Impact of biochar amendment in agricultural soils on the sorption, desorption, and degradation of pesticides: A review

Sorptive removal of neonicotinoid pesticides by nanobiochars: Efficiency, kinetics, and reusability

The widespread use of neonicotinoid (NEO) pesticides has raised significant environmental concerns due to their toxicity. We investigated the performance of 16 nanobiochars (NBCs), including NBC produced by Douglas fir at 900 °C (Doug 900 NBC), as sustainable sorbents for removing three common NEOs from aqueous solutions: imidacloprid, clothianidin, and thiamethoxam. The NBCs showed high sorption efficiency (∼ 100 %) and fast sorption kinetics (< 0.5 h) for three NEOs at environmentally relevant concentrations (100 ng/L). The sorption efficiency of NEOs was determined by the physicochemical properties of NBCs, including specific surface area (SSA), pore volume (PV), pore diameter (PD), and elemental composition (carbon, nitrogen, and hydrogen contents). The NBCs with higher SSA and larger PV offered more abundant sorption sites, facilitating fast NEO sorption. Particularly, the Doug 900 NBC achieved ∼ 100 % removal efficiency of NEOs within 0.5 h under simulated groundwater conditions (67.5 mg/L of total dissolved solids and 10 mg/L of humic acid). The Doug 900 NBC also maintained high removal efficiency over four continuous reuse cycles. The structural equation modeling revealed that pyrolysis temperature indirectly affects NEO sorption by modifying NBC's properties of SSA, PV, and PD. Our findings highlight the high potential of NBCs for sustainable removal of NEO pesticides in aquatic environments at environmentally relevant concentrations.

Effective microbial formulations using sustainable carriers for the remediation of plastic-affected soils

The increasing use of mulching films in intensive agriculture, together with their inefficient end-of-life disposal, has led to a significant plastic accumulation in soils, which contributes to disrupting ecosystems. The aim of this work was to determine the ability of different sustainable carriers to harbor and introduce plastic-degrading microorganisms into contaminated soils to provide a biotechnological tool that potentially enhances plastic decontamination, ameliorating the harmful effect of this type of pollutant in soil. To this end, pure cultures and co-cultures of Bacillus subtilis and Pseudomonas alloputida (specialized plastic-degrading strains) were added to three sustainable carriers (vermicompost, biochar, and calcium alginate beads) for the preparation of microbial formulations. After a storage period, the maintenance of cell viability and enzymatic activities related to the bioremediation potential of plastic materials of the inocula tested in the different microbial formulations (carrier + inoculant) were evaluated. The effectiveness of the formulations for plastic mineralization was tested by measuring CO2 emissions after two months. The results showed that biochar, followed by vermicompost, favored greater microbial survival (107 CFU g-1), while alginate formulations showed variable cell viability results, from 107 to 104 CFU g-1. Biochar also excelled in maintaining enzymatic activities related to plastic degradation, achieving the expression of 100% of the tested enzymes. Additionally, biochar-based formulations applied to soils contaminated with LLDPE plastic showed the highest mineralization rates, with statistically significant differences compared to the plastic-free control. These results lay the foundation for the development of new plastic decontamination technologies paving the way for the sustainable treatment of polluting and recalcitrant materials such as plastic.

Advancements in Biochar for Soil Remediation of Heavy Metals and/or Organic Pollutants

The rapid industrialization and economic growth have exacerbated the contamination of soils with both heavy metals and organic pollutants. These persistent contaminants pose substantial threats to ecosystem integrity and human health due to their long-term environmental persistence and potential for bioaccumulation. Biochar, with its high specific surface area, well-developed pore structure, and abundant surface functional groups, has emerged as a promising material for remediating soils contaminated by heavy metals and organic pollutants. While some research has explored the role of biochar in soil remediation, several aspects remain under investigation. Fully harnessing the potential of biochar for soil contamination remediation is of critical importance. This review provides an overview of the preparation methods and physicochemical properties of biochar, discusses its application in soils contaminated by organic compounds and/or heavy metals, and examines the mechanisms underlying its interaction with pollutants. Additionally, it summarizes the toxicity assessments of biochar during soil remediation and outlines future research directions, offering scientific insights and references for the practical deployment of biochar in soil pollution remediation.

Effects of soil bulk density and corresponding soil infiltration rate on the migration and transformation of gibberellic acid

High intensity agricultural activities can lead to a decrease in soil fertility and an increase in soil bulk density, which may significantly impact the migration and transformation of pesticides in soil. As a new widely-used micro-toxic pesticide, gibberellic acid (GA3) is more soluble and hydrophilic than most pesticides, which could readily migrate throughout the soil during water infiltration and impact groundwater quality. In this study, the leaching of GA3 in saturated soils with different bulk densities (1.15-1.75 g/cm3) and infiltration rates (0.2215-0.0017 mm/s) were analyzed using column experiments. The migration and distribution of GA3 in the soil with a depth of 50 cm were also investigated. The results indicated that GA3 could completely penetrate the soil with bulk densities less than 1.45 g/cm3, and GA3 mass variation in the effluent was normally distributed. The maximum mass of GA3 in the effluent was calculated using the equation Moutlet(max) = 79.01 t-0.97 (R2 = 0.9811), and 83.69-93.16 % mass of the added GA3 migrated downward in the soil. The analysis of the distribution of GA3 in the soil showed that GA3 accumulated in the upper soil layers with depths of 0-25 cm (the total depth of soil was 50 cm). In addition, the residual and hydrolyzed GA3 amounts in the soil were 75.07-96.47 % and 5-30 % of the added GA3, respectively. Overall, the soil bulk density and irrigation volume determine what type of impact that GA3 may potentially have on the environment.

