Metal Pollution Research Articles

Chitosan-NiFe2O4 Nanocomposite Synthesis for Effective Removal of Pb(II) and Zn(II) from Aqueous Solution

The purpose of present work is to synthesize and investigate the use of chitosan-based nanobiocomposites integrated with magnetic nanoparticles (NiFe2O4) for the adsorptive removal of Pb(II) and Zn(II) ions from aquatic media. The research is focused on addressing the urgent global problem of heavy metal pollution, especially in aquatic environments, with effective and sustainable solutions. Chitosan nanoparticles are prepared using an ionic gelation method, which are then used to synthesize a magnetic nanobiocomposite via ultrasonication and chemical co-precipitation with Ni and Fe precursors. The structural, morphological, and elemental properties of the resultant chitosan-NiFe2O4 nanobiocomposite (Fe/Ni@Chitosan NCs.) are characterized using XRD, FTIR, and Electron Microscopy (TEM and FE-SEM). The adsorption tests were conducted in a batch system, with varying contact times, pH levels, adsorbent dosages, and temperatures. The experimental adsorption of Pb(II) and Zn(II) ions showed a good fit with model of Langmuir. The nanocomposite's computed Langmuir maximum adsorption capacity (qmax) values were (91.0581, 90.7080) mg/g for Pb(II) at pH (4.0±0.01) and Zn(II) at pH (6.0±0.01), respectively, at a temperature of 45°C. The thermodynamic assessment involved the determination of change of Gibbs free energy (ΔG), change of enthalpy (ΔH), and entropy ΔS. The observation of a positive ΔH value implies that the interaction between Pb(II) or Zn(II) adsorbed by Fe/Ni@Chitosan NCs is endothermic. On the other hand, a negative ΔG value suggests that the adsorption of these two ions occurs spontaneously.

Heavy metal dynamics in riverine mangrove systems: A case study on content, migration, and enrichment in surface sediments, pore water, and plants in Zhanjiang, China

Mangroves serve a crucial role as metal accumulators in tropical and subtropical marine ecosystems, particularly in riverine mangroves, which frequently interact with terrestrial sources. In this study, we focused on the Gaoqiao and Jiuzhou Rivers within the Zhanjiang mangrove forest in Guangdong, China, and collected leaves and surface sediments from the dominant mangrove plant, Aegiceras corniculatum, near the riverbanks. We focused on seven heavy metals (Cr, Cu, Zn, As, Cd, Pb, and Hg) in mangrove leaves, surface sediments, and pore water due to their environmental significance and frequent occurrence in mangrove ecosystems. We employed multivariate statistical methods and pollution indicators to assess the potential sources and risk levels of heavy metals in these sediments. Our results reveal that the concentrations of the seven heavy metals in the sediments of the Gaoqiao and Jiuzhou Rivers varied significantly, ranging from 0.03 mg/kg to 100.00 mg/kg. Cd posed the highest ecological risk, followed by Hg and As. The comprehensive potential ecological risk in the Gaoqiao River was lower than that in the Jiuzhou River, likely due to the distribution of industrial enterprises (such as printing and cement plants) in the upper reaches of the Jiuzhou River. Additionally, the heavy metal content in the leaves and pore water of A. corniculatum ranged from 0.01 to 51.58 mg/kg and 0.001 to 133.70 μg/L, respectively. There was a significant correlation between the heavy metal concentrations in the leaves and the pore water of A. corniculatum. Notably, the leaves of A. corniculatum exhibited a remarkable Hg-enrichment capability, highlighting its potential as a mercury accumulator. Most heavy metals in A. corniculatum leaves, pore water, and sediment were concentrated in the middle and upper reaches of the river, primarily due to anthropogenic terrestrial inputs from residential production activities upstream. Consequently, heavy metal pollution in riverine mangroves is primarily associated with human activities such as aquaculture, agricultural planting, and industrial production.

