Abundance Of Heavy Metals Research Articles

Heavy metal contamination of the Nigerian environment from e-waste management: A systematic review of exposure pathway and attendant pathophysiological implications

Nigerian environment has become a depository of worrisome levels of toxicants including heavy metals. Electrical and electronic equipment which leads to the generation of e-waste is one of the considerable sources of environmental contaminants in Nigeria. This systematic review deployed Preferred Reporting Items for Systematic Reviews and Meta-Analysis (PRISMA) method to analyze various empirical and quantitative outputs on heavy metal components of e-waste management sites in Nigeria and investigated the distribution of heavy metals in several environmental matrices such as soil, water, surface dust, plant and blood of e-waste scavengers. Also, the probable environmental multi-transformation that ultimately potentiates the susceptibility of humans to the pathophysiological effects and genetic related disorders of exposure to heavy metal component of e-waste was discussed. The relative abundance of metals in soils due to inappropriate e-waste handling is given as follow: Fe>Cu>Pb>Zn>Mn>Co>Cr>Ni>As>Cd, in underground and surface water: Zn>Fe>Cu>Cr>Mn>Pb>Hg>Ni>Co>Cd>As; in surface dusts: Fe>Zn>Pb>Cu>Mn>Cr>Ni>Cd>Co; in plants: Pb>Cu>Mn>Zn>Ni>Cr>Cd obtained from the Nigerian environment. Moreso, the estimated abundance of heavy metals in the blood of e-waste scavengers is Nigeria is given as Cr>Cd>Hg>Zn>As>Pb>Cu>Mn>Fe. Conclusively, this study does not only show that various matrices of Nigerian environment is contaminated with heavy metal but also that the pattern of abundance differ in the environment and in biological systems with the latter having the abundance of Pb, Cr and Cd and the former having the abundance of Cu, Zn and Fe.

Impact of agricultural inputs on the abundance of heavy metals (Cu, Zn) in soil, water, and plants in the south of Algeria

he aim of our study is to assess the impact of agricultural inputs on the levels of heavy metals, specifically copper (Cu) and zinc (Zn), in soil, water, and plants in the oasis of El Ghrous, Branis, and Sidi Okba in Algeria. The existence of perilous substances in the surroundings is a significant ecological issue, endangering both human well-being and agricultural output. The overuse of fertilizers and pesticides may be causing heavy metals build-up. The aim will be to highlight a better understanding of the concentrations of copper (Cu) and zinc (Zn), considering as detrimental contaminants, after extensive utilization of agricultural inputs. In order to examine the levels of trace metals (TMs), we performed additional tests by comparing field samples using metal analysis techniques that involved ammonium acetate and EDTA, and detection by atomic absorption spectrophotometry. Our findings suggest that in soils affected by fertilizers and phytosanitary agents, the concentrations of Cu++ and Zn++ are below levels that would cause toxicity. Indeed, the levels of Cu++ are measured at 6.14 µg/g and the levels of Zn++ are measured at 4.97 µg/g. Nevertheless, the copper contents in irrigation waters from sites 01 and 02 beyond the levels that are considered dangerous. Similarly, copper levels in plants are categorized as hazardous. The findings emphasize the significance of implementing integrated pest management strategies in order to reduce the negative consequences of excessive use of agricultural inputs. Additionally, our study imposes the need to closely monitoring agricultural practices in order to mitigate environmental and public health hazards. Implementing sustainable farming practices and employing effective resource management strategies is crucial for safeguarding agricultural ecosystems and guaranteeing sustainable food production in the long run. Adopting an all-encompassing strategy is crucial for preserving the well-being of both the ecosystem and the populace.

