Levels Of Metals In Soils Research Articles

Exploring the Levels of Heavy Metals in Soil: A Case Study of Ahoada West Local Government Area in Rivers State, Nigeria

Background: Heavy metal-polluted soils are becoming more widespread around the world, as geologic and anthropogenic activity grow. The risk of soil contamination by metals increases drastically with increasing industrialization, urbanization, and oil spillage. Thus, it is necessary to monitor heavy metals concentration in agricultural areas because they can pose serious risks to human health and the environment. Objectives: the objective of the study was to investigate heavy metals concentration (lead, cadmium, chromium and iron) in soils of Ahoada West Local Government Area, specifically Akinima, Oruama, and Joinkrama 4. Methods: Soil samples were collected from three places at varying depths (0-5, 0-10, and 0-15 cm). Concentrations of heavy metals were quantified using a Flame Atomic Absorption Spectrophotometer. ANOVA was employed to ascertain significant differences in heavy metal concentrations at p<0.05 (IBM SPSS, 21 version). Results: Results indicated that the concentrations (ppm) of lead (1.44-13.99), chromium (5.23-23.57), cadmium (0.22-2.28), and iron (3.92-13.36) were below the WHO limits. Also, it was observed that heavy metal concentrations increased with increasing soil depths, in the following order 0-15 > 0-10 > 0-5 cm. In terms of spatial distribution, Oruama had significantly higher heavy metal concentrations, followed by Joinkrama 4, and Akinima, with the exception of chromium, which was significantly higher in Joinkrama 4 (8.00; 17.29) in comparison with Oruama (7.30; 15.34), and Akinima (5.23; 12.43) for 0-5 and 0-10 cm respectively. Conclusion: The study concludes that Oruama community generally had significantly higher levels of heavy metals, although the analyzed soil samples were below WHO permissible limits. This study, advances the understanding of heavy metal dynamics in soil health and agricultural sustainability in Ahoada West, by providing localized information on concentrations relative to depth of soil and locations. It emphasizes the need for regular monitoring to avoid possible pollution and bioaccumulation.

Integrated Evaluation of Chemical Properties and Heavy Metal Levels in Agricultural Soils for Sustainable Environmental Management

Agricultural soil health is crucial for sustainable food production and environmental sustainability. This study integrates the evaluation of chemical properties and heavy metal levels in agricultural soils to assess their impact on soil health and environmental sustainability. Soil samples from [location/region] were analyzed for pH, electrical conductivity, nutrient levels, and heavy metals (Ni, Pb, Cd, Cr). Results showed significant variations in chemical properties and heavy metal concentrations, exceeding permissible limits in some cases. The study identifies correlations between chemical properties and heavy metal levels, highlighting potential risks to soil biota, human health, and the environment. The findings emphasize the need for sustainable soil management practices, including efficient irrigation systems, organic amendments, and regular monitoring.

Multimethod Analysis of Heavy Metal Pollution and Source Apportionment in a Southeastern Chinese Region

Excessive levels of heavy metals in soil can significantly impact human health and ecological safety. Evaluating heavy metal pollution and identifying its sources are crucial for environmental management. This study investigates the status of heavy metal pollution in a southeastern region of China and aims to identify its sources using data from the first national soil pollution survey, which includes 282 sampling points. Indicators such as the geoaccumulation index (Igeo), the potential ecological risk index (RI), the hazard index (HI), and the total lifetime cancer risk (TLCR) were utilized to assess contamination levels. Geographic information systems (GIS), positive matrix factorization (PMF) receptor modeling, cluster analysis (ClusA) and human health risk assessments were integrated to analyze the sources of heavy metals. The results indicate that agricultural pollution sources have a minor impact on overall heavy metal contamination, with low ecological risk levels in the eastern and western regions. In contrast, the central region exhibited moderate risk, with areas of extremely high risk distributed across the central-west and central-south regions. PMF analysis identified pollution sources including natural origins, coal combustion, industrial emissions, and traffic, with contributions of 17.62%, 18.50%, 28.35%, and 35.56%, respectively. Overall, the carcinogenic risk in the study area is not high. Targeted recommendations were made in response to the pollution situation in the study area. This research enhances our understanding of heavy metal pollution in the soil of the study area and provides a reference for pollution source delineation in other regions.

