Mixtures Of Heavy Metals Research Articles

Polynomial Regression Analysis for Removal of Heavy Metal Mixtures in Coagulation/Flocculation of Electroplating Wastewater

Wastewater produced from the electroplating industry generally consists of heavy metals mixture and organic materials that need to be treated before it can be discharged to the environment. Thus, the present investigation was focused on the selectivity removal of heavy metal mixtures consists of Copper (Cu), Cadmium (Cd), and Zinc (Zn). Several operating conditions, including the effect of pH and coagulant (FeCl3) dosage, were varied to find the best performance of heavy metal removal. Results show the efficiency of heavy metals removal for both wastewater characteristics were approximately 99%. The experimental data on the treatment of synthetic wastewater was plotted using polynomial regression (PR) via Excel software. The value of adjusted R2 obtained for the final concentration of Cu, Zn, and Cd after treatment were 0.6884, 0.9676, and 0.9283, respectively, which shows data were acceptably fitted for Cu and very well fitted for Zn and Cd. The coagulation/flocculation process performed on actual wastewater shows that the lowest final concentration of Cu, Zn, and Cd after treatment were 0.487, 1.232, and 0 mg/L respectively at pH of 12.

Long-term effect of heavy metals Cr(III), Zn(II), Cd(II), Cu(II), Ni(II), Pb(II) on the anammox process performance

The process of the anaerobic ammonia oxidation (anammox) has been successfully used to remove nitrogen from reject water after dewatering of the digested sewage sludge. However, it is also used on other types of wastewater, including industrial wastewater, which may contain substances that inhibit this process. Examples of such substances include heavy metals which may be found in tanning wastewater, landfill leachate, or coke oven wastewater. The study presented shows the influence of two different mixtures of heavy metals on the anammox process in a long-term test. In SBR1, a mixture of nickel (Ni2+), copper (Cu2+), and zinc (Zn2+) was tested, while in SBR3 a mixture of chromium (Cr3+), cadmium (Cd2+), and lead (Pb2+) was checked, whereas the SBR2 reactor was a control reactor. The study demonstrated that even the highest levels of chromium, cadmium, and lead tested did not inhibit the process. However, in the case of the second metal mixture, strong inhibition of the nitrogen removal efficiency was observed. It was shown that zinc is the metal that was predominantly responsible for the inhibition, and its elimination from the incoming sewage allowed to restore the initial efficiency of the process.

Effects of heavy metal mixture exposure on hematological and biomedical parameters mediated by oxidative stress

Background Heavy metal mixture pollution is currently a serious global environmental health concern. The toxicity of heavy metal mixture is mainly mediated by oxidative stress. However, the effects of heavy metal mixture exposure on hematological and biochemical parameters mediated by oxidative stress are unclear.Methods Our cross-sectional study had a final sample of 585 participants who were divided into exposure and non-exposure groups according to whether their areas of residence were near the ferroalloy factory. The assessment of internal heavy metal exposure markers was based on blood concentrations of chromium, lead, and manganese. Linear regression models were used to explore the relationships between heavy metal mixture exposure, hematological and biochemical parameters, and oxidative stress parameters. Furthermore, mediation analysis was conducted to evaluate the mediation effects of oxidative stress on the relationship between heavy metal mixture exposure and hematological or biochemical parameters.Results Compared with participants who were not exposed to heavy metal mixture, those who were exposed had greater levels of hematological (e.g., white blood cell and red blood cell markers) and biomedical (e.g., liver function markers, glucose, and lipid metabolism markers) parameters (p < 0.05), whereas levels of platelet markers were lower in participants who were exposed to heavy metal mixture (p < 0.05). We observed significant mediation effects of oxidative stress on the association between exposure status (exposure vs. no exposure group) and hematological parameters (e.g., red blood cell markers, platelet markers, and white blood cell markers) as well as biomedical parameters (e.g., liver function markers, glucose and lipid metabolism markers).Conclusion Heavy metal mixture exposure is associated with hematological and biochemical parameters, and oxidative stress potentially mediates this relationship.

