Multiple Toxic Metals Research Articles

Associations of toxic metals and their mixture with hyperuricemia in Chinese rural older adults.

Previous studies have related single toxic metals (TMs) to hyperuricemia (HUA) among the general population, however, the association of the TM mixture with HUA, especially in older adults, remains poorly understood. We aimed to examine the relationships between individual TMs and their mixture and HUA in Chinese rural older adults. This study consisted of 2075 rural older adults aged 60years or over. Blood concentrations of aluminum (Al), arsenic (As), barium (Ba), cadmium (Cd), cesium (Cs), gallium (Ga), mercury (Hg), lead (Pb), thallium (Tl), and uranium (U) were detected using inductively coupled plasma mass spectrometry. The associations of single TMs with HUA were assessed using logistic regression and restricted cubic spline (RCS) models, and the association of TM mixture with HUA was explored using the elastic net with environmental risk score (ENET-ERS), quantile g-computation (QGC), and Bayesian kernel machine regression (BKMR) models, respectively. Adjusted logistic regression model showed that Cs (OR = 1.65, 95% CI 1.37-1.99) and Pb (OR = 1.46, 95% CI 1.28-1.67) were positively related to HUA, andRCS model exhibited a positive linear association of Cs and Pb with HUA. ENET-ERS and QGC models quantified a positive correlation between the TM mixture and the odds of HUA, with estimated ORs of 1.15 (95% CI 1.11-1.19) and 1.84 (95% CI 1.37-2.47), respectively, and Cs and Pb had the most weight. BKMR model demonstrated a significant linear association between the TM mixture and increased odds of HUA, with the posterior inclusion probabilities (PIPs) of both Cs and Pb being 1.00. Moreover, we observed a positive interaction between Cs and Pb on HUA. The TM mixture is associated with increased odds of HUA in rural older adults, which may mainly be driven by Cs and Pb. Subsequent studies are warranted to confirm these findings and clarify the mechanisms linking multiple TMs with HUA.

Association Between Exposure to Multiple Toxic Metals in Follicular Fluid and the Risk of PCOS Among Infertile Women: The Mediating Effect of Metabolic Markers.

Polycystic ovary syndrome (PCOS) severely affects women's fertility and accompanies serious metabolic disturbances, affecting 5%-20% of women of reproductive age globally. We previously found that exposure to toxic metals in the blood raised the risk of PCOS, but the association between exposure to toxic metals and the risk of PCOS in the follicular fluid, the microenvironment for oocyte growth and development in females, and its effect on metabolism has not been reported. This study aimed to evaluate the associations between the concentrations of cadmium (Cd), mercury (Hg), barium (Ba) and arsenic (As) in FF and the risk of PCOS, and to explore the mediating effect of metabolic markers in FF on the above relationship. We conducteda case-control study, including 557 women with PCOS and 651 controls. Ba, Cd, Hg and As levels in FF were measured by ICP-MS, metabolites levels in FF was measured by LC-MS/MS among 168 participants randomly selected from all the participants. Logistic regression models were used to assess the association of a single metal level with the PCOS risk, and linear regression models were used to assess the relationships of a single metal level with clinical phenotype parameters and metabolites levels. Combined effect of metals mixture levels on the risk of PCOS were assessed via weighted quantile sum (WQS) regression and bayesian kernel machine regression (BKMR). Medication analysis was performed to explore the role of metabolic markers on the relationship of toxic metals levels with the risk of PCOS. The exposure levels of Cd, Hg, Ba and As in FF were all positively and significantly associated with the PCOS risk (with respect to the highest vs. lowest tertile group: OR = 1.57, 95% CI = 1.17 ~ 2.12 for Cd, OR = 1.69, 95% CI = 1.22 ~ 2.34 for Hg, OR = 1.76, 95% CI = 1.32 ~ 2.34 for Ba, OR = 1.42, 95% CI = 1.05 ~ 1.91 for As). In addition, levels of metal mixture also significantly correlated with the risk of PCOS, Cd level contributed most to it. Moreover, we observed significant positive relationships between Cd level and LH (β = 0.048, 95% CI = 0.002 ~ 0.094), T (β = 0.077, 95% CI = 0.029 ~ 0.125) and HOMA-IR value (β = 0.060, 95% CI = 0.012 ~ 0.107), as well as Hg level with LH, FSH/LH ratio and TC. Furthermore, we revealed that estrone sulfate, LysoPE 22:6 and N-Undecanoylglycine were significantly and positively mediating the association between Cd level and the risk of PCOS (with mediated proportion of 0.39, 0.24 and 0.35, respectively), and between Hg level and the risk of PCOS (with mediated proportion of 0.29, 0.20 and 0.46, respectively). These highly expressed metabolites significantly enriched in the fatty acid oxidation, steroid hormone biosynthesis and glycerophospholipids metabolism, which may explain the reason why the levels of Cd and Hg in FF associated with the phenotype of PCOS. Ba and As in FF was not found the above phenomenon. Our results suggested that exposure to multiple toxic metals (Cd, Hg, Ba and As) in FF associated with the increased risk of PCOS, Cd was a major contributor. Levels of Cd and Hg in FF significantly associated with the phenotype of PCOS. The above association may result from that Cd and Hg in FF related with the disturbance of fatty acid oxidation, steroid hormone biosynthesis and the glycerophospholipids metabolism.