Enhancement of Wheat (Triticum aestivum L.) Growth and Yield Attributes in a Subtropical Humid Climate through Treated Ganga Sludge-based Organic Fertilizers.

Sewage sludge is a by-product of urbanization that poses environmental and health challenges. However, it can also be a valuable source of organic matter and nutrients for agriculture. This study aimed to assess the potential of five types of organic fertilizers derived from treated Ganga sludge on the growth of wheat plants. The Patanjali Organic Research Institute has developed five types of granulated organic fertilizer from the stabilized Ganga sludge. The results showed that the organic fertilizers significantly improved the wheat performance in terms of plant height, biomass accumulation, chlorophyll content, leaf area and other yield parameters. Furthermore, the fertilizers ameliorated soil physicochemical attributes and augmented the availability of macro- and micronutrients. Importantly, levels of heavy metals in soil and wheat grains remained within permissible limits, affirming the safety and appropriateness of these fertilizers for wheat cultivation. This study underscores the efficient utilization of treated Ganga sludge as a valuable organic fertilizer source, proposing a sustainable and ecologically sound approach for sewage sludge management and enhancement of agricultural productivity.

The Effect of Pesticide and Insecticide Use on Orchard Soils – A Case Study of Orchards in Dambovita County

Abstract In the early 2000s, the European Commission laid the groundwork for soil protection with a report titled “Towards a Thematic Strategy for Soil Protection”[1]. This report outlined guidelines for preserving and enhancing soil quality. As a result, understanding the levels of heavy metals in soils and their sources became a key priority for the European Union. The main objective of this study is to investigate the effect of pesticide and insecticide use on the soils of the main orchards in Dambovita County. Using WDXRF spectrometry, the elemental concentrations of As, Cd, and Pb were determined in samples collected from 10 points located in the main orchards of Dambovita County. The distribution maps obtained, as well as the comparisons made with the maximum allowable limits of pollutant elements in soils, demonstrated the impact that pesticide and insecticide use can have on soil.

Spatial distribution, ecological and ecotoxicity evaluation of heavy metals in agricultural soils along Lala-Manjo Highway, Cameroon Volcanic Line

This study aims at assessing the spatial distribution, ecological and toxicity levels of heavy metals in agricultural soils of Lala-Manjo Highway in Cameroon. The soil samples were collected and analyzed by inductively coupled plasma-mass spectrometry. The result shows that Co, Cr, Cu, Hg, Mn, Ni, Sr, V and Zn concentrations are higher than those of the upper continental crust reference values except those of As, Cd and Pb. Correlation coefficient indicate similar input sources governed by same geochemical characteristics. Spatial distribution maps show high concentration of heavy metals in east, south and western part of the study area. Pollution indicators show that enrichment factor varied from moderate to high enrichment of heavy metals. The contamination degree (27.12–35.59), geo-accumulation index (0.01–4.94), and potential ecological risk index (RI = < 150) revealed a low to moderate levels of metallic pollution. The majority of stations have pollution load index and Nemerow integrated pollution index values greater than one, indicating serious pollution. Modified hazard quotient and toxic risk index suggest significant severity of pollution and low toxicity risk of heavy metals, pointing low toxicity effects of heavy metals to fauna and flora in the soil ecosystem. Considering the factors governing soils accumulation such as geology, climate and anthropogenic activities as well as the correlation with commonly used environmental background, it is proposed that the data from this study can be considered as a baseline of pollution to plan major agricultural developments in the area. The study underlines the importance of continuous monitoring and adaptive management for the preservation of soil ecosystem. The results may assist companies and local population in setting realistic targets for monitoring and remediation programs.

