtures exposure in Chinese preschoolers: Joint effect models

Heavy metal exposure is a known risk factor for hematologic disorders in children, yet the impact of co-exposure to multiple metals remains underexplored. This cross-sectional study investigates the relationship between urinary levels of 23 metals and haemoglobin (Hb) in 1460 Chinese preschoolers. The concentrations of the 23 urinary metals were quantified using an inductively coupled plasma mass spectrometer, while Hb levels were assessed through finger prick blood samples. To evaluate the co-exposure effects, we employed three approaches: Generalized linear regression model, joint effect models including Quantile g-Computation and Bayesian Kernel Machine Regression (BKMR). From the generalized linear regression and Quantile g-computation, urinary uranium, thallium, aluminium, iron and tungsten were correlated negatively with Hb, while urinary barium was correlated positively (all P < 0.05). Moreover, significant negative associations between metal mixtures exposure with Hb were identified in both Quantile g-computation [β (95% CI): -0.083 (-0.132, -0.033), P = 0.0012] and BKMR [90th percentile vs. 50th percentile β (95% CI): -0.238 (-0.368, -0.107), P < 0.001] with aluminium emerging as the primary contributor to this joint effect (weight in Quantile g-computation = 0.399, PIPs in BKMR = 0.896). These findings provide a potential explanation for environmental exposure to metals and Hb-related disease in preschoolers.

Combined exposure to multiple metals on abdominal aortic calcification: results from the NHANES study.

Exposure to metals increases the risk of many diseases and has become a public health concern. However, few studies have focused on the effect of metal on abdominal aortic calcification (AAC), especially the combined effects of metal mixtures. In this study, we aim to investigate the combined effect of metals on AAC risk and determine the key components in the multiple metals. We tried to investigate the relationship between multiple metal exposure and AAC risk. Fourteen urinary metals were analyzed with five statistical models as follows: generalized linear regression, weighted quantile sum regression (WQS), quantile g-computation (Qgcomp), and Bayesian kernel machine regression (BKMR) models. A total of 838 participants were involved, of whom 241 (28.8%) had AAC. After adjusting for covariates, in multiple metal exposure logistic regression, cadmium (Cd) (OR = 1.364, 95% CI = 1.035-1.797) was positively associated with AAC risk, while cobalt (Co) (OR = 0.631, 95% CI = 0.438-0.908) was negatively associated with AAC risk. A significant positive effect between multiple metal exposure and AAC risk was observed in WQS (OR = 2.090; 95% CI = 1.280-3.420, P < 0.01), Qgcomp (OR = 1.522, 95% CI = 1.012-2.290, P < 0.05), and BKMR models. It was found that the positive association may be driven primarily by Cd, lead (Pb), uranium (U), and tungsten (W). Subgroups analysis showed the association was more significant in participants with BMI ≥ 25kg/m2, abdominal obesity, drinking, and smoking. Our study shows that exposure to multiple metals increases the risk of AAC in adults aged ≥ 40years in the USA and that Cd, Pb, U, and W are the main contributors. The association is stronger in participants who are obese, smoker, or drinker.

The potential of Stenotrophomonas maltophilia KB2 for 1 phenol degradation 2 under exposure to heavy metal

The large diversity of chemical substances present in air, water, or soil makes it necessary tostudy their mutual impact on the effectiveness of microbiological decomposition ofcontaminants. This publication presents the results of the studies aimed at evaluating the effect of two biogenic heavy metals - zinc and copper - on the phenol biodegradation by the Stenotrophomonas maltophilia KB2 strain. The tests were carried out for concentrations ofmetals significantly exceeding the legally permitted wastewater values: for zinc up to13.3 g·m -3, and copper up to 3.33 g·m -3. In the tested metal concentration range, phenol biodegradation by the S. maltophilia KB2 strain was not significantly influenced by theintroduced dose of zinc. While the presence of copper inhibited both biomass growth andsubstrate degradation. Kinetic data of metal and phenol mixtures were analyzed and very goodcorrelations were obtained for the proposed equations. An equation consistents with the Hanand Levenspiel model was proposed for the system S. maltophilia KB2-phenol-copper, whilean equation consistents with the Kai model for the system St. maltophilia KB2-phenol-zinc. The simultaneous presence of Zn and Cu ions in the culture resulted in a stronger inhibition ofphenol biodegradation.

