Contamination Of Agricultural Soils Research Articles

Heavy Metal(oid)s Contamination and Potential Ecological Risk Assessment in Agricultural Soils.

Soil pollution caused by heavy metal(oid)s has generated great concern worldwide due to their toxicity, persistence, and bio-accumulation properties. To assess the baseline data, the heavy metal(oid)s, including manganese (Mn), iron (Fe), Cobalt (Co), nickel (Ni), copper (Cu), zinc (Zn), arsenic (As), lead (Pb), mercury (Hg), chromium (Cr), and cadmium (Cd), were evaluated in surface soil samples collected from the farmlands of Grand Forks County, North Dakota. Samples were digested via acid mixture and analyzed via inductively coupled plasma mass spectrometry (ICP MS) analysis to assess the levels, ecological risks, and possible sources. The heavy metal(oid) median levels exhibited the following decreasing trend: Fe > Mn > Zn > Ni > Cr > Cu > Pb > Co > As > Cd > Hg. Principal component analysis (PCA) and hierarchical cluster analysis (HCA) suggested the main lithogenic source for the studied metal(oid)s. Metal(oid) levels in the current investigation, except Mn, are lower than most of the guideline values set by international agencies. The contamination factor (Cf), geo accumulation index (Igeo) and enrichment factor (EF) showed considerable contamination, moderate contamination, and significant enrichment, respectively, for As and Cd on median value basis. Ecological risk factor (Er) results exhibited low ecological risk for all studied metal(oid)s except Cd, which showed considerable ecological risk. The potential ecological risk index (PERI) levels indicated low ecological risk to considerable risk. Overall, the results indicate the accumulation of As and Cd in the study area. The high nutrients of the soils potentially affect their accumulation in crops and impact on consumers' health. This drives the impetus for continued environmental monitoring programs.

Physiological and molecular bases of the nickel toxicity responses in tomato

Nickel (Ni), a component of urease, is a micronutrient essential for plant growth and development, but excess Ni is toxic to plants. Tomato (Solanum lycopersicum L.) is one of the important vegetables worldwide. Excessive use of fertilizers and pesticides led to Ni contamination in agricultural soils, thus reducing yield and quality of tomatoes. However, the molecular regulatory mechanisms of Ni toxicity responses in tomato plants have largely not been elucidated. Here, we investigated the molecular mechanisms underlying the Ni toxicity response in tomato plants by physio-biochemical, transcriptomic and molecular regulatory network analyses. Ni toxicity repressed photosynthesis, induced the formation of brush-like lateral roots and interfered with micronutrient accumulation in tomato seedlings. Ni toxicity also induced reactive oxygen species accumulation and oxidative stress responses in plants. Furthermore, Ni toxicity reduced the phytohormone concentrations, including auxin, cytokinin and gibberellic acid, thereby retarding plant growth. Transcriptome analysis revealed that Ni toxicity altered the expression of genes involved in carbon/nitrogen metabolism pathways. Taken together, these results provide a theoretical basis for identifying key genes that could reduce excess Ni accumulation in tomato plants and are helpful for ensuring food safety and sustainable agricultural development.

A comparative evaluation of biochar and Paenarthrobacter sp. AT5 for reducing atrazine risks to soybeans and bacterial communities in black soil

Application of biochar and inoculation with specific microbial strains offer promising approaches for addressing atrazine contamination in agricultural soils. However, determining the optimal method necessitates a comprehensive understanding of their effects under similar conditions. This study aimed to evaluate the effectiveness of biochar and Paenarthrobacter sp. AT5, a bacterial strain known for its ability to degrade atrazine, in reducing atrazine-related risks to soybean crops and influencing bacterial communities. Both biochar and strain AT5 significantly improved atrazine degradation in both planted and unplanted soils, with the most substantial reduction observed in soils treated with strain AT5. Furthermore, bioaugmentation with strain AT5 outperformed biochar in enhancing soybean growth, photosynthetic pigments, and antioxidant defenses. While biochar promoted higher soil bacterial diversity compared to strain AT5, the latter selectively enriched specific bacterial populations. Additionally, soil inoculated with strain AT5 displayed a notable increase in the abundance of key genes associated with atrazine degradation (trzN, atzB, and atzC), surpassing the effects observed with biochar addition, thus highlighting its effectiveness in mitigating atrazine risks in soil.