Interaction between a mixture of heavy metals (lead, mercury, arsenic, cadmium, manganese, aluminum) and GSTP1, GSTT1, and GSTM1 in relation to autism spectrum disorder

BackgroundExposure to many environmental chemicals, including metals, often does not occur in isolation, hence requires assessment of the associations between exposure to mixtures of chemicals and human health. ObjectivesTo investigate associations of a metal mixture of lead (Pb), mercury (Hg), arsenic (As), cadmium (Cd), manganese (Mn), and aluminum (Al) in children with autism spectrum disorder (ASD), additively or interactively with each of three glutathione S-transferase (GST) genes (GSTP1, GSTT1, and GSTM1). MethodUsing data from 266 case-control pairs of Jamaican children (2–8 years old), we fitted negative and positive generalized weighted quantile sum (gWQS) regression models to assess the aforementioned associations. ResultsBased on additive and interactive negative gWQS models adjusted for maternal age, parental education, child’s parish, and seafood consumption, we found inverse associations of the overall mixture score with ASD [MOR (95 % CI) = 0.70 (0.49, 0.99); P < 0.05) and [MOR (95 % CI) = 0.46 (0.25, 0.84); P = 0.01], respectively. In an unadjusted negative gWQS model, we found a marginally significant interaction between GSTP1 and a mixture of three metals (Pb, Hg, and Mn) (P = 0.07) while the association was no longer significant after adjustment for the same covariates (P = 0.24). ConclusionsDifferences in diet between ASD and control groups may play a role in the inverse associations we found. The possible interactive association between Mn and GSTP1 in ASD based on gWQS is consistent with our previous reports. However, possible interaction of GSTP1 with Pb and Hg in ASD requires further investigation and replication.

Copula-based exposure risk dynamic simulation of dual heavy metal mixed pollution accidents at the watershed scale

Most heavy metal exposure and pollution results from multiple industrial activities, including metal processing in refineries, and microelectronics. These issues pose a great threat to human health, ecological balance, and even societal stability. During 2012–2017, China, in particular, faced the challenge of 23 heavy metals accidents, six of which were extraordinarily serious accidents. Accidental environmental pollution is rarely caused by a single heavy metal, but rather by heavy metal mixtures. To address the need for a joint exposure risk assessment for heavy metal mixed pollution accidents at the watershed scale, a Copula-based exposure risk dynamic simulation model was proposed. A coupled hydrodynamic and accidental heavy metal exposure model is constructed for an hourly simulation of the exposure fate of heavy metals from each risk source once accidental leakage has occurred. The Copula analysis was introduced to calculate the dual heavy metal joint exposure probability in real time. This method was applied to an acute Cr6+-Hg2+ joint exposure risk assessment for 43 electroplating plants in nine sub-watersheds within the Dongjiang River downstream basin. The results indicated seven risk sources (i.e., S1, S4, H18, H23, H27–H28, and H34) that presented relatively high exposure risk to their surrounding sub-watersheds. Spatially, the acute exposure risk level was highest in the tributary basin (sub-watershed XW) than in the mainstream (sub-watershed DW2) and the river network (sub-watershed RW) of the lower reaches of the Dongjiang River. This research highlights an effective probabilistic approach for performing a joint exposure risk analysis of heavy metal mixed pollution accidents at the watershed scale.

Tight sorption of arsenic, cadmium, mercury, and lead by edible activated carbon and acid-processed montmorillonite clay.

Heavy metal exposure in humans and animals commonly occurs through the consumption of metal-contaminated drinking water and food. Although many studies have focused on the remediation of metals by purification of water using sorbents, limited therapeutic sorbent strategies have been developed to minimize human and animal exposures to contaminated water and food. To address this need, a medical grade activated carbon (MAC) and an acid processed montmorillonite clay (APM) were characterized for their ability to bind heavy metals and mixtures. Results of screening and adsorption/desorption isotherms showed that binding plots for arsenic, cadmium, and mercury sorption on surfaces of MAC (and lead on APM) fit the Langmuir model. The highest binding percentage, capacity, and affinity were shown in a simulated stomach model, and the lowest percentage desorption (< 18%) was shown in a simulated intestine model. The safety and protective ability of MAC and APM were confirmed in a living organism (Hydra vulgaris) where 0.1% MAC significantly protected the hydra against As, Cd, Hg, and a mixture of metals by 30-70%. In other studies, APM showed significant reduction (75%) of Pd toxicity, compared with MAC and heat-collapsed APM, suggesting that the interlayer of APM was important for Pb sorption. This is the first report showing that edible sorbents can bind mixtures of heavy metals in a simulated gastrointestinal tract and prevent their toxicity in a living organism. Graphical abstract.

