High Levels Of Metals Research Articles

An enhanced electrokinetic system for remediation of Cu-polluted clay soils by integrating purging solutions and intermittent power

This study investigated the effectiveness and underlying mechanisms of purging solutions enhanced by intermittent power in improving electrokinetic (EK) restoration of clay soils even under high levels of heavy metals (HM). In so doing, the artificially contaminated specimens containing a wide range of copper (Cu) were prepared and then subjected to a series of EK tests with various electrolytes and electric regimes. Macro and micro scale examinations revealed that under the unenhanced EK condition (i.e., continuous current without agents), the formation of non-conducting solid phases and/or the clogged fabric in the samples with the high dosages (> 250 mg/kg) of HM could dramatically impede the metal separation from the soil. Hence, increasing the remediation time would not be very effective in facilitating the decontamination process. It was observed that the EDTA-ameliorated treatment accompanied by pentetic acid and acetic acid can mitigate the metal precipitation/encapsulation effects induced by EK actions, resulting in improved rate of HM removal. In this case; however, a high portion of these enhancers would be required to ensure the stable mobility of ions and to achieve successful recovery. Such a limitation has been shown to be overcome by incorporating pulsed power (PP) at an optimal frequency. In fact, as evidenced by SEM-EDX and XRD analyses, the integration of chemical agents with PP could simultaneously retain the solubilized Cu species in the soil mass and modify the matrix tortuosity (i.e., the establishment of well-linked pores), two features that have been found to play essential roles in providing for favorable activity of HM ions during the EK operation. The corresponding refinements in the binary system would cause an almost 8 folds increase in the removal efficiency and a shorter (up to 30 %) time of treatment compared to conventional EK.

Metal availability shapes early life microbial ecology and community succession.

The gut microbiota plays a critical role in human health and disease. Microbial community assembly and succession early in life are influenced by numerous factors. In turn, assembly of this microbial community is known to influence the host, including immune system development, and has been linked to outcomes later in life. To date, the role of host-mediated nutritional immunity and metal availability in shaping microbial community assembly and succession early in life has not been explored in depth. Using a human infant cohort, we show that the metal-chelating protein calprotectin is highly abundant in infants. Taxa previously shown to be successful early colonizers of the infant gut, such as Enterococcus, Enterobacteriaceae, and Bacteroides, are highly resistant to experimental metal starvation in culture. Lactobacillus, meanwhile, is highly susceptible to metal restriction, pointing to a possible mechanism by which host-mediated metal limitation shapes the fitness of early colonizing taxa in the infant gut. We further demonstrate that formula-fed infants harbor markedly higher levels of metals in their gastrointestinal tract compared to breastfed infants. Formula-fed infants with high levels of metals harbor distinct microbial communities compared to breastfed infants, with higher levels of Enterococcus, Enterobacter, and Klebsiella, taxa which show increased resistance to the toxic effects of high metal concentrations. These data highlight a new paradigm in microbial community assembly and suggest an unappreciated role for nutritional immunity and dietary metals in shaping the earliest colonization events of the microbiota.IMPORTANCEEarly life represents a critical window for microbial colonization of the human gastrointestinal tract. Surprisingly, we still know little about the rules that govern the successful colonization of infants and the factors that shape the success of early life microbial colonizers. In this study, we report that metal availability is an important factor in the assembly and succession of the early life microbiota. We show that the host-derived metal-chelating protein, calprotectin, is highly abundant in infants and successful early life colonizers can overcome metal restriction. We further demonstrate that feeding modality (breastmilk vs formula) markedly impacts metal levels in the gut, potentially influencing microbial community succession. Our work suggests that metals, a previously unexplored aspect of early life ecology, may play a critical role in shaping the early events of microbiota assembly in infants.

Assessment of microplastic and heavy metal pollution in agricultural soils of Ernakulam District, Kerala, India.