Preparation of iron composite filler for PRB technology and its application in the removal of toxic metals(loids) from groundwater

Iron-based materials have garnered significant research interest due to their high surface reactivity, exhibiting potential for remediating metal(loid)s in groundwater. However, agglomeration and blockage limit its long-term and stability performance in application in permeable reactive barrier (PRB) technology. In this study, three innovative and low-cost iron composite fillers were prepared using a mass-producible impregnation method and applied as fillers for PRB. Static sorption and dynamic column experiments were conducted to assess the long-term performance of these composites to remediate multiple toxic metals(loids) contaminated groundwater. The results showed that the iron composite fillers had the excellent adsorption capacities for Co(II), Cu(II), Cr(VI) and As(III) from simulated contaminated groundwater even under the interference of Fe(III) and Mn(II). The pH of the influent favored the adsorption of toxic metals(loids) by the iron composite fillers in the order of 3.00＞5.00＞8.00＞7.00＞9.00＞6.00. The overall adsorption process was more consistent with the quasi-secondary kinetic equation. The corresponding constant values of Cr, Co, Cu, and As on CZ were 0.022, 0.093, 0.756, and 0.342 h−1, respectively. And that of CP-I and CP-II were 0.004, 0.022, 0.001, 0.126, 0.008, 0.041, 0.001, and 0.154 h−1, respectively. The specific surface area of the composite zeolite (Na92Al92Si100O384) and composite pumice was 48.185 m2/g and 0.63 m2/g, respectively. The dynamic column experiment was run steadily for 40 days, during which the average removal rates of toxic metals(loids) were above 95% and approximate 20 times its own volume of contaminated water was purified. FeO(OH) on composite zeolite and Fe3O4 on composite pumice played a dominant role in the removal of toxic metals(loids). The toxic metals(loids) adsorbed in the PRB were mainly in a stable phase of residual fraction and Fe-Mn oxide fraction, making them less likely to cause secondary pollution problems.

Elemental biomapping of human tissues suggests toxic metals such as mercury play a role in the pathogenesis of cancer.

Toxic metals such as mercury, lead, and cadmium have multiple carcinogenic capacities, including the ability to damage DNA and incite inflammation. Environmental toxic metals have long been suspected to play a role in the pathogenesis of cancer, but convincing evidence from epidemiological studies that toxic metals are risk factors for common neoplasms has been difficult to gain. Another approach is to map the location of potentially toxic elements in normal human cells where common cancers originate, as well as in the cancers themselves. In this Perspective, studies are summarized that have used elemental biomapping to detect toxic metals such as mercury in human cells. Two elemental biomapping techniques, autometallography and laser ablation-inductively coupled-mass spectrometry imaging, have shown that multiple toxic metals exist in normal human cells that are particularly prone to developing cancer, and are also seen in neoplastic cells of breast and pancreatic tumors. Biomapping studies of animals exposed to toxic metals show that these animals take up toxic metals in the same cells as humans. The finding of toxic metals such as mercury in human cells prone to cancer could explain the increasing global incidence of many cancers since toxic metals continue to accumulate in the environment. The role of toxic metals in cancer remains to be confirmed experimentally, but to decrease cancer risk a precautionary approach would be to reduce emissions of mercury and other toxic metals into the environment from industrial and mining activities and from the burning of fossil fuels.