Exploring the significance of different amendments to improve phytoremediation efficiency: focus on soil ecosystem services

Phytoremediation is recognized as an environmentally, economically and socially efficient phytotechnology for the reclamation of polluted soils. To improve its efficiency, several strategies can be used including the optimization of agronomic practices, selection of high-performance plant species but also the application of amendments. Despite evidences of the benefits provided by different types of amendments on pollution control through several phytoremediation pathways, their contribution to other soil ecosystem functions supporting different ecosystem services remains sparsely documented. This current review aims at (i) updating the state of the art about the contribution of organic, mineral and microbial amendments in improving phytostabilization, phytoextraction of inorganic and phytodegradation of organic pollutants and (ii) reviewing their potential beneficial effects on soil microbiota, nutrient cycling, plant growth and carbon sequestration. We found that the benefits of amendment application during phytoremediation go beyond limiting the dispersion of pollutants as they enable a more rapid recovery of soil functions leading to wider environmental, social and economic gains. Effects of amendments on plant growth are amendment-specific, and their effect on carbon balance needs more investigation. We also pointed out some research questions that should be investigated to improve amendment-assisted phytoremediation strategies and discussed some perspectives to help phytomanagement projects to improve their economic sustainability.

Transforming Food Biowaste into Selective and Reusable Adsorbents for Pesticide Removal from Water

With growing concerns regarding environmental pollution and the need for sustainable waste management practices, this study investigates the potential of utilizing spent coffee grounds (SCG) as a precursor for producing functional carbon materials aimed at organophosphorus pesticide remediation under environmentally relevant conditions. Carbonization of SCG is followed by various activation methods, including treatment with potassium hydroxide, phosphoric acid, and carbon dioxide, individually or in combination. The resulting biochars are systematically analyzed for their adsorption performance towards malathion and chlorpyrifos. Screening tests revealed a selective adsorption preference towards aromatic chlorpyrifos over aliphatic malathion. Activation processes significantly influence adsorption kinetics and efficiency, with physical activation showing notable adsorption rates and capacity enhancements. Moreover, the SCG-derived biochars exhibit a pronounced dependency on adsorption temperature. Adsorption, regeneration, and reuse of the most promising material are tested in a real, spiked tap water sample, proving that the presence of ions in tap water did not affect the adsorption and that the material has the potential to be reused more than ten times. This work proposes a straightforward approach for recycling SCG by converting it into functional carbon materials, underscoring the importance of selecting the appropriate activation processes and conditions for practical applications in pesticide remediation.

Enhanced remediation of acetochlor-contaminated soils using phosphate-modified biochar: Impacts on environmental fate, microbial communities, and plant health

Given that acetochlor (ACT) persists in soil for extended periods, disrupting microbial community structure and causing phytotoxicity to sensitive crops, this study investigated the potential of phosphate-modified biochar (PBC-800) to remediate ACT-contaminated soil. Incorporating 0.5 % PBC-800 into fluvo-aquic, red, and black soils increased their adsorption capacities by 80.4 mg g-1, 76.6 mg g-1, and 76.0 mg g-1, respectively. Even after six months of aging, the Kf values remained 1.6 to 5.1 times higher than in untreated soils. PBC-800 also accelerated ACT degradation across all three soil types, reducing residual ACT levels by 34.3 % to 76.4 % after 60 days, and shortening the degradation half-life by 5 to 7 days. High-throughput sequencing revealed that ACT reduced soil microbial diversity and disrupted community structure, while 0.5 % PBC-800 amendments promoted the growth of degradation-capable genera such as Rhodococcus, Lysobacter, and Gemmatimonas, enhancing microbial ecosystem stability. Furthermore, the amendment of soil with 0.5 % PBC-800 reduced ACT residue concentrations in maize and soybeans by 76.5 % to 82.9 %, and restored plant biomass, leaf chlorophyll content, and mesophyll cell ultrastructure to levels comparable to the control. Therefore, amending ACT-contaminated soil with PBC-800 mitigates ecological and environmental risks, boosts microbial activity, and safeguards plant health.

Pre-emergence herbicides used in urban and agricultural settings: dissipation and ecological implications

Herbicides are widely recognized as the most cost-effective solution for weed control, but their extensive use in both urban and agricultural settings raise serious concerns about nontarget effects. We assessed the possible hazards associated with pre-emergence herbicides such as dimethenamid-P, metazachlor, and pyroxasulfone, which are frequently applied in both urban and agricultural soils. The dissipation rate constant values (k day-1: 0.010-0.024) were positively linked to total organic carbon (TOC), silt, clay, soil pH, and Al and Fe oxides, but negatively correlated with sand content. In contrast, half-life values (DT50: 29-69 days) of the herbicides showed negative correlations with TOC, clay, silt, soil pH, and Fe and Al oxides, while sand content showed a positive impact. The selected herbicides showed minimal impact on soil dehydrogenase activity (DHA). Mostly, soils with higher organic matter (OM) content exhibited increased DHA levels, highlighting the role of OM in influencing this soil enzyme across different soils. Assessment of environmental indicators like groundwater ubiquity score (GUS:1.69-6.30) and leachability index (LIX: 0.23-0.97) suggested that the herbicides might reach groundwater, posing potential risks to nontarget biota and food safety. Human non-cancer risk evaluation, in terms of hazard quotient (HQ < 1) and hazard index (HI < 1), suggests minimal or no risks from exposure to soil containing herbicide residues at 50% of the initial concentrations. Our data thus help the stakeholders and regulatory agencies while applying these pre-emergence herbicides in soils and safeguarding human and environmental health.