Microplastics (MPs) and heavy metal pollution pose significant environmental threat, potentially leading to agroecosystem toxicity and jeopardizing food security. Therefore, this study aims to evaluate the abundance and risk assessment of these pollutants in five different farmlands of Ernakulam district, India. Results showed that MPs content in agricultural fields near commercialized areas such as Kakkanad Nedungapuzha, Nedumbassery, and Kadamakuddy was dominant compared to Nechoor, a rural area. The average microplastic abundance was found to be 45.6 ± 26.4 items kg⁻1 dw. Polypropylene (PP) and polyethylene (PE) were the dominant polymers found in the soil samples, constituting 45% and 25% of the microplastic content, respectively. The pollution load index of MPs indicates that the sampling sites are considered to be polluted as PLI > 1 with hazard level I. The heavy metal pollution status follows the order: Cu (80.3 to 724mg/kg) > Zn (77 to 543.5mg/kg) > Cr (171.65 to 334.65mg/kg) > As (10.25 to 79.5mg/kg) > Pb (2.05 to 30.3mg/kg) > Cd (0.3 to 14.35mg/kg). Calculated pollution load index (PLI) geo-accumulation index (Igeo), ecological risk assessment values indicate that commercialized regions exhibit high levels of trace metals, namely Cu, Zn, As, Cd, and Cr, posing a significant concern for the agricultural ecosystem. Our results indicate heightened microplastics and heavy metals prevalence in farmlands adjacent to commercial zones, necessitating immediate preventive action to mitigate increasing concentrations.

Investigating the Spatial Patterns of Heavy Metals in Topsoil and Asthma in the Western Salt Lake Valley, Utah

Mining activities, particularly in large excavations like the Bingham Canyon Copper Mine in Utah, have been increasingly linked to respiratory conditions due to heavy-metal-enriched waste and dust. Operating continuously since 1906, the Bingham Canyon Copper Mine contributes 4.4% of the Salt Lake Valley PM2.5 pollution. However, the extent of its contributions to larger-sized particulate matter (PM10) dust, soil and water contamination, and human health impacts is largely unknown. Aerosol optical depth data from Sentinel-2 imagery revealed discernible dust clouds downwind of the mine and smelter on non-prevailing-wind days, suggesting potential heavy metal dispersion from this fugitive dust and subsequent deposition to nearby surface soils. Our analysis of topsoils from across the western Salt Lake Valley found mean arsenic, copper, lead, and zinc concentrations to be well above global background concentrations. Also, the minimum values for arsenic and maximum values for lead were well above the US EPA regional screening levels for residential soils. Thus, arsenic is the metal of greatest concern for impacts on human health. Elevated concentrations of all metals were most notable near the mine, smelter, and tailings pond. Our study linked these elevated heavy metal levels to regional asthma outcomes through cluster analysis and distance-related comparison tests. Significant clusters of high asthma rates were observed in regions with elevated topsoil heavy metal concentrations, impacting both low- and high-income neighborhoods. The findings of this preliminary study suggest that the mine, smelter, and recent construction activities, especially on lands reclaimed from former tailings ponds, could be contributing to atmospheric dust containing high levels of heavy metals and exacerbating asthma outcomes for residents. However, the methods used in the study with aggregated health outcome data cannot determine causal links between the heavy metal contents of soil and health outcomes; they can only point to potential links and a need for further investigation. Such further investigation should involve individual-level data and control for potential confounding factors, such as socioeconomic status, access to healthcare, and lifestyle factors, to isolate the effect of metal exposures on asthma outcomes. This study focused on atmospheric deposition as a source of heavy metal enrichment of topsoil. However, future research is also essential to assess levels of heavy metals in subsoil parent materials and local surface and groundwaters to be able to assess the links between the sources or methods of soil contamination and health outcomes.