Environmental risk assessment, spatial distribution, and abundance of heavy metals in surface sediments of Dal Lake-Kashmir, India

This study assesses the pollution levels of Dal Lake in Kashmir, India, focusing on the spatial distribution, abundance, and risk of heavy metals in surface sediments. Granulometric analysis revealed a complex interplay of sedimentation processes, characterized by a wide range of sand (1.25% to 47.03%), silt (2.65% to 58.21%), and clay (38.35% to 94.48%) contents across sediment samples. The average CaCO3 content of 18.65% is notably higher than observed in other regional and global lakes, indicating higher production or preservation of carbonates. The organic matter (OM) content within the sediment samples varied significantly, ranging from 3.9% to 25.01%, reflecting complex sedimentary dynamics. Utilizing environmental assessment indices (Contamination Factor, degree of contamination, Pollution Load Index, Potential ecological risk index, Enrichment Factor, and Geo-accumulation Index) and multivariate statistical analyses (Pearson's Correlation, Principal Component Analysis, Cluster Analysis), it examines the contamination by Iron, Manganese, Cobalt, Chromium, Copper, Nickel, Lead, and Zinc across 32 samples. Results indicate spatial variability in metal concentrations, with Cobalt ranging from 24.1178 ppm to 52.95 ppm and Iron from 25,800.99 ppm to 164,747.82 ppm, highlighting areas of significant contamination and potential ecological risks, especially from Nickel, which exceeds safe levels for benthic invertebrates. The Pollution Load Index suggests moderate contamination of the lake. These findings emphasize the urgent need for continuous monitoring and effective management to protect Dal Lake's ecological integrity.

Heavy Metals Levels and Contamination Status in Soils of Koudalwa, Tchad

This study is aimed at determining the heavy metal levels in agricultural soils and around oil drilling pits in Koudalwa, Tchad and evaluating pollution levels. Soil sampling was done on three sites AA (AA1 & AA2), BB (BB1 & BB2), CC (CC1 & CC2) with two samples collected per site, giving a total of six samples. The subsamples with code one represent the 0-30 cm depth and code two represent the 30-60 cm depth. A control sample was taken far from sites having any oil activities. 2 mm sieved soil samples were digested in a mixture of HCl and HNO<sub>3</sub> in the ratio 1:3 and the concentrations of Cr, Cd, Pb, Hg, Cu, Mn, Fe and Ni in the digested solutions determined by atomic absorption spectroscopy. The contamination level of the heavy metals was assessed using the Geo-Accumulation Index (Igeo), Contamination factor, Pollution load index (PLI), Enrichment Factor (EF), and Potential Ecological Risk Assessment (PER) models. Results obtained shows that the abundance of heavy metals in the soils of Koudalwa is in the order; Cu ˃ Hg ˃ Cr ˃ Mn ˃ Fe ˃ Cd ˃ Ni ˃ Pb. The site AA shows the highest levels of all the determined heavy metals except Ni with highest amount of Cr (197.98 mg/kg), Cd (6.49 mg/kg), Hg (531.46 mg/kg), Ni (0.088 mg/kg) in the 30-60 cm soil depth, and Pb (0.021 mg/kg), Cu (815.24 mg/kg), Mn (166.55 mg/kg) and Fe (60.04 mg/kg) in the top soil, 0-30 cm depth. PLI analysis confirms that sites AA1 and AA2 present a decline of site quality as compared to other sites which are of perfect site quality. ER values for Cd, Cr, Cu, Hg showed severe enrichment due to contributions of anthropogenic sources with higher values in subsurface samples, thus indicating their high mobility in these soils. Results of this study shows that critical attention must be given to site AA as well as other activities in other sites that can contaminate the soils with special focus on remediation measures and sensitization of the population on the dangers of different activities on the soils.

Investigation of heavy metals uptake in root-shoot of native plant species adjoining wastewater channels.