Multiresistensi dan Akumulasi Acinetobacter sp. IrC2 terhadap Logam Berat

The increasing industrial activity in Indonesia, that is not equipped with appropriate waste treatment, has caused an increase of heavy metal contaminants in water bodies. Heavy metals contamination such as copper (Cu), mercury (Hg), cadmium (Cd), and lead (Pb) contamination in water bodies have endangered aquatic life and public health. For this reason, it is urgently important to lower down the concentration of heavy metal pollutants in the water bodies surrounding industrial areas. Compared to chemical remediation, bioremediation of heavy metal by using indigenous bacteria is more effective and economical, since it can be applied in situ directly and be used repeatedly. Acinetobacter sp. IrC2, used in this study, is Indonesian indigenous bacteria isolated from the industrial waste treatment facility in Rungkut, Surabaya. This study aims, firstly, to investigate the heavy metal multiresistance of Acinetobacter sp. IrC2 against mercury, cadmium, and lead. Secondly, this study intends to examine its bioaccumulation capacity for single and heavy metal alloys. The heavy metal multiresistance test was carried out by measuring the minimum heavy metal concentrations that inhibit bacterial growth (Minimum Inhibitory Concentration/MIC). The bioaccumulation capacity was measured using an atomic absorption spectrophotometer (AAS).  It is shown that Acinetobacter sp. IrC2 has high multiresistance to mercury, cadmium, and lead with MIC values of 12 mM, 8 mM, and 18 mM, respectively. Furthermore,  it is also resistant to  heavy metal mixture of 4.5 mM.  The mechanism of bacterial resistance in response to heavy metal toxicity, in general, is by accumulating heavy metals in the cells. The highest amount of accumulated heavy metals identified, from bacteria grown in the medium contains a mixture of heavy metals, were 0.023 mg, 0.084 mg, 0.684 mg, and 1.476 mg per gram of cell dry weight for copper, mercury, cadmium and lead respectively.  In conclusion, Acinetobacter sp. IrC2 is a promising heavy metal bioremediation agent due to its heavy metal multiresistance and accumulator characteristics.  Key words: Acinetobacter sp. IrC2; cadmium; copper; lead; merkuri

Protective Effect of Costus afer Aqueous Leaf Extract (CALE) on Low-Dose Heavy Metal Mixture-Induced Alterations in Serum Lipid Profile and Hematological Parameters of Male Wistar Albino Rats.

The present work investigated the protective effects of Costus afer Ker Gawl. aqueous leaf extract (CALE) on lipid profile and hematological changes induced by exposure to low-dose heavy metal mixture in male albino rats. The experimental animals were divided into six weight matched groups. The normal (group 1) and toxic (group 2) controls received deionized water and metal mixture (20 mg/kg PbCl2, 1.61 mg/kg CdCl2, and 0.40 mg/kg HgCl2), respectively. Test rats in groups 3, 4, and 5 were treated with metal mixture and CALE (750, 1500, and 2250 mg/kg, respectively), and group 6 received metal mixture and ZnCl2. All treatments were administered through oral gavage for 12 weeks. LDHMM caused a marked increase (p < 0.05) in cholesterol, triglyceride, low-density lipoprotein (LDL), and very low-density lipoprotein (VLDL) levels and a decrease in high-density lipoprotein (HDL), percentage body weight gain, and feed and fluid intake. Also, a significant decrease in RBC, Hb, and PCV, a significant increase in WBC, and no significant increase in platelet PLT were observed in the metal mixture-treated group. But in CALE treated groups, their levels were found to attain almost normal values as found in normal control which is also similar to the zinc-treated group. Costus afer may hold a promise in improving lipid profile and hemodynamic picture in cardiovascular diseases.

Chemical mixtures and neurobehavior: a review of epidemiologic findings and future directions.