Occupational exposure assessment of heavy metals among construction workers in Rawalpindi Pakistan

Construction is one of the primary drivers of development and economic activity in Pakistan. Many activities are performed at the construction site including cement mixing, carpentry, and painting. Workers working in these activities are exposed to toxic heavy metals. Due to exposure to these heavy metals, subjects are at high risk of developing diseases mainly respiratory diseases. Human hair and nail samples of construction workers in Rawalpindi, Pakistan were collected to assess the heavy metals. Heavy metals such as Al, As, Cd, Cr, Ni, K, Pb, and Zn were analyzed in the hair and fingernails of the construction workers. To determine the level of selected heavy metals, Inductively Coupled Plasma optical emission spectrometry was used. Results revealed that Al was the highest with a mean concentration of 7.54 μg/g in all three groups. Whereas Cd was below the detection limit. Heavy metal concentration was high in hair (1.77 μg/g) in two groups including cement mixing and carpentry. However, in the carpentry group heavy metal concentration was high in nails (1.19 μg/g). Additionally, the workers of the carpentry group have higher metal concentrations when compared to the other two groups and this group was at high risk of toxic metal exposure. After the correlation analysis, the results revealed that age was significantly correlated to body burden of metals (r = 0.496, p ≤ 0.05). Moreover, some of the heavy metals in hair and nails were significantly correlated with each other. Since all groups, especially carpenters, show high levels of heavy metals, there is a need for regular monitoring of heavy metals at construction sites. Most importantly, the implementation of training programs is needed to raise awareness among construction workers.

Effect of Residual Cuts on Deactivation of Hierarchical Y Zeolite-Based Catalysts during Co-Processing of Vacuum Gas Oil (VGO) with Atmospheric Residue (ATR)

The influence of residual cuts on the deactivation of hierarchical Y zeolite-based catalysts during the co-processing of vacuum gas oil (VGO) with atmospheric residue (ATR) was investigated. The experiments were conducted in a laboratory-scale MAT-type reactor. The conversion of VGO, ATR, and their 70:30 (mass basis) mixture was examined using two composite catalysts: Cat.Y.0.00 and Cat.Y.0.20. The operating conditions closely resembled those of the commercial catalytic cracking process (550 °C and contact times of 10 to 50 s). When ATR was processed individually, the conversion remained below 50 wt%. However, significant improvements in conversion rates were achieved and catalyst deactivation was mitigated when ATR was co-processed with VGO. Notably, the BET surface area and average mesopore volume were adversely impacted by ATR, which also led to the accumulation of high levels of metals and nitrogen on the spent catalyst, detrimentally affecting its acidic and structural properties. Moreover, substantial coke deposition occurred during ATR cracking. The soluble and insoluble coke analysis revealed H/C ratio values of up to 0.36, indicative of polycondensed coke structures with more than ten aromatic rings. The nature of the coke was confirmed through TPO and FTIR analyses. Interestingly, the CatY.0.20 catalyst exhibited less activity loss, retaining superior acid and structural properties. Co-processing Colombian atmospheric residue with ATR loadings of 30 wt% (higher than the typical 20 wt%) in catalysts formulated with hierarchical zeolites presents a promising alternative for commercial applications. This research opens avenues for optimizing catalytic cracking processes.

Leveraging machine learning for sustainable cultivation of Zn-enriched crops in Cd-contaminated karst regions

Karst soils often exhibit elevated zinc (Zn) levels, providing an opportunity to cultivate Zn-enriched crops. (meanwhile) However, these soils also frequently contain high background levels of toxic metals, particularly cadmium (Cd), posing potential health risks. Understanding the bioaccumulation of Cd and Zn and the related drivers in a high geochemical background area can provide important insights for the safe development of Zn-enriched crops. Traditional models often struggle to accurately predict metal levels in crop systems grown on soils with high geochemical background. This study employed machine learning models, including Random Forest (RF), Support Vector Machine (SVM), and Extreme Gradient Boosting (XGBoost), to explore effective strategies for sustainable cultivation of Zn-enriched crops in karst regions, focusing on bioaccumulation factors (BAF). A total of 10,986 topsoil samples and 181 paired rhizosphere soil-crop samples, including early rice, late rice, and maize, were collected from a karst region in Guangxi. The SVM and XGBoost models demonstrated superior performance, achieving R2 values of 0.84 and 0.60 for estimating the BAFs of Zn and Cd, respectively. Key determinants of the BAFs were identified, including soil iron and manganese contents, pH level, and the interaction between Zn and Cd. By integrating these soil properties with machine learning, a framework for the safe cultivation of Zn-enriched crops was developed. This research contributes to the development of strategies for mitigating Zn deficiency in crops grown on Cd-contaminated soils.