Metal pollution in water, soil, and vegetation is an emerging environmental issue. Therefore, this study investigated the abundance of heavy metals (HMs) within roots and shoots of native plant species i.e., Bromus pectinatus, Cynodon dactylon, Poa annua, Euphorbia heliscopa, Anagallis arvensis, and Stellaria media grown in the adjoining area of municipal wastewater channels of a Pakistani city of Abbottabad. HMs concentrations (mg L-1) in municipal wastewater were: chromium (Cr) (0.55) > nickel (Ni) (0.09) > lead (Pb) (0.07) > cadmium (Cd) (0.03). Accumulation of HMs in both roots and shoots of plant species varied as B. pectinatus > C. dactylon > P. annua > E. heliscopa > A. arvensis > S. media. Irrespective of the plant species, roots exhibited higher concentrations of HMs than shoots. Higher amount of Cr (131.70 mg kg-1) was detected in the roots of B. pectinatus and the lowest amount (81 mg kg-1) in A. arvensis, Highest Cd concentration was found in the shoot of B. pectinatus and the lowest in the E. heliscopa. The highest concentration of Ni was found in the roots of S. media (37.40 mg kg-1) and the shoot of C. dactylon (15.70 mg kg-1) whereas the lowest Ni concentration was achieved in the roots of A. arvensis (12.10 mg kg-1) and the shoot of E. heliscopa (5.90 mg kg-1). The concentration of HMs in individual plant species was less than 1000 mg kg-1. Considering the higher values (> 1) of biological concentration factor (BCF), biological accumulation co-efficient (BAC), and translocation factor (TF), B. pectinatus and S. media species showed greater potential for HMs accumulation than other species. Therefore, these plants might be helpful for the remediation of HM-contaminated soil.

The role of topography feedbacks in enrichment of heavy metal elements in terrace type region

Minerals, metallurgy, and other production activities will cause a large number of heavy metal elements to leak into the natural environment. A large number of heavy metal elements have been found in the farmland soil, where the adsorption of plants enhances the enrichment. Here, we have selected a region with three terraces to conduct a whole-area soil sample collection and satellite hyperspectral data processing study to explore the role of terrain in this enrichment process. Five spectral transformation methods and four feature enhancement algorithms were designed, and the content extraction model was established to quantitatively retrieve eight heavy metal elements. The results indicates that the three terraces are the source state, transition state, and stable state of heavy metals respectively with the decrease of elevation; The correlation coefficient of various heavy metal elements exceeds 0.92, and the enrichment pattern is consistent although slope and aspect have no significant correlation with the enrichment of heavy metal elements; Local Cd exceeds 30.00%, Hg exceeds 10 times, and As exceeds 48.30% according to the indicator provisions of Chinese national standard (GB 15618-2018). Such knowledge extends our understanding of the abundance, migration, and enrichment of heavy metals from the perspective of topography, which is crucial for pollution assessment and soil remediation.

Heavy metal pollution in the nearshore surface sediments north of the Shandong Peninsula and the Western Miao Islands, China

Surface sediment samples (N = 94) were obtained from the west Miao Islands, northern Shandong Peninsula, China, and analyzed for grain size and elements. Based on the classification by Folk and Ward, surface sediments were dominated by silt-sized components, sandy silt, and silt. The mean abundance of heavy metals could be ordered according to Cr > Zn > Ni > Cu> Pb > As> Cd > Hg. According to sediment quality guidelines, surface sediments have a 21 % probability of being toxic. The potential ecological risk index indicates low potential ecological risk, while the enrichment factor and geo-accumulation indices indicate slight to moderate pollution across most of the study area. Pollution load indexes indicate that 38 % of sites are moderately metal contaminated and 62 % of sites are not polluted. The study area was classified according to the level of heavy metal contamination and its sources.

Spatial distribution of heavy metal abundance at distance gradients of roadside agricultural soil from the busiest highway in Bangladesh: A multi-index integration approach