Partial purification and characterization of protease extracted from kinema

Proteases are large group of highly demanded enzymes having huge application in food and pharmaceutical industries. Numerous sources, including plants, microorganisms, and animals, can be used to obtain protease. Due to its affordability and safety consideration, fermented foods have recently attracted more attention as a source of microbial protease. The present study aimed to extract protease from kinema, partially purify the extracted protease following dialysis after precipitation with ammonium sulfate, and determine general characteristics of protease. The kinema having highest proteolysis activity after three days of control fermentation (Temperature 30±2 °C, RH 66 ± 2%) was taken for the study. About 2.45 fold of purification with overall recovery of 63.21% was achieved after precipitation with ammonium sulfate at 30–70% saturation level followed by dialysis of crude extracted protease. The dialysed kinema protease had specific activity of 7.90 U/mg. The enzyme remained actively functional across a wider pH (5–9) and temperature (40-60 °C) range. SDS-PAGE and Zymogram confirmed the presence of three major active bands respectively of 29.04 kDa, 36.09 kDa and 46.35 kDa in the kinema protease extract. The enzyme kinetics data on casein, fitted to Mechaelis Mentens’ plots showed the protease had Vmax of 1.001 U/ml with corresponding Km value of 0.825 mg/ml. Metal ions such as iron, mercury and aluminium showed the inhibition effect whereas presence of sodium, zinc, and calcium shows the activation effect on protease performance. The enzyme was active over various natural substrates; showing maximal activity on casein, and subsequent to bovine serum albumin, gelatin, hemoglobin and whey protein respectively. Furthermore, molecular weight distribution of the protease extract and activity inhibition with ethylenediaminetetraacetic acid and phenylmethylsulfonyl fluoride, suggesting the protease from kinema could be a metal dependent serine protease or mixture of them.

The Correlation between Metal Mixed Exposure and Lung Function in Different Ages of the Population.

Herein, we explored the overall association between metal mixtures and lung functions in populations of varying ages and the relationship among the associated components. The 2007-2012 National Health and Nutrition Examination Survey data of 4382 American participants was analyzed, and generalized linear, elastic net, quantile g-computation, and Bayesian kernel machine regression models were used to evaluate the relationship between exposure to the metal mixture and lung function at various ages. The results of barium exposure at distinct stages revealed that children and adolescents exhibited greater lung function changes than those in adults and the elderly. Additionally, compared with children and adolescents, cadmium- and arsenic-containing metabolites contributed to nonconductive lung function changes in adults and the elderly exposed to metal mixtures. The results showed that the effects of exposure to metal mixtures on lung function in children and adolescents were predominantly caused by lead and barium. Altogether, children and adolescents were found to be more susceptible to metal-exposure-mediated lung function changes than adults and the elderly.

Covalently Immobilized EDTA onto Graphene Oxide Using Ethylene Diamine as a Crosslinker for Cu(II), Pb(II), and Zn(II) Sorption

ABSTRACT This study introduces a novel method of EDTA immobilization onto graphene oxide (GO) using ethylene diamine as a crosslinker for heavy metal removal. GO was prepared from graphite via a modified Hummer method. Ethylene diamine was used as a novel crosslinker to immobilize EDTA onto GO via amide coupling. GO was functionalized with ethylene diamine to produce GO-NH2 onto which EDTA (H-form) was covalently immobilized producing GO-EDTA. FTIR and TGA show successful covalent immobilization of EDTA. Pb(II), Cu(II), and Zn(II) were tested for sorption from aqueous solutions onto GO-EDTA (Na-form). Initial pH 6.0 was found optimum for metal sorption. The kinetic sorption data were found to fit the pseudo-second-order model well with better performance as the temperature rises. The activation energy (E a ) of metal sorption was between 10.6 and 32 kJ/mol indicating metal physisorption. Equilibrium sorption data were found to fit well the Langmuir model with higher uptake as the temperature rises. The sorption capacity was 72.4, 46.5, and 28.0 mg/g at 25°C while it was 86.2, 56.8, and 31.95 mg/g at 35°C for Pb(II), Cu(II), and Zn(II), respectively. Metal sorption follows the order of GO-EDTA > GO-NH2 > GO and follows the order of Pb(II) > Cu(II) > Zn(II) from the metal mixture. Metal sorption is endothermic and spontaneous. GO-EDTA shows efficient recycle properties for metal sorption.