Environmental and Health Impacts Resulting From Burning Solid Waste Near Residential Areas in Diyala Governorate, Iraq

General Background: Rapid development, population growth, and improper disposal of municipal solid waste are prevalent issues in developing countries, leading to significant environmental and health challenges. Specific Background: In Iraq’s Diyala Governorate, the absence of integrated waste management exacerbates pollution through waste burning and heavy metal contamination, posing risks to nearby residential areas. Knowledge Gap: While previous studies have addressed waste management in developing countries, there is limited research on how local waste disposal practices impact air, soil, and water quality in specific areas of Diyala. Aims: This study evaluates the air quality and levels of heavy metals in soil and water near five landfill sites in Diyala Governorate: Kanaan, Al-Khalis, Baladruz, Khanaqin, and Hamrin, aiming to assess the pollution levels and the potential health risks to nearby communities. Results: The findings reveal significant differences across the sites, with the highest pollutant concentrations in Kanaan for air (40±445.8), soil (22.18±35.64), and water (3.037±3.146), while Hamrin recorded the lowest concentrations. All sites demonstrated statistically significant differences (P &lt; 0.05). Novelty: This study provides the first comprehensive analysis of the environmental impact of waste disposal practices in Diyala, linking pollutant concentrations with specific landfill sites. Implications: The results underscore the need for improved waste management strategies, including monitoring, waste sorting, and recycling initiatives, to mitigate the negative effects on public health and the environment, particularly in areas near waste dumps. Highlights: Pollution levels vary significantly across Diyala's landfill sites. Kanaan site has the highest air, soil, and water contamination. Better waste management is needed to reduce environmental and health risks. Keywords: Municipal waste, environmental pollution, heavy metals, Diyala Governorate, landfill impact

Evaluation of Physicochemical Parameters, Total Bacteria Count and some Heavy Metal Levels in Soil from Automobile Workshop Activities at Nnewi Local Government Area, Anambra State, Nigeria

Disposal of used motor oil and chemical substances on land leads to loss in soil quality by minimal abundance and variety of microorganisms in soil. The objective of this paper was to evalaute the physicochemical parameters, total bacteria count and some heavy metal levels in soil from automobile workshop activities at Nnewi Local Government Area, Anambra State, Nigeria. Using field survey and appropriate standard laboratory analyses, the results showed that the control uncontaminated soil samples recorded high bacteria count (6.9 x106 cfu/g). The available soil nitrogen(9.0), soil nutrients nitrate (15.10) and phosphorous (17.3) all recorded appropriate values when compared with WHO standard. The acidity of the soil using pH value as an indicator showed that the uncontaminated control soil samples were acceptable for crops also the Ec values. The heavy metals analysed indicates that the control soil samples were also moderate in heavy metals accumulation when compared with the contaminated soil samples particularly Cd, Pb (0.08) and Hg (0.01) while Cd was not detectable. These findings have shown that automobile activities can denature soil properties which could lead to soil infertility. The automobile activities has to be controled by the concerned agencies in Nigeria. Environmental education should be encouraged to reduce effects of anthropogenic activities on soil quality in the study area.

Improved mapping of heavy metals in agricultural soils using machine learning augmented with spatial regionalization indices

The accurate spatial mapping of heavy metal levels in agricultural soils is crucial for environmental management and food security. However, the inherent limitations of traditional interpolation methods and emerging machine-learning techniques restrict their spatial prediction accuracy. This study aimed to refine the spatial prediction of heavy metal distributions in Guangxi, China, by integrating machine learning models and spatial regionalization indices (SRIs). The results demonstrated that random forest (RF) models incorporating SRIs outperformed artificial neural network and support vector regression models, achieving R2 values exceeding 0.96 for eight heavy metals on the test data. Hierarchical clustering for feature selection further improved the model performance. The optimized RF models accurately predicted the heavy metal distributions in agricultural soils across the province, revealing higher levels in the central-western regions and lower levels in the north and south. Notably, the models identified that 25.78 % of agricultural soils constitute hotspots with multiple co-occurring heavy metals, and over 6.41 million people are exposed to excessive soil heavy metal levels. Our findings provide valuable insights for the development of targeted strategies for soil pollution control and agricultural soil management to safeguard food security and public health.

