Mixtures Of Heavy Metals Research Articles

Synergistic/antagonistic toxicity characterization and source-apportionment of heavy metals and organophosphorus pesticides by the biospectroscopy-bioreporter-coupling approach

Many anthropogenic chemicals are manufactured and eventually enter the surrounding environment, threatening food security and human health. Considering the additive or synergistic effects of pollutant mixtures, there is an expanding need for rapid, cost-effective and field-portable screening methods in environmental monitoring. This study used a recently developed biospectroscopy-bioreporter-coupling (BBC) approach to investigate the binary toxicity of Ag(I), Cr(VI) and four organophosphorus pesticides (dichlorvos, parathion, omethoate and monocrotophos). Ag(I) and Cr(VI) altered the toxicity mechanisms of pesticides, explained by the synergistic or antagonistic effect of Ag/Cr-induced cytotoxicity and pesticide-induced genotoxicity. The discriminating Raman spectral peaks associated with organophosphorus pesticides were 1585 and 1682 cm−1, but 750, 1004, 1306 and 1131 cm−1 were found in heavy metal and pesticide mixtures. More spectral alterations were related to pesticides rather than Ag(I) or Cr(VI), hinting at the dominant toxicity mechanisms of pesticides in mixtures. Ag(I) supplement significantly increased the levels of reactive oxygen species induced by organophosphorus pesticides, attributing to the increased permeability of cell membrane and entrance of toxic substances into the cells by the oligodynamic actions. This study lends deeper insights into the interactions between microbes and pollutant mixtures, offering clues to assess the cocktail effects of multiple pollutants comprehensively.

Selenium and zinc alleviate hepatotoxicity induced by heavy metal mixture (cadmium, mercury, lead and arsenic) via attenuation of inflammo-oxidant pathways.

Heavy metals (HM) are believed to be injurious to humans. Man is exposed to them on daily basis unknowingly, with no acceptable protocol to manage its deleterious effects. These metals occur as mixture of chemicals with varying concentrations in our atmosphere. There are growing calls for the use of essential metals in mitigating the injurious effects induced by heavy metals exposure to man; therefore, the aim of this study was to evaluate the protective effects of essential metals (Zinc and Selenium) in a mixture of heavy metal toxicity. In this study, except for negative controls, all other groups were treated with lead (PbCl2 , 20 mg kg-1 ); cadmium (CdCl2 , 1.61 mg kg-1 ); mercury (HgCl2 , 0.40 mg kg-1 ), and arsenic (NaAsO3, 10 mg kg-1 ) that were formed in distilled water. Pb, Cd, As, and Hg were administered as mixtures to 35, 6 weeks old rats weighing between 80 to 100 g for 60 days. Group I served as normal control without treatment, group II positive control received HM mixture, while groups III to V received HMM with Zn, Se, and Zn + Se respectively. Animal and liver weights, HM accumulation in the liver, food intake (FI), water intake (WI), liver function test, malondialdehyde (MDA), and inflammatory/transcription factor/apoptosis markers were checked. Also, antioxidant enzymes, and histological studies were carried out. Metal mixture accumulated in the liver and caused toxicities which were ameliorated by Zn and Se administration. HM caused significant decrease in FI, WI and distorted the level of liver enzymes, lipid peroxidation, inflammatory markers, antioxidants and architecture of the liver. Co administration with Zn or Se or both reversed the distortions. This study lays credence to the evolving research on the public health implications of low dose metal mixtures and the possible ameliorative properties of Zn and Se.

Associations between exposure to cadmium, lead, mercury and mixtures and women’s infertility and long-term amenorrhea