Background Epidemiological studies have historically focused on single toxicants, or toxic chemicals, and neurodevelopment, even though the interactions of chemicals and nutrients may result in additive, synergistic, antagonistic, or potentiating effects on neurological endpoints. Investigating the impact of environmentally-relevant chemical mixtures, including heavy metals and endocrine disrupting chemicals (EDCs), is more reflective of human exposures and may result in more refined environmental policies to protect the public. Objective In this review, we provide a summary of epidemiological studies that have analyzed chemical mixtures of heavy metals and EDCs and neurobehavior utilizing multi-chemical models, including frequentist and Bayesian methods. Content Studies investigating chemicals and neurobehavior have the opportunity to not only examine the impact of chemical mixtures, but they can also identify chemicals from a mixture that may play a key role in neurotoxicity, investigate interactive effects, estimate non-linear dose response, and identify potential windows of susceptibility. The examination of neurobehavioral domains is particularly challenging given that traits emerge and change over time and subclinical nuances of neurobehavior are often unrecognized. To date, only a handful of epidemiological studies examining neurodevelopment have utilized multi-pollutant models in the investigation of heavy metals and EDCs. However, these studies were successful in identifying contaminants of importance from the exposure mixtures. Summary and Outlook Investigators are encouraged to broaden their focus to include more environmentally relevant mixtures of chemicals using advanced statistical approaches, particularly to aid in identifying potential mechanisms underlying associations.

Predicting the combined toxicity of binary metal mixtures (Cu–Ni and Zn–Ni) to wheat

In order to investigate and model toxicity and interactions between metals in mixtures, inhibition of wheat root elongation in response to additions of single-metals of copper (Cu), zinc (Zn), and nickel (Ni) and of binary mixed-metal combinations of Cu–Ni and Zn–Ni was tested, using water culture experiments under different Mg concentrations and pH values. A biotic ligand model (BLM) of single-metal Cu, Zn, and Ni was established. The results showed that the toxicity of Cu, Zn or Ni in isolation decreased with increasing Mg concentration whereas the effects of pH on Cu, Zn, or Ni toxicity were related not only to free Cu2+, Zn2+, and Ni2+ concentrations, but also to inorganic metal complexes. In binary mixtures, the two metals in the Cu–Ni mixture showed a weakly antagonistic effect, whereas the two metals in the Zn–Ni mixture showed greater antagonism. Using data from single-metal Cu, Zn, and Ni BLMs, combined with the toxicity index and the overall amounts of metal ions bound to the biotic ligands, one simple model was developed. This model consisted of the toxic unit (TUM, no competition included) and two extended BLMs, BLM-TUf (f as a function of TU, including competition between Mg2+ and metal ions) and BLM-fmix (including the competition between Mg2+ and metal ions, as well as between free metal ions). They were then used to predict the joint toxicity of Cu–Ni and Zn–Ni binary mixtures to wheat. Both of the extended BLMs could provide more accurate predictions of toxic effects of Cu–Ni and Zn–Ni than TUM. BLM-fmix performed best for the Zn–Ni binary mixture (r2 = 0.93; root-mean-square error, RMSE = 9.87). On the other hand, for the Cu–Ni mixture, the predictive effect based on BLM-TUf (r2 = 0.93; RMSE = 9.60) was similar to that of BLM-fmix (r2 = 0.93; RMSE = 9.56). The results provide a theoretical basis for the evaluation and remediation of soils contaminated with mixtures of heavy metals.

Multi-omics analysis reveals that co-exposure to phthalates and metals disturbs urea cycle and choline metabolism