Global meta-analysis and machine learning reveal the critical role of soil properties in influencing biochar-pesticide interactions

Biochar application in soils is increasingly advocated globally for its dual benefits in enhancing agricultural productivity and sequestering carbon. However, lingering concerns persist regarding its environmental impact, particularly concerning its interactions with pesticide residues in soil. Previous research has fragmentarily indicated elevated pesticide residues and prolonged persistence in biochar-amended soil, suggesting a potential adverse consequence of biochar application on pesticide degradation. Yet, conclusive evidence and conditions for this phenomenon remain elusive. To address this gap, we conducted a comprehensive assessment using meta-analysis and machine learning techniques, synthesizing data from 58 studies comprising 386 observations worldwide. Contrary to initial concerns, our findings revealed no definitive increase in pesticide concentrations in soil following biochar application. Moreover, a significant reduction of 66 % in pesticide concentrations within soil organisms, such as plants and earthworms, was observed. The quantitative analysis identified soil organic matter content as a key factor influencing biochar-pesticide interactions, suggesting that applying biochar to soils rich in organic matter is less likely to increase pesticide persistence. This study provides a critical assessment of the environmental fate of pesticides under biochar application, offering valuable guidance for the optimal utilization of both pesticides and biochar in sustainable agricultural practices.

The adsorption mechanism and optimal dosage of walnut shell biochar for chloramphenicol

Biochar derived from biomass pyrolysis has proven to be an excellent material for pesticide adsorption and can be used as soil amendment for pesticide non-point pollution. However, the adsorption and desorption mechanisms for certain biochar and pesticide are still unclear. In this study, we investigated the properties of biochar derived from walnut (Juglans regia L.) shell (WSB), and used batch equilibrium method to investigate the adsorption and desorption behavior for chlorantraniliprole (CAP). The physical-chemical analysis showed that there were mainly lignin charcoal of alkyl carbon, methoxyl carbon, aromatic carbon, and carboayl carbon as the primary carbon compounds of WSB. The π - π electron donor acceptor interaction, electrostatic interaction, and hydrogen bond were the primary adsorption mechanisms of the WSB adsorption. Batch equilibrium study under 298 K showed that WSB application in the soil significantly improved the adsorption ability for CAP, and the adsorption behavior was a mono-layer adsorption process as Langmuir model fitted the adsorption isotherm data better than the Freundlich model. While Freundlich model analysis showed that WSB addition to the soil changed the isothermal adsorption line from the S style to the L style. The spontaneous degree reaction of sorbents from strong to weak was in the following order: 5%-WSB >7%-WSB >10%-WSB >1%-WSB >3%-WSB > soil > WSB, and the maximum application effect was achieved at 5 % (m/m) WSB dosage mixed with the soil. Therefore, we considered that WSB addition in soil increased its CAP adsorption capacity, and 5 % (m/m) WSB application was the best choice for CAP pollution control. These data will contribute to the adsorption mechanism and the optimal use dosage of WSB for CAP pollution control.

Raw feedstock vs. biochar from olive stone: Impact on the sorption-desorption of diclosulam and tropical soil improvement

The addition of carbon-rich materials, such as raw feedstocks (RAW) and biochars, to agricultural soils is on the rise. This activity has many advantages, such as improving fertility, increasing water retention, and sequestering carbon. However, they can also increase the sorption of residual herbicides in the soil, reducing the effectiveness of weed control. Thus, the objective of this study was to evaluate soil improvement and the sorption-desorption process of diclosulam in soil unamended and amended with RAW from olive stone and their biochars produced in two pyrolysis temperatures (300 and 500 °C). Oxisol was used in this study, unamended and amended with RAW and biochars (BC300 and BC500) in a rate of 10% (w w-1). The sorption-desorption process was assessed by batch-equilibrium experiments and the analysis was performed using high-performance liquid chromatography (HPLC). The addition of the three materials to the soil increased the contents of pH, organic carbon, P, K, Ca, Mg, Zn, Fe, Mn, Cu, B, cation exchange capacity, base saturation and decreased H + Al. The unamended soil had Kf (Freundlich sorption coefficient) values of diclosulam sorption and desorption of 1.56 and 12.93 mg(1 - 1/n) L1/n Kg-1, respectively. Unamended soil sorbed 30.60% and desorbed 13.40% of herbicide. Soil amended with RAW, BC300, and BC500 sorbed 31.92, 49.88, and 30.93% of diclosulam and desorbed 13.33, 11.67, and 11.16%, respectively. The addition of RAW and biochars from olive stone has the potential to change the soil fertility, but does not interfere with the bioavailability of diclosulam in weed control under field conditions, since the materials slightly influenced or did not alter the sorption-desorption of diclosulam.

Effect of natural aging on biochar physicochemical property and mobility of Cd (II)

This project utilized both field experiment and laboratory analyses to address the gap in understanding regarding the alterations in properties and functions of biochar, and the impact of heavy metal passivation in soil over long-term natural field aging. The study aimed to examine the changes in the physical and chemical characteristics of biochar over an extended period of natural aging. Additionally, it sought to analyze the impact and mechanisms of biochar in reducing of the harmful effects of the heavy metal cadmium (Cd) during the aging process. Both original and aged biochar conformed to the pseudo-second-order kinetics model and the Langmuir model. The aging process enhanced the adsorption of Cd by biochar and mitigated the leaching of Cd2+ into the soil. These findings provide a scientific basis for evaluating biochar's environmental behavior and its potential use in the remediation of soil contaminated with heavy metals.