Association between Heavy Metals and Trace Elements in Cancerous and Non-cancerous Tissues with the Risk of Colorectal Cancer Progression in Northwest China.

Alterations in heavy metals and trace element levels may be associated with various cancers. However, the role of this interaction in colorectal cancer (CRC) progression is unclear. In recent years, Principal Component Analysis (PCA) and Bayesian Kernel Machine Regression (BKMR) models have provided new ideas for analyzing the effects of metal mixtures on CRC progression. Herein, we assessed the differences in the levels of arsenic (As), cadmium (Cd), cobalt (Co), chromium (Cr), copper (Cu), nickel (Ni), selenium (Se), and zinc (Zn) in tumors and adjacent healthy tissues, to investigate the relationship between heavy metals/trace elements and CRC progression. Surgical samples of CRC and noncancerous tissues were collected, and trace metal levels were analyzed using inductively coupled plasma mass spectrometry (ICP-MS). Logistic regression, PCA, and BKMR models were used to investigate the relationship between heavy metals and trace elements and the degree of tumor differentiation and lymph node metastasis in CRC. Cancer tissues showed lower As, Cd, Co, and Cr concentrations, and higher Se concentrations than healthy tissues (P < 0.05). In addition, CRC patients with poorly differentiated tumors and/or positive lymph node metastases had lower levels of Cd, Zn, Cu, and Se (P < 0.05). Logistic regression showed that single metal concentration was negatively correlated with CRC progression. PCA and BKMR models also showed that the metal mixture concentration was negatively correlated with CRC progression, with Cd contributing the most. Overall, changes in heavy metal and trace element levels may be related to the development of CRC; however, further mechanistic studies are required.

Use of the small punch test for mechanical characterization of co– based laser cladding joint

This work evaluates the capacity of the small punch test (SPT) to determine the mechanical properties of wear-resistant cobalt-based fabricated by laser cladding. The joint is made up of three zones: the cladding material, the interface, and the base material, each of which must be characterized individually. SPT specimens extracted from each zone were tested and the mechanical properties were obtained by using various correlations. The validity of these correlations was evaluated by comparing the properties obtained for the base and cladding metals with those obtained by standard tests. With this verification, the properties of the interface, which is a mixture of the base metal and the cladding, were extracted. The mechanical properties of the joint change with the hardness, which depends on the microstructure and the thermal distribution of the different zones. The results demonstrate the suitability of the SPT for characterizing layers of laser cladding, providing values similar to those obtained with tensile or fracture tests. The increase in strength and decrease in toughness in the interface and the cladding metal were in agreement with the microstructure in each zone.

Predicting the Metal Mixture Toxicity with a Toxicokinetic-Toxicodynamic Model Considering the Time-Dependent Adverse Outcome Pathways.

Chemicals mainly exist in ecosystems as mixtures, and understanding and predicting their effects are major challenges in ecotoxicology. While the adverse outcome pathway (AOP) and toxicokinetic-toxicodynamic (TK-TD) models show promise as mechanistic approaches in chemical risk assessment, there is still a lack of methodology to incorporate the AOP into a TK-TD model. Here, we describe a novel approach that integrates the AOP and TK-TD models to predict mixture toxicity using metal mixtures (specifically Cd-Cu) as a case study. We preliminarily constructed an AOP of the metal mixture through temporal transcriptome analysis together with confirmatory bioassays. The AOP revealed that prolonged exposure time activated more key events and adverse outcomes, indicating different modes of action over time. We selected a potential key event as a proxy for damage and used it as a measurable parameter to replace the theoretical parameter (scaled damage) in the TK-TD model. This refined model, which connects molecular responses to organism outcomes, effectively predicts Cd-Cu mixture toxicity over time and can be extended to other metal mixtures and even multicomponent mixtures. Overall, our results contribute to a better understanding of metal mixture toxicity and provide insights for integrating the AOP and TK-TD models to improve risk assessment for chemical mixtures.