This study aimed to evaluate the response of HepaRG cells after co-exposure to phthalates and heavy metals, using a high-dimensional biology paradigm (HDB). Liver is the main metabolism site for the majority of xenobiotics. For this reason, the HepaRG cell line was used as an in vitro model, and cells were exposed to two characteristic mixtures of phthalates and heavy metals containing phthalates (DEHP, DiNP, BBzP) and metals (lead, methylmercury, total mercury) in a concentration-dependent manner. The applied chemical mixtures were selected as the most abundant pollutants in the REPRO_PL and PHIME cohorts, which were studied using the exposome-wide approach in the frame of the EU project HEALS. These studies investigated the environmental causation of neurodevelopmental disorders in neonates and across Europe. The INTEGRA computational platform was used for the calculation of the effective concentrations of the chemicals in the liver through extrapolation from human biomonitoring data and this dose (and a ten-times higher one) was applied to the hepatocyte model. Multi-omics analysis was performed to reveal the genes, proteins, and metabolites affected by the exposure to these chemical mixtures. By extension, we could detect the perturbed metabolic pathways. The generated data were analyzed using advanced bioinformatic tools following the HEALS connectivity paradigm for multi-omics pathway analysis. Co-mapped transcriptomics and proteomics data showed that co-exposure to phthalates and heavy metals leads to perturbations of the urea cycle due to differential expression levels of arginase-1 and -2, argininosuccinate synthase, carbamoyl-phosphate synthase, ornithine carbamoyltransferase, and argininosuccinate lyase. Joint pathway analysis of proteomics and metabolomics data revealed that the detected proteins and metabolites, choline phosphate cytidylyltransferase A, phospholipase D3, group XIIA secretory phospholipase A2, α-phosphatidylcholine, and the a 1,2-diacyl-sn-glycero-3-phosphocholine, are responsible for the homeostasis of the metabolic pathways phosphatidylcholine biosynthesis I, and phospholipases metabolism. The urea, phosphatidylcholine biosynthesis I and phospholipase metabolic pathways are of particular interest since they have been identified also in human samples from the REPRO_PL and PHIME cohorts using untargeted metabolomics analysis and have been associated with impaired psychomotor development in children at the age of two. In conclusion, this study provides the mechanistic evidence that co-exposure to phthalates and metals disturb biochemical processes related to mitochondrial respiration during critical developmental stages, which are clinically linked to neurodevelopmental perturbations.

Experimental study and parameters optimization of microalgae based heavy metals removal process using a hybrid response surface methodology-crow search algorithm

This study investigates the use of microalgae as a biosorbent to eliminate heavy metals ions from wastewater. The Chlorella kessleri microalgae species was employed to biosorb heavy metals from synthetic wastewater specimens. FTIR, and SEM/XRD analyses were utilized to characterize the microalgal biomass (the adsorbent). The experiments were conducted with several process parameters, including initial solution pH, temperature, and microalgae biomass dose. In order to secure the best experimental conditions, the optimum parameters were estimated using an integrated response surface methodology (RSM), desirability function (DF), and crow search algorithm (CSA) modeling approach. A maximum lead(II) removal efficiency of 99.54% was identified by the RSM–DF platform with the following optimal set of parameters: pH of 6.34, temperature of 27.71 °C, and biomass dosage of 1.5 g L−1. The hybrid RSM–CSA approach provided a globally optimal solution that was similar to the results obtained by the RSM–DF approach. The consistency of the model-predicted optimum conditions was confirmed by conducting experiments under those conditions. It was found that the experimental removal efficiency (97.1%) under optimum conditions was very close (less than a 5% error) to the model-predicted value. The lead(II) biosorption process was better demonstrated by the pseudo-second order kinetic model. Finally, simultaneous removal of metals from wastewater samples containing a mixture of multiple heavy metals was investigated. The removal efficiency of each heavy metal was found to be in the following order: Pb(II) > Co(II) > Cu(II) > Cd(II) > Cr(II).

Exploring the carcinogenic and non-carcinogenic risk of chemicals present in vegetable oils

ABSTRACT As humans are always exposed to chemical mixtures, in the present work, we tried to assess the risk of oral exposure to a mixture of pesticide, heavy metals and polycyclic aromatic hydrocarbons (PAHs) residues in 375 vegetable oil samples analysed by Gas Chromatography-Mass Spectrometry (GC-MS) and Inductively Coupled Plasma-Optical Emission Spectrometry (ICP-OES), for humans. Probabilistic risk assessment showed Target Hazard Quotient (THQ) <1 for all pesticide residues, and calculated total Hazard Index (HI) values reflected no major risk. The 50th and 95th Incremental Life Time Cancer Risk (ILCRs) for carcinogenic heavy metals (HMs) (As and Pb) only showed potential risk for As; while for non-carcinogenic HMs, HI values were <1 in both related percentiles reflecting no appreciable risk. In addition, at 50th and 95th percentiles, ILCR values of PAHs indicated no potential risk except for Benzo (a) pyrene (BaP). Estimated Margins of exposure (MOEs) at 95th percentiles, Chrysene (Chr) and BaP showed the most and least MOE values, respectively. In sensitivity analyses, concentration of analytes had the greatest effect on carcinogenic and non-carcinogenic risk assessment.