BackgroundCadmium (Cd), lead (Pb), and mercury (Hg) have been shown to exhibit endocrine disrupting properties. Their effects on women’s reproductive health, however, remain elusive. Here, we investigated associations between blood concentrations of Pb, Cd, Hg, and their mixture and infertility and long-term amenorrhea in women aged 20–49 years using the US National Health and Nutrition Examination Survey (NHANES) 2013–2018 cross-sectional survey.MethodsA total of 1,990 women were included for the analysis of infertility and 1,919 women for long-term amenorrhea. The methods of log-transformation and use of quartiles were used to analyze blood heavy metal concentrations. Statistical differences in the covariates between the outcome groups were evaluated using a chi-squared test for categorical variables and a t-test for continuous variables. Multiple logistic regression models were used to examine the associations.ResultsThe blood concentrations of Pb and heavy metal mixtures were significantly higher in ever-infertile women than pregnant women, but the concentrations of Cd and Hg were comparable. After full adjustment, multiple logistic regression analyses revealed a significant and dose-dependent positive association between blood Pb concentrations and women’s historical infertility, a negative association between Cd and women’s long-term amenorrhea, and no associations between Hg and heavy metal mixture and women’s infertility or long-term amenorrhea.ConclusionsOur study suggests that exposure to heavy metals exhibit differential associations with history of infertility and amenorrhea, and Pb may adversely impact women’s reproduction and heighten the risks of infertility and long-term amenorrhea.

Insight into the highly-selective separation of Fe(III) with cinnamon-like blended fiber

The separation and recovery of Fe(III) in heavy metal mixtures is a great challenge due to its strong ion exchange property. In this study, we developed a novel cinnamon-like blended fiber (PAN/PEG) using electrostatic spinning and dissolution post-treatment, which exhibited highly selective separation properties and satisfactory adsorption capacity for Fe(III). Owing to the preferential coordination of Fe(III) with both cyanide and hydroxyl groups, PAN/PEG possessed such excellent adsorption capacity as 1.12 mmol/g. Notably, the infinite selective separation coefficient between Fe(III) and other heavy metal ions (HMIs) achieved even from the octa-mixed metal systems. Furthermore, PAN/PEG demonstrated good anti-interference ability against coexisting inorganic salts. In addition, PAN/PEG was highly effective in removing lower concentration Fe(III) from complex PTA wastewater with super-high selectivity, which enabled the subsequent purification of Co(II) and Mn(II). Overall, PAN/PEG could be prepared and recovered facilely, and had great potential in the exclusive separation of Fe(III).

Tolerance of anaerobic digestion sludge to heavy metals: COD removal, biogas production, and microbial variation

This study used six identical reactors to investigate the effects of heavy metals on anaerobic digestion sludge. The addition of 1–50 mg L−1 of Zn(II), Cd(II), Pb(II), Hg(II), and a mixture of four metals had a slight impact on COD removal. The removal efficiency decreased slightly to 92.9%, 92.0%, 92.7%, 91.8%, and 93.7% compared with 95.8% in control when 50 mg L−1 of heavy metals were added. The biogas production also varied slightly when exposed to 1–50 mg L−1 of heavy metals, with average production rates of 0.271, 0.244, 0.263, 0.269, 0.255, and 0.261 L d−1, respectively. Extracellular polymeric substance increased to protect microorganisms from the toxicity of heavy metals, and dehydrogenase activity increased from 0.42 to 1.20, 0.44, 0.51, 0.71, and 0.59 EU g−1 SS, respectively. The relative abundance of Methanothrix decreased from 91.2% to 88.5%, 87.6%, 85.7%, and 87.0% when Cd(II), Pb(II), Hg(II), and the mixture of heavy metals were added. Among the heavy metals, Zn(II) had the least impact on microbial activity but the most severe inhibition on biogas production, while the mixture of heavy metals showed relatively slight inhibition due to an antagonistic effect. Anaerobic digestion sludge exhibited good tolerance to heavy metals and could be a potential treatment option for heavy metal-containing wastewater. Environmental implicationAnaerobic digestion has a promising application prospect for treating organic wastewater. Heavy metal pollution exists in many industrial wastewaters. However, few studies have comprehensively compared the effects of Zn(II), Cd(II), Pb(II), Hg(II), and the mixture of heavy metals on anaerobic digestion, especially in the treatment of relatively low-strength wastewater. The main objectives of this study were to investigate the effects of heavy metals on COD removal, biogas production, sludge properties, and microbial characteristics of anaerobic digestion sludge. The results have proved that the anaerobic digestion process can be used as a pretreatment unit for treating heavy metal-containing wastewater.

Associations of exposure to heavy metal mixtures with kidney stone among U.S. adults: A cross-sectional study.