Plant traits regulated metal(loid)s in dominant herbs in an antimony mining area of the karst zone, China.

Understanding how plant functional traits respond to mining activities and impact metal(loid)saccumulation in dominant species is crucial for exploring the driving mechanisms behind plant community succession and predicting the ecological restoration potential of these plants. In this study, we investigated four dominant herbaceous species (Artemisia argyi, Miscanthus sinensis, Ficus tikoua, and Ageratina adenophora) growing on antimony (Sb) mining sites (MS) with high Sb and arsenic (As) levels, as well as non-mining sites (NMS). The aim was to analyze the variations in functional traits and their contribution to Sb and As concentrations in plants. Our results indicate that mining activities enhanced soil nitrogen (N) limitation and phosphorus (P) enrichment, while significantly reducing the plant height of three species, except for F. tikoua. The four species absorbed more calcium (Ca) to ensure higher tolerance to Sb and As levels, which is related to the activation of Ca signaling pathways and defense mechanisms. Furthermore, plant Sb and As concentrations were dependent on soil metal(loid) levels and plant element stoichiometry. Overall, these findings highlight the regulatory role of plant element traits in metal(loid) concentrations, warranting widespread attention and further study in the future.

THE POTENTIAL OF Catharanthus Roseus AS A PHYTOREMEDIATION AGENT FOR HEAVY METAL REMOVAL IN CONTAMINATED SOIL

Heavy metals from human activities, such as industrial emissions and mining waste, contribute to environmental, nutritional, and health issues. Catharanthus roseus, a phytoremediation plant, was tested to determine the levels of heavy metals in soil and plants. The experiment involved preparing various amounts of heavy metals by combining four elements: Cadmium (Cd), Copper (Cu), Lead (Pb), and Zinc (Zn). Four treatment groups were tested, each with varying levels of heavy metal contamination. The initial group (T0) served as the positive control, while the next four groups (T1-T4) were subjected to escalating levels of heavy metals. T1 was given a 200ml solution containing 0.9 (Cd) + 4.0 (Cu) + 0.18 (Pb) + 6.9 (Zn). T2 was given a 200ml solution containing 11.90 (Cd) +19.80 (Cu) +36.00 (Pb) + 54.3 (Zn). T3 was given a 200ml solution containing 23.80 (Cd) + 39.60 (Cu) + 72.00 (Pb) + 108.6 (Zn). T4 was given a 200ml solution containing of 23.80 (Cd) + 39.60 (Cu) + 72.00 (Pb) + 108.6 (Zn). The dataset included measurements of soil pH, heavy metal concentrations, plant height, and shoot and root length. The results showed that the T3 solution, consisting of 23.80 (Cd) + 39.60 (Cu) + 72.00 (Pb) + 108.6 (Zn), had the most favourable plant growth performance based on soil and plant concentrations. This suggests that immediate action is needed to ensure safe food availability.

Exploring Phytoremediation Potential: A Comprehensive Study of Flora Inventory and Soil Heavy Metal Contents in the Northeastern Mining Districts of Morocco.

Mining activities produce waste materials and effluents with very high metal concentrations that can negatively impact ecosystems and human health. Consequently, data on soil and plant metal levels are crucial for evaluating pollution severity and formulating soil reclamation strategies, such as phytoremediation. Our research focused on soils and vegetation of a highly contaminated site with potentially toxic metals (Pb, Zn, and Cu) in the Touissit mining districts of eastern Morocco. Vegetation inventory was carried out in three mine tailings of the Touissit mine fields using the "field tower" technique. Here, 91 species belonging to 23 families were inventoried: the most represented families were Poaceae and Asteraceae, and the biological spectrum indicated a predominance of Therophytes (55.12%). From the studied areas, 15 species were selected and collected in triplicate on the tailings and sampled with their corresponding rhizospheric soils, and analyzed for Pb, Zn, and Cu concentrations. Reseda lutea, lotus marocanus, and lotus corniculatus can be considered as hyperaccumulators of Pb, as these plants accumulated more than 1000 mg·kg-1 in their aerial parts. According to TF, these plant species could serve as effective plants for Pb phytoextraction.