Evaluation of the Adriatic Sea pollution using mesozooplankton as an environmental indicator

The Adriatic Sea is an enclosed basin threatened by marine pollution due to its hydrographic features and anthropogenic pressure. Although zooplankton has been worldwide regarded as an immediate warning signal of contamination, limited information is available on the contamination of these organisms at the Adriatic level. Hence, this study provides comprehensive data on the presence and levels of multiple pollutants in zooplankton collected from 46 locations. With regards to legacy contaminants, both PCB and DDT levels have declined since the 1980s. Specifically, most samples were characterized by low DDT contamination (average of 3 ± 2.7 ng g− 1 dry weight) and only few of these accumulated levels of concern for what concerns PCB, pointing out possible hotspots of contamination in the central-eastern Adriatic Sea. As regards metal(loid)s, the Metal Pollution Index identified areas of concern in the north Adriatic Sea (Gulf of Venice) with high levels of Co, Cu, Hg, Cr and Pb; in the Central Adriatic Sea (Tremiti islands) with high levels of Co, Ni, Hg, Cr and Pb; in the Southern Adriatic Sea (Taranto and offshore Corfu), with high levels of most metal(loid)s, especially Cr, Ni and Zn. Certain metal(loid)s (e.g. Cd, Pb and Hg) have declined over time and most of them are lower than well-known contaminated worldwide marine ecosystems. Only Cu appears to be particularly high in the Mediterranean zooplankton. Overall, this work suggests a general improvement of the status of contamination of the Adriatic Sea.

A comprehensive toxicological analysis of panel of unregulated e-cigarettes to human health

Electronic cigarettes, commonly referred to as e-cigarettes have gained popularity over recent years especially among young individuals. In the light of the escalating prevalence of the use of these products and their potential for long-term health effects, in this study as the first of its kind a comprehensive toxicological profiling of the liquid from a panel of unregulated e-cigarettes seized in the UK was undertaken using an in vitro co-culture model of the upper airways. The data showed that e-cigarettes caused a dose dependent increase in cell death and inflammation manifested by enhanced release of IL1ß and IL6. Furthermore, the e-cigarettes induced oxidative stress as demonstrated by a reduction of intracellular glutathione and an increase in generation of reactive oxygen species. Moreover, the assessment of genotoxicity showed significant DNA strand breaks (following exposure to Tigerblood flavoured e-cigarette). Moreover, relevant to the toxicological observations, was the detection of varying and frequently high levels of hazardous metals including cadmium, copper, nickel and lead. This study highlights the importance of active and ongoing collaborations between academia, governmental organisations and policy makers (Trading standards, Public Health) and national health service in tackling vape addiction and better informing the general public regarding the risks associated with e-cigarette usage.

Use of Scalp Hair as a Biomarker to Determine Airborne Heavy Metal Concentrations for the Academic Laboratory Employees

Academic chemical laboratories (ACL) are considered public places the employees come in contact with a variety of pollutants. The aim of the current study was to detect heavy metals levels in the indoor air of ACL in two universities in Baghdad city and assess their levels in the academic employees’ scalp hair as biomarkers. Air samples inside ACL were collected to detect Fe, Cd, Zn, Pb and Cu. Scalp hair samples were collected from 40 adult chemical laboratory employees aged 30-60 years, who worked 5 days/week for 6 hours a day. Personal information relating to employees such as age, duration of exposure, smoking habit and sex, was collected as a questionnaire. The results of this study concluded that academic laboratory employees were exposed to high levels of heavy metals which was proven through the use of scalp hair; old ages, prolonged working periods, smoking habit have significant effects in increasing the levels of heavy metals in scalp hair, while the employees’ gender variation did not have a significant effect.