Preparation, Characterization of Pearl Powder and its In Vivo Detoxification Potential for Heavy Metals in Mice

Rapid industrialization has heightened concerns over heavy metal pollution, its persistence in the environment, and the potential health risks posed to humans and ecosystems. Traditional Chinese Medicine (TCM) has utilized natural compounds for their medicinal properties, including detoxification, for centuries. This study aims to evaluate the detoxifying efficacy of pearl powder, derived from Hong Kong pearl oyster shells, a product with a long history of use in TCM, in chelating heavy metals like mercury, lead, and aluminium, and assess its protective effects against organ damage. Through a combination of in vitro and in vivo methodologies, In vitro experiments assessed pearl powder's chelation capabilities in controlled conditions, while in vivo studies in animal models investigated its impact on kidney and liver health and its overall safety profile. The results demonstrate that pearl powder, at doses up to 500 mg/kg body weight (b.w), effectively chelates heavy metals, facilitating their removal and offering protective effects against renal and liver damage. Safety assessments, including cytotoxicity and acute toxicity tests, confirmed the non-toxic nature of pearl powder, with a median lethal dose (lethal dose 50%, LD50) of 5000 mg/kg body weight. Pearl powder from Hong Kong pearl oyster shells demonstrates significant potential as a natural detoxifying agent against heavy metal accumulation. These findings validate the traditional use of pearl powder in TCM, showcasing its potential as a natural remedy to mitigate heavy metal accumulation and its associated health risks. Integrating traditional knowledge with modern scientific methods, this research highlights the relevance of natural detoxifying agents in combating heavy metal pollution.

Eu-doped carbon dots-MOF based turn-on fluorescent probe for trace Hg2+ and Pb2+ and construction of the simultaneous detection model

Multiple trace heavy metal pollutants present a serious threat to the aquatic environment, and their coexistence also affected the detection efficiency. This work prepared Eu doped metal organic framework (MOF) complexed with S-containing carbon dots (CD(s)) exhibited dual-emission fluorescence. Its chelation-enhanced fluorescence with heavy metals replaced the original agglomerative fluorescence quenching of pure CD(s), which was utilized to construct a “turn on” fluorescence sensing probe. Based on the XPS, DFT and fluorescence lifetime results, the N, S functional groups on the surface of the materials could bind specifically to Hg2+ and Pb2+ with enhanced sensitivity. The limit of detection reached 76.67 nM for Hg2+ and 5.12 nM for Pb2+ within 2 min detection time. Furthermore, due to the different response mechanism of the two signal peaks to Hg2+ and Pb2+, a three-dimensional data model was developed for simultaneous detection in the co-existence system. The model had been successfully applied to actual Hg2+-Pb2+ containing water samples with recoveries ranged from 93.15 ∼ 105.08 %. The results provided a new strategy for simultaneous detection of trace environmental pollutants.

Mining soil heavy metal inversion based on Levy Flight Cauchy Gaussian perturbation Sparrow Search algorithm Support Vector Regression (LSSA-SVR)

Soil heavy metal pollution in mining areas poses severe challenges to the ecological environment. In recent years, machine learning has been widely used in heavy metal inversion by hyperspectral data. However, deterministic algorithms and probabilistic algorithms may confront local optimal solutions in practical applications. The local optimal solution is not the optimal value obtained within the entire defined interval, and as a result will affect the reliability of these approaches. This paper proposes a Levy Flight Cauchy Gaussian perturbation Sparrow Search algorithm Support Vector Regression (LSSA-SVR) soil heavy metal content prediction model. It introduces Levy Flight (LF) measurement and Cauchy Gaussian perturbation based on the Sparrow search algorithm. The LSSA-SVR model was shown to increase the breadth of solutions searched, avoiding the local optimal solution problem. When applied to mining soil heavy metal experiments, we found that the LSSA-SVR model gave a good fit for the elements Cu, Zn, As, and Pb. The correlation coefficients between the predicted results and the actual results of the four elements were all above 0.94. The heavy metal predicted results of LSSA-SVR have a small error margin in both the overall distribution and in individual differences. This study provides an efficient and accurate monitoring method for mining soil heavy metal inversion. It also provides strong support for environmental management and soil remediation.