Assessment of heavy metals in soil, leaf litter, and their bioaccumulation in terrestrial macroinvertebrates in Sohag Governorate, Egypt.

The presence of elevated levels of heavy metals in soil poses a significant environmental concern with implications for human health and other organisms. The main objective of our study was to reduce the gap information of seasonal abundance, distribution of heavy metals in soil, leaf litter, and some macroinvertebrates in a citrus orchard (Citrus sinensis) in Sohag Governorate, Egypt. The heavy metals copper (Cu), zinc (Zn), lead (Pb), and cadmium (Cd) were determined by atomic absorption spectrometry. Degree of contamination (DC) was determined for both soil and leaf litter contamination. However, the bioaccumulation factor (BAF) was estimated to determine metal accumulation in the macroinvertebrates including earwigs Anisolabis maritima, chilopoda Scolopendra moristans, spider Dysdera crocata, and earthworm Aporrectodea caliginosa. The study area had clay-loam with varying organic matter, salinity, and pH levels. The degree of contamination varied among seasons, with the highest levels typically observed in autumn in both soil and leaf litter. The soil ranged from low contamination (1.82) to high contamination levels (4.4), while the leaf litter showed extremely high (30.03) to ultra-high (85.92) contamination levels. The mean ecological risk index results indicated that the sampling area had moderate ecological risk levels for Cd (44.3), Zn (42.17), and Pb (80.05), and extremely high levels for Cu (342.5). Heavy metal concentrations in the selected fauna were the highest in autumn, and the bioaccumulation factor varied among species and seasons with some species classified as e-concentrators, micro-concentrators, and macro-concentrators of certain heavy metals. Scolopendra moristans exhibited the highest mean metal concentrations (Cd, Pb, and Zn), while Aporrectodea caliginosa had the lowest. Thus, the differences in heavy metal concentrations found in different soil taxa highlight the significance of taxing a holistic understanding of feeding mechanisms into account when evaluating the potential risk for animals that consume invertebrates.

Assessment of Heavy Metal Contamination in Irrigated Farmland and Associated Health Risks in Kano State, Nigeria: A Review

Study’s Excerpt/Novelty Soil pollution in Kano State is primarily caused by the use of contaminated irrigation water and household/industrial sludge as fertilizers, leading to heavy metal contamination in crops. The buildup of heavy metals in soil and crops poses significant health risks and potential food insecurity, necessitating multiple research projects to assess and address the situation. Implement regular monitoring of heavy metal levels in soils and crops, and establish guidelines for safe cultivation and consumption of vegetables grown on contaminated soils to mitigate health risks. Full Abstract The primary causes of soil pollution in Kano state, which leads to heavy metal contamination in crops grown from such soils, are using contaminated water for irrigation and household and industrial sludge as fertilizers. Along waterways where untreated wastewater flows, vegetables are planted. To determine the existing situation and potential preventative and remediation measures, it has become necessary to conduct multiple research projects on the levels of heavy metals in the soil and plants grown in Kano state, Nigeria. In light of this, this study has focused on the present and potential state of heavy metal buildup in soils and farmed crops and the potential health risks that may arise from this, including food insecurity. The main findings of the conducted research were that regular monitoring of the level of heavy metals in soils and crops should be established, and guidelines for the cultivation and consumption of leafy vegetables grown on contaminated soils should be set equally to avoid health risks.

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 &amp;amp; AA2), BB (BB1 &amp;amp; BB2), CC (CC1 &amp;amp; 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&lt;sub&gt;3&lt;/sub&gt; 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.

Differentiating anthropogenic effects from natural metal(loid) levels in residential soil near a zinc smelter in South Korea.