Bangladesh is currently experiencing significant infrastructural development in road networking system through the construction or reconstruction of multiple roads and highways. Consequently, there is a rise in traffic intensity on roads and highways, along with a significant contamination of adjacent agricultural soils with heavy metals. The purpose of this study was to evaluate the ecological risk, health risk and the abundance of seven heavy metals (Cu, Mn, Pb, Cd, Cr, As, and Ni) in three distance gradients (0, 300, and 500 m) of agricultural soil along the Dhaka-Chattogram highway. The concentration of heavy metals was measured with an Atomic Absorption Spectrophotometer (AAS) on a total of 36 soil samples that were taken from 12 different sampling sites. Based on the findings, Cd had a high contamination factor for all distance gradients, whereas Cr had a moderate contamination factor in 67% of the study areas. According to the Pollution Load Index (PLI), Cd, Cr, and Pb were the predominant pollutants. Principal component analysis (PCA) result shows these metals mainly came from anthropogenic sources. The considerable positive correlations between Cu–Pb, Cu–Cd, Pb–Cd, and Cr–Ni all pointed to shared anthropogenic origins. As per Potential Ecological Risk Assessment (PERI) analysis, Pb, Cd, Cr, and Ni each contribute significantly and pose a moderate threat. The Target Hazard Quotient (THQ) values for all pathways of exposure to Pb and Cr in soils were more than 1, which would pose a significant risk to human health in the following order: THQadult female > THQadult male > THQchildren. This study will help to evaluate the human health risk and develop a better understanding of the heavy metal abundance scenario in the agricultural fields adjacent to this highway.

Linear models for describing relations between sensitive bacterial taxa and ecological risk from heavy metals in soils of coal mines in semi-arid region

Soil heavy metal pollution induced by coal production is a significant environmental issue, particularly in semi-arid region, where the ecosystem is vulnerable. The current comprehension of the impacts of heavy metals on soil microbial ecology in the vicinity of coal mines remains insufficient. As the first in-depth study that aimed to establish models for describing relations between the abundance of sensitive bacterial taxa and heavy metals in soils of coal mines in semi-arid region, soil samples were collected from six mines with different production scales (0.6–8.0 × 106 t/year), and analyzed for heavy metals and bacterial communities based on both quantitative PCR and high-throughput sequencing. The potential ecological risk from Arsenic (As), Cadmium (Cd), Chromium (Cr), Copper (Cu), Nickel (Ni), Lead (Pb), and Zinc (Zn) was assessed, and their relations with the bacterial community in terms of abundance, diversity and structure were quantitatively evaluated. For bacterial abundance, statistically negative correlations with the overall ecological risk from all heavy metals and individual risk from Cr, Cd, and Zn were revealed, whereas, for bacterial diversity, a negative correlation appeared to exist with Zn. Twelve bacterial taxa sensitive to the overall risk and the individual risk from Cr, Cd, and Zn were identified, and twelve linear models were established based on their absolute abundance and the potential ecological risk from heavy metals. Water content and total phosphorus were also found vital in regulating the bacterial community in the soils of coal mines in semi-arid region. The results obtained provide more in-depth and closely relevant information for better management of the environment surrounding the coal mine areas and for realizing sustainable coal production without sacrificing the environment.

Improved Calculations of Heavy Metal Toxicity Coefficients for Evaluating Potential Ecological Risk in Sediments Based on Seven Major Chinese Water Systems.

Several methods have been used to assess heavy metal contamination in sediments. However, an assessment that considers both composite heavy metal speciation and concentration is necessary to accurately study ecological risks. This study improved the potential ecological risk index method and calculated the toxicity coefficients of seven heavy metals: Arsenic (As), Cadmium (Cd), Chromium (Cr), Copper (Cu), Nickel (Ni), Lead (Pb), and Zinc (Zn). The newly calculated toxicity coefficients were validated by using previously published heavy metal distribution data of the Henan section of the Yellow River. The calculation procedure is based on the principle that the abundance of heavy metals in the environment and their bioavailable forms affect the toxicity of heavy metals. The toxicity coefficients for the seven heavy metals were calculated as follows: As = 10, Cd = 20, Cr = 5, Cu = 2, Ni = 5, Pb = 5, Zn = 1. Ecological risk assessment of the Henan section of the Yellow River using the improved toxicity coefficients revealed that the ecological risk of Cd and total heavy metals is higher than previous calculations, reaching the strength and moderate risk levels, respectively. The improved potential ecological risk index method is more sensitive to heavy metal pollution and thus provides a better indication of ecological risk. This is a necessary improvement to provide more accurate pollution assessments.