Assessment of Toxic Heavy Metal Content in Children Toys

The children toys are the most favorable things for children to play. But these children toys are not safe from toxic chemicals too. There is presence of different toxic heavy metals such as mercury, lead, barium, chromium, zinc etc. The standard value for different heavy metals is set up by the government of Nepal that came into effective from July 15, 2017. The standard was set up for the 12 toxic heavy metals as cadmium, chromium, lead, mercury, zinc, antimony, arsenic, barium, bisphenol A, bromine, selenium and phthalates. The study was focused on the study of the compliance of toxic heavy metals in children toys with the national standard. For the study total 52 toys were collected from different places of Nepal: Bhaktapur, Kathmandu, Lalitpur, Chitwan, Janakpur and Nepalgunj from the local vendors to the supermarkets. The toys were generally made up of plastic, rubber, metal, foam etc. After the collection and sampling of the toys they were tested in the lab of Nepal Handicraft Association of Nepal Bureau of Standard and Metrology (NBSM) by the X-Ray Fluorescence (XRF) technology. Among the 52 toys, no any heavy metals were detected in 15 toys and 37 toys were detected with multiple toxic heavy metals. The heavy metals detected in the toys were lead, cadmium, bromine, chromium, zinc and barium. Even most of the detected result is under the compliance it is very serious issue that the non-compliance result of heavy metals like lead is very much more (4688 ppm) than the standard value (90 ppm) in the toy: tortoise. In the same way, 22 children toys have the labelling and rest do not have the labelling. But the labelled children toys don’t have the labelling about the chemical safety. Though the national standard has been formulated the local or the parents themselves are unaware about the toxic heavy metals present in the toys. As well there has raised a big confusion in the standard of the toxic heavy metals as the new standard has been published omitting the standard of the heavy metals as phthalates, BPA, bromine and zinc. Thus, these points should be considered in order to implement the standard effectively and to save the children from the chemical hazards.

Metals and per- and polyfluoroalkyl substances mixtures and birth outcomes in the New Hampshire Birth Cohort Study: Beyond single-class mixture approaches

We aimed to investigate the joint, class-specific, and individual impacts of (i) PFAS, (ii) toxic metals and metalloids (referred to collectively as “metals”), and (iii) essential elements on birth outcomes in a prospective pregnancy cohort using both established and recent mixture modeling approaches. Participants included 537 mother-child pairs from the New Hampshire Birth Cohort Study. Concentrations of 6 metals and 5 PFAS were measured in maternal toenail clippings and plasma, respectively. Birth weight, birth length, and head circumference at birth were abstracted from medical records. Joint, index-wise, and individual associations of the metals and PFAS concentrations with birth outcomes were evaluated using Bayesian Kernel Machine Regression (BKMR) and Bayesian Multiple Index Models (BMIM). After controlling for potential confounders, the metals-PFAS mixture was associated with a larger head circumference at birth, which was driven by manganese. When using BKMR, the difference in the head circumference z-score when changing manganese from its 25th to 75th percentiles while holding all other mixture components at their medians was 0.22 standard deviations (95% posterior credible interval [CI]: −0.02, 0.46). When using BMIM, the posterior mean of index weight estimates assigned to manganese for head circumference z-score was 0.72 (95% CI: 0, 0.99). Prenatal exposure to the metals-PFAS mixture was not associated with birth weight or birth length by either BKMR or BMIM. Using both traditional and new mixture modeling approaches, prenatal exposure to manganese was associated with a larger head circumference at birth after accounting for exposure to PFAS and multiple toxic and essential metals.

Cadmium, lead, mercury and arsenic in fresh vegetables and vegetable products intended for human consumption in the Republic of Serbia, 2015–2017

ABSTRACT The concentrations of cadmium (Cd), lead (Pb), mercury (Hg) and arsenic (As) were determined in 455 samples of 27 species of vegetables and 28 different processed vegetables collected during the period from January 2015 to December 2017. Vegetables (n = 387) and vegetable products (n = 68) originated from 31 countries, including Serbia. The samples were analysed by inductively coupled plasma – optical emission spectrometry (ICP-OES). The concentrations of Cd, Pb, Hg and As in the vegetables and vegetable products were compared to the maximum levels set by the European Union and the Serbian legislation. The concentration of mercury was less than the limit of detection in each analysed sample. One or multiple measurable toxic metals (Cd, Pb and/or As) were found in 250 samples (54.9%; n = 455). According to the Regulations which were valid until the end of August 2021, the maximum levels of Cd, Pb and As were exceeded in 19 samples (4.2% of the samples of vegetable and vegetable products; n = 455), i.e. in 13 samples of vegetables: Cd in three, Pb in nine and As in one sample and in 6 samples of vegetables products: Cd in three, Pb in one and As in two samples. Regarding the new EU and Serbian legislation which is valid since September 2021 the maximum levels of Cd and Pb for vegetables and vegetable products were exceeded in 118 samples (25.9% of the samples of vegetable and vegetable products; n = 455), i.e. in 95 samples of vegetables: Cd in 67 and Pb in 28 samples and in 23 samples of vegetable products: Cd in 20 and Pb in 3 samples.