Geochemical characterization of waste rock dump and its potential to predict acid mine drainage

Acid Mine Drainage (AMD) is an environmental phenomenon that is being experienced by mining companies in Ghana. High levels of heavy metals have been reported in mining areas especially in Obuasi over the years; however, as to whether these heavy metals are being released from the mine wastes (waste rocks) is of concern. Therefore, this paper evaluates the potential of the abandoned Anyankyirem waste rock dump located in Obuasi to cause AMD. Twenty rock samples were collected from various locations of the dump site and their elemental and physicochemical compositions were examined. XRD analysis was conducted to assess the mineralogy of the samples. Acid Base Accounting (ABA) test was used to ascertain the AMD potential of the dump. The ABA test comprises calculating the Acid Neutralization Capacity (ANC) and Maximum Potential Acidity (MPA) of the various samples. The MPA and ANC values were used to compute the rock samples' Net Neutralization Potential (NNP). A column leaching test was carried out. Leachates were collected over a period of 20 weeks. From the column leaching experiment, the rate of weathering of calcium carbonate throughout the 20-week leaching experiment was 3.6 %. Leachates from the column test showed a circumneutral pH (7.1–8.0). The sulphate concentrations from the leachates decreased over the entire period from 96.60 to 3.70 mg/L. Iron recorded the highest concentration of 7783.65 mg kg-1 and the lowest of 0.645 mg kg-1 was recorded in Bi. From ABA test and the column leaching test results, Anyankyirem waste rock dump is not acid generating and therefore can serve as buffer for high pyrite waste rocks. However, significant levels of some heavy metals (As, Fe, Zn, Cr, Mn and Se) were recorded in the leachates even though the leachates’ pH were circumneutral. The results suggest that not only acidic conditions can leach out heavy metals.

Los humedales del sureste de Tamaulipas: Un prioritario sistema lacunario ignorado y amenazado

A perspective of the current situation and the deterioration of the complex lacunary system of the Tampico, Madero and Altamira Conurbed Zone, is provided, as well as the causes and effects this has had on local flora and fauna, with emphasis on aquatic birds and mangrove. Degradation and fragmentation are among the main causes of population expansion and rapid population growth, which led to the division and invasion of local gaps, several of them even being considered as “habitat islands”. This can be particularly damaging to the four mangrove species distributed in the region, due to their marginalization in isolated water bodies. Another cause is the contamination, exploitation and filling of wetlands by companies in the area, which has led to several gaps in high levels of heavy metals. This is particularly harmful for aquatic birds, which depend on these sites to carry out their biological cycle, which is why they can be forced to move to other sites or their health can be affected. All of the above highlights the urgency of declaring more protected natural areas in the area, as well as increasing regulations imposed on companies and recruiting trained people to carry out management plans suitable to the current situation.

Removal Potentials of Heavy Metals by Cassava Peels, Parts of Pawpaw Plant, Coconut Husk, Guinea Corn Chaff, and Pineapple Peels from Bonny Light Crude Oil Polluted Soil

Removal of environmental contamination such as heavy metals in soil, water and environment is of great importance for human welfare. Hence, the objective of this paper is to comparatively evaluate the removal potentials of heavy metals by cassava peels, parts of pawpaw plant, coconut husk, guinea corn chaff, and pineapple peels from bonny light crude oil polluted soil using appropriate standard methods. Results obtained indicated significantly high levels of heavy metals in the untreated crude oil contaminated soil at weeks 1, 8 and 12. There was a significant (P<0.05) decreasing trend in heavy metal levels in the contaminated soil after treatment with the various agro-residues after the 12-week period. The highest reduction of the heavy metals was observed in the test Group treated with a combination of the agro-residues under study; Ni (46.8%), Pb (61%), Cr (46.3%), Cd (34.1%) and As (49.8%) reduction. The results showed that the agro-residues under study can effectively enhance microbial removal of heavy metals in crude oil polluted soil.

Metals Transfer in Mushroom Tricholoma matsutake from Regional High Geochemical Background Areas: Environmental Influences and Human Health Risk.