Heavy metal (Pb, Cd and Cr) contamination and human health risk assessment of groundwater in Kuakata, southern coastal region of Bangladesh

This study investigates the quality of groundwater in Kuakata, a coastal area in southwestern Bangladesh, by analyzing the levels of lead (Pb), cadmium (Cd), and chromium (Cr) in 50 groundwater samples. The concentrations of these heavy metals were determined using atomic absorption spectrometry. The results indicated that while cadmium was not detected, significant levels of lead and chromium exceeded recommended safety thresholds. The contamination was evaluated using several indices, including the heavy metal evaluation index (HEI), heavy metal pollution index (HPI), and degree of contamination (Cd). Health risk assessments for adults and children revealed potential non-carcinogenic and carcinogenic risks, particularly from lead. This study provides essential data to guide groundwater management and improve public health in the region. The groundwater samples contain traces of additional heavy metals including lead and chromium. The lead concentration ranges from 0.0003 to 0.1049 mg/L, while chromium ranges from 0.00074 to 0.1828 mg/L. The levels of certain substances in groundwater exceeded the maximum limit set by international and local health authorities for safe drinking water. Heavy metal evaluation index (HEI), along with the degree of contamination (Cd) and heavy metal pollution index (HPI), were used to assess the pollution load. The results of HEI and HPI revealed that a significant portion of the samples in the study area, specifically 34% and 38%, were found to be strongly and seriously affected, whereas 38% samples were within the highest values (>4) of Cd. Based on the hazard index (HI) and incremental lifetime cancer risk (ICLR) values, the deep groundwater in the coastal area presents a notable health risk to the local population, particularly children. This study provides essential data that can be used as a foundation for developing effective groundwater management strategies in the coastal region, with the ultimate goal of ensuring the availability of safe drinking water.

Hyperspectral Inversion of Soil Cu Content in Agricultural Land Based on Continuous Wavelet Transform and Stacking Ensemble Learning

Heavy metal pollution in agricultural land poses significant threats to both the ecological environment and human health. Therefore, the rapid and accurate prediction of heavy metal content in agricultural soil is crucial for environmental protection and soil remediation. Acknowledging the limitations of traditional single linear or nonlinear machine learning models in terms of prediction accuracy, this study developed an ensemble learning model that integrates multiple linear or nonlinear learning models with a random forest (RF) model to improve both the prediction accuracy and reliability. In this study, we selected a typical copper (Cu) polluted area in the Pearl River Delta of Guangdong Province as the research site and collected Cu content data and indoor soil reflectance spectral data from 269 surface soil samples. First, the soil spectral data were preprocessed using Savitzky–Golay (SG) smoothing, multiplicative scattering correction (MSC), and continuous wavelet transform (CWT) to reduce noise interference. Next, principal components analysis (PCA) was employed to reduce the dimensionality of the preprocessed spectral data, eliminating redundant features and lowering the computational complexity. Finally, based on the dimensionality-reduced data and Cu content, we established a stacked ensemble learning model, where the base models included SVR, PLSR, BPNN, and XGBoost, with RF serving as the meta-model to estimate the soil heavy metal content. To evaluate the performance of the stacking model, we compared its prediction accuracy with that of individual models. The results indicate that, compared to the traditional machine learning models, the prediction accuracy of the stacking model was superior (R2 = 0.77; RMSE = 7.65 mg/kg; RPD = 2.29). This suggests that the integrated algorithm demonstrates a greater robustness and generalization capability. This study presents a method to improve soil heavy metal content estimation using hyperspectral technology, ensuring a robust model that supports policymakers in making informed decisions about land use, agriculture, and environmental protection.