Nitric oxide, hormesis and plant biology

The present paper provides the first integrative assessment of the occurrence of nitric oxide (NO) induced hormetic effects in plant biology. Hormetic dose responses were commonly reported for NO donors on numerous plant species of agricultural and other commercial value. The NO donors were also shown to protect plants from a wide range of chemical (i.e., multiple toxic metals) and physical stressors (i.e., heat, drought) in preconditioning (aka priming) experimental protocols showing hormetic dose responses. Practical approaches for the use of NO donors to enhance plant growth using optimized dose response frameworks were also assessed. Considerable mechanistic findings indicate that NO donors have the capacity to enhance a broad range of adaptive responses, including highly integrated antioxidant activities. The integration of the hormesis concept with NO donors is likely to become a valuable practical general strategy to enhance plant productivity across a wide range of valuable plant species facing environmental pollution and climate changes.

Metal Exposures in Residents Living Near an Urban Oil Drilling Site in Los Angeles, California.

Urban environmental justice communities are potentially exposed to multiple toxic metals, through contaminated air, soil, water, and food. However, information on metals and their sources is lacking. This study uses non-negative matrix factorization (NMF) in a community-based participatory research study to identify potential sources and to understand how these metals cluster in a population near an urban oil drilling site. We recruited 203 Latinx, Black, and Asian residents who lived within 1 km of an oil drilling site in south Los Angeles and collected toenail clippings to assess exposure to arsenic (As), cadmium (Cd), mercury (Hg), manganese (Mn), nickel (Ni), lead (Pb), and antimony (Sb). Using NMF, we identified three clusters based on concentrations in the participants' toenails. As, Cd, Pb, and Sb grouped together, indicative of an industrial source. A second grouping was composed of Ni and Mn, which may be related to oil drilling. We also identified a third source factor predominantly driven by Hg and As, which may arise from dietary sources. Utilizing NMF, a dimension reduction method, we identified a source factor high in Ni and Mn in residents living in a neighborhood near an active oil drilling site.

The association between exposure to multiple toxic metals and the risk of endometriosis: Evidence from the results of blood and follicular fluid

BackgroundEndometriosis affects up to 10 % of women of reproductive age and can lead to infertility. Research investigating whether combined exposure to arsenic (As), cadmium (Cd), lead (Pb) and mercury (Hg) is related to an increased risk of endometriosis, especially using different biological samples to validate the association, is very limited. ObjectiveThis investigation aimed to evaluate the associations between the concentrations of As, Cd, Pb and Hg in blood and follicular fluid and the risk of endometriosis. MethodsA total of 609 endometriosis cases and controls seen at the reproductive center of the First Affiliated Hospital of Anhui Medical University in Hefei, China, between April 2020 and December 2021 were included in our study. Blood (217 cases and 234 controls) and follicular fluid (182 cases and 203 controls) samples were collected from these subjects. The concentrations of Cd, Hg, As and Pb in the blood and follicular fluid were determined by inductively coupled plasma–mass spectrometry (ICP–MS). Unconditional logistic regression models were used to assess the associations between Cd, Hg, As or Pb levels and the risk of endometriosis; Bayesian kernel machine regression (BKMR) was used to evaluate the combined effect of metals on the risk of endometriosis. ResultsWe found significant associations between blood concentrations of As (highest vs. lowest tertile: aOR = 5.53, 95 % CI: 2.97, 10.30), Cd (second vs. lowest tertile: aOR = 1.96, 95 % CI: 1.07, 3.58; highest vs. lowest tertile: aOR = 3.21, 95 % CI: 1.79, 5.77), Pb (highest vs. lowest tertile: aOR = 2.73, 95 % CI: 1.56, 4.78) and Hg (high-level group vs. low-level group: aOR = 13.10, 95 % CI: 6.74, 25.44; second vs. lowest tertile: aOR = 15.27, 95 % CI: 4.96, 46.97; highest vs. lowest tertile: aOR = 35.66, 95 % CI: 11.99, 106.08) and increased risk of endometriosis adjusting for confounders. Follicular fluid As (highest vs. lowest tertile: aOR = 2.42, 95 % CI: 1.35, 4.33), Hg (highest vs. lowest tertile: aOR = 1.86, 95 % CI: 1.05, 3.29), Cd (second vs. lowest tertile: aOR = 2.45, 95 % CI: 1.29, 4.65; highest vs. lowest tertile: aOR = 3.12, 95 % CI: 1.67, 5.83), and Pb (second vs. lowest tertile: aOR = 1.97, 95 % CI: 1.11, 3.52) concentrations were positively associated with endometriosis risk. The BKMR analyses showed linear associations between the metal mixtures and the risk of endometriosis. Both in blood and in follicular fluid, As exhibited the highest contribution. ConclusionThe data from this study suggest that toxic metals, individually and as a mixture, play a role in the risk of endometriosis, thus providing a novel idea for endometriosis prevention.