Collapse of terrestrial ecosystems linked to heavy metal poisoning during the Toarcian oceanic anoxic event

Abstract The Early Jurassic Toarcian oceanic anoxic event (T-OAE, ca. 183 Ma) was accompanied by a major biotic turnover in the oceans and substantial vegetation change on land. The marine biotic crisis has been attributed to several triggers, e.g., anoxia, warming, ocean acidification, yet the processes underlying the collapse of the terrestrial ecosystem are poorly understood. New high-resolution geochemical and palynological data across the T-OAE from a lacustrine succession in North China reveal elevated occurrences of spore dwarfism, asymmetrical Classopollis tetrads, and aberrant spores coeval with increases in heavy metal (Hg, Cu, Cr, Cd, Pb, As) abundances. The occurrence of teratological spores and pollen in multiple plant groups suggests overall vegetation-scale ecological pressure. Our data indicate that the combination of a widespread floral crisis with higher terrestrial organic matter oxidation and decomposition, enhanced hydrological cycle, and coeval large-scale volcanism resulted in higher concentrations of toxic heavy metals in terrestrial ecosystems. These heavy metals could poison plants, causing mutations and disrupting their reproductive cycle, and making them more vulnerable to secondary stresses such as climatic extremes and/or habitat shifts, eventually leading to widespread collapse across all terrestrial trophic levels.

Risk Assessment of the Impact of Oil Spill on the Heavy Metal Content of Santa Barbara River in Bayelsa State, Nigeria

This study was aimed at assessing both the effect (risk) and impact of a recent oil spill on heavy metal concentration in the Santa Babara River in Bayelsa State, Nigeria. Samples were collected and preserved based on standard methods. The heavy metals of interest were Mercury (Hg), Arsenic (As), Cadmium (Cd), Chromium (Cr) and Copper (Cu) due to their levels of toxicities and presence in water bodies while the five study stations were Worokuma (W), Uwanga (W), Tuweni (T), Shellikiri (S), Inarakiri (I) and Esenfakiri (E). The solar thermos elemental flame atomic absorption spectrometer (AAS), model SE-71096 made in Germany with detection limit of 0.001 mg·kg−1 was used for the heavy metal analysis. The trend of heavy metal abundance was found in this order Cr>Cu>Cd>Pb>Hg=As. All the detectable metals had risk index of greater than 5 but the highest was found in the order, Cd> Pb > Cu > Cr (149, 35, 26 and 12 respectively) which meant extremely high level of pollution. This also indicated the probability of non-carcinogenic effects occurring and increases as HI increases signifying carcinogenic risk via direct ingestion of water. Graphs were used to show trends in both mean heavy metal concentrations and risk assessment indices. Chromium and Pb had moderate contaminations for CF and CDI values, hence regular monitoring of the Santa Barbara River is of essence as most of the inhabitants take this as the only source of potable water as their wells have very high iron content.

Hydrochemistry and groundwater quality assessment around solid waste landfill sites in peri-urban Jaipur, NW India.