Preparation of cellulose nanofiber/polyvinyl alcohol-based composite films for metal ion detection by starch/disodium calcium ethylenediaminetetraacetate synergistic complexation effect

Heavy metal pollution causes irreversible damage to plants, animals, and humans. Therefore, it is meaningful to develop facile, fast, and efficient strategies for heavy metal ion (HMI) detection. Here, a portable composite film (CPSE) was designed for HMI detection with high sensitivity and wide detection range. The CPSE was prepared by using cellulose nanofibers (CNF)/polyvinyl alcohol (PVA) as the matrix and utilizing modified starch (HPS) to assist disodium calcium ethylenediaminetetraacetate (EDTA-Ca) to form stable complexes with HMI. The R, G and B values (the three primary colors of light) were captured using an image acquisition system to produce an HMI standard color card successfully. Specifically, the composite film can effectively distinguish Cu2+, Pb2+ and Fe3+. The response time of the composite film to HMI was 2–4 s, and the detection ranges of Cu2+ and Fe3+ were 5–700 ppm and 10–1000 ppm, respectively. Additionally, the synergistic effect of HPS and EDTA-Ca led to the increase in tensile strength (1.59–1.71 times), tear strength (3.29–3.57 times), and glass transition temperature (~ 6 °C) compared to CNF/PVA/HPS and CNF/PVA/EDTA-Ca films. This study confirms the value of CPSE films as materials for HMI detection and suggests innovative ideas for designing similar biomass detection materials in the future.

Soil moisture determines the consistency of organic matter decomposition in field and lab test patterns

Litter decomposition serves as the primary process for soil organic matter formation and renewal. However, few studies have been conducted to validate field large-scale litter decomposition patterns. In this study, cotton strips and Solanum nigrum were used to explore the decomposition differences between standardized litter and conventional litter, along with the release of heavy metal Cadmium (Cd). The indoor characteristics of organic matter decomposition were further verified. After 6 months of Cd pretreatment, litter was placed on the surface of soil collected from 15 sites across the China for 3 months of lab tests. The results indicated that the decomposition rates of both litter types were regulated by soil moisture and generally showed a trend of deceleration from east to west, consistent with the field decomposition pattern. In addition, the mass loss of cotton strip was significantly lower than S. nigrum due to the higher Cd concentration. With the decomposition process, both litter types showed a decreasing trend in Cd concentration, especially the cotton strip. Interestingly, our study found soil factors had the highest relative influence on decomposition. A higher soil microbial moisture use efficiency in the mid-latitude region during litter decomposition may be attributed to the adaptability of microorganisms. Our research demonstrated the consistency of lab test patterns with the field experiments, emphasizing the distinctions between standardized and conventional litter. This study not only revealed the influence mechanism of soil moisture and Cd on litter decomposition rate but also emphasized the important role of microorganisms in the litter decomposition process, which provided a new perspective for a deeper understanding of the ecosystem carbon cycle and heavy metal pollution.

Heavy metal pollution in farmland soils surrounding mining areas in China and the response of soil microbial communities

Mining activities lead to significant heavy metal pollution in nearby farmland soils, affecting the soil's microbial community and functions. To comprehensively investigate the heavy metal contamination in farmland soils caused by mining activities and the impacts on soil microbial communities and functions, we collected 87 soil samples from farmlands near 29 mining sites nationwide, measured levels of cadmium, lead, copper, and zinc. Our findings revealed that 75.8% of the sampled farmlands exhibited varying degrees of heavy metal pollution. Cadmium contamination stood out, being 2.84 to 5.35 times higher compared to other metals. This pollution notably decreased microbial diversity in agricultural soils (P ≤ 0.04), causing a shift from intricate interconnected microbial co-occurrence modules to a higher number of simpler ones, indicating a fragmentation of the microbial interaction network. Additionally, heavy metal contamination led to a 10.9% increase in the importance of the heterogeneous selection process in community assembly. Despite reduced microbial alpha diversity, we observed an increase in the diversity and abundance of metal resistance genes (MRGs) and intensified microbe-MRG interaction. This suggests that microbial communities, even when altered, maintain functionality through enhanced redundancy, which probably facilitates the preservation of microbial activities. We also identified key taxa with intense connectivity in the microbial interaction networks, 58% of which have been recognized in previous studies for their predictive effects on soil health. These findings offer important insights for developing strategies to enhance soil health, such as promoting the presence of "super-connectors" in microbial networks for the maintenance of microbial community.

Analysis of Heavy Metal Pollution in the Water of the Halda River: A Distinctive Breeding Habitat for Carp Fish in Bangladesh.