Insecticidal activity of essential oils from Piper aduncum against Ctenocephalides felis felis: a promising approach for flea control

Piper aduncum L., a Brazilian medicinal plant, is known for its bioactive properties, including repellent and insecticidal effects. This study investigated the insecticidal potential of essential oils (EOs) from P. aduncum, collected during the dry and rainy seasons, against fleas (Ctenocephalides felis felis Bouché, 1835) in egg and adult stages. The EOs were obtained by hydrodistillation using a modified Clevenger apparatus for 2 h. Qualitative and quantitative analysis were performed via gas chromatography. The findings revealed that dillapiole was the predominant substance in both EOs, accounting for 77.6% (rainy) and 85.5% (dry) of the EOs. These EOs exhibited high efficacy against the parasite C. felis felis, resulting in 100% egg mortality at a concentration of 100 μg/mL and 100% mortality for adult fleas starting from 1,000 μg/mL. Dillapiole standard was also effective but at a relatively high concentration. This finding suggested that EOs from P. aduncum exhibit cytotoxicity against these pests and might hold potential for commercial production, offering practical applications for such bioprospecting. This study uniquely revealed that the EOs from P. aduncum, which is rich in dillapiole, demonstrated pulicidal activity against the parasite C. felis felis, particularly in inhibiting the hatching of the eggs of these parasites.

Impact of biochar on the degradation rates of three pesticides by vegetables and its effects on soil bacterial communities under greenhouse conditions

A 28 days pesticide degradation experiment was conducted for broccoli (Brassica oleracea L. var. italica Planch) and pakchoi (Brassica chinensis L.) with three pesticides (chlorantraniliprole (CAP), haloxyfop-etotyl (HPM), and indoxacarb (IXB)) to explore the effects of biochar on pesticide environmental fate and rhizosphere soil diversity. Rice straw biochar (RB) was applied to soil at a 25.00 t ha-1 dosage under greenhouse conditions, and its effects on the degradation of three pesticides in vegetables and in soil were investigated individually. Overall, RB application effectively facilitated CAP and HPM degradation in broccoli by 13.51-39.42% and in broccoli soil by 23.80-74.10%, respectively. RB application slowed the degradation of CAP, HPM and IXB in pakchoi by 0.00-57.17% and slowed the degradation of CAP in pakchoi by 37.32-43.40%. The results showed that the effect of RB application on pesticide degradation in crops and soil was related to biochar properties, pesticide solubility, plant growth status, and soil characteristics. Rhizosphere soil microorganisms were also investigated, and the results showed that biochar application may be valuable for altering bacterial richness and diversity. The effect of biochar application on pesticide residues in crops and soil was influenced by the vegetable variety first, and the second was pesticide characteristics. RB applied to soil at a 25.00 t ha-1 dosage under greenhouse conditions is recommended for broccoli production to ensure food safety. Our results suggested that biochar application in soil could reduce pesticide non-point source pollution, especially for highly soluble pesticides, and could affect soil microorganisms.

The boom era of emerging contaminants: A review of remediating agricultural soils by biochar

Emerging contaminants (ECs) are widely sourced persistent pollutants that pose a significant threat to the environment and human health. Their footprint spans global ecosystems, making their remediation highly challenging. In recent years, a significant amount of literature has focused on the use of biochar for remediation of heavy metals and organic pollutants in soil and water environments. However, the use of biochar for the remediation of ECs in agricultural soils has not received as much attention, and as a result, there are limited reviews available on this topic. Thus, this review aims to provide an overview of the primary types, sources, and hazards of ECs in farmland, as well as the structure, functions, and preparation types of biochar. Furthermore, this paper emphasizes the importance and prospects of three remediation strategies for ECs in cropland: (i) employing activated, modified, and composite biochar for remediation, which exhibit superior pollutant removal compared to pure biochar; (ii) exploring the potential synergistic efficiency between biochar and compost, enhancing their effectiveness in soil improvement and pollution remediation; (iii) utilizing biochar as a shelter and nutrient source for microorganisms in biochar-mediated microbial remediation, positively impacting soil properties and microbial community structure. Given the increasing global prevalence of ECs, the remediation strategies provided in this paper aim to serve as a valuable reference for future remediation of ECs-contaminated agricultural lands.

Enhanced copper removal by magnesium modified biochar derived from Alternanthera philoxeroides

Adsorption processes are being widely used by various researchers for the removal of heavy metals from waste streams and biochar has been frequently used as an adsorbent. In this study, a MgO-loaded biochar derived from Alternanthera philoxeroides (MAPB) was synthesized for the removal of Cu(II). Compared with other biochar absorbents, MAPB showed a relatively slow adsorption kinetics, but an effective removal of Cu(II) with a maximum sorption capacity of 1, 238 mg/g. The adsorption mechanism of Cu(II) by MAPB was mainly controlled by chemical precipitation as Cu2(OH)3NO3, complexation and ion replacement. Fixed bed column with MAPB packed in same dosage (1, 000 mg) and different bed depth (1.3, 2.6 and 3.9 cm) showed that the increased of bed depth by mixing MAPB with quartz sand could increase the removal of Cu(II). The fitted breakthrough (BT) models showed that mixing MAPB with support media could reduce the mass transfer rate, increase the dynamic adsorption capacity and BT time. Therefore, MAPB adsorbent act as a highly efficient long-term adsorbent for Cu(II) contaminated water treatment may have great ecological and environmental significance.