Metabolomics perspectives into the co-exposure effect of polycyclic aromatic hydrocarbons and metals on renal function: A meet-in-the-middle approach

Studies on the dose effects of kidney impairment and metabolomes in co-exposure to polycyclic aromatic hydrocarbons (PAHs) and metals are limited. We aimed to identify overall associations and metabolic perturbations in 130 participants (53 petrochemical workers and 77 controls) exposed to a PAHs-metals mixture in Southern China. The urinary 7 hydroxylated PAHs and 15 metal(loid)s were determined, and serum creatinine, beta-2 microglobulin, and estimated glomerular filtration rate were health outcomes. The liquid chromatography-mass spectrometry-based method was applied to serum metabolomics. Generalized weighted quantile sum (gWQS) regressions were used to estimate the overall dose-response relationships, and pathway analysis, “meet-in-the-middle” approach, and mediation effect analyses were conducted to identify potential metabolites and biological mechanisms linking exposure with nephrotoxic effects. Our results indicated that renal function reduction was associated with a PAHs-metals mixture in a dose-dependent manner, and 1-hydroxynaphthalene and copper were the most predominant contributors among the two families of pollutants. Furthermore, the metabolic disruptions associated with the early onset of kidney impairment induced by the combination of PAHs and metals encompassed pathways such as phenylalanine-tyrosine-tryptophan biosynthesis, phenylalanine metabolism, and alpha-linolenic acid metabolism. In addition, the specifically identified metabolites demonstrated excellent potential as bridging biomarkers connecting the reduction in renal function with the mixture of PAHs and metals. These findings shed light on understanding the overall associations and metabolic mechanism of nephrotoxic effects of co-exposure to PAHs and metals.

Computational Fluid Dynamics Numerical Simulation on Flow Behavior of Molten Slag–Metal Mixture over a Spinning Cup

Centrifugal granulation technology using a spinning cup opens a potential way to recycle steel slag that is currently difficult to reuse. The objective of this research was to study the flow characteristics of a molten slag–metal mixture that was produced during smelting reduction in molten steel slag, passing over a spinning cup, so as to explore the feasibility of using centrifugal granulation technology to treat the steel slag. This was achieved by developing and implementing a computational fluid dynamics (CFD) model that incorporated free-surface multiphase flow to predict the thickness of the liquid slag film at the edge of the spinning cup (slag film thickness for short), which was an important parameter for estimating the size of the slag particles resulting from centrifugal granulation of the molten slag–metal mixture. The influences of various relevant parameters, including spinning cup diameter, slag feeding rate, cup spinning speed, etc., on the slag film thickness were analyzed. Additionally, hot experiments on centrifugal granulation of a molten slag–metal mixture were conducted to verify the results of the numerical simulations. The experimental results indicated a progressive reduction in the Sauter mean diameter of the slag particles as the metallic iron content in the slag increased. Specifically, when the iron content rose from 5% to 15% at a cup spinning speed of 2500 RPM, the Sauter mean diameter decreased by 13.77%. The numerical simulation results showed that the slag film thickness had a positive relationship to the slag feeding rate but a negative relationship to the spinning cup diameter and the cup spinning speed. Furthermore, the ratio between the mean slag particle diameter and the slag film thickness decreased nearly linearly with the increase in the metallic iron content in slag, with the average ratio being approximately 4.25, and this relationship was useful for estimating the slag particle size from the slag film thickness. Therefore, the present research results can provide theoretical guidance for the industrial application of spinning cup centrifugal granulation technology to effectively treat and recycle steel slags.

Metal mixtures and oral health among children and adolescents in the National Health and Nutrition Examination Survey (NHANES), 2017–2020

IntroductionDental caries is the most common non-communicable human disease, yet little is known about the role of environmental metals, despite teeth consisting of a hard matrix of trace elements. We conducted a cross-sectional study of associations between environmental metals and objective assessment of dental caries and subjective assessments of oral health among a representative sample of U.S. children and adolescents. MethodsData were from the 2017–March 2020 pre-pandemic data file of the National Health and Nutrition Examination Survey (NHANES). To account for metal mixtures, we used weighted quantile sum (WQS) regression to estimate the joint impact of multiple trace elements assessed in blood and urine with oral disease outcomes. ResultsThe blood metal mixture index was associated with a 32% (95% CI: 1.11, 1.56) increased risk of decayed surfaces while the urine metal mixture index was associated with a 106%, RR (95% CI = 2.06 (1.58, 2.70) increased caries risk. For both blood and urine, Mercury (Hg) had the largest contribution to the mixture index followed by Lead (Pb). The WQS blood metal mixture index was also significantly associated with poorer self-rated oral health, although the magnitude of the association was not as strong as for the objective oral disease measures, RR (95% CI) = 1.04 (1.02, 1.07). DiscussionIncreased exposure to a metal mixture was significantly related to poorer objective and subjective oral health outcomes among U.S. children and adolescents. These are among the first findings showing that metal mixtures are a significant contributor to poor oral health.