Exploring the impact of organic and inorganic amendments, with foliar application of iron nanoparticles, on cadmium stabilization and growth of maize in wastewater irrigated-soil

ObjectivesThis study addresses the critical issue of Cd contamination in agricultural soils, posing substantial risks to crop productivity and food safety. While prior pot experiment has undertook this issue on a small scale, this study aims to evaluate the efficacy of selected best soil amendments, at a large-scale field experiment. MethodologyPress mud and humic acid were applied at 0.5%, while gypsum and Fe2O3 were applied at 5 mg/kg alone and with foliar application of Fe nanoparticles at 5 mg/L. AnalysisComparative analysis with control revealed the immobilization efficiency of all amendments in descending order of effectiveness as follows: 100, 102, 104, 104, 105, 102, 105, and 105% for PM, HA, GYP, Fe, PM + Fe Nps, HA + Fe Nps, GYP + Fe Nps, and Fe + Fe Nps. Additionally, reduced growth, photosynthetic activities, and elevated levels of malondialdehyde and hydrogen peroxide, indicative of oxidative damage in control plant. FindingsApplication of these amendments with foliar spraying of Fe Nps effectively mitigates Cd toxicity in maize crops, leading to improved growth, biomass, photosynthetic pigments, and antioxidant enzyme activities. Novelty/ImprovementThese findings highlight the significance of exploring innovative approach of combining different amendments with foliar application of nanoparticles to mitigate Cd contamination and enhance soil health, thereby contributing to global efforts in ensuring food safety and security.

Amelioration of chromium toxicity in wheat plants through exogenous application of nano silicon

Chromium (Cr) contamination in agricultural soils poses a risk to crop productivity and quality. Emerging nano-enabled strategies show great promise in remediating soils contaminated with heavy metals and enhancing crop production. The present study was aimed to investigate the efficacy of nano silicon (nSi) in promoting wheat growth and mitigating adverse effects of Cr-induced toxicity. Wheat seedlings exposed to Cr (K2Cr2O7) at a concentration of 100 mg kg−1 showed significant reductions in plant height (29.56%), fresh weight (35.60%), and dry weight (38.92%) along with enhanced Cr accumulation in roots and shoots as compared to the control plants. However, the application of nSi at a concentration of 150 mg kg−1 showcased substantial mitigation of Cr toxicity, leading to a decrease in Cr accumulation by 27.30% in roots and 35.46% in shoots of wheat seedlings. Moreover, nSi exhibited the capability to scavenge oxidative stressors, such as hydrogen peroxide (H2O2), and malondialdehyde (MDA) and electrolyte leakage, while significantly enhancing gas exchange parameters, total chlorophyll content, and antioxidant activities (enzymatic and nonenzymatic) in plants grown in Cr-contaminated soil. This study further found that the reduced Cr uptake by nSi application was due to downregulating the expression of HMs transporter genes (TaHMA2 and TaHMA3), alongwith upregulating the expression of antioxidant-responsive genes (TaSOD and TaSOD). The findings of this investigation highlight the remarkable potential of nSi in ameliorating Cr toxicity. This enhanced efficacy could be ascribed to the distinctive size and structure of nSi, which augment its ability to counteract Cr stress. Thus, the application of nSi could serve as a viable solution for production of crops in metal contaminated soils, offering an effective alternative to time-consuming and costly remediation techniques.

Rice rhizospheric effects and mechanism on soil cadmium bioavailability during silicon application

Exogenous Si mitigates the mobility and bioavailability of Cd in the soil, thereby alleviating its phytotoxicity. This study focused on specific Si-induced immobilisation effects within the rhizosphere (S1), near-rhizosphere (S2), and far-rhizosphere (S3) zones. Based on the rhizobox experiment, we found that applying Si significantly elevated soil pH, and the variation amplitudes in the S3 soil exceeded those in the S1 and S2 soils. Si-induced changes in the rhizosphere also included enhanced dissolved organic carbon and diminished soil Eh, particularly in the Si400 treatment. Meanwhile, the introduction of Si greatly enhanced the Fe2+ and Mn2+ concentrations in the S1 soil, but reduced them in the S2 soil. The rhizosphere effect of Si which enriched Fe2+ and Mn2+ subsequently promoted the formation of Fe and Mn oxides/hydro-oxides near the rice roots. Consequently, the addition of Si significantly reduced the available Cd concentrations in S1, surpassing the reductions in S2 and S3. Moreover, Si-treated rice exhibited increased Fe plaque generation and fixation on soil Cd, resulting in decreased Cd concentrations in rice tissues, accompanied by reduced Cd translocation from roots to shoots and shoots to grains. Structural equation modelling further highlighted that Si is essential in Cd availability in S1 and Fe plaque development, ultimately mitigating Cd accumulation in rice. Si-treated rice also exhibited higher biomass and grain yield than those of control groups. These findings provide valuable insights into Si-based strategies for addressing the Cd contamination of agricultural soils.