Wild-grown edible mushrooms are important in world diets and are also efficient metal accumulators. Yunnan, Southwest China, is the main producing region, with typically high levels of geochemical metals. The environmental factors, bioaccumulation, distribution and human health risks of metals were examined in paired soil and Tricholoma matsutake (n = 54). T. matsutake grows on acidified soils (pH = 3.95-6.56), and metals show a strong heterogeneity, with Fe, Mn, Zn and Cu in the ranges of 16-201, 0.046-8.58 g kg-1, and 22.6-215, 3.7-155 mg kg-1. High soil Fe content led to great accumulation in T. matsutake (0.24-18.8 g kg-1). However, though the soil Mn content was higher than that of Zn and Cu, their concentrations in T. matsutake were comparable (21.1-487 vs. 38.7-329 and 24.9-217 mg kg-1). This suggested that T. matsutake prefers to accumulate Zn and Cu compared to Mn, and this is supported by the bioaccumulation factors (BAFs = 0.32-17.1 vs. 0.006-1.69). Fe was mainly stored in stipes, while Mn, Zn and Cu were stored in caps, and the translocation factors (TFs) were 0.58 vs. 1.28-1.94. Therefore, stipe Fe showed the highest health risk index (HRI) at 1.28-26.9, followed by cap Cu (1.01-2.33), while 98-100% of the Mn and Zn were risk-free. The higher concentration and greater risk of Fe was attributed to the significant effect of soil Fe content (R = 0.34) and soil pH (R = -0.57). This study suggested that Fe, as an essential mineral, may exert toxic effects via the consumption of T. matsutake from high geochemical background areas.

Metagenomic insights into the prokaryotic communities of heavy metal-contaminated hypersaline soils

Saline soils and their microbial communities have recently been studied in response to ongoing desertification of agricultural soils caused by anthropogenic impacts and climate change. Here we describe the prokaryotic microbiota of hypersaline soils in the Odiel Saltmarshes Natural Area of Southwest Spain. This region has been strongly affected by mining and industrial activity and feature high levels of certain heavy metals. We sequenced 18 shotgun metagenomes through Illumina NovaSeq from samples obtained from three different areas in 2020 and 2021. Taxogenomic analyses demonstrate that these soils harbored equal proportions of archaea and bacteria, with Methanobacteriota, Pseudomonadota, Bacteroidota, Gemmatimonadota, and Balneolota as most abundant phyla. Functions related to the transport of heavy metal outside the cytoplasm are among the most relevant features of the community (i.e., ZntA and CopA enzymes). They seem to be indispensable to avoid the increase of zinc and copper concentration inside the cell. Besides, the archaeal phylum Methanobacteriota is the main arsenic detoxifier within the microbiota although arsenic related genes are widely distributed in the community. Regarding the osmoregulation strategies, “salt-out” mechanism was identified in part of the bacterial population, whereas “salt-in” mechanism was present in both domains, Bacteria and Archaea. De novo biosynthesis of two of the most universal compatible solutes was detected, with predominance of glycine betaine biosynthesis (betAB genes) over ectoine (ectABC genes). Furthermore, doeABCD gene cluster related to the use of ectoine as carbon and energy source was solely identified in Pseudomonadota and Methanobacteriota.

Leaching behavior of Cu, Zn, Fe and Pb from polymetallic tailings

ABSTRACT Copper tailings are a common byproduct of copper production, containing high levels of heavy metals which are released into the environment. Conventional methods have historically prioritized copper recovery, and often overlooking the leaching of other valuable elements. However, the rising demand for nonferrous metals necessitates understanding their leaching behavior from copper tailings. This study examined the atmospheric leaching of Cu, Fe, Pb, Zn, and CuO from a polymetallic tailing ore. Leaching recoveries of 63.5% for Cu, 97.5% for CuO, 1% for Fe, and 100% for Zn were achieved under the optimum conditions of 0.5 M sulfuric acid concentration, 25% solids percentage, 65°C, stirring speed of 100rpm, particle size of 75 µm within 30 minutes. Results indicated that the dissolution of oxide minerals such as CuO and ZnO was significant; however, copper sulfides need oxidant to be dissolved. In this condition, iron oxides and silicates were partially reacted by sulfuric acid, and Pb-bearing minerals formed lead sulfate. The presence of iron and lead-bearing minerals in the leaching residue was confirmed by XRF, XRD, and SEM analyses, and was in agreement with the information displayed in the Eh-pH diagrams.