Reciprocal Effects of Metal Mixtures on Phytoplankton

Several types of contaminants are anthropogenically introduced into natural aquatic ecosystems and interact with other chemicals and/or with living organisms. Although metal toxicity alone has been relatively well studied, the toxic metal ion effects in the mixture have been thoroughly studied only during the last decades. This review focuses on the published reciprocal effects of different metals on different species of algae, together with describing their toxic effects on studied parameters. Phytoplankton as a bioindicator can help to estimate the reciprocal metal risk factor. Many methodologies have been developed and explored, such as the biotic ligand model (BLM), concentration addition (CA), independent action (IA), sensitivity distribution of EC50 species sensitivity distribution (SSD curves), and others, to study reciprocal metal toxicity and provide promising results, which are briefly mentioned too. From our review, we can commonly conclude the following: Zn acted antagonistically with most heavy metals (Al, Cu, Cd, and Ni). The Cu interaction with Cd, Fe, and Pb was mostly antagonistic. Cd showed synergistic behaviour with Hg, Cu, Zn, and Pb and antagonistic behaviour with Co and Fe in many cases. Methods and techniques need to be developed and optimised to determine reciprocal metal toxicity so that the ecotoxicological predictions made by using phytoplankton can be more accurate and related to real-time toxic metals risks to the aquatic ecosystem. This is the main objective of ecotoxicological tests for risk assessment. Understanding how metals enter algal cells and organelles can help to solve this challenge and was one of the main parts of the review.

An Industry-Relevant Metal Mixture, Iron Status, and Reported Attention-Related Behaviors in Italian Adolescents.

Exposure to environmental metals has been consistently associated with attention and behavioral deficits in children, and these associations may be modified by coexposure to other metals or iron (Fe) status. However, few studies have investigated Fe status as a modifier of a metal mixture, particularly with respect to attention-related behaviors. We used cross-sectional data from the Public Health Impact of Metals Exposure study, which included 707 adolescents (10-14 years of age) from Brescia, Italy. Manganese, chromium, and copper were quantified in hair samples, and lead was quantified in whole blood, using inductively coupled plasma mass spectrometry. Concentrations of Fe status markers (ferritin, hemoglobin, transferrin) were measured using immunoassays or luminescence assays. Attention-related behaviors were assessed using the Conners Rating Scales Self-Report Scale-Long Form, Parent Rating Scales Revised-Short Form, and Teacher Rating Scales Revised-Short Form. We employed Bayesian kernel machine regression to examine associations of the metal mixture with these outcomes and evaluate Fe status as a modifier. Higher concentrations of the metals and ferritin were jointly associated with worse self-reported attention-related behaviors: metals and ferritin set to their 90th percentiles were associated with 3.0% [; 95% credible interval (CrI): , 0.06], 4.1% (; 95% CrI: 0.00, 0.08), and 4.1% (; 95% CrI: 0.00, 0.08) higher -scores for self-reported attention deficit/hyperactivity disorder (ADHD) index, inattention, and hyperactivity, respectively, compared with when metals and ferritin were set to their 50th percentiles. These associations were driven by hair manganese, which exhibited nonlinear associations with all self-reported scales. There was no evidence that Fe status modified the neurotoxicity of the metal mixture. The metal mixture was not materially associated with any parent-reported or teacher-reported scale. The overall metal mixture, driven by manganese, was adversely associated with self-reported attention-related behavior. These findings suggest that exposure to multiple environmental metals impacts adolescent neurodevelopment, which has significant public health implications. https://doi.org/10.1289/EHP12988.