Exploring Bacillus mycoides PM35 efficacy in enhancing rice (Oryza sativa L.) response to different types of microplastics through gene regulation and cellular fractionation.

Soil contamination with microplastics (MPs) is a persistent threat to crop production worldwide. With a wide range of MP types, including polystyrene (PS), polyvinyl chloride (PVC) and polyethylene (PE), contaminating our environment, it is important to understand their impact on agricultural productivity. The present study was conducted to investigate the effects of different types of MPs (PS, PVC and PE) on various aspects of plant growth. Specifically, we examined growth and biomass, photosynthetic pigments, gas exchange attributes, oxidative stress responses, antioxidant compound activity (both enzymatic and non-enzymatic), gene expression, proline metabolism, the AsA-GSH cycle and cellular fractionation and nutritional status, in different parts of rice (Oryza sativa L.) seedlings, which were also exposed to plant growth promoting rhizobacteria (PGPR), i.e. Bacillus mycoides PM35, i.e. 20 μL. The research outcomes indicated that the different types of MPs in the soil notably reduced plant growth and biomass, photosynthetic pigments and gas exchange attributes. However, MP stress also induced oxidative stress in the roots and shoots of the plants by increasing malondialdehyde (MDA), hydrogen peroxide (H2O2) and electrolyte leakage (EL) which also induced increased compounds of various enzymatic and non-enzymatic antioxidants and also the gene expression. Furthermore, a significant increase in proline metabolism, the AsA-GSH cycle, and the fractionations of cellular components was observed. Although the application of B. mycoides PM35 showed a significant increase in plant growth and biomass, gas exchange characteristics, enzymatic and non-enzymatic compounds and their gene expression and also decreased oxidative stress. In addition, the application of B. mycoides PM35 enhanced cellular fractionation and decreased the proline metabolism and AsA-GSH cycle in O. sativa plants. These results open new insights for sustainable agriculture practices and hold immense promise in addressing the pressing challenges of MP contamination in agricultural soils.

Bioaugmentation of manures by a tiamulin-degrading Sphingomonas as a means to alleviate environmental dispersal of antibiotic residues

Bioaugmentation of veterinary antibiotic (VA)-contaminated feces with VA-degrading bacteria, can reduce the VA-selective pressure on manure microorganisms toward antibiotic resistance during organic soil fertilization. We explored the efficiency of a Sphingomonas isolate, able to degrade tiamulin (TIA), as a bioaugmentation agent for removing TIA from pig manures fortified with TIA at two concentrations (5 and 50 µg g−1). Bioaugmentation efficiency was compared with stockpiling and anaerobic digestion. Bioaugmentation accelerated TIA dissipation (DT50 = 32.3 and 66.2 days) compared with anaerobic digestion (DT50 = 103 and 126.7 days) and stockpiling (DT50 = 95.38 and 113.8 days). Furthermore, we determined the impact of TIA on methane production and followed microbial succession during anaerobic digestion. The lower TIA concentration stimulated biomethanation, seemingly, through induction of the increase of Methanosarcina (from below detection at the TIA-free samples to 17.1% of relative abundance at the low in TIA content samples), commonly linked with aceticlastic biomethanation. Our findings highlight (i) the potential of bioaugmentation in treating VA-contaminated manures for mitigating the dispersal of VA residues in agricultural settings (ii) the high risk of contamination of agricultural soils by the use of TIA-contaminated manures that have been stockpiled or anaerobically digested before their use in agricultural settings.

Health and ecological risk of heavy metals in agricultural soils related to Tungsten mining in Southern Jiangxi Province, China.