Examining temporal trends in heavy metal levels to analyze sediment pollution dynamics in the Saida urban watershed (N-W Algeria).

The study focuses on current pollution in the Saïda basin, a semi-arid region in north-western Algeria. By analyzing sediments, the study provides interesting results on urban pollution and its environmental impact. The research consists of two main phases, each addressing different aspects of pollution. In the first phase, different pollution indicators are used to analyze heavy metals and organic pollutants in urban drainage sediments. The results are compared with sediment quality guidelines, regulatory thresholds, and local and international references. Most of the metallic contaminants exceed the toxicity levels established by the continental crust and sediment quality guidelines, suggesting an anthropogenic origin. In addition, contamination indices show significant accumulation. In this context, the results highlight the importance of accumulation and transport processes in urban sediments. Hydrological parameters significantly influence heavy metal distribution mechanisms. Remarkable variations between copper (Cu) and lead (Pb) suggest a combined or singular source during transport. Conversely, chromium (Cr), nickel (Ni), and iron (Fe) are mainly derived from natural lithological sources. Cadmium (Cd) is associated with anthropogenic sources related to the agricultural use of phosphate fertilizers, whereas zinc (Zn) is mainly derived from physical corrosion processes. In the second phase, a combined descriptive and multivariate statistical analysis examines the mobility and distribution of heavy metals and their relationships with organic matter (OM) over time. Pronounced temporal variations in Cd, Zn, and Cu concentrations are attributed to human activities. Strong correlations exist between OM and cobalt (Co), Cu and Pb, confirming the ability of OM to adsorb these metals under specific geochemical conditions associated with waste disposal. Conversely, Zn, Cd, Cr, and Ni show weak or negative correlations with OM, suggesting diverse sources, including potential agricultural, industrial, and natural origins. The dendrogram confirms the existence of previously identified contaminant groups, suggesting common sources and potential co-occurrence patterns. This analysis highlights the role of the drainage network as a physico-chemical reactor in the mobilization of contaminants. It underlines the importance of sediment interactions in urban pollution processes. Finally, recommendations are proposed to ensure effective pollution control and remediation. PRACTITIONER POINTS: Useful information on pollution and its environmental impact is provided by the analysis of sediments in the urban basin of Saida (NW-Algeria). The results of this study indicate high levels of heavy metals in the sediments, in excess of toxicity limits, and evidence of anthropogenic sources. Temporal variations in metal concentrations indicate the influence of human activities. The study has made it possible to identify the sources, to understand the mobility and distribution, and to control the contamination by heavy metals in the urban sediments. Drainage system serves as a pathway for dispersing contaminants.

Harnessing the chromium reduction potential of Pseudomonas aeruginosa JRHM33: A comprehensive study on bioinformatics, phenotype microarray, and CCD-RSM optimization

Large amounts of wastewater are generated due to overpopulation and industrialization, The bioavailability, toxicity, and permanence of metals make heavy metal contamination a big environmental hazard. In order to maximize chromium (Cr+6) removal efficiency, the current investigation was carried out from industrial wastewater using Pseudomonas aeruginosa JRHM33.35 bacterial strains were discovered based on their physical, and biochemical properties and resistance towards chromium (Cr+6) heavy metal. The most significant bacterial strain JRHM33 found the highest-level of 1000 mg/L of chromium (Cr+6) resistance. The bacterial strain JRHM33, which has 99 % similarity to Pseudomonas aeruginosa, was found using 16 S rRNA sequencing and is employed in subsequent steps. Sequencing and study of conserved domains indicate that JRHM33 contains the laccase gene and belongs to the multicopper oxidase superfamily, which is known for its ability to reduce metal ions. Analysing phenotype microarray (PM) technology sheds light on Pseudomonas aeruginosa JRHM33 metabolic profile of microbial cells. Additionally, a series of process parameter optimizations were tried using the central composite design of response surface methodology (CCD-RSM) in an effort to reduce the amount of chromium (Cr+6) in the effluent as much as possible. At 6.8 pH, 90 min of incubation, inoculum size is 3.8 ml, and agitation is 104 rpm, a maximum 71 % Cr+6 reduction was attained. The model constructed has an R2 score of 0.983 indicates a very statistically significant outcome from the analysis of variance. The experimental outcomes and the predicted results were remarkably similar, according to the validation experiment. Studies have revealed that bacterial strains obtained from effluent containing high levels of metals utilize their inherent capability to change harmful heavy metals into less dangerous or harmless forms.