Exposure to multiple toxic metals and polycystic ovary syndrome risk: Endocrine disrupting effect from As, Pb and Ba

BackgroundPolycystic ovarian syndrome (PCOS) affects 5 % ~ 20 % of women of reproductive age and is a serious health problem. Whether exposure to lead (Pb), mercury (Hg), arsenic (As), barium (Ba) or (cadmium) Cd is associated with an increased risk of PCOS, particularly their joint effect as well as their association with the clinical phenotype of PCOS is limited and unclear. ObjectivesWe aimed to explore the associations of the blood Pb, Hg, As, Ba and Cd levels and risk of PCOS in Chinese women of reproductive age. MethodsA case–control study was used and included 369 women with PCOS and 441 controls. The levels of Pb, Hg, As, Ba and Cd were measured in fasting blood samples collected on the 2nd or 3rd day of menstruation or vaginal bleeding after drug withdrawal; basal sex hormone levels, fasting glucose and fasting insulin were measured simultaneously. Unconditional logistic regression models were used to assess the relationship of the blood Pb, Hg, As, Ba or Cd levels with PCOS risk. Bayesian kernel machine regression (BKMR) was used to assess the joint effect of Pb, Hg, As, Ba and Cd on PCOS risk and estimate which metal or metals contributed most to the association. Multiple linear regression models were used to investigate the relationships between the levels of selected metals and parameters of the clinical PCOS phenotype. ResultsThe mean ± SD ages of women in the case and control groups were 28.80 ± 3.39 and 28.97 ± 2.39 years, respectively; their mean ± SD BMIs were 23.86 ± 3.51 kg/m2 and 22.08 ± 3.14 kg/m2, respectively. The blood levels of three metals (Pb, As and Ba) were statistically associated with PCOS risk based on single-metal models. With each natural logarithm transformed (ln) unit increase in blood concentrations of Pb, higher likelihood of PCOS can be found, the adjusted odd ratio (aOR) and 95 % confidence interval (CI) was 1.83 (1.35–2.48), and these for As and Ba were 2.49 (1.86–3.33) and 1.20 (1.04–1.39), respectively. Compared with women at the first tertile group, higher likelihoods of PCOS among women in the second and third tertiles of the Pb group were observed, aORs and 95 % CIs were 1.81 (1.22–2.68) and 2.08 (1.42–3.04), respectively; and higher likelihoods of PCOS among women in the third tertiles of As and Ba group were also observed, the aORs and 95%CIs were 2.83 (1.93–4.15) and 1.89 (1.32–2.72), respectively. BKMR analysis also showed a statistically significant and positive joint effect of five metals on PCOS risk when the blood levels of five metals were all above the 55th percentile compared with their median levels, and As (100 %) and Pb (67.44 %) were the major contributors to the association. The blood As levels were positively associated with the luteinizing hormone (LH) levels and LH/FSH (follicle–stimulating hormone) ratio values, the blood Ba levels were negatively associated with the FSH levels, and the blood Pb levels were positively associated with the fasting insulin levels and homeostasis model assessment of insulin resistance (HOMA–IR) values. ConclusionsOur results suggest a positive association between exposure to multiple toxic metals (Pb, Hg, As, Ba and Cd) and PCOS risk. As and Pb were the major contributors, evaluated either as a single agent or metal mixture; and Pb, As, and Ba were associated with different parameters of the clinical PCOS phenotype. Additional studies are warranted to confirm these associations, particularly regarding the synergistic effect of toxic metals.

Efficient removal of As, Cu and Cd and synthesis of photo-catalyst from Cu-smelting waste acid through sulfide precipitation by biogenic gaseous H2S produced by anaerobic membrane bioreactor