Dayu County, a major tungsten producer in China, experiences severe heavy metal pollution. This study evaluated the pollution status, the accumulation characteristics in paddy rice, and the potential ecological risks of heavy metals in agricutural soils near tungsten mining areas of Dayu County. Furthermore, the impacts of soil properties on the accumulation of heavy metals in soil were explored. The geo-accumulation index (Igeo), the contamination factor (CF), and the pollution load index (PLI) were used to evaluate the pollution status of metals (As, Cd, Cu, Cr, Pb, Mo, W, and Zn) in soils. The ecological risk factor (RI) was used to assess the potential ecological risks of heavy metals in soil. The health risks and accumulation of heavy metals in paddy rice were evaluated using the health risk index and the translocation factor (TF), respectively. Pearson's correlation coefficient was used to discuss the influence of soil factors on heavy metal contents in soil. The concentrations of metals exceeded the respective average background values for soils (As: 10.4, Cd: 0.10, Cu: 20.8, Cr: 48.0, Pb: 32.1, Mo: 0.30, W: 4.93, Zn: 69.0, mg/kg). The levels of As, Cd, Mo, and tungsten(W) exceeded the risk screening values for Chinese agricultural soil contamination and the Dutch standard. The mean concentrations of the eight tested heavy metals followed the order FJ-S > QL > FJ-N > HL > CJ-E > CJ-W, with a significant distribution throughout the Zhangjiang River basin. Heavy metals, especially Cd, were enriched in paddy rice. The Igeo and CF assessment indicated that the soil was moderately to heavily polluted by Mo, W and Cd, and the PLI assessment indicated the the sites of FJ-S and QL were extremely severely polluted due to the contribution of Cd, Mo and W. The RI results indicated that Cd posed the highest risk near tungsten mining areas. The non-carcinogenic and total carcinogenic risks were above the threshold values (non-carcinogenic risk by HQ > 1, carcinogenic risks by CR > 1 × 10-4 a-1) for As and Cd. Correlation analysis indicated that K2O, Na2O, and CaO are main factors affecting the accumulation and migration of heavy metals in soils and plants. Our findings reveal significant contamination of soils and crops with heavy metals, especially Cd, Mo, and W, near mining areas, highlighting serious health risks. This emphasizes the need for immediate remedial actions and the implementation of stringent environmental policies to safeguard health and the environment.

Prediction of the impact of ecological restoration technology on the restoration of heavy metal pollution in agricultural soil

ABSTRACT Heavy metal in agricultural soils increases its contamination and infertility in a due course of time. The vast expansion of industrialization along the agricultural soils has led to such adverse effects impacting vegetation. Several existing learning techniques are utilized to analyze the contamination in agricultural soil; however, the learning process consumes a high restoration error rate. This article introduces a Concentration-specific Restoration Prediction Technique (CRPT) for heavy metal-exposed agricultural soils. This technique relies on the heavy metal level present in different soil types for assessing its adverse impact. The vegetation failures and infertility progressions are accounted for by the continuous recurrent learning for predicting its restoration age. The restoration procedures preferred in the earlier stages are used for training the recurrent neural network. Based on the more feasible restoration method, the failure and infertility are validated for achieving a maximum prediction value. The learning process accounts for soil type, crop resistance, and climatic factors for holding restoration procedures. Therefore, the learning process performs restoration prediction along with resistance analysis for progressive restoration prediction. The least possible prediction value is validated using different training inputs for matching outputs. This technique is reliable in detecting pollution possibility with maximum restoration prediction (9.41%) and less training error (14.53%).

A Perspective on Plastics and Microplastics Contamination in Garden Soil in British Columbia, Canada

Plastic contamination is commonly reported in urban and rural soils, as well as in fresh and ocean waters. Canada’s government has attempted to limit the contamination of single-use plastic by banning the manufacturing and selling of specific types of plastic. In British Columbia, current regulations governing commercial composting state that when compost has less than 1% of its dry weight representing foreign materials (including plastic), it can be sold and used in soils. However, due to the low density of plastic and its potential to break down into microparticles, this amount may be enough to become toxic when used in agricultural soils. This paper studies contamination of plastic in garden soils and summarizes how this can affect the environment with a preliminary examination of a garden soil sample. The examination showed that the garden soil sample contained mainly low-density polyethylene, polyethylene and polypropylene plastics (identified through ATR-FTIR) in oxidized and unoxidized forms that can come from commercial composting and hypothesizes that this plastic could break down into microplastic particles. In order to limit the amount of plastic contamination in agricultural soils, it is necessary to modify current compost regulations in order to treat plastic differently than other foreign materials (glass, metal, wood).