Prenatal exposure to metal mixtures and childhood temporal processing in the PROGRESS Birth Cohort Study: Modification by childhood obesity

Children are frequently exposed to various biological trace metals, some essential for their development, while others can be potent neurotoxicants. Furthermore, the inflammatory and metabolic conditions associated with obesity may interact with and amplify the impact of metal exposure on neurodevelopment. However, few studies have assessed the potential modification effect of body mass index (BMI). As a result, we investigated the role of child BMI phenotype on the relationship between prenatal exposure to metal mixtures and temporal processing. Leveraging the PROGRESS birth cohort in Mexico City, children (N = 563) aged 6–9 years completed a Temporal Response Differentiation (TRD) task where they had to hold a lever down for 10–14 s. Blood and urinary metal (As, Pb, Cd, and Mn) measurements were collected from mothers in the 2nd and 3rd trimesters. Child BMI z-scores were dichotomized to normal (between −2 and +0.99) and high (≥1.00). Covariate-adjusted weighted quantile sum (WQS) regression models were used to estimate and examine the combined effect of metal biomarkers (i.e., blood and urine) on TRD measures. Effect modification by the child's BMI was evaluated using 2-way interaction terms. Children with a high BMI and greater exposure to the metal mixture during prenatal development exhibited significant temporal processing deficits compared to children with a normal BMI. Notably, children with increased exposure to the metal mixture and higher BMI had a decrease in the percent of tasks completed (β = −10.13; 95 % CI: −19.84, −0.42), number of average holds (β = −2.15; 95 % CI: −3.88, −0.41), longer latency (β = 0.78; 95 % CI: 0.13, 1.44), and greater variability in the standard deviation of the total hold time (β = 2.08; 95 % CI: 0.34, 3.82) compared to normal BMI children. These findings implicate that high BMI may amplify the effect of metals on children's temporal processing. Understanding the relationship between metal exposures, temporal processing, and childhood obesity can provide valuable insights for developing targeted environmental interventions.

Memantine versus Ginkgo biloba Extract: A Comparative Study on Cognitive Dysfunction Treatment in a Novel Rat Model.

Extracellular senile plaques and intraneuronal neurofibrillary tangles are two devastating brain proteinopathies that are indicative of Alzheimer's disease, the most prevalent type of dementia. Currently, no effective medications are available to stop or reverse Alzheimer's disease. Ginkgo biloba extract, commonly referred to as EGb 761, is a natural product made from the leaves of the G. biloba tree. It has long been demonstrated to have therapeutic benefits in Alzheimer's disease. The current study assessed the beneficial effects of EGb 761 against Alzheimer's disease in comparison with memantine, a standard treatment for Alzheimer's disease. The scopolamine-heavy metals mixture rat Alzheimer's disease model is a newly created model to study the effects of EGb 761 oral therapy on cognitive performance and other Alzheimer's disease-like changes over a 28-day experimental period. This new Alzheimer's disease model provides better criteria for Alzheimer's disease hallmarks than the conventional scopolamine model. The EGb 761 reversed memory and learning deficits induced by the scopolamine-heavy metals mixture. These outcomes were linked to a more pronounced inhibitory effect on acetylcholinesterase, caspase-3, hippocampal amyloid-beta protein (Aβ1 - 42), phosphorylated tau protein counts, and proinflammatory cytokines (tumor necrosis factor-α and interleukin-1β) compared to the memantine-treated group. Furthermore, EGb 761 treatment considerably reduced lipid peroxidation (malondialdehyde) and improved reduced glutathione levels compared to memantine. Our results suggest EGb 761's potential in treating central nervous system disorders. It's a promising candidate for future Alzheimer's disease therapeutic exploration. This study also highlights the need for future research to focus on the positive benefits of herbal medicines.

Enzymatic and transcriptional level changes induced by the co-presence of lead and procymidone in hook snout carp (Opsariichthys bidens)

Understanding the interactions between different environmental pollutants is necessary in ecotoxicology since environmental contaminants never appear as single components but rather in combination with other substances. Heavy metals and pesticides are commonly detected in the environment, but the characterization of their mixture toxicity has been inadequately explored. This research aimed to elucidate the mixture impacts of the heavy metal lead (Pb) and the pesticide procymidone (PCM) on the hook snout carp (Opsariichthys bidens) using an array of biomarkers. The data showed that Pb and PCM possessed almost equivalent acute toxicity to the animals, with 4-days LC50 values of 120.9 and 85.15 mg L−1, respectively. Combinations of Pb and PCM generated acute synergistic effects on O. bidens. The contents of malondialdehyde (MDA), antioxidative (SOD), apoptotic (caspase-9), and detoxifying enzymes glutathione S-transferase (GST) and cytochrome P450 (CYP450) significantly changed after most of the mixture exposures compared with the baseline level and the corresponding individual exposures. This suggests the induction of oxidative stress, cell damage, and detoxification dysfunction. The expressions of eight genes (mn-sod, cu-sod, p53, cas3, erβ1, esr, ap, and klf2α) associated with oxidative stress, cell apoptosis, immune response, and hormonal functions exhibited pronounced changes when challenged with the mixture compared to the individual treatments. This indicates the occurrence of immune dysregulation and endocrine disorder. These findings provide an overall understanding of fish upon the challenge of sublethal toxicity between Pb and PCM and can be adopted to evaluate the complicated toxic mechanisms in aquatic vertebrates when exposed to heavy metal and pesticide mixtures. Additionally, these results might guide environmental regulation tactics to protect the population of aquatic vertebrates in natural ecosystems.