Jaipur, the capital city of Rajasthan State in northwestern India, is one of the fastest-growing urban centers in the country. The city and the region around it have documented a substantial drop in the water table due to the over-abstraction of groundwater resources to cater to the increasing water demands of the growing population. Consequently, the entire Jaipurdistrict has been categorized as a "dark zone," prohibiting any further groundwater development activity. Besides its dwindling availability, water quality is also a matter of concern. In places, the water is geogenically contaminated and unsuitable for drinking purposes due to high levels of undesired elements in groundwater, such as high fluoride in the southern part and high chloride in the southwestern part of the district. Groundwater contamination can also occur through several anthropogenic factors, such as industrialization and excessive use of insecticides and pesticides. Water pollution through sewage disposal in open land-fill sites is also an important factor, especially in the growing urban centers. In this study, the water quality evaluation around three landfill sites in the Jaipur district, namely Mathura Das Pura and Langadiyawas (east of the city) and Sewapura (northwest of the city), was carried out. The cation-anion analysis of 45 groundwater samples collected around these sites reveals a wide variation in the abundance of constituent parameters. In a majority of cases, most of the parameters are within acceptable limits prescribed by the national and international agencies (Bureau of Indian Standards and World Health Organization). The fluoride content is more than the prescribed limit of 1.5mg/l in several cases. This could be an intrinsic property of deeper aquifers. The majority of Mathura Das Pura and Langadiyawas samples classify as Na + K - CO3 + HCO3 to Mg - CO3 + HCO3 types in the Piper classification scheme, while a small proportion shows mixed water type characteristics, i.e., with no dominant parameter. Most of the samples have heavy metal abundances within the permissible limits while slightly elevated Cd and Pb levels were observed in some samples. A positive correlation between these two metals can be attributed to a common pollutant, possibly sourced from solid waste. The percent pollution index of Sewapura samples shows lower pollution levels (PPI < 40%) and a dominant chemical weathering trend while the majority of Mathura Das Pura-Langdiyawas samples show a high pollution effect (PPI 40 to 80%). In general, the chemical parameters of Sewapura (relatively new landfill site) samples define a more coherent group while water quality parameters in Mathura Das Pura and Langdiyawas (old landfill sites) samples show a wide variation, unsystematic distribution, and significantly higher than prescribed values for most of the hydrochemical parameters. The study shows that some of the water quality issues may be geogenic, while municipal waste dumping and leachate infiltration have adversely affected the groundwater quality.

Multidecadal heavy metals and microplastic deposition records in an urban lake: the ecological risk assessments and influencing factors.

With the development of urbanization and economic growth, the urban lake ecosystem faces many challenges derived from external factors. As pollutants in the aquatic environment, heavy metals and microplastics negatively influence the urban lake ecosystem due to their intrinsic properties. To understand the distribution patterns and multidecadal deposition characteristics of heavy metals and microplastics, six sediment cores were collected in March 2021 from a Chinese urban lake, Xinghu Lake, and the isotopic composition of cesium-137 and lead-210 was analyzed for the chronology of the sediment core. Here, the classifications of comprehensive ecological risk evaluation methods for heavy metals and microplastics were adjusted further. Meanwhile, the correlations among heavy metals, microplastics, sediment grains, and natural and social factors were further analyzed. The results showed that the sediments of Xinghu Lake were mainly fine silt (39%), and the average surface area of sediment was 1.82 ± 0.60 m2/g. The average concentrations of cadmium, chromium, copper, nickel, lead, vanadium, and zinc were 0.268 ± 0.077, 59.91 ± 16.98, 23.29 ± 6.48, 52.16 ± 13.11, 36.83 ± 11.78, 119.57 ± 26.91, and 88.44 ± 29.68mg/kg, respectively. The average comprehensive potential ecological risk indexes of heavy metals and microplastics in sediment cores were 46.59 ± 9.98 and 105.78 ± 23.32 in Xinghu Lake, and their risks were projected to reach high and very high levels by 2030 and 2050. The annual average temperature was the key natural factor for the abundances of heavy metals and microplastics, and the small sediment grain had a significant correlation with these. Agricultural activities were major pollution sources of heavy metals and microplastics, while the chemical fibers and plastic products were closely related to the abundance of microplastics.

Attomolar analyte sensing technique for detection of Pb2+ and Hg2+ ions based on liquid crystal

Detecting the ultra-low abundance of heavy metals in real samples remains challenging and it requires the development of high-performance biosensing modalities. This work describes a novel strategy for design an ultra-sensitive liquid crystal (LC) aptasensor, in which the LCs reorientation induced by conformational changes of a triple helix molecular switch (THMS) structure is utilized for the quantitative detection of Pb2+ and Hg2+ ions. The developed aptasensor exhibits a wide linear range with the ultralow detection limits as low as 0.021 aM and 0.068 aM for Pb2+ and Hg2+, respectively. Besides, the results show that other analytes cause no interference. Noteworthy, this sensing strategy is easy to expand for other targets by altering the aptamer sequence without change of the triple-helix structure and can be used for multiple analyte detection. The developed aptasensor is promising powerful platform as a LC AttoSens for precision screening of hazardous residues in food analysis.