Microbiodiversity Landscape Present in the Mine-Tailings of the “Sierra de Huautla” Biosphere Reserve, Mexico

Large-scale mining activities generate significant amounts of waste that accumulates in the environment. These wastes, known as mine tailings, contain high levels of heavy metals, posing risks to human health and causing severe damage to ecosystems. In this study, we determined the heavy metal content of mine tailings in the Sierra de Huautla Biosphere Reserve (REBIOSH), Mexico, and investigated their effect on microbial composition. One of the sites historically contaminated with metals was sampled in three different locations, labeled S1, S2, and S3. A fourth site free of heavy metals (S4) was also used as a control. Our results showed high levels of As, Pb, Cd, and Ag, potentially dangerous metals that exceed thresholds set by international regulatory agencies. Metal contamination indices indicated moderate to extreme enrichment for As, Cd, and Pb, posing potential ecological risks. A metagenomic study of mine tailings showed a core specie-specific microbiome covered by Sinimarinibacterium flocculans, Jiangella anatolica, Thiobacillus denitrificans, Fontimonas thermophile, Sphingomonas koreensis. These may be associated with the processing of heavy metals. A comparative study using the ALDEx2 revealed that less represented species like Variovorax paradoxus, Usitatibacter rugosus, Usitatibacter palustris, Sphingosinicella microcystinivorans, Sphingobium yanoikuyae, and Stella humosa may serve as microbial markers in metal-contaminated environments. In addition, we detected rare or low-abundance species belonging to the phylum Armatimonadota, Candidatus Melainobacteriota, Candidatus Saccharimonadota, Chlamydiota, Deinococcota, Elusimicrobiota, Bacillota, Rhodothermota and Verrucomicrobiota, which could play an important role in ecosystems contaminated with heavy metals. Also, we found site-specific taxonomic representatives such as Nitrososphaera gargensis and Nitrospira nitrificans dominating the S3 ecosystem; Ensifer aridi (S2 and S1), N. nitrificans (S2), while Reyranella soli dominate the S1 soil. These organisms could be crucial for nitrogen access in oligotrophic environments and underscore the adaptability of microbial life to extreme conditions. This is the first comprehensive study of the microbial composition in this important ecological site of the Mexican geography and can provide future guidance for the management and biological treatment of mining wastes.

Prenatal Parental Exposure to Metals and Birth Defects: A Prospective Birth Cohort Study.

While maternal exposure to high metal levels during pregnancy is an established risk factor for birth defects, the role of paternal exposure remains largely unknown. We aimed to assess the associations of prenatal paternal and maternal metal exposure and parental coexposure with birth defects in singletons. This study conducted within the Jiangsu Birth Cohort recruited couples in early pregnancy. We measured their urinary concentrations for 25 metals. A total of 1675 parent-offspring trios were included. The prevalence of any birth defects among infants by one year of age was 7.82%. Paternal-specific gravity-corrected urinary concentrations of titanium, vanadium, chromium, manganese, cobalt, nickel, copper, and selenium and maternal vanadium, chromium, nickel, copper, selenium, and antimony were associated with a 21-91% increased risk of birth defects after adjusting for covariates. These effects persisted after mutual adjustment for the spouse's exposure. Notably, when assessing the parental mixture effect by Bayesian kernel machine regression, paternal and maternal chromium exposure ranked the highest in relative importance. Parental coexposure to metal mixture showed a pronounced joint effect on the risk of overall birth defects, as well as for some specific subtypes. Our findings suggested a couple-based prevention strategy for metal exposure to reduce birth defects in offspring.