Metal(loid)s pose a significant hazard due to inherent toxicity. Individuals are particularly exposed to metal(loid)s in soil through direct or indirect contact. Identifying metal(loid) sources in soil is required for exposure mitigation to anthropogenic metal(loid)s, while metal(loid)s are natural constitutes of soil. Metal(loid) concentrations and Pb isotopes were determined in residential soil profiles impacted by a Zn smelter to distinguish the anthropogenic effect from natural levels. One hundred sixty-nine core soil samples were collected from depths down to 5.5m below ground level at 19 sites and were divided into Zn-Cd-As- and As-contaminated groups based on the worrisome level (WL) of soil contamination. The Zn-Cd-As-contaminated group (n = 62) was observed at depths < 1m, showed high Zn levels (mean of 1168mg/kg) and Cd and As frequently exceeding WLs, and had low 206Pb/207Pb ratios close to the Zn smelter. In contrast, the As-contaminated group (n = 96) was observed at depths > 1m, did not have other metals exceeding WLs, and showed a wide range of 206Pb/207Pb ratios far away from the Zn smelter. The results indicated that the pollution sources of Zn-Cd-As- and As-contaminated soils were fugitive dust emissions from smelter stacks and geology, respectively. The metal(loid)s in host rock set geochemical baselines in soil profiles, while smelting activities affected the upper layers over 50years. This study demonstrated the effectiveness of utilizing the vertical distribution of metal(loid) concentrations and Pb isotopes in soil profiles for distinguishing between anthropogenic and geogenic origins, in combination with baseline assessment.

Heavy metal content in dumpsite soils and vegetables: A case study of Ondo Town, Nigeria

The investigation scrutinized the levels and distribution of five heavy metals (iron, cadmium, copper, lead, and nickel) at two dumpsites (Site A and Site B) and a control zone in Ondo Town, Nigeria. Moreover, the examination assessed the presence of these heavy metals in vegetable plants (Talinum triangulare and Chromolaena odorata) commonly encountered in these areas, employing atomic absorption spectrophotometry (Buck AAS 210 VGP). Conventional methodologies were utilized to evaluate specific soil physicochemical characteristics. In the control region, minimal levels of each metal were identified, with the exception of nickel. The quantities of metals varied, with lead at 0.02 mg/kg in the control area and iron at 3.54 mg/kg in Site A. The metal levels in both soil and vegetables investigated generally remained below the maximum thresholds established by the World Health Organization (WHO) for soil and vegetables, except for cadmium in Site A. The dumpsites and the associated vegetables displayed elevated levels of the heavy metals in comparison to the control area, suggesting a gradual accumulation of these metals in the vegetable flora. Hence, the consumption of vegetables cultivated near the examined sites and the use of these areas for agricultural activities should be discouraged.

Plant colonizers of a mercury contaminated site: trace metals and associated rhizosphere bacteria

Background and aimsMercury (Hg) contamination poses severe human and environmental health risks. We aimed to evaluate the colonization of Hg-contaminated sites by native plants and the prokaryotic composition of rhizosphere soil communities of the dominant plant species.MethodsA field study was conducted at a Hg-contaminated site in Romania. Metal concentrations in soil and plant samples were analyzed using portable X-ray fluorescence spectrometry. The prokaryotic composition of rhizosphere soil communities was determined through 16S rRNA amplicon sequencing and community functionality was predicted through PICRUSt2.ResultsSite-specific trace metal distribution across the site drove plant species distribution in the highly contaminated soil, with Lotus tenuis and Diplotaxis muralis associated with higher Hg concentrations. In addition, for the bacterial communities in the rhizosphere soil of D. muralis, there was no observable decrease in alpha diversity with increasing soil Hg levels. Notably, Actinomycetota had an average of 24% relative abundance in the rhizosphere communities that also tested positive for the presence of merA, whereas in the absence of merA the phylum’s relative abundance was approximately 2%. merA positive rhizosphere communities also displayed an inferred increase in ABC transporters.ConclusionsThe results suggest a dependence of species-wise plant survival on local trace metal levels in soil, as well as an intricate interplay of the latter with rhizosphere bacterial diversity. Knowledge of these interdependencies could have implications for phytoremediation stakeholders, as it may allow for the selection of plant species and appropriate soil microbial inoculates with elevated Hg tolerance.