The proper disposal of Cu-smelting waste acid (CSWA) is a major challenge in sulfide ores pyrometallurgy industry due to its high content of H2SO4, extremely high concentration of As and multiple toxic metals. The neutralization precipitation using cheap CaO is the most widely used process in tackling CSWA. However, a large amount of hazardous wastes covering As and other heavy metals which requires further disposal is generated, and the valuable H2SO4 cannot be reused. Herein, anaerobic membrane bioreactor (AnMBR) is used to continuously produce gaseous H2S for sulfide precipitation of the refractory CSWA and simultaneous fabrication of photo-catalyst for the first time. The 200L AnMBR respectively gained the highest total H2S production of 6.41 g/h and the highest gaseous H2S production of 5.05 g/h under the optimal conditions, being 3–9 times higher than previous reports by other types of bioreactors. And the sulfide precipitation triggered by the maximum gaseous H2S of 5.05 g/h harvested almost 100 % removal for Cu, As and Cd from CSWA within a short time from 0.35 to 3.69 days. Moreover, the phase 1 precipitate covering Cu-S compounds displayed an efficient photo-catalytic activity. The sulfide precipitation by AnMBR showed an application potential in tackling the refractory CSWA and fabrication of valuable nanoparticle photo-catalyst.

Fabrication of nitrogen-doped graphene quantum dots hybrid membranes and its sorption for Cu(II), Co(II) and Pb(II) in mixed polymetallic solution

With the rapid development of new–energy batteries, heavy-metals pollution from spent batteries has drawn much attention. Various techniques are recently proposed to delete or eliminate such pollution. Among which, membrane sorption exhibits exceptional advantages for the separation of multi-metal solution. For such a purpose, nitrogen-doped graphene quantum dots (N-GQDs) hybrid membranes were fabricated via sol–gel technique and hydrothermal synthesis, in which the precursor powder of N-GQDs was obtained by the combination of urea (used as a nitrogen source) and citric acid (used as a carbon source). Subsequently, the N-GQDs precursor was mixed with silane and PVA to generate N-GQDs hybrid membranes (NHMs). Competitive sorption of Cu(II), Co(II) and Pb(II) in the mixed polymetallic solution, such as a mixed Cu(II), Co(II) and Pb(II) ternary solution, a mixed Cu(II), Pb(II), Ca(II), Co(II) and Cr(III) quintuple solution, was investigated. It indicated that Cu(II) sorption on NHMs had better selectivity in these mixed polymetallic solutions. Moreover, sorption mechanism of Cu(II), Co(II) and Pb(II) demonstrates that the sorption of NHMs for Cu(II) and Pb(II) abided by Elovich model, indicating the properties of heterogeneous chemisorption. Such a trend shows that the sorption via chemical process between the active sites on the top-layer of NHMs, and Cu(II) and Pb(II) is one of the dominant interfering factors. Desorption testing demonstrated that EDTA-2Na is a best de-sorbent for Cu(II) sorption on NHMs and the number of cycles of these membranes can reach up to 10 times. These findings suggest that NHMs can be used to adsorb Cu(II), Co(II) and Pb(II) from mixed polymetallic solution, indicating promising applications in the successive separation of wastewater containing multiple mixed toxic metals from spent new-energy batteries and other metal-containing wastewater.

Toxic metals in rice-fish co-culture systems and human health

The threat of contamination with toxic metals (TMs) to food security and human health has become a high priority in recent decades. Hence, countless studies have investigated the safe cultivation of rice and fish, respectively, as the main food crop and protein source worldwide. For the present study, a literature search of the PubMed, Web of Science, ScienceDirect, and China National Knowledge Infrastructure databases identified 11 studies that met the inclusion criteria and provided sufficient data to assess the relationship between TM contamination of rice, fish, and shrimp products from rice-fish co-culture systems and carcinogenic risk (CR) and non-carcinogenic risk (non-CR) to humans. The result showed that consumption of Monopterus albus and rice contaminated with a single TM had a slight non-CR, which is synergistically increased by multiple TMs. Consumption of Procambarus clarkii posed no non-CR to humans. The CR of all studies ranged from 1.77 × 10-10 to 5.65 × 10-8, and less than 1 × 10-6, indicating that under current food safety guidelines, rice and fish produced by rice-fish co-culture systems pose no CR. Rice-fish co-culture systems can greatly reduce the CR and non-CR of TMs to humans.

Exposure to multiple toxic metals and the risk of early embryonic arrest among women undergoing assisted reproductive techniques