The present study aimed to assess the heavy metal concentrations in water from different sampling sites of the Halda River, the only natural breeding ground of Indian major carps. We have analysed the contamination level and seasonal variations of heavy metals (viz. Fe, Cu, Zn, Cr, Cd and Pb). The favourability of the breeding environment was assessed by different contamination indices. Samples were collected from six sampling sites for four different seasons, and the metal concentrations were determined for water samples using Flame atomic absorption spectrophotometer. The obtained order of mean concentrations of heavy metals for four seasons was winter>spring>monsoon>pre-monsoon, and the assessed mean concentrations (mg/L) of heavy metals follow the trend: Fe (9.129)>Pb (0.033)>Zn (0.024)>Cr (0.017)>Cu (0.012)>Cd (0.002). The concentration of Fe was found above the permissible limit set by the World Health Organization (WHO) (Guidelines for Water Quality) and ECR (1997), and the concentrations for Pb were found above the USEPA (2006) limit in all four seasons. Contamination indices (heavy metal pollution Index [HPI] and metal index [MI]) indicate that during winter and monsoon, the river water metal condition is critical (HPI>100) and the sites are moderately as well as slightly (1<MI<2) affected by the studied heavy metals. Contamination indices, such as contamination factors (Cf), degree of contamination (Cdeg) and the pollution load index (PLI), demonstrate the fact that Fe and Pb remarkably contaminated the studied sampling sites. The Pearson correlation matrix and the principal component analysis (PCA) revealed that the studied metals are connected by their sources, which can be geological or anthropogenic. Urgent initiatives need to be taken, and effective strategies must be implemented to control the different sources responsible for the entry of heavy metals into the Halda River water.

Origin of Ca II emission around polluted white dwarfs

Dozens of white dwarfs with anomalous metal polluted atmospheres are currently known to host dust and gas discs. The line profiles of the Ca II triplet emitted by the gas discs show a significant asymmetry. In recent decades, researchers have also discovered several minor planets orbiting such white dwarf stars. The most challenging burden of modelling gas discs around metal polluted white dwarfs is to simultaneously explain the asymmetry and metal pollution of the star's atmosphere over a certain period of time. Furthermore, models should also be consistent with other aspects of the observations, such as the morphology of the emission lines. This paper aims to construct a self-consistent model to explain the simultaneous white dwarf pollution and Ca II line asymmetry over at least three years. In our model, an asteroid disintegrates in an eccentric orbit, periodically entering below the star's Roche limit. The debris resulting from the disintegration sublimates at a temperature of 1500 K, producing gas that viscously spreads to form a disc. The evolution of the disc is studied over a period of 1.2 years (over 21000 orbits) using two-dimensional hydrodynamic simulations. Synthetic Ca II line profiles are calculated using the surface mass density and velocity distributions provided by the simulations, taking into account for the first time the asymmetric velocity distribution in the disc. An asteroid disintegrating on an eccentric orbit gives rise to the formation of an asymmetric disc and asymmetric Ca II triplet emission. Our model can explain the periodic reversal of the redshifted and blueshifted peak of the Ca II lines caused by the precession of the disc on timescales of 10.6 to 177.4 days. Our work suggests that the persistence of Ca II asymmetry over decades and its periodic change in the peaks can be explained by asteroids on eccentric orbits in two scenarios. In the first case, the asteroid disrupts on a short timescale (a couple of orbits), and the gas has a low viscosity range ($0.001&lt; to maintain the Ca II signal for decades. In the other scenario, the asteroid disrupts on a timescale of a year, and the viscosity of the gas is required to be high, $

Mitigating Health Risks Through Biosorption: Effective Removal of Nickel (II) and Chromium (VI) from Water with Acid-Treated Potato Peels