The genotoxic effects of mixture of aluminum, arsenic, cadmium, cobalt, and chromium on the gill tissue of adult zebrafish (Danio rerio, Hamilton 1822)

The aim of this study is to investigate the genotoxic effects of mixtures of five metals on zebrafish at two different concentrations; at the permissible maximum contamination levels in drinking water and irrigation waters. The drinking water limits are as follows: 300 µg/L for Aluminum (Al+3), 10 µg/L for Arsenic (As+3), 5 µg/L for Cadmium (Cd+2), 10 µg/L for Cobalt (Co+2), and 50 µg/L for Chromium (Cr+2). The irrigation water limits: 5000 µg/L for Al+3, 100 µg/L for As+3, 10 µg/L for Cd+2, 50 µg/L for Co+2, and 100 µg/L for Cr+2. The zebrafish underwent chronic exposure for periods of 5, 10, and 20 days. The gene expressions for mitochondrial superoxide dismutase (SOD2), stress-specific receptor protein NCCRP1, the heat shock proteins: Hsp9, Hsp14, Hsp60, Hsp70, DNA repair (XRCC1 and EXO1), and apoptosis (BOK and BAX) were evaluated. It was found that exposure to the low- and high-concentrations of the heavy metal mixtures caused cell stress, an increased expression of the antioxidant genes, and repair proteins. As the duration of exposure was increased, the cells progressed through the apoptotic pathway. This was more evident in the high-concentration exposure groups. The results demonstrated the necessity for a reevaluation of the maximum values of heavy metal and toxic element concentrations as prescribed by the Local Standing Rules of Water Pollution Control Regulation, as well as a reevaluation of the limitations of heavy metal mixture interactions with respect to ecological balance and environmental health. Highlights The purpose of this study was to investigate the genotoxic effects of a mixture of Aluminum, Arsenic, Cadmium, Cobalt, Chromium on zebrafish, within drinking water, and irrigation water limits determining the concentration. The zebrafish were exposed to two different concentrations of each metal mixture for 5-, 10-, and 20-day periods. Following exposure, gene expressions of the zebrafish’s gill tissues were examined. As a result of the exposure to the metal mixtures, the following occurred: cell stress, increased antioxidant gene activity, and attempts to protect cell viability. However, the cells progressed through the apoptotic pathway after prolonged exposure. The results demonstrated the necessity for a reevaluation of the maximum limits of metal and toxic element concentrations as stated in the Standing Rules of Water Pollution Control Regulation.

Biosorption of Cr (VI) from aqueous solution by extracellular polymeric substances (EPS) produced by Parapedobacter sp. ISTM3 strain isolated from Mawsmai cave, Meghalaya, India

In the current study, EPS producing strain Parapedobacter sp. ISTM3 was isolated from Mawsmai cave, Meghalaya, India. The strain ISTM3 showed enhanced EPS production (4.65 ± 0.10 g L−1) at optimized parameters, i.e., pH 8 and 3% molasses as a carbon source. The extracted EPS was structurally characterized by GC-MS, NMR, and FTIR analysis to investigate its monomer compositions, functional groups, and linkage analysis. GC-MS study confirmed the heteropolymeric nature of EPS, whereas the FTIR study confirmed the presence of an aliphatic group, amine group, uronic acid, and saccharides group in the EPS structure. Biosorption of heavy metals by EPS from an aqueous solution was investigated by using heavy metals mixture (Zn2+, Cu2+, Pb2+, Cr6+, Fe2+, and Cd2+) with 20 mg L−1 concentration of each metal. EPS showed the highest removal efficiency and metal adsorption capability for Cr6+ as compared to other heavy metals studied. Also, metal adsorption capability (19.032 mg g−1) and removal efficiency (95.10%) of Cr6+ by EPS were further increased in acidic conditions (pH 5.0). FTIR and SEM-EDX analysis confirmed the biosorption mechanism of EPS. The Freundlich and Langmuir adsorption isotherms were employed to discover the biosorption parameters for Cr6+ uptake with a concentration range of 10–200 mg L−1 by EPS (1 g L−1). The Langmuir model was found to better fit the Cr6+ adsorption by EPS having a maximum adsorption capacity of 33.783 mg g−1. With this, the present study highlights the EPS production potential of Parapedobacter sp. ISTM3, as well as the potential of extracted EPS for heavy metals removals via adsorption.