Assessing the effects of heavy metals (HMs) on kidney stone is often limited to analyzing individual metal exposures, with studies on the effects of exposure to mixtures of HMs being scarce. To comprehensively evaluate the relationship between exposure to mixed HMs and kidney stones, we analyzed data from the National Health and Nutrition Examination Survey (NHANES) from 2007-2016, which included 7809 adults. We used multiple statistical methods, including multiple logistic regression models, weighted quantile sum (WQS) regression, quantile g-computation (qgcomp) and bayesian kernel machine regression (BKMR), to assess the association between single HM and mixed exposure to HMs and kidney stones. Firstly, in single exposure analysis, urinary cadmium (Cd) and cobalt (Co) demonstrated a positive association with the risk of kidney stones. Secondly, various other approaches consistently revealed that mixed exposure to HMs exhibited a positive association with kidney stone risk, primarily driven by Cd, Co, and barium (Ba) in urine, with these associations being particularly notable among the elderly population. Finally, both BKMR and survey-weighted generalized linear models consistently demonstrated a significant synergistic effect between urinary Co and urinary uranium (Ur) in elevating the risk of kidney stones. Overall, this study provides new epidemiological evidence that mixed exposure to HMs is associated with an increased risk of kidney stones. Further prospectively designed studies are needed to confirm these findings.

Blood multiple heavy metals exposure and lung function in young adults: A prospective Cohort study in China

The content of single heavy metal in blood is associated with lung function decline, but there is little evidence on the joint effect of multiple heavy metals on lung function. To explore whether heavy metal mixture exposure is associated with lung function reduction among young adults. The study based on a cohort of 518 students recruited from a college in Shandong, China. We measured their lung function and blood heavy metal concentrations. The BKMR model was used to analyse the association between blood heavy metals mixture levels and lung function, and to identify the critical single heavy metal which contributes most to joint effects. As the sensitivity analysis, we used quantile g-computation model and GLM to explore the joint effect and independent effects of heavy metals. Our findings revealed a significant reduction of FVC and FEV1 levels after exposure to heavy metals mixture. An IQR increase in Cu was associated with a 0.079 L and 0.083 L decrease in FEV1 and FVC, respectively. And an IQR increase in Fe was associated with 0.036 L higher FEV1 and 0.033 L higher FVC. For adults, reducing blood heavy metals concentration might be an effective intervention to protect lung function.

Heavy metals mixture affects the blood and antioxidant defense system of mice

Heavy metals mixture affects the blood and antioxidant defense system of mice

Hippocampal LIMK1-mediated Structural Synaptic Plasticity in Neurobehavioral Deficits Induced by a Low-dose Heavy Metal Mixture.

Humans are commonly exposed to the representative neurotoxic heavy metals lead (Pb), cadmium (Cd), and mercury (Hg). These three substances can be detected simultaneously in the blood of the general population. We have previously shown that a low-dose mixture of these heavy metals induces rat learning and memory impairment at human exposure levels, but the pathogenic mechanism is still unclear. LIM kinase 1 (LIMK1) plays a critical role in orchestrating synaptic plasticity during brain function and dysfunction. Hence, we investigated the role of LIMK1 activity in low-dose heavy metal mixture-induced neurobehavioral deficits and structural synaptic plasticity disorders. Our results showed that heavy metal mixture exposure altered rat fear responses and spatial learning at general population exposure levels and that these alterations were accompanied by downregulation of LIMK1 phosphorylation and structural synaptic plasticity dysfunction in rat hippocampal tissues and cultured hippocampal neurons. In addition, upregulation of LIMK1 phosphorylation attenuated heavy metal mixture-induced structural synaptic plasticity, dendritic actin dynamics, and cofilin phosphorylation damage. The potent LIMK1 inhibitor BMS-5 yielded similar results induced by heavy metal mixture exposure and aggravated these impairments. Our findings demonstrate that LIMK1 plays a crucial role in neurobehavioral deficits induced by low-dose heavy metal mixture exposure by suppressing structural synaptic plasticity.