Trophic Transfer and Toxic Potency of Rare Earth Elements along a Terrestrial Plant-Herbivore Food Chain.

Extensive rare earth element (REE) mining activities have caused REE contamination of ambient agricultural soils, posing threats to associated food webs. Here, a simulated lettuce-snail food chain was conducted to evaluate the trophic transfer characteristics and the consequent effects of REEs on consumers. After 50-day exposure to soil, lettuce roots dose-dependently accumulated 9.4-76 mg kg-1 REEs and translocated 3.7-20 mg kg-1 REEs to shoots. Snails feeding on REE-contaminated shoots accumulated 3.0-6.7 mg kg-1 REEs with trophic transfer factors of 0.20-0.98, indicating trophic dilution in the lettuce-snail system. REE profiles in lettuce and snails indicated light REE (LREE) enrichment only in snails and the varied REE profiles along the food chain. This was corroborated by toxicokinetics. Estimated uptake (Ku) and elimination (Ke) parameters were 0.010-2.9 kgshoot kgsnail-1 day-1 and 0.010-1.8 day-1, respectively, with higher Ku values for LREE and HREE. The relatively high Ke, compared to Ku, indicating a fast REE elimination, supports the trophic dilution. Dietary exposure to REEs dose-dependently affected gut microbiota and metabolites in snails. These effects are mainly related to oxidative damage and energy expenditure, which are further substantiated by targeted analysis. Our study provides essential information about REE bioaccumulation characteristics and its associated risks to terrestrial food chains near REE mining areas.

Source Analysis and Contribution Estimation of Heavy Metal Contamination in Agricultural Soils in an Industrial Town in the Yangtze River Delta, China

Farmland soil quality is a crucial determinant for agricultural productivity, food safety, and human well-being. Among the various contaminants, heavy metals have emerged as pervasive factors significantly impacting farmland quality, attracting widespread societal concern. In this study, we systematically applied multivariate statistical analysis, geostatistical methods, and the positive matrix factorization (PMF) source apportionment technique to elucidate the sources and contributions of eight heavy metals (Cd, Hg, As, Pb, Cr, Cu, Zn, Ni) in farmland soils within an industrialized town. Our findings reveal that Cd, Hg, Pb, and Zn exhibit pollution or enrichment in farmland soils compared to natural background levels, with Hg and Cd surpassing 164.3% and 50.2%, respectively. Notably, Zn demonstrates discernible point-source pollution. Source apportionment results highlight industrial point sources, coal combustion, and agriculture as the primary anthropogenic contributors to heavy metal contamination, with zinc-plating enterprises being the predominant industrial point sources. Addressing the specific issue of point-source pollution from Zn in industrial activities, further analysis establishes a correlation between soil Zn content and the distance from zinc-plating enterprises. Utilizing an atmospheric transport model, we observe that the impact of industrial activities on soil Zn is limited when the distance exceeds 1.5 km, emphasizing the importance of monitoring Zn pollution within areas less than 1.5 km. This study pioneers a progressive source apportionment approach, considering the origins of different heavy metals, pollution levels, distance factors, and the cost-effectiveness of environmental measures. The insights gained provide scientifically sound strategies for future decision making in environmental protection.

Contaminated soil remediation with nano-FeS loaded lignin hydrogel: A novel strategy to produce safe rice grains while reducing cadmium in paddy field

Cadmium (Cd) contamination in agricultural soil has been an elevated concern due to the high health risks associated with the transfer through the soil-food chain, particularly in the case of rice. Recently, there has numerous researches on the use of nanoparticle-loaded materials for heavy metal-polluted soil remediation, resulting in favorable outcomes. However, there has been limited research focus on the field-scale application and recovery. This study was aimed to validate the Cd reduction effect of the nano-FeS loaded lignin hydrogel composites (FHC) in mildly polluted paddies, and to propose a field-scale application method. Hence, a multi-site field experiment was conducted in southern China. After the application for 94–103 days, the FHC exhibited a high integrity and elasticity, with a recovery rate of 91.90%. The single-round remediation led to decreases of 0.42–31.72% in soil Cd content and 1.52–49.11% in grain Cd content. Additionally, this remediation technique did not adversely impact rice production. Consequently, applying FHC in the field was demonstrated to be an innovative, efficient, and promising remediation technology. Simultaneously, a strategy was proposed for reducing Cd levels while cultivating rice in mildly polluted fields using the FHC.