Metal mixtures and kidney function: An application of machine learning to NHANES data

BackgroundExposure to heavy metals may increase risk of kidney disease, but most studies have examined individual metals or two-way interactions. There is increasing recognition of the importance of studying exposure to metal mixtures and health outcomes. ObjectivesWe used Bayesian kernel machine regression (BKMR) to examine associations between a mixture of four heavy metals and indicators of kidney function. MethodsWe used NHANES 2015-16 data on 1435 adults aged 40 and over to study cross-sectional associations between blood levels of four heavy metals (Co, Cr, Hg and Pb) and kidney function. Kidney function was assessed by estimated glomerular filtration rate (eGFR) and by albumin to creatinine ratio (ACR), measured continuously and dichotomized into indicators of chronic kidney disease (CKD) and albuminuria, respectively. BKMR tested for non-linearity in the exposure-specific responses to evaluate dose-response relationships between mixtures and outcomes and possible interaction effects among exposures. Interactions among continuous outcomes were identified using the NLinteraction package in R. ResultsA higher metals mixture was significantly associated with all four measures of kidney function in dose-response patterns. Pb had the strongest association with eGFR, albuminuria and ACR, and the second strongest association with CKD. We also observed an interaction between Pb and Co for eGFR and an interaction between Pb and Cd for ACR. ConclusionsExposure to a co-occurring heavy metals mixture was associated with indicators of poor kidney function. Within this mixture, Pb, Co and Cd considered singly and jointly made the greatest contributions to the observed effects. Future prospective study is needed to confirm the association between metal mixtures and kidney function.

Long-term exposure of high concentration heavy metals induced toxicity, fatality, and gut microbial dysbiosis in common carp, Cyprinus carpio

Heavy metals (HMs) in an aquatic environment mainly affects fish, and thus, fish are convenient pollution bio-indicators. In this study, the toxic effects of HM mixture (chromium (Cr), cadmium (Cd), copper (Cu)) in 0 mg/L to 3.2 mg/L concentration range was investigated in Cyprinus carpio (28 days). HM accumulation, histopathology, oxidative stress, and gut microbial changes were evaluated. HMs accumulated in the order of Cr > Cu > Cd, primarily in the kidneys and finally scales. Reactive oxygen species generation increased in all exposure groups up to day 14, with maximum generation at 3.2 mg/L mixture, which later decreased on day 28 in all. Malondialdehydeand and superoxide dismutase levels increased from day 7 to 28 with increased HM concentrations, while total protein showed an inverse trend. Gill histopathology showed major changes such as uplifted and disintegrated primary lamella, and secondary lamella shortening. The kidneys were characterized by glomerular necrosis, Bowman’s capsule expansion, and tubular space dilatation. Proteobacteria and Firmicutes abundance increased up to 59.4% and 99.16% in 0.8 mg/L and 3.2 mg/L treatment groups, respectively. This study provided a better understanding on the physiology and gut microbiota alteration in C. carpio under multiple HM stress.