Microplastics derived from plastic mulch films and their carrier function effect on the environmental risk of pesticides

Plastic film mulching can maintain soil water and heat conditions, promote plant growth and thus generate considerable economic benefits in agriculture. However, as they age, these plastics degrade and form microplastics (MPs). Additionally, pesticides are widely utilized to control organisms that harm plants, and they can ultimately enter and remain in the environment after use. Pesticides can also be sorbed by MPs, and the sorption kinetics and isotherms explain the three stages of pesticide sorption: rapid sorption, slow sorption and sorption equilibrium. In this process, hydrophobic and partition interactions, electrostatic interactions and valence bond interactions are the main sorption mechanisms. Additionally, small MPs, biodegradable MPs and aged conventional MPs often exhibit stronger pesticide sorption capacity. As environmental conditions change, especially in simulated biological media, pesticides can desorb from MPs. The utilization of pesticides by environmental microorganisms is the main factor controlling the degradation rate of pesticides in the presence of MPs. Pesticide sorption by MPs and size effects of MPs on pesticides are related to the internal exposure level of biological pesticides and changes in pesticide toxicity in the presence of MPs. Most studies have suggested that MPs exacerbate the toxicological effects of pesticides on sentinel species. Hence, the environmental risks of pesticides are altered by MPs and the carrier function of MPs. Based on this, research on the affinity between MPs and various pesticides should be systematically conducted. During agricultural production, pesticides should be cautiously selected and used plastic film to ensure human health and ecological security.

An effective strategy for biodegradation of high concentration phenol in soil via biochar-immobilized Rhodococcus pyridinivorans B403

High concentration of phenol residues in soil are harmful to human health and ecological safety. However, limited information is available on the in-situ bioremediation of phenol-contaminated soil using biochar as a carrier for bacteria. In this study, bamboo -derived biochar was screened as a carrier to assemble microorganism-immobilized composite with Rhodococcus pyridinivorans B403. Then, SEM used to observe the micromorphology of composite and its bioactivity was detected in solution and soil. Finally, we investigated the effects of free B403 and biochar-immobilized B403 (BCJ) on phenol biodegradation in two types of soils and different initial phenol concentrations. Findings showed that bacterial cells were intensively distributed in/onto the carriers, showing high survival. Immobilisation increased the phenol degradation rate of strain B403 by 1.45 times (37.7 mg/(L·h)). The phenol removed by BCJ in soil was 81% higher than free B403 on the first day. Moreover, the removal of BCJ remained above 51% even at phenol concentration of 1,500 mg/kg, while it was only 15% for free B403. Compared with the other treatment groups, BCJ showed the best phenol removal effect in both tested soils. Our results indicate that the biochar-B403 composite has great potential in the remediation of high phenol-contaminated soil.

Bioretention Design Modifications Increase the Simulated Capture of Hydrophobic and Hydrophilic Trace Organic Compounds

Stormwater rapidly moves trace organic contaminants (TrOCs) from the built environment to the aquatic environment. Bioretention cells reduce loadings of some TrOCs, but they struggle with hydrophilic compounds. Herein, we assessed the potential to enhance TrOC removal via changes in bioretention system design by simulating the fate of seven high-priority stormwater TrOCs (e.g., PFOA, 6PPD-quinone, PAHs) with log KOC values between -1.5 and 6.74 in a bioretention cell. We evaluated eight design and management interventions for three illustrative use cases representing a highway, a residential area, and an airport. We suggest two metrics of performance: mass advected to the sewer network, which poses an acute risk to aquatic ecosystems, and total mass advected from the system, which poses a longer-term risk for persistent compounds. The optimized designs for each use case reduced effluent loadings of all but the most polar compound (PFOA) to <5% of influent mass. Our results suggest that having the largest possible system area allowed bioretention systems to provide benefits during larger events, which improved performance for all compounds. To improve performance for the most hydrophilic TrOCs, an amendment like biochar was necessary; field-scale research is needed to confirm this result. Our results showed that changing the design of bioretention systems can allow them to effectively capture TrOCs with a wide range of physicochemical properties, protecting human health and aquatic species from chemical impacts.

Mechanisms of adsorption and functionalization of biochar for pesticides: A review

Agricultural production relies heavily on pesticides. However, factors like inefficient application, pesticide resistance, and environmental conditions reduce their effective utilization in agriculture. Subsequently, pesticides transfer into the soil, adversely affecting its physicochemical properties, microbial populations, and enzyme activities. Different pesticides interacting can lead to combined toxicity, posing risks to non-target organisms, biodiversity, and organism-environment interactions. Pesticide exposure may cause both acute and chronic effects on human health. Biochar, with its high specific surface area and porosity, offers numerous adsorption sites. Its stability, eco-friendliness, and superior adsorption capabilities render it an excellent choice. As a versatile material, biochar finds use in agriculture, environmental management, industry, energy, and medicine. Added to soil, biochar helps absorb or degrade pesticides in contaminated areas, enhancing soil microbial activity. Current research primarily focuses on biochar produced via direct pyrolysis for pesticide adsorption. Studies on functionalized biochar for this purpose are relatively scarce. This review examines biochar's pesticide absorption properties, its characteristics, formation mechanisms, environmental impact, and delves into adsorption mechanisms, functionalization methods, and their prospects and limitations.