Insights into Agricultural Soil Contamination by a Veterinary Antibiotic TYLOSIN Through Continuous Run-Off Conditions

ABSTRACT Broad-spectrum veterinary antibiotic tylosin (TYL) is utilized in livestock and poultry. Due of its extensive usage and animal excretion in urine and feces, it affects the environment and human health. For determining the equilibrium time, the adsorption maximum capacity and the optimal isotherm model, adsorption batch tests have been conducted. Sips and Pseudo-second order models had R2 values of 0.9937 and 0.9764, respectively, and best matched experimental isotherm and kinetic data. The maximum TYL uptake onto soil was 2355.08 mg.kg−1. Using fixed bed adsorption experiments, the current study clarifies the issue of soil contamination in conditions that are close to natural phenomena. Fixed bed adsorption tests demonstrated that the inlet TYL concentration, soil bed height, and flow rate, influenced saturation and breakthrough times. Bohart-Adams, Thomas, and Yoon-Nelson models matched the experimental findings well in a variety of conditions. With 100 mg.L−1 concentration, 4 cm bed height, and 5 mL.min−1 flow rate, the maximal bed capacity of 1277.06 mg.kg−1 was achieved with R2 value of 0.9797. Experimental findings also indicated that the adsorption capacity in batch and dynamic tests are of the same range of magnitude. Based on this, tylosin is a probable soil contaminant.

Early warning of heavy metals contamination in agricultural soils: Spatio-temporal distribution and future trends in the Hexi Corridor

Conducting risk and early warning assessments of heavy metals (HMs) pollution in agricultural soils holds significant importance for pollution prevention and sustainable agricultural development. Early warning studies on heavy metal contamination of agricultural soils in oases in arid zones are rare in previous studies, therefore, this study carried out spatial and temporal simulation and early warning studies on the environmental capacity of agricultural soils in the Hexi Corridor based on field monitoring data and remote sensing technology and other methods. The results revealed that agricultural soils have been affected by human activities, leaving HMs at a moderate pollution level. The mean environmental capacity indices for Cr, Ni, Cu, Zn, As and Pb showed that they all belonged to the medium-capacity state, and 7.01 % of the sampling points being overloaded and in the low capacity for As. Cr, Ni, Zn and As were found in the moderate and high capacity zones located in the study area's western part, and the spatial distribution was basically the same. HMs in the middle parts area were dominated by low to medium capacity status, which may be related to agricultural activities such as application of fertilizers and pesticides and sewage irrigation. Based on the soil dynamic capacity model, it was found that in the next 20 years, HMs showed a decrease of 70–80 %, and the soil environment dynamic capacity was smaller than both the static and existing capacity, and it showed a decreasing trend with the change of time, which indicated that the soil's capacity for pollutants in the study area would be reduced if no pollution control measures were taken. Risk warning results showed that the overall spatial distribution pattern of the probability of pollution in the study area during the next 10 and 20 years was lower in the west and the northern part of Wuwei City, and higher in the middle part. This study suggests constructing a management system of “pollution evaluation - source treatment - risk early warning” for heavy metal contaminated sites, formulating corresponding policies and early warning measures, strengthening the research and development of monitoring, remediation, and treatment technologies, and realizing the prevention and control of agricultural soil pollution and sustainable development in the study area.

Herbicide contamination of Batak plain agricultural soils and risk assessment

Herbicide residue levels were analyzed in agricultural soils of Batak plain and health risk assessments were made for relevant pesticides. Herbicide contamination levels were analyzed with the use of Quick-Easy-Cheap-Efficient-Rugged-Safe (QuEChERS)-liquid chromatography/tandem mass spectrometry (LC–MS/MS) procedure. Herbicide-free soil samples were spiked at two different levels. Overall recovery of the method was 87.32%. Present findings were parallel to SANTE recovery limits. About 50% of collected samples from the study sites contained herbicides at different concentrations. Totally, eight herbicides were detected, and herbicide concentrations ranged between 1.085 and 1724.23 μg kg−1. Metolachlor had the highest concentration (1724.23 μg kg−1) in a sample taken close to the pesticide waste disposal area. Six herbicides were detected at different concentrations in the same sample. Persistent herbicides (terbuthylazine and pendimethalin) were detected in 35 samples. Risk assessments revealed that hazard index (HI) and hazard quotient (HQ) were less than 1. The greatest HQ values were identified for terbuthylazine as 2772.48 × 10−7 and 20793.61 × 10−7 for adults and children, respectively. The HI for all herbicides were 3916.05 × 10−7 for adult and 29370.39 × 10−7 for children.