Introduction: Nickel (Ni(II)) and chromium (Cr(VI)) are associated with serious health risks, including respiratory problems, kidney damage, and cancer, along with potential threats to ecosystems. Given their persistence and significant toxicity, effective removal from contaminated water is essential to mitigate these health risks. This study explores the efficacy of acid-treated potato peels (ATPP) as an economical and readily accessible biosorbent for the removal of Ni(II) and Cr(VI) from water solutions. Methods: The study explored two biosorbents: raw potato peels (RPP) and ATPP. Fourier Transform Infrared (FTIR) spectroscopy was utilized to analyze changes in surface functional groups. Batch biosorption experiments were performed using distinct contact times (30-180min), pH (3–11), and biosorbent dosages (0.1–0.5 g). The Mann-Whitney U test was applied for the statistical analysis. Results and Discussion: The FTIR analysis indicated an enhancement in carboxyl groups on the ATPP surface after acid treatment, with stronger transmittance peak at 1645 cm⁻¹. ATPP showed significant improvements in biosorption capacity compared to RPP, removing 18.23% of 10 mg/L Ni(II) at pH 5 in 120minutes using 0.5 g of ATPP. For Cr(VI), 52.28% removal was achieved at pH 7 with 0.2 g of ATPP within the same time frame. Statistical analysis confirmed the superior performance of ATPP in removing Ni(II) (p = 0.024) and Cr(VI) (p = 0.004). Conclusion: ATPP offers significantly higher biosorption capabilities than RPP attributed to the increased presence of carboxyl groups on the modified surface, indicating potential for eco-friendly effective material in mitigating the heavy metal pollution's health risks.

Assessment of Metal Pollution in Umm el-Surab Archaeological Layers, Northeast Jordan

This study aims to assess the extent of the anthropogenic pollution of Area A at the Umm el-Surab archaeological site, Jordan. It examines the concentrations of 21 metals from four Roman, Byzantine, and early and late Ayyubid-Mamluk layers. The site, located near Bosra and Umm el-Jimal, was continuously settled from the Roman till the Islamic periods. The chemical analysis and pollution indices (enrichment and contamination factors (EF, CF), and geo-accumulation index Igeo) show low enrichment in Zn, K, Sr, Na, Pb, Ba, Li, Mn, Mg, Mo, and Cu, and moderate enrichment in Cd, Ag, Ca, As, and Ni. Co is significantly enriched in one sample and moderately enriched in the other ones. The results show pollutant metals more enriched in the Byzantine layer than the rest of the layers. A likely primary source of the limited pollution is organic fuels and their firing product of ash, while a likely secondary source might be the pottery fragments spread in the layers. The results agree with the fact that the site was rural with limited industrial activities, especially metal production, like iron and copper, that would have increased the concentration of the analyzed metals.

Biosorption of Pb2+, Cd2+ and Zn2+ from aqueous solutions by Agrobacterium tumefaciens S12 isolated from acid mine drainage

Heavy metal pollution is a global environmental issue, and microorganisms play a crucial role in the bioremediation of heavy metal-contaminated wastewater. The study isolated heavy metal-resistant bacterium and observed their absorption ability toward Pb2+, Cd2+ and Zn2+. We isolated Agrobacterium tumefaciens S12 from acid mine drainage. The various factors influencing its adsorption performance, including pH, biomass dosage, initial metal ion concentration, and adsorption temperature, were investigated in detail. Chemisorption controls the adsorption rate due to the results better fitted by pseudo-second order kinetics. The maximum adsorption capacities of Pb2+, Cd2+ and Zn2+ on A. tumefaciens S12 were 234, 58 and 51 mg g−1 at 30 °C from Langmuir isotherm, respectively. The adsorption processes for the three heavy metal ions were spontaneous and exothermic in nature. In bimetallic systems, biosorption of Pb2+ ions was preferential to that of Cd2+ and Zn2+. Furthermore, scanning electron microscopy coupled to energy dispersive spectroscopy, Fourier-transform infrared spectra and X-ray photoelectron spectroscopy analysis demonstrated that the adsorption mechanisms include ion-exchange, complexation interaction between the heavy metal ions and the functional groups on the surface of biomass. The obtained results indicated that A. tumefaciens S12 can be applied as an efficient biosorbent in bioremediation technology to sequestrate heavy metal ions from aqueous solution.