Risk assessment of pesticide compounds: IPT and TCZ cause hepatotoxicity, activate stress pathway and affect the composition of intestinal flora in red swamp crayfish (Procambarusclarkii)

Isoprothiolane (IPT) and tricyclazole (TCZ) are widely used in rice farming and recently in combined rice-fish farming. However, co-cultured animals are affected by these pesticides. To investigate the organismal effects and toxicity of pesticides, crayfish were exposed to 0, 1, 10, or 100 ppt TCZ or IPT for 7 days. Pesticide bioaccumulation, survival rate, metabolic parameters, structure of intestinal flora, and antioxidant-, apoptosis-, and HSP-related gene expression were determined. Pesticide exposure caused bioaccumulation of IPT or TCZ in the hepatopancreas and muscles of crayfish; however, IPT bioaccumulation was higher than that of TCZ. Both groups showed significant changes in hepatopancreatic serum biochemical parameters. Mitochondrial damage and chromosomal agglutination were observed in hepatopancreatic cells exposed to 100 ppt IPT or TCZ. IPT induced more significant changes in serum biochemical parameters than TCZ. The results of intestinal flora showed that Vibro, Flavobacterium, Anaerorhabdus and Shewanella may have potential for use as a bacterial marker of TCZ and IPT. Antioxidant-, apoptosis-, and HSP-related gene expression was disrupted by pesticide exposure, and was more seriously affected by IPT. The results suggest that IPT or TCZ induce hepatopancreatic cell toxicity; however, IPT or TCZ content in dietary crayfish exposed to 1 ppt was below the food safety residue standard. The data indicated that IPT exposure may be more toxic than TCZ exposure in hepatopancreas and intestines and toxicity of organism are alleviated by activating the pathway of stress-response, providing an understanding of pesticide compounds in rice-fish farming and food safety.

Biochar modulating soil biological health: A review

Biochar can be used for multifunctional applications including the improvement of soil health and carbon storage, remediation of contaminated soil and water resources, mitigation of greenhouse gas emissions and odorous compounds, and feed supplementation to improve animal health. A healthy soil preserves microbial biodiversity that is effective in supressing plant pathogens and pests, recycling nutrients for plant growth, promoting positive symbiotic associations with plant roots, improving soil structure to supply water and nutrients, and ultimately enhancing soil productivity and plant growth. As a soil amendment, biochar assures soil biological health through different processes. First, biochar supports habitats for microorganisms due to its porous nature and by promoting the formation of stable soil micro-aggregates. Biochar also serves as a carbon and nutrient source. Biochar alters soil physical and chemical properties, creating optimum soil conditions for microbial diversity. Biochar can also immobilize soil pollutants and reduce their bioavailability that would otherwise inhibit microbial growth. However, depending on the pyrolysis settings and feedstock resources, biochar can be comprised of contaminants including polycyclic aromatic hydrocarbons and potentially toxic elements that can inhibit microbial activity, thereby impacting soil health.

Potential of silicon-rich biochar (Sichar) amendment to control crop pests and pathogens in agroecosystems: A review

We reviewed the potential of silicon (Si)-rich biochars (sichars) as crop amendments for pest and pathogen control. The main pathosystems that emerged from our systematic literature search were bacterial wilt on solanaceous crops (mainly tomato, pepper, tobacco and eggplant), piercing-sucking hemipteran pests and soil-borne fungi on gramineous crops (mainly rice and wheat), and parasitic nematodes on other crops. The major pest and pathogen mitigation pathways identified were: i) Si-based physical barriers; ii) Induction of plant defenses; iii) Enhancement of plant-beneficial/pathogen-antagonistic soil microflora in the case of root nematodes; iv) Alteration of soil physical-chemical properties resulting in Eh-pH conditions unfavorable to root nematodes; v) Alteration of soil physical-chemical properties resulting in Eh-pH, bulk density and/or water holding capacity favorable to plant growth and resulting tolerance to necrotrophic pathogens; vi) Increased Si uptake resulting in reduced plant quality, owing to reduced nitrogen intake towards some hemi-biotrophic pests or pathogens. Our review highlighted synergies between pathways and tradeoffs between others, depending, inter alia, on: i) crop type (notably whether Si-accumulating or not); ii) pest/pathogen type (e.g. below-ground/root-damaging vs above-ground/aerial part-damaging; "biotrophic" vs "necrotrophic" sensu lato, and corresponding systemic resistance pathways; thriving Eh-pH spectrum; etc.); iii) soil type. Our review also stressed the need for further research on: i) the contribution of Si and other physical-chemical characteristics of biochars (including potential antagonistic effects); ii) the pyrolysis process to a) optimize Si availability in the soil and its uptake by the crop and b) to minimize formation of harmful compounds e.g. cristobalite; iii) on the optimal form of biochar, e.g. Si-nano particles on the surface of the biochar, micron-sized biochar-based compound fertilizer vs larger biochar porous matrices.

Biodiversity of network modules drives ecosystem functioning in biochar-amended paddy soil

Introduction

Soil microbes are central in governing soil multifunctionality and driving ecological processes. Despite biochar application has been reported to enhance soil biodiversity, its impacts on soil multifunctionality and the relationships between soil taxonomic biodiversity and ecosystem functioning remain controversial in paddy soil.