The Effects of Five-Year Biosolid Application on the Diversity and Community of Soil Arthropods

Land application of biosolids is a beneficial form of management, although heavy metal contamination is a major concern. Biosolid application can shape the abundance, species richness, and community structure of arthropods, which are important regulators of soil processes. We investigated the effect of the five-year (2012–2017) application of domestic biosolids at 0, 15, 30, and 45 ton ha−1 on the soil properties, enzyme activity, heavy metal concentrations, abundance, and diversity of soil arthropods in degraded sandy soil. The results showed that the application of a high amount of biosolids resulted in an increase in soil organic carbon of 2.6 times and in the water content of 2.8 times compared with CK (no biosolids). The total metal concentrations of Cr, Ni, Cu, Zn, Cd, and Pb increased by 6.6%, 3.2%, 6.6%, 7.7%, 13.3%, and 22.5%, respectively, compared with CK in soil (p &gt; 0.05). The activities of seven enzymes, which mainly participate in carbon (C), nitrogen (N), phosphate (P), and sulfur (S) transformation, increased by 1.53%~122.7%, indicating that the soil function did not change under biosolid application. The number of individual arthropods collected from a square meter of soil changed from 0 to 2560. The total abundance of arthropods increased from 1.2 to 4 times under biosolid application (p &lt; 0.05), but biosolid application had no effects on simple measures of richness and diversity (Shannon–Weaver index). Multivariate ordination techniques showed a significant shift of the arthropod community structure under biosolid application due to differing responses of several taxa to the biosolids. Redundancy analysis highlighted the influential role of soil chemical properties (soil organic C, total N, water content, microbial biomass, and pH) and cadmium in shaping the soil arthropod structure. These results suggest that long-term biosolid application with limited heavy metal concentrations does not have detrimental effects on soil arthropods or microbial-related soil function.

Occurrence and influencing factors of antibiotics and antibiotic resistance genes in sediments of the largest multi-habitat lakes in Northern China.

Baiyangdian Lake is a typical and largest multi-habitat lake in the North plain of China. To understand the generation and transmission of antibiotics resistance genes (ARGs) in multi-habitat lakes, the contents of nutrients (TC, TOC, TN, TP and TS), heavy metals (Zn, Cr, Ni, Cu, Pb, As, Cd and Hg), 22 antibiotics, 16S-rRNA(16S), Class I integron (intI1) and 20 ARGs were determined. Samples were taken from the Fuhe river, river estuaries, reed marshes, living area, fish ponds and open water of Baiyangdian Lake. The results showed that quinolones were the main pollutants in six habitats, and the content range was ND-104.94ng/g. Thereinto, aac (6') -IB, blaTEM-1, ermF, qnrA, qnrD, tetG, sul1, sul2 and tetM were detected in all the analyzed samples. The absolute abundance of sul1 was the highest (5.25 × 105 copies/g-6.21 × 107 copies/g) in most of the samples. In these different habitats, the abundance of antibiotics and ARGs in river estuary was the highest, and that in reed marshes was the lowest. There was a significant positive correlation between the abundance of heavy metals (Cu, Pb, Zn, Ni, Cd, Hg) and the absolute abundance of 11 ARGs (P < 0.01). Redundancy analysis showed that Cu, Zn, intI1, TP and macrolides were the important factors affecting the distribution of ARGs. Our finding provides a more likely driving and influencing factor for the transmission of ARGs in lakes with complex and diverse habitats.