BackgroundEarly embryonic arrest is a great challenge for in vitro fertilization. Whether exposure to toxic metals is associated with an increased risk of early embryonic arrest warrants investigation. ObjectivesHere, we conducted a case-control study in infertile women to estimate the associations between blood barium (Ba), arsenic (As), mercury (Hg), and lead (Pb) exposure levels and the risk of early embryonic arrest. MethodsBa, As, Hg, and Pb exposure levels in fasting blood collected from 74 infertile women (123 cycles) with early embryonic arrest and 157 infertile women (180 cycles) without early embryonic arrest were measured by ICP–MS. Bayesian kernel machine regression (BKMR) was used to assess the association of exposure level of toxic metals mixture with the risk of early embryonic arrest as well as to evaluate which metal playing a leading role in the association, and then generalized estimating equations (GEEs) were used to evaluate the relationship between the selected harmful metal and the risk of early embryonic arrest. Finally, the potential causes of early embryonic arrest originating from the harmful metal exposure were explored. ResultsBlood Ba levels were significantly higher in the case group than that in the control group (p = 0.009) rather than As, Pb and Hg. Results from BKMR showed that exposure to toxic metals mixture increased the risk of early embryonic arrest, with Ba playing a leading role (PIP = 0.9612). GEE analysis showed that high Ba exposure level was related with the increased risk of early embryonic arrest (p < 0.05) and it impacted on the oogenesis significantly. ConclusionsOur study found that exposure to toxic metals mixture was associated with the increased risk of early embryonic arrest, and Ba contributed most to the increased risk. Higher Ba exposure in whole blood corresponds to a higher risk of early embryonic arrest and impacted on the oogenesis significantly.

Three-dimensional graphene/amino-functionalized metal-organic framework for simultaneous electrochemical detection of Cd(II), Pb(II), Cu(II), and Hg(II).

Trace detection of multiple toxic heavy metals is a very important and difficult problem, conveniently, sensitively, and reliably. In this work, we developed an innovative electrochemical sensor for simultaneously detected heavy metal ions (Cd2+, Hg2+, Cu2+, and Pb2+). In order to detect trace amounts of Cd(II), Pb(II), Cu(II), and Hg(II) in food quickly, accurately, and at low cost, this study used electrochemical reduction to prepare a screen-printed electrode (3DGO) modified with 3DGO and UiO-66-NH2 composite nanomaterials (UiO-66-NH2/SPCE). The sensing platform is composed of three-dimensional graphene (3DGO), aminated UiO-66 metal-organic framework, named 3DGO/UiO-66-NH2. It is worth noting that the porous structure, amino functional groups on the surface, and large specific surface area of UiO-66-NH2 can enrich and promote the absorption of heavy metal ions. 3DGO was introduced to improve the electrochemical activity and conductivity of UiO-66-NH2 material. The construction of this new sensing platform, which can synchronously, reliably, and sensitively simultaneously detect Cd2+, Pb2+, Cu2+, and Hg2+ only in 150s in the linear range of 0.01-0.35pM with the detection limitations, is 10.90 fM, 5.98 fM, 2.89 fM, and 3.1 fM, respectively. This method provides a new strategy that uses MOF materials for electrochemical detection of a variety of heavy metal ions in food.

Bio-separator and bio-synthesizer of metallic nanoparticles - A new vision in bioremediation

The conception of a bio-separator and bio-synthesizer synchronics of nanoparticles (NPs) from dead cells of the yeast Rhodotorula mucilaginosa (R. mucilaginosa), presents itself as a strong candidate for bioremediation. In this research, the dead yeast cells allowed the synthesis and simultaneous separation of silver, copper and nickel NPs, in aqueous medium, under green physical–chemical conditions. Through the yeast cell wall occurred, the formation of two bimetallic systems of NPs: one of Ni/NiO NPs extracellularly - Ag/Ag2O NPs intracellularly, and another of Ni/NiO NPs extracellularly - Cu NPs intracellularly. This sustainable protocol represents an efficient metals uptake method. Such natural bioprocess is a rational platform for the distinct synthesis of NPs (extra and intracellularly), for possible use in nanobioremediation of sites impacted by multiple toxic metals, being easy to handle, effective cost, and concomitant synthesis of NPs.

Potential liver damage due to co-exposure to As, Cd, and Pb in mining areas: Association analysis and research trends from a Chinese perspective