The national maize hybrid as a potential mediator in the contamination of the food chain with heavy metals

ABSTRACT The ability of the maize hybrid ZP666 to uptake cadmium (Cd), chromium (Cr), copper (Cu), nickel (Ni), and lead (Pb) from artificially contaminated soil in a pot experiment was investigated. The applied ICP-OES methods are of satisfactory accuracy (Recovery values from 88.9 to 103.0%) and negligible matrix effect (slope ratio from 0.95 to 1.11). The determined contents of the investigated heavy metals in plant parts of maize, the mass of roots, stems and leaves, the height of the aboveground parts as well as the BCF (Biological Concentration Factor), MR (Mobility Ratio), TF (Translocation Factor) and EF (Enrichment Factor) values show the highest influence of Cd. The strongest negative effect on mass (roots 59.7%, stems 56.6%, and leaves 42.5%) and on the height of aboveground parts (13.5%) was observed in the unit treated with Cd. Also, BCF and TF (stem/root) are higher than 1 only for Cd (1.65 and 1.07, respectively) and the highest EF values are for Cd in roots in units treated with Cd and with a mixture of heavy metals (37.30 and 24.04, respectively ZP 666). MR values were less than 1 in all cases. The results obtained are useful for tracing the migration of heavy metals from the roots to the aboveground parts as well as the potential of plant parts for the enrichment of added heavy metals through possible synergistic or antagonistic interactions.

Insight into the effect of a heavy metal mixture on neurological damage in rats through combined serum metabolomic and brain proteomic analyses

The heavy metals lead (Pb), cadmium (Cd), and mercury (Hg) that cause neurocognitive impairment have been extensively studied. These elements typically do not exist alone in the environment; they are often found with other heavy metals and can enter the body through various routes, thereby impacting health. Our previous research showed that low Pb, Cd, and Hg levels cause neurobehavioral impairments in weaning and adult rats. However, little is known about the biomarkers and mechanisms underlying Pb, Cd, and Hg mixture-induced neurological impairments. A combined analysis of metabolomic and proteomic data may reveal heavy metal-induced alterations in metabolic and protein profiles, thereby improving our understanding of the molecular mechanisms underlying heavy metal-induced neurological impairments. Therefore, brain tissue and serum samples were collected from rats exposed to a Pb, Cd, and Hg mixture for proteomic and metabolomic analyses, respectively. The analysis revealed 363 differential proteins in the brain and 206 metabolites in serum uniquely altered in the Pb, Cd, and Hg mixture exposure group, compared to those of the control group. The main metabolic impacted pathways were unsaturated fatty acids biosynthesis, linoleic acid metabolism, phenylalanine metabolism, and tryptophan metabolism. We further identified that the levels of arachidonic acid (C20:4 n-3) and, adrenic acid (C22:4 n-3) were elevated and that kynurenic acid (KA) and quinolinic acid (QA) levels and the KA/QA ratio, were decreased in the group exposed to the Pb, Cd, and Hg mixture. A joint analysis of the proteome and metabolome showed that significantly altered proteins such as LPCAT3, SLC7A11, ASCL4, and KYAT1 may participate in the neurological impairments induced by the heavy metal mixture. Overall, we hypothesize that the dysregulation of ferroptosis and kynurenine pathways is associated with neurological damage due to chronic exposure to a heavy metal mixture.

Selenium and zinc alleviate quaternary metal mixture -induced neurotoxicity in rats by inhibiting oxidative damage and modulating the expressions of NF-kB and Nrf2/Hmox-1 pathway

BackgroundThis study evaluated the potential protective effects of Zn and Se in the cerebellum and cerebral cortex, two fundamentally important brain regions, in albino rats that were exposed to heavy metals mixture (Al, Pb, Hg and Mn). MethodsAnimals were divided into five groups of seven animals per group with following patterns of exposure, controls group 1 were orally treated with deionized water for 60 days; group 2 was exposed to heavy metal mixture (HMM) with following concentrations (20 mg·kg−1 of Pb body weight; 0.40 mg·kg−1 of Hg; 0.56 mg·kg−1 of Mn; and 35 mg·kg−1; of Al), while groups 3,4 and 5 were exposed to HMM and orally co-treated with zinc chloride (ZnCl2; 0.80 mg/kg), sodium selenite (Na2SeO3;1.50 mg/kg) and zinc chloride plus sodium selenite (ZnCl0.2 + Na2SeO3) respectively. ResultsExposure to HMM depressed cellular antioxidant apparatus, induced generation of lipid peroxidation markers (Malondialdehyde and NO), downregulated expression of transcription factors (Nrf2, and NF-kB) and upregulated Caspase 3 levels. HMM potentiated acetylcholinesterase activity and induced moderate histopathological alterations. Nevertheless, Zn, Se and in particular Zn + Se had recovering effects on all mentioned hazardous effects produced by HMM exposure in the cerebral cortex and cerebellum. ConclusionsSelenium and zinc exert neuroprotection via Nrf2/NF-kB signaling pathways against quaternary heavy metal mixture-induced impairments in albino Sprague Dawley rats.