Associations of heavy metal mixtures with blood pressure among U.S. adults in NHANES 2017-2018 by four statistical models.

Associations of heavy metal mixtures with blood pressure among U.S. adults in NHANES 2017-2018 by four statistical models.

Correlation between Combined Urinary Metal Exposure and Grip Strength under Three Statistical Models: A Cross-sectional Study in Rural Guangxi

ObjectiveThis study aimed to investigate the potential relationship between urinary metals copper (Cu), arsenic (As), strontium (Sr), barium (Ba), iron (Fe), lead (Pb) and manganese (Mn) and grip strength. MethodsWe used linear regression models, quantile g-computation and Bayesian kernel machine regression (BKMR) to assess the relationship between metals and grip strength. ResultsIn the multimetal linear regression, Cu (β = −2.119), As (β = −1.318), Sr (β = −2.480), Ba (β = 0.781), Fe (β = 1.130) and Mn (β = −0.404) were significantly correlated with grip strength (P < 0.05). The results of the quantile g-computation showed that the risk of occurrence of grip strength reduction was −1.007 (95% confidence interval: −1.362, −0.652; P < 0.001) when each quartile of the mixture of the seven metals was increased. Bayesian kernel function regression model analysis showed that mixtures of the seven metals had a negative overall effect on grip strength, with Cu, As and Sr being negatively associated with grip strength levels. In the total population, potential interactions were observed between As and Mn and between Cu and Mn (Pinteractions of 0.003 and 0.018, respectively). ConclusionIn summary, this study suggests that combined exposure to metal mixtures is negatively associated with grip strength. Cu, Sr and As were negatively correlated with grip strength levels, and there were potential interactions between As and Mn and between Cu and Mn.

Associations between prenatal metal exposure and growth rate in children: Based on Hangzhou Birth Cohort Study

BackgroundIt has been reported that prenatal metal exposure is associated with child anthropometry. However, studies focusing on the growth rate of anthropometry among children have not been conducted. This study aimed to examine associations between the exposure of multiple metals during pregnancy and the growth rate of anthropometry among offspring. Methods743 mother-child pairs from the Hangzhou Birth Cohort Study (HBCS) were included. Levels of eleven metals in mother's blood during pregnancy were measured. Offspring had a mean of 5.7 measurements on anthropometric indicators including weight, length/height, head circumference, and body mass index (BMI) within 1.5 years of birth. Generalized estimating equation (GEE) model was used to investigate the associations between maternal metal exposure and growth rate of anthropometric indicators in children. Stratification analysis by sex was also examined. ResultsLevels of selenium (Se, β = 0.213, 95 % CI = 0.017 to 0.409, P = 0.033) were positively associated with length/height gain per month in children. Levels of chromium (Cr, β = 0.025, 95 % CI = 0.018 to 0.033, P < 0.001) were positively associated with the rate of weight gain. Levels of manganese (Mn, β = −0.030, 95 % CI = −0.052 to −0.008, P = 0.009) and cobalt (Co, β = −0.012, 95 % CI = −0.024 to −0.000, P = 0.044) were inversely associated with growth rate of head circumference. Children with higher maternal Mn levels had a lower BMI change rate. Associations between metals and growth rate were stronger in girls than in boys. Besides, significant associations between metal mixtures and growth rate were found. ConclusionPrenatal exposure to Se, Cr, Mn, and Co was associated with growth rate in children, with sex-specific disparities. Our results suggested important effects of maternal exposure to multiple metals on development in offspring.