Heavy Metal Pollution in Soils near Ilesha Gold Mining Area, Nigeria

Background The discovery of extensive gold deposits has raised concerns about potential heavy metal contamination in waterways and adjacent soils, particularly in developing nations like Nigeria where environmental regulations may not be stringent enough. Objective A research study was conducted to assess the levels of heavy metals in surface soils (0 to 25 cm deep) across 30 sites within three selected areas (Epe, Igun, and Ijana) located in the gold mining region of Ilesha, Osun State Nigeria. Methods The study employed an atomic absorption spectrophotometer to measure the total concentrations of heavy metals, specifically arsenic (As), cadmium (Cd), cobalt (Co), chromium (Cr), copper (Cu), nickel (Ni), lead (Pb), and zinc (Zn). Furthermore, the research encompassed an examination of various physicochemical properties of the soil samples, including organic matter content, pH levels, organic carbon content, calcium content, phosphorus levels, cation exchange capacity, and particle size distribution. Results Results showed a range mean concentration with standard deviation of As, Cd, Co, Cr, Cu, Ni, Pb and Zn of 1.0 – 7.1 ± 1.77 mg kg-1, 0.9 – 4.2 ± 0.84 mg kg-1, 1.0 – 6.0 ± 1.29 mg kg-1, 1.1 – 6.4 ± 1.57 mg kg-1, 2.90 – 20.9± 4.00 mg kg-1, 1.1 – 6.4 ±1.56 mg kg-1, 0.7 – 6.7 ±1.26 mg kg-1 and 11.7 – 70.7± 17.75 mg kg-1, respectively. The investigation of soils in three specific locations revealed significant contamination by heavy metals. However, it is worth noting that the concentrations of these metals fell below the established intervention levels outlined by environmental protection agencies such as the World Health Organization and the Food and Agriculture Organization. The distribution of heavy metals and their availability exhibited a direct correlation with the distance from the mining sites, spanning from 0 to 900 meters. Two critical factors influencing the concentration of heavy metals in these areas were identified as soil particle size, specifically the clay percentage, and pH levels. Conclusion Despite the presence of heavy metal pollution in the soils of Epe, Igun, and Ijana, they managed to maintain metal levels below the intervention thresholds set by environmental protection agencies, with the exception of cadmium (Cd).

Remediate and sense: alginate beads empowered by portable electrochemical strips for copper ion removal and detection at environmental sites.

The contamination of environmental sites due to the presence of persistent species represents an important issue to be tackled. In particular, the presence of high levels of metals in soil and surface water is more frequent. One of the metals that sometimes exceeds the permissible limit set by regulatory authorities is copper. For instance, copper-based fungicides are widely used in viticulture. However, copper ions remain in soil and can enter the food chain, posing threats to human health and environmental safety. Although the rapid detection of copper ions using portable sensors is effective in enhancing early warning, it sometimes solves only half of the problem as remediation is not considered. In this paper, we present a novel integrated/portable approach that merges the remediation and sensing of metals by proposing a remediate-and-sense concept. In order to realize this concept, alginate beads were coupled with printed electrochemical strips for on-site copper detection. Within the same architecture, alginate beads were used to remove copper ions from the soil, and printed electrochemical strips were used to evaluate the efficacy of remediation at the point of need. The concept was applied towards soil containing copper ions at the parts per billion level; with few alginate beads and in the absence of additional species, copper ions were quantitatively removed from the matrix; and 3D printing allowed us to combine the printed strips and spheres within a unique tool. The architecture was optimized and the results were compared to inductively coupled plasma-mass spectrometry (ICP-MS) measurements with a recovery percentage of 90%-110%. It should be noted that this novel portable approach may be applied to other pollutants, opening new possibilities for integrated remediation and sensing.