There is global concern regarding the public health hazards of environmental exposure to multiple toxic heavy metals. The effects of toxic heavy metals on liver function have been suggested in previous reports, but the association between exposure to multiple toxic heavy metals and liver function has not been elucidated. The aim of this study was to investigate the effects of exposure to multiple toxic heavy metals, arsenic(As), lead(Pb), and cadmium(Cd), on liver function through population-based and animal studies. A total of 3590 participants were enrolled from the mining areas in Western Hunan Province. The concentrations of As, Pb, and Cd in the urine and plasma samples were determined using quadrupole inductively coupled plasma mass spectrometry (ICP-MS). Bayesian kernel machine regression (BKMR) was employed for the joint association assay. An animal study was conducted to further verify the cumulative effects of metals on liver damage-related parameters such as alanine aminotransferase (ALT), aspartate aminotransferase (AST), and lactate dehydrogenase (LDH) levels. Research trends regarding toxic metals were also explored to obtain in-depth understanding of the current knowledge in this field. Typically, for single-exposure analysis, in most mines, Pb exhibited a significantly negative association with ALT levels, whereas for cumulative effects analysis, when As, Pb, and Cd concentrations were at the 50thpercentile, a significantly negative effect on liver ALT levels was observed. Furthermore, animal studies have shown that co-exposure to As, Pb, and Cd could aggravate liver dysfunction in mice compared to that in the single-metal treated group (p < 0.05). From 1990 to 2019, 1965 projects relating to As, Pb, and Cd research have been initiated, and the total RMB(RenMingBi) funded was approximately 800 million in China, as opposed to 2500 projects in the US with an approximate amount of US$ 1 billion, which is substantially greater than that of China. Finally, from a global viewpoint, scientists should continue to substantially contribute to the field of heavy metal contamination through more extensive academic investigation, global cooperation, and the development of novel control methods. Overall, this study identified that elevated combined concentrations of As, Pb, and Cd were significantly negatively associated with liver function.

Gestational blood levels of toxic metal and essential element mixtures and associations with global DNA methylation in pregnant women and their infants

BackgroundPregnant women and their fetuses are exposed to multiple toxic metals that together with variations in essential element levels may alter epigenetic regulation, such as DNA methylation. ObjectivesThe aim of the study was to investigate the associations between gestational levels of toxic metals and essential elements and mixtures thereof, with global DNA methylation levels in pregnant women and their newborn children. MethodsUsing 631 mother-child pairs from a prospective birth cohort (The Norwegian Mother, Father and Child Cohort Study), we measured maternal blood concentration (gestation week ~18) of five toxic metals and seven essential elements. We investigated associations as individual exposures and two-way interactions, using elastic net regression, and total mixture, using quantile g-computation, with blood levels of 5-methylcytocine (5mC) and 5-hydroxymethylcytosine (5hmC) in mothers during pregnancy and their newborn children (cord blood). Multiple testing was adjusted for using the Benjamini and Hochberg false discovery rate (FDR) approach. ResultsThe most sensitive marker of DNA methylation appeared to be 5mC levels. In pregnant mothers, elastic net regression indicated associations between 5mC and selenium and lead (non-linear), while in newborns results indicated relationships between maternal selenium, cobalt (non-linear) and mercury and 5mC, as well as copper (non-linear) and 5hmC levels. Several possible two-way interactions were identified (e.g. arsenic and mercury, and selenium and maternal smoking in newborns). None of these findings met the FDR threshold for multiple testing. No net effect was observed in the joint (mixture) exposure-approach using quantile g-computation. ConclusionWe identified few associations between gestational levels of several toxic metals and essential elements and global DNA methylation in pregnant mothers and their newborn children. As DNA methylation dysregulation might be a key mechanism in disease development and thus of high importance for public health, our results should be considered as important candidates to investigate in future studies.

Metal-mixtures in toenails of children living near an active industrial facility in Los Angeles County, California.

Children residing in communities near metalworking industries are vulnerable to multiple toxic metal exposures. Understanding biomarkers of exposure to multiple toxic metals is important to characterize cumulative burden and to distinguish potential exposure sources in such environmental justice neighborhoods impacted by industrial operations. Exposure to metal mixtures has not been well-characterized among children residing in the United States, and is understudied in communities of color. In this study we used toenail clippings, a noninvasive biomarker, to assess exposure to arsenic (As), cadmium (Cd), mercury (Hg), manganese (Mn), lead (Pb), antimony (Sb), selenium (Se), and vanadium (V). We used nonnegative matrix factorization (NMF) to identify "source" signatures and patterns of exposure among predominantly working class Latinx children residing near an industrial corridor in Southeast Los Angeles County. Additionally, we investigated the association between participant demographic, spatial, and dietary characteristics with identified metal signatures. Through NMF, we identified three groupings (source factors) for the metal concentrations in children's toenails. A grouping composed of Sb, Pb, As, and Cd, was identified as a potential industrial source factor, reflective of known airborne elemental emissions in the industrial corridor. We further identified a manganese source factor primarily composed of Mn, and a potential dietary source factor driven by Se and Hg. We observed differences in the industrial source factor by age of participants, while the dietary source factor varied by neighborhood. Utilizing an unsupervised dimension reduction technique (NMF), we identified a "source signature" of contamination in toenail samples from children living near metalworking industry. Investigating patterns and sources of exposures in cumulatively burdened communities is necessary to identify appropriate public health interventions.