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.

Iron-modified biochar effectively mitigates arsenic-cadmium pollution in paddy fields: A meta-analysis

The escalating problem of compound arsenic (As) and cadmium (Cd) contamination in agricultural soils necessitates the urgency for effective remediation strategies. This is compounded by the opposing geochemical behaviors of As and Cd in soil, and the efficacy of biochar treatment remains unclear. This pioneering study integrated 3780 observation pairs referred from 92 peer-reviewed articles to investigate the impact of iron-modified biochar on As and Cd responses across diverse soil environments. Regarding the treatments, 1) biochar significantly decreased the exchangeable and acid-soluble fraction of As (AsF1, 20.9%) and Cd (CdF1, 24.0%) in paddy fields; 2) iron-modified biochar significantly decreased AsF1 (32.0%) and CdF1 (27.4%); 3) iron-modified biochar in paddy fields contributed to the morphological changes in As and Cd, mainly characterized by a decrease in AsF1 (36.5%) and CdF1 (36.3%) and an increase in the reducible fraction of As (19.7%) and Cd (39.2%); and 4) iron-modified biochar in paddy fields increased As (43.1%) and Cd (53.7%) concentrations in the iron plaque on root surfaces. We conclude that iron-modified biochar treatment of paddy fields is promising in remediating As and Cd contamination by promoting the formation of iron plaque.

Ecological risk assessment of potentially toxic elements (PTEs) in agricultural soil, vegetables and fruits with respect to distance gradient in proximity to lead-acid battery industry

Lead-acid battery industries in Bangladesh have proliferated in urban areas, leading to the release of significant amounts of potentially toxic elements (PTEs) and metalloids into the environment. This study aimed to assess the spatial distribution, sources, contamination status, and ecological risks in agricultural soils, vegetables, and fruits near these industries. Soil samples were collected from four sites at varying distances (0 m, 100 m, 250 m, and 500 m) around three lead-acid battery industries (AA, AB, and AC) in Dhaka and Gazipur Districts during June-July 2020. The concentrations of the Pb, As, Cd and Zn in agricultural soils were ranged between 8.40–116.61, 8.99–28.21, 0.03–1.28, and 25.38–68.72 mg/kg, respectively. The concentrations of Pb, As, and Cd were found to be considerably higher than background levels across all industries, with a gradual decrease in PTE concentrations from 0 m to 500 m. The contamination factor indicated high to moderate contamination in agricultural soils by As, Cd, and Pb, and low contamination by Zn. pollution load index, modified contamination degree, and nemerow comprehensive index revealed varying pollution levels in the vicinity of the industries, with AA and AB showing higher pollution compared to AC. The individual risk factors demonstrated significant risks associated with Cd and As exposure, while Pb and Zn posed lower risks. The potential ecological risk index indicated considerable ecological risk for AA (risk index = 192.41), moderate risk for AB (risk index = 111.80), AC (risk index = 65.08), respectively. Correlation and principal component analysis revealed strong positive associations (p < 0.01) among the chemical parameters and potentially toxic elements in soils, and demonstrated the lead-acid battery industry as the primary contamination source in the studied areas. There were strong positive relationships (p < 0.01) existed between As, Cd, and Zn in soils and vegetables; while a strong negative association found between As in soils with As in Fruits. The cluster analysis showed EC, OC, OM, Pb, As and Zn into separate group, implied their same source of origin as anthropogenic source. The metal uptake was in the decreasing order of Cd > Zn > As > Pb and Cd > Zn > Pb > As in vegetable and fruit samples, respectively and transfer factor analysis highlighted Cd and Zn as metals with higher absorption rates in vegetables and fruits. Among the industries, AA and AB were significantly impacted on soil quality, and considerable metal accumulation found on vegetables. The human health risk assessment results indicate a potential noncarcinogenic health hazard for the populations surrounding the industries (AA, AB, and AC). This is evidenced by the calculation of the total target hazard quotient and the hazard index, both of which exceeded the acceptable level (>1). However, the carcinogenic health risks arising from the consumption of potentially toxic elements are within threshold values. This study provides crucial insights into the environmental as well as health impact of lead-acid battery industries, emphasizing the urgency of implementing effective environmental management practices to mitigate their consequences.