Nickel phytoremediation potential of Plantago major L.: Transcriptome analysis

Plantago major L, a ubiquitous perennial weed thriving in diverse harsh environments, possesses a substantial reservoir of resistance genes, particularly those conferring resistance to heavy metals. Despite its prevalence, the intricate molecular mechanisms underpinning its exceptional ability to endure heavy metal pollution remain largely unexplored. Through transcriptome analysis, this study intended to reveal the mechanisms behind the enrichment of heavy metal Ni (nickel) in P. major and its potential for phytoremediation. In total, 7848 differentially expressed genes (DEGs) exhibited dynamic changes in tissues treated with different Ni concentrations. It was discovered that the root of P. major exhibited a more pronounced and significant response when exposed to higher concentrations of Ni. Furthermore, the upregulated genes associated with adversity stress were significantly observed in response to Ni stress. The majority of pathways related to plant growth and photosynthesis were significantly reduced; however, pathways related to metabolite synthesis, chitin synthesis, and adversity signal transduction were stimulated, and pathways related to root cell wall organization or biogenesis were suppressed. We identified that the rate-limiting enzyme PmHISN1A/B in the histidine synthesis pathway significantly enhanced Ni tolerance of the transgenic Arabidopsis without side effects, which was different to its Arabidopsis homologs. The study uncovered a molecular basis for the Ni tolerance of P. major, a heavy metal remediation plant, and provided potential genetic resources to cultivate novel P. major varieties or breed stress resilience crops.

Spatial and seasonal variations in trace metals in marine sediments from the Dubai coastal environment.

This study was conducted to assess sediment trace metals (Cd, Cr, Cu, Pb, Ni and Zn) contamination using a systematic approach by collecting sediment samples from 8 transects along the Dubai coastline, each 10 km long, and each transect included its nearshore sediment sampling station. Additionally, 10 sediment samples were collected from the Dubai creek and other potential sources of metal pollution. The sediment samples were collected in December and again in August. However, no significant difference in sediment metal concentration was found between the two sampling campaigns. The sediment trace metal concentrations (0.92-1.31mg Cd/kg, 2.82-176.6mg Cr/kg, 2.27-621.67mg Cu/kg, 0.88-23.6mg Pb/kg, 1.92-192.2mg Ni/kg and 9.1-391.05mg Zn/kg) showed considerable variability, except for Cd (1.08 ± 0.06mg/kg, 5.55% variability). Despite this, no significant differences in sediment metal concentrations were found between the sampled transects. However, significant variations in Cr, Cu, Pb and Zn were evident between distances from the shoreline to offshore stations along the Dubai coast, and the nearshore locations presented clear evidence of elevated/maximum sediment metal concentrations. Most of the sediment trace metal concentrations, however, were found well within the sediment quality guidelines (SQGs) for nearshore sediments. Trace metal contamination hotspots, nonetheless, were identified at some nearshore stations as determined by metal level exceedance over the SQGs, background levels and the pollution load index, with limited potential ecological risk. Overall, the findings suggest that sediments in the Dubai coastal environment are mainly influenced by anthropogenic activities in stations located in the proximity of ship maintenance, ports, and industrial areas such as Dry Dock, Jaddaf, Jebel Ali Port, Wharfage, Hamriya and DUBAL.

Crossed effects of helminth infection and lead exposure on fitness: An experimental study in feral pigeons (Columba livia).

Living organisms are exposed to multiple environmental factors that can affect their fitness. The negative effects of these simultaneous stressors can be additive or can interact in negative synergistic or antagonistic ways to affect the health of exposed individuals. Parasites can accumulate pollutants in their own tissues and have been shown to increase the tolerance of their hosts to different pollutants (antagonistic interaction between parasites and pollutants). Through an experimental approach, we tested the existence of combined antagonistic effects between intestinal parasites and lead exposure on urban feral pigeons (Columba livia) which are known to be exposed to trace metal pollution and harbour a wide variety of internal and external parasites. We experimentally exposed wild feral pigeons in captivity to two treatments: an anthelmintic treatment to eliminate intestinal nematode parasites; an exposure to lead for a period of 6 months. We tested the effects of these crossed treatments on several components of fitness: immunocompetence, reproduction, and body mass. Our findings suggest that the overall effects of lead exposure, either alone or in combination with the presence of intestinal parasites (without anthelmintic treatment) were negative, through either additive or synergistic means. Our results reveal the existence of negative combined effects between pollutant exposure and intestinal parasites, highlighting the importance of accounting for multiple stress factors when studying the effects of exposure to pollutants and/or other environmental stressors on the fitness of organisms.