Methods

Herein, we characterized the biodiversity information on soil communities, including bacteria, fungi, protists, and nematodes, and tested their effects on twelve ecosystem metrics (including functions related to enzyme activities, nutrient provisioning, and element cycling) in biochar-amended paddy soil.

Results

The biochar amendment augmented soil multifunctionality by 20.1 and 35.7% in the early stage, while the effects were diminished in the late stage. Moreover, the soil microbial diversity and core modules were significantly correlated with soil multifunctionality.

Discussion

Our analysis revealed that not just soil microbial diversity, but specifically the biodiversity within the identified microbial modules, had a more pronounced impact on ecosystem functions. These modules, comprising diverse microbial taxa, especially protists, played key roles in driving ecosystem functioning in biochar-amended paddy soils. This highlights the importance of understanding the structure and interactions within microbial communities to fully comprehend the impact of biochar on soil ecosystem functioning in the agricultural ecosystem.

Research progress on remediation of organochlorine pesticide contamination in soil

Deteriorated soil pollution has grown into a worldwide environmental concern over the years. Organochlorine pesticide (OCP) residues, featured with ubiquity, persistence and refractoriness, are one of the main pollution sources, causing soil degradation, fertility decline and nutritional imbalance, and severely impacting soil ecology. Furthermore, residual OCPs in soil may enter the human body along with food chain accumulation and pose a serious health threat. To date, many remediation technologies including physicochemical and biological ways for organochlorine pollution have been developed at home and abroad, but none of them is a panacea suitable for all occasions. Rational selection and scientific decision-making are grounded in in-depth knowledge of various restoration techniques. However, soil pollution treatment often encounters the interference of multiple factors (climate, soil properties, cost, restoration efficiency, etc.) in complex environments, and there is still a lack of systematic summary and comparative analysis of different soil OCP removal methods. Thus, to better guide the remediation of contaminated soil, this review summarized the most commonly used strategies for OCP removal, evaluated their merits and limitations and discussed the application scenarios of different methods. It will facilitate the development of efficient, inexpensive and environmentally friendly soil remediation strategies for sustainable agricultural and ecological development.

A critical review of sustainable pesticide remediation in contaminated sites: Research challenges and mechanistic insights

Incidental pesticide application on farmlands can result in contamination of off-target biota, soil, groundwater, and surrounding ecosystems. To manage these pesticide contaminations sustainably, it is important to utilize advanced approaches to pesticide decontamination. This review assesses various innovative strategies applied for remediating pesticide-contaminated sites, including physical, chemical, biological, and nanoremediation. Integrated remediation approaches appear to be more effective than singular technologies. Bioremediation and chemical remediation are considered suitable and sustainable strategies for decontaminating contaminated soils. Furthermore, this study highlights key mechanisms underlying advanced pesticide remediation that have not been systematically studied. The transformation of applied pesticides into metabolites through various biotic and chemical triggering factors is well documented. Ex-situ and in-situ technologies are the two main categories employed for pesticide remediation. However, when selecting a remediation technique, it is important to consider factors such as application sites, cost-effectiveness, and specific purpose. In this review, the sustainability of existing pesticide remediation strategies is thoroughly analyzed as a pioneering effort. Additionally, the study summarizes research uncertainties and technical challenges associated with different remediation approaches. Lastly, specific recommendations and policy advocacy are suggested to enhance contemporary remediation approaches for cleaning up pesticide-contaminated sites.

Mitigating Salinity Stress in Quinoa (Chenopodium quinoa Willd.) with Biochar and Superabsorber Polymer Amendments

In agriculture, soil amendments are applied to improve soil quality by increasing the water retention capacity and regulating the pH and ion exchange. Our study was carried out to investigate the impact of a commercial biochar (Bc) and a superabsorbent polymer (SAP) on the physiological and biochemical processes and the growth performance of Chenopodium quinoa (variety ICBA-5) when exposed to high salinity. Plants were grown for 25 days under controlled greenhouse conditions in pots filled with a soil mixture with or without 3% Bc or 0.2% SAP by volume before the initiation of 27 days of growth in hypersaline conditions, following the addition of 300 mM NaCl. Without the Bc or soil amendments, multiple negative effects of hypersalinity were detected on photosynthetic CO2 assimilation (Anet minus 70%) and on the production of fresh matter from the whole plant, leaves, stems and roots (respectively, 55, 46, 64 and 66%). Moreover, increased generation of reactive oxygen species (ROS) was indicated by higher levels of MDA (plus 142%), antioxidant activities and high proline levels (plus 311%). In the pots treated with 300 mM NaCl, the amendments Bc or SAP improved the plant growth parameters, including fresh matter production (by 10 and 17%), an increased chlorophyll content by 9 and 13% and Anet in plants (by 98 and 115%). Both amendments (Bc and SAP) resulted in significant salinity mitigation effects, decreasing proline and malondialdehyde (MDA) levels whilst increasing both the activity of enzymatic antioxidants and non-enzymatic antioxidants that reduce the levels of ROS. This study confirms how soil amendments can help to improve plant performance and expand the productive range into saline areas.