Lead, zinc, nickel and chromium ions removal from polluted waters using zeolite formed from bauxite, obsidian and their combination with red mud: Behaviour and mechanisms

Synthetic zeolites obtained combining natural sources (bauxite and obsidian), pure alumina/silica reagents, and waste material (red mud) were tested for heavy metals (i.e., Pb2+, Zn2+, Ni2+, Cr3+) removal. The adsorption capabilities of the formed sodalite, zeolite A and zeolite X (LTA and FAU topology, respectively), were compared through thermodynamic and kinetic experiments. Although all the newly-formed zeolites were able to remove the pollutant elements within 24 h, Zeolite X and sodalite synthesized combining obsidian (natural material as silica source) and red mud (waste material as alumina source) proved to be a better sorbent phase (qmax 20–25 mg g−1) compared to Zeolite A formed from treated bauxite (qmax 4–18 mg g−1). Their removal efficiency was also evaluated in polluted waters (wastewater treatment plant [WWTP] effluent, heavy metals mixture, native pH). Depending on synthesized zeolite type, the adsorption mechanism was accredited to ion exchange and precipitation mechanisms. The location of metal-ions inside the zeolite channels was defined by X-ray Powder Diffraction (XRPD) Rietveld analysis. Host–guest interactions among the framework oxygen atoms, co-adsorbed water molecules, and metal-ions were highlighted by the refined bond distances. Finally, magnetic characterization allowed the recognize of different magnetic properties as a function of raw materials used for zeolite synthesis.

Prenatal polymetallic exposure and small for gestational age: A case-control study in Taiyuan, China

BackgroundStudies focused on independent effects of metals on small for gestational age, failing to account for potential interdependence among metals. MethodsIn this case-control study, we selected 187 pregnant women and 187 matched controls from the First Hospital of Shanxi Medical University. Determination of 12 elements in the venous blood of pregnant women before delivery by ICP-MS. Logistic regression, weighted quantile sum regression (WQSR) and Bayesian kernel machine regression (BKMR) were used to estimate the overall effect and identify important mixture components that drive the associations with SGA. ResultsAn increased risk of SGA was associated with As (OR= 1.06,95%CI: 1.01,1.12), Cd (OR= 1.24,95%CI: 1.04,1.47) and Pb (OR= 1.05,95%CI: 1.02,1.08), while Zn (OR= 0.58,95%CI: 0.45,0.76) and Mn (OR= 0.97,95%CI: 0.94,0.99) were protective factors for SGA. In the WQSR positive model, the mixture of heavy metals has a positive combined effect on SGA (OR= 1.74,95%CI: 1.15, 2.62), with Sb and Cd having the highest weights. The BKMR models confirmed that the metal mixture was associated with decreased risk of SGA when the concentration of 12 metals was between the 30th percentile and the 65th percentile, and Zn and Cd had the greatest independent effect. Zn and SGA may not be linearly correlated, higher Zn level may reduce the effect of Cd on the risk of SGA. ConclusionsOur study suggested that exposure to multiple metals was associated with risk of SGA, and the observed association with multiple metals was dominated by Zn, Cd. Sb exposure during pregnancy may also increase the risk of SGA.