Usability of Robinia pseudoacacia in monitoring changes and reducing airborne palladium pollution

Palladium (Pd), whose use has been increasing in recent years, is one of the heavy metals that pose a danger to the environment and human health, and it is known that heavy metals can be extremely harmful when inhaled from the air and taken into the human body. Therefore, monitoring and reducing the change of Pd pollution in the air is very important. This study aimed to determine the usability of Robinia pseudoacacia, which is grown intensively in urban areas where heavy metal pollution may be high, to monitor and reduce the change in Pd pollution in the air. Within the scope of the study, changes in Pd concentration in Robinia pseudoacacia stem sections grown in Düzce, among the 5 most polluted cities in Europe, depending on organ, direction, and age range in the last 60 years, were evaluated. As a result, it was determined that Pd pollution in the region may have been released into nature through agricultural activities or transported from much more distant sources. It was also determined that the species is not a suitable biomonitor that can be used to monitor the change in Pd pollution. Still, it is an accumulator species that is extremely suitable for reducing Pd pollution.

Evaluation and risk assessment of heavy metals in wetland soil in the University of Lagos

A study was conducted to evaluate the concentration of heavy metals, and the physicochemical and microbiological properties of wetland soils at the University of Lagos. Soil samples were randomly collected from the Faculty of Science (FSC), Lagoon Front, and Distance Learning Institute areas at depths of 5 cm, 10 cm, 15 cm, and 20 cm using a soil auger. The samples were stored in sterile nylon bags, appropriately labelled, and transported to the University of Lagos Central Research Laboratory for chemical analysis. The physicochemical characteristics measured included soil pH, determined using a pH meter, and moisture content, assessed through the oven-drying method. Heavy metal concentrations were analyzed using an Atomic Absorption Spectrophotometer. Microbial population diversity was examined using the disc diffusion method. Statistical analysis was performed using SPSS version 20, and mean values were evaluated using Tukey’s multiple comparison test at a probability level of P &lt; 0.05. The results revealed that soil pH ranged from 7.20 to 8.81, with the highest value (8.81) recorded near the Faculty of Science (FSC-3). Eight heavy metals, including Pb, Ni, Cr, Cd, Fe, Cu, Mn, and Zn, were analyzed. Lead concentrations ranged from 0.02 to 0.29 ppm, followed by nickel, which ranged from 0.01 to 0.13 ppm. Chromium ranged from 0.0 to 0.25 ppm, cadmium from 0.03 to 0.08 ppm, iron from 1.02 to 2.96 ppm, copper from 3.31 to 4.60 ppm, manganese from 3.31 to 5.16 ppm, and zinc from 1.67 to 9.17 ppm. Lead and zinc concentrations were found to be below the permissible limit at all locations, while chromium and cadmium were within permissible limits. However, Zn, Mn, Cu, Fe, and Ni exceeded the permissible limits. Correlation analysis revealed a significant correlation (P &lt; 0.05) between Pb and Zn, likely due to effluents from human waste and seepage from nearby dumpsites into the lagoon, streams, or beaches. The isolated microbial flora included three bacterial genera, Bacillus megaterium, Bacillus spp, and Enterobacter spp, as well as four fungal genera, Aspergillus, Penicillium, Aspergillus flavus, and Fusarium. Bacterial counts were lower than fungal counts in polluted soils, likely due to the nutrient status of the soil. The isolates were found to be tolerant to slightly alkaline pH and heavy metal pollutants, with microbial variation attributed to the impact of pH and heavy metals on the microbial population.