Induction of genotoxicity and mutagenic potential of heavy metals in Thai occupational workers

Heavy metals are widely used in many industries in Thailand and found in the environment. Occupational exposure to heavy metals is often chronic and caused by environmental contaminations, potentially leading to mutations and cancer. Although the genotoxic effects of occupational exposure to multiple heavy metals have been extensively studied, the findings regarding their genotoxicity are conflicting. In this study, we focused on investigating the genotoxic effects of certain heavy metals mixtures, including lead (Pb), copper (Cu), zinc (Zn), and tin (Sn), to which workers are exposed in the manufacturing industry. The cytokinesis-blocked micronucleus (CBMN) assay in peripheral blood lymphocytes was performed, and DNA damage was assessed by measuring tumour-associated protein levels and 8-hydroxy-2′-deoxyguanosine (8-OHdG) generated by oxidative stress that causes cytotoxicity. The occupational exposure group included 110 workers exposed to heavy metal mixtures and 105 matched control subjects. We found statistically significant differences in the blood Pb, Sn, and Cu levels between the exposed workers and the control subjects (p < 0.001). Analysis of micronuclei (MN) in peripheral blood lymphocytes revealed a significantly increased frequency of MN in exposed workers compared with that in control subjects (p<0.05). Non-smoking exposed workers were selected for 8-OHdG formation and mutant p53 tests, and significant differences in the mean plasma 8-OHdG concentration (p < 0.001) were found between the occupational exposure and the control group, but no differences were found in the levels of mutant p53. Thus, chronic exposure to different heavy metals causes genotoxic effects in humans. Furthermore, the CBMN assay and 8-OHdG formation can be used as surrogate biomarkers to identify and monitor groups with higher carcinogenic risk in the early stages of toxicity. In summary, our results indicate that mixtures of heavy metals (Pb, Sn, and Cu) in manufacturing industries pose an elevated health risk due to DNA damage.

The effect of the combined action of nickel and copper ions on the initial stages of ontogenesis of Alisma plantago-aquatica

Surface water pollution has a complex multicomponent nature, due to a combination of various heavy metals that have a synergistic or antagonistic effect on various physiological parameters. Under model conditions, the combined effect of several heavy metals on aquatic plants was studied in terms of their toxicity, taking into account the nature of the interaction. In laboratory conditions, we studied the effect of nickel and copper ions and their mixtures in different concentrations on seed germination, growth and development of seedlings of the coastal-aquatic plant Alisma plantago-aquatica L. At the end of the experiment, seed germination, inhibition coefficient, morphometric indicators of seedlings and tolerance index were determined. Alisma seeds are highly resistant to nickel and copper chlorides and their mixtures. The toxicity limit for seed germination at 1–500 mg/L was not detected, although the inhibition coefficient in all variants of the experiment increased. A greater toxic effect of copper ions was noted compared to nickel ions. With the joint action of two metals on seed germination, a change in the nature of the effect from an independent action at low concentrations to antagonism at high concentrations was revealed. The growth and development of seedlings was observed at 1–100 mg/L. The main inhibitory effect of heavy metals was on the length of the main root, the first true leaf, and the number of adventitious roots. Necrosis of the root system and hypocotyl, a weakening of the differentiation of the site of transition of the hypocotyl to the cotyledon, a change in the shape of the cotyledon, the colour intensity and turgor of the cotyledon and leaves were noted. The tolerance index showed that resistance at a level above 50% to the action of nickel, copper and their mixture was maintained at 1 mg/L. In the case of the development of hypocotyl and cotyledon, copper was more toxic than nickel; nickel had a greater inhibitory effect on leaves. Under the action of the heavy metal mixture on the growth and development of seedlings, the independent action at low concentrations changed to antagonistic at high concentrations, which is probably due to competition in a number of indicators between nickel and copper.

Genotoxic stress of particulate matter in the electric furnace of an iron casting industry on human lung epithelial cells; an in vitro study

In foundries, various ores are used. Genotoxic assessment of ore-particles was the important aim of this study. In this regard, Ferrochromium, Ferrosilicon, Ferromanganese, and graphite were collected from an iron-casting industry. Also, the analysis has been performed by inductively coupled plasma optical emission spectroscopy (ICP-OES) and Fourier transform-infrared spectroscopy (FT-IR). The effective particle doses for A549-cells and genetic damages were evaluated using MTT and comet assay, respectively. The analysis indicated that, the samples contain Cr, Al, Cu, Fe, Mn, Zn, Ni, Pb, and SiO2. Ferrosilicon was known as the highest toxic ore. Ore particles significantly induced DNA breaks (p < 0.01) in a dose-dependent manner. A mixture of heavy-metals and silica in trace amounts caused genetic impairment. Moreover, the human health risk of the green–melting procedure is still notable in the casting industry.