Comparative nutritional and toxicity analyses of beverages from date seed and barley powders as caffeine-free coffee alternatives

Coffee is one of the most preferred beverages due to its flavour and aroma, which is partially contributed by the presence of caffeine. However, there are many negative effects of caffeine on human health. Alternative products like date seed and barley beverage have become an interest to switch from caffeine to caffeine-free beverages. The present work thus aimed to evaluate the nutritional properties and toxicity of date seed and barley powders as compared to Arabica coffee powder. Samples were analysed for its caffeine content, antioxidant activity, and toxicity activity from boiled water extract, whereas the nutrition compositions and heavy metal contents were analysed based on respective extraction method performed. A mass spectral peak of caffeine was detected in the Arabica coffee but not in the date seed and barley powders. All three samples were shown to possess antioxidant activities with Arabica coffee yielding the highest. Arabica coffee, however, exhibited a moderate level of toxicity to human lung fibroblast (MRC-5) cell line with IC50 of 230 ± 40 µg/mL at the extract concentration. There was no inhibition on 50% MRC-5 cell viability showed by the date seed and barley powders up to 10 mg/mL extract concentration. The abundance of heavy metals detected in all samples was lower than the regulatory limits. Our findings therefore further supported the advantages of date seed and barley powders as alternatives to coffee beverage as both contained undetected amount of caffeine, low fat and high carbohydrate contents, and possessed good antioxidant activity with low potential health risks.

Spatial distribution and pollution assessment of heavy metals in sediments from the Brahmaputra River watershed in Bangladesh.

Spatial distribution and pollution assessment of selected heavy metals such as barium (Ba), chromium (Cr), nickel (Ni), lead (Pb), vanadium (V), arsenic (As), zinc (Zn), and copper (Cu) in sediments of the Brahmaputra River watershed in Bangladesh was investigated. The mean abundances (ppm) of heavy metals in sediment samples were in decreasing order Ba (375.60) > V (67.60) > Cr (54.10) > Zn (48.20) > Ni (22.28) > Pb (20.25) > Cu (7.59) > As (4.21). Concentrations of Pb and As in the sediments are enriched relative to the average upper continental crust composition, while Ba, V, Cr, Zn, Ni, and Cu decrease considerably. A higher concentration of Pb and Ni indicates that Brahmaputra River watershed samples receive a significant contribution from anthropogenic sources of heavy metals. Chromium displays marked positive correlation with V (r = 0.91, p = < 0.01), inferring a similar source materials input into the watershed. The geo-accumulation index (Igeo) values suggest that the sediments were uncontaminated to moderately contaminated by Ni, Zn, Pb, V, and Cr, whereas moderate to heavily contaminated by As and Cu. The contamination factor (CF) confirmed that sediments in the watershed were moderate to highly contaminated by As, Cu, and Cr. The pollution load index (PLI) values for most of the samples were over one (> 1), indicating an advanced decline in the watershed sediment quality. The overall results of a multivariate statistical analysis suggest that Ba, V, Cr, and Zn contents were all-natural sources, and Pb, Ni, As, and Cu were derived from both natural and anthropogenic sources.

Application of chromium-silicon cluster for selective removal of arsenic and sulfide from wastewater

The development of industrialisation increases the abundance of heavy metals, anionic, and harmful gases in the environment. Several techniques are already being used for the removal of different kinds of contaminants, but most of them are far away from their optimum performance. Among different approaches, the capturing of water and air pollutants by functionalised materials has been investigated widely due to cost-effectiveness, and high efficiency. From this point of view, silicon-based nanoclusters have attracted much attention due to their outstanding performance in terms of sensing properties. In the present work, we have applied the CrSi14 cluster for selective capturing of environmental pollutants. To this end, the adsorptions of heavy metal ions (As3+, Pb2+, Cd2+, Hg2+), inorganic anions (CN−, S2−, NO2 −), and gas molecules (CO, N2, CH4, CO2, NO2, H2S) on the pristine CrSi4 cluster (PC) and the functionalised cluster (FC) by 1-ethyl-3-methyl imidazolium have been investigated using first-principles methods. The results indicate that PC is not only sensitive to capture As3+ but also acts highly selective so that other examined metals would not interfere with the arsenic removal. The PC also exhibits high sensitivity toward S2- and can be considered as a prominent sorbent for the removal of sulfide.