Metal mixture-induced non-transgenic animal model of Alzheimer’s disease: Pros and cons

Alzheimer’s disease (AD) is a multifaceted and heterogeneous age-related disease and represents the most common cause of dementia among the elderly. Over the past two decades, transgenic models of AD appreciably contribute to the understanding of the molecular mechanisms involved in the onset and progression of AD. However, transgenic models generally identify with the familial form of AD that accounts for just 5% of AD cases. Thus, non-transgenic models are also essential to thoroughly understand AD pathophysiology. Environmental exposure to heavy metals has been linked to the pathogenesis of the non-familial, sporadic form of AD. This review summarizes our previously published research that showed a mixture of heavy metals, i.e. Arsenic (As), cadmium (Cd) and lead (Pb) at environmentally relevant doses induced AD-parameters and AD-like pathology in the young rats. Our previous findings suggest that the amyloid beta-42 (Aβ1-42) levels in the As+Cd+Pbmixture treated Postnatal-90 day rat brain were comparable with the intracerebroventricular Aβ1-42 infusion rat model, which is well- established non-transgenic model of AD. Additionally, As+Cd+Pb-mixtureinduced Aβ and amyloid precursor protein could be attenuated by known AD-directed drugs, memantine, and donepezil. These findings helped us to conclude that As+Cd+Pb-treated animals could be utilized as a non-transgenic model of AD. This review also summarizes the merits of a nontransgenic animal model of AD, generated through environmental doses of As, Cd and Pb-mixture and its demerits.

Ameliorative Effects of Zn and Se Supplementation on Heavy Metal Mixture Burden via Increased Renal Metal Excretion and Restoration of Redoxo-Inflammatory Alterations.

Heavy metals (HM)in the environment have provoked global attention because of its deleterious effects. This study evaluated the protection offered by Zn or Se or both against HMM-induced alterations in the kidney. Male Sprague Dawley rats were distributed into 5 groups of 7 rats each. Group I served as normal control with unrestricted access to food and water. Group II received Cd, Pb, and As (HMM) per oral daily for 60 days while groups III and IV received HMM in addition to Zn and Se respectively for 60 days. Group V received both Zn and Se in addition to HMM for 60 days. Metal accumulation in feces was assayed at days 0, 30, and 60 while accumulation in the kidney and kidney weight were measured at day 60. Kidney function tests, NO, MDA, SOD, catalase, GSH, GPx, NO, IL-6, NF-Κb, TNFα, caspase 3, and histology were assessed. There is a significant increase in urea, creatinine, and bicarbonate ions while potassium ions decreased. There was significant increase in renal function biomarkers, MDA, NO, NF-Κb, TNFα, caspase 3, and IL-6 while SOD, catalase, GSH, and GPx decrease. Administration of HMM distorted the integrity of the rat kidney, and co-treatment with Zn or Se or both offered reasonable protection suggesting that Zn or Se could be used as an antidot against the deleterious effects of these metals.

Novel modified wood ear mushroom sticks biochar aerogel spheres for efficient capture of [formula omitted] and [formula omitted] mix-ions from water

A novel adsorbent was synthesized for the capture of heavy metals mixture in water by encapsulating hydroxyapatite-modified wood ear mushroom sticks biochar in calcium alginate beads (CA-HAPMB). The surface structure and adsorption mechanism of the CA-HAPMB were characterized by Scanning electron microscopy and X-ray energy dispersion spectroscopy (SEM-EDS), Fourier transform infrared spectrometer (FTIR), X-ray diffraction patterns (XRD), and X-ray photoelectron spectroscopy (XPS). Under different conditions, CA-HAPMB for Cd2+ and Pb2+ were investigated for their adsorption properties in water and their competition. The adsorption capacities of Cd2+ and Pb2+ on the aerogel spheres reached 302.2 mg g−1 (2.69 mmol g−1) and 564.5 mg g−1 (2.73 mmol g−1), respectively (based on Langmuir). The aerogel spheres are easier to collect than biochar materials. The results show that CA-HAPMB composite aerogel spheres have a good application prospect in capturing heavy metal ions from water.

Associations of exposure to blood and urinary heavy metal mixtures with psoriasis risk among U.S. adults: A cross-sectional study

Accumulating evidence showed that environmental exposure to toxic metals was harmful to human health. However, information about the effects of exposure to metal mixtures on psoriasis was scarce. To investigate the independent and comprehensive associations between heavy metal co-exposure and psoriasis in adults, data of 6534 adults aged 20–80 years from the National Health and Nutrition Examination Survey (NHANES) were used. Among them, 187 (2.86 %) were diagnosed with psoriasis and the rest were participants without psoriasis. We examined the independent and combined associations of 3 blood metals and 11 urinary metals with psoriasis risk. In the single-metal analyses, urinary barium (Ba), cesium (Cs), antimony (Sb), uranium (Ur), and cadmium (Cd) were positively correlated with psoriasis risk, while urinary molybdenum (Mo) was identified as a protective factor for psoriasis. Moreover, weighted quantile sum (WQS) regression and Bayesian kernel machine regression (BKMR) models consistently revealed the positive effect of urinary metal co-exposure on psoriasis risk. The associations were more evident in the young and middle-aged group than the elderly group. In the urinary mixtures, Ba was the highest weighted metal in the whole population and the young and middle-aged people, whereas Sb was the top weighted metal in the elderly group. Additionally, BKMR analysis revealed the potential interaction between certain components of urinary metal mixtures in psoriasis. The results of quantile-based g computation (qgcomp) model further proved the toxic effect of urinary metal mixtures on psoriasis, and the positive linear relationship between urinary Ba and psoriasis risk was identified by restricted cubic splines (RCS) regression. We concluded that co-exposure to multiple heavy metals was associated with psoriasis risk. Given the limitations of the NHANES study, further prospective designed studies are warranted.

Modeling integrated biomarker response (IBR) index for the mussel Mytilus galloprovincialis (Lamark 1819) exposed to heavy metal mixture using the CCF design

Marine pollutants such as heavy metals (HMs) are considered among the most copious oxidative stress (OS) inducers in marine organisms which leads to reactive oxygen species (ROS) formation. Complementary to our previous bioassays studies, the present research focuses on Catalase (CAT), Glutathione S-transferase (GST) and Malondialdehyde (MDA) as oxidative stress biomarkers and the integrated biomarker response (IBR) indexes (IBR1 and IBR2) as an ecotoxicological assessment tool in Mytilus galloprovincialis using central composite face centered (CCF) design. The oxidative stress biomarkers were measured in adult mussels (45-55 mm) on 3 days-exposed under different sub-lethal concentrations of cadmium (Cd), zinc (Zn), and copper (Cu). Using multiple regressions, ANOVA analysis revealed that experimental data fitted to second-order (quadratic) polynomial equations. The results showed that types, concentrations and metals combinations has a direct effect in CAT and GST activities, MDA level and IBR indexes. Additionally, metal-metal interactions were found synergistic (supra-additive), antagonistic (infra-additive) or zero interaction in the toxicological effect. As necessary, the optimization of the experimental results was done in order to determine the optimal conditions for the oxidative stress responses and IBR indexes. It was demonstrated that the CCF design combined with the multi-biomarker approach and IBR index can be used as an appropriate tool in ecotoxicological modulation and prediction of oxidative stress and antioxidant status by heavy metals in the mussels Mytilus galloprovincialis.

Impacts of microplastics and heavy metals on the earthworm Eisenia fetida and on soil organic carbon, nitrogen, and phosphorus

Microplastics (MPs) are increasingly being studied because they have become ubiquitous in aquatic and terrestrial environments. However, little is known about the negative effects of co-contamination by polypropylene microplastic (PP MPs) and heavy metal mixtures on terrestrial environment and biota. This study assessed the adverse effects of co-exposure to PP MPs and heavy metal mixture (Cu2+, Cr6+, and Zn2+) on soil quality and the earthworm Eisenia fetida. Soil samples were collected in the Dong Cao catchment, near Hanoi, Vietnam, and analyzed for changes in extracellular enzyme activity and carbon, nitrogen, and phosphorus availability in the soil. We determined the survival rate of earthworms Eisenia fetida that had ingested MPs and two doses of heavy metals (the environmental level - 1 × - and its double - 2 ×). Earthworm ingestion rates were not significantly impacted by the exposure conditions, but the mortality rate for the 2 × exposure conditions was 100%. Metal-associated PP MPs stimulated the activities of β-glucosidase, β-N-acetyl glucosaminidase, and phosphatase enzymes in soil. Principle component analysis showed that these enzymes were positively correlated with Cu2+ and Cr6+ concentrations, but negatively correlated with microbial activity. Zn2+ showed no correlation with soil extracellular enzyme activity or soil microbial activity. Our results showed that co-exposure of earthworms to MPs and heavy metals had no impact on soil nitrogen and phosphorus but caused a decrease in total soil carbon content, with a possible associated risk of increased CO2 emissions.