First surveillance of pesticides in soils of the perimeter of Tadla, a Moroccan sugar beet intensive area

With the long-term application of pesticides on sugar beet farms in the irrigated perimeter of Tadla in Morocco for over 50 years, pesticide monitoring is necessary to assess soil health. The objective of our study was to monitor multiple pesticide residues in topsoil samples collected from post-harvest sugar beet fields and verify their migration to deep soil layers. Topsoil and deep soil samples were collected from arbitrarily selected sugar beet fields in the IPT. In this study, a target-screening method was applied. All target pesticides were detected in soil samples, with tefluthrin being the most frequently detected pesticide. The residue with the highest concentration in soil samples was DDE. All the soil samples contained a mixture of pesticide residues, with a maximum of 13 residues per sample. The total pesticide content decreased toward more profound layers of soil, except in one field where it reached a concentration of 348 µg/kg at the deeper soil layer. For pesticides detected at the three soil depths, only tefluthrin concentration increased in the deep soil layer. The results provide comprehensive and precise information on the pesticide residue status in sugar beet soils warning against the multiple risks that this contamination can cause. This study indicates the need of regular monitoring of pesticides over a large area of the perimeter to enable decision-makers to pronounce the impacts of the extension and intensification of sugar beet cultivation at the irrigated perimeter of Tadla.

Prospects for application of microorganisms in bioremediation of soils contaminated with pesticides

The contamination of soil with residual amounts of pesticides remains an urgent challenge for human community. The most efficient approach to address this challenge is the direct microbial degradation of a pesticide in agricultural lands. To this end, the selected microorganisms, which quickly and completely utilize pesticides, are employed. In the present work, two herbicides belonging to different classes of chemical compounds, that is, imazamox and chlorsulfuron were used. The screening of promising microorganisms was carried out among different strains of bacteria and fungi in a liquid mineral medium containing a pesticide as the only source of carbon. It was found that the most active microorganisms were capable of utilizing up to 90% of the active substance for a short time. The dynamics of pesticides degradation indicated that the maximum destruction of the studied substances occurred during the first two weeks of cultivation. Further, the rate of degradation dramatically dropped or stopped at all. An increase in the concentration of pesticides in the cultivation medium almost completely suppressed their degradation. It is interesting that the bacteria were more suitable for the degradation of imazamox, while the fungi rendered the destruction of chlorsulfuron.

Degradation of Pesticide Residues in Water, Soil, and Food Products via Cold Plasma Technology

Water, soil, and food products contain pesticide residues. These residues result from excessive pesticides use, motivated by the fact that agricultural productivity can be increased by the use of these pesticides. The accumulation of these residues in the body can cause health problems, leading to food safety concerns. Cold plasma technology has been successfully employed in various applications, such as seed germination, bacterial inactivation, wound disinfection, surface sterilization, and pesticide degradation. In recent years, researchers have increasingly explored the effectiveness of cold plasma technology in the degradation of pesticide residues. Most studies have shown promising outcomes, encouraging further research and scaling-up for commercialization. This review summarizes the use of cold plasma as an emerging technology for pesticide degradation in terms of the plasma system and configuration. It also outlines the key findings in this area. The most frequently adopted plasma systems for each application are identified, and the mechanisms underlying pesticide degradation using cold plasma technology are discussed. The possible factors influencing pesticide degradation efficiency, challenges in research, and future trends are also discussed. This review demonstrates that despite the nascent nature of the technology, the use of cold plasma shows considerable potential in regards to pesticide residue degradation, particularly in food applications.

Environmental fate and metabolic transformation of two non-ionic pesticides in soil: Effect of biochar, moisture, and soil sterilization

Soil moisture, organic matter, and soil microbes are the key considering factors that control the persistence, degradation, and transformation of applied pesticides under varied soil conditions. In this study, underlying influence of these factors was assessed through the fates and metabolic transformation of two non-ionic pesticides (e.g., Phorate and Terbufos) in soils. Concisely, two distinct experiments including a customized batch equilibrium (sorption study), and a lab incubation trial (degradation study) were performed, following the OECD guidelines. As per study findings, biochar (BC) amendment was found to be the most influential factors during sorption study, particularly, 1% BC amendment contributed to achieve the best results. In addition, the non-linearity of sorption isotherm (1/n < 1.0) was revealed through Freundlich isotherm, indicating the strong adsorption of studied pesticides onto the soils. On the other hand, during degradation study, soil moisture initiates the enhanced degradation of parent pesticides and subsequent metabolism. In the presence of 40% water holding capacity (WHC), 1% BC amendment enhances the metabolic transformation, while H2O2 treatment could hinder the process. Additionally, the half-life degradation (t1/2) of phorate and terbufos was controlled by biochar amendment, moisture, and soil sterilization, respectively. Finally, BC can accelerate the metabolic transformation, whereas, phorate underwent a metabolic change into sulfoxide and sulfone while terbufos turned into solely sulfoxide. This pioneering study gathered crucial data for understanding the persistence and metabolic transition of non-ionic pesticides in soils and their patterns of degradation.

Fermented biochar has a markedly different effect on fate of pesticides in soil than compost, straw, and a mixed biochar-product

Current knowledge about how biochars affect the fate of pesticides in soil is based on studies that used pure biochars. After finding that an additional biological post-pyrolysis treatment, such as co-composting or lactic fermentation, is required for biochars for superior performance in temperate arable soils, a knowledge gap formed of how such further processed biochar products would affect the fate of pesticides in soil. This study compared the effects of a novel fermented biochar alone or mixed with biogas residues on the fate of two pesticides, 4-chloro-2-methylphenoxyacetic acid (MCPA) and metalaxyl-M, in a temperate arable soil to the traditional organic amendments wheat straw and compost. The fate of 14C-labeled MCPA was markedly affected in different ways. Fermented biochar effectively reduced the water-extractability and mineralization due to adsorption that was comparable to adsorption strengths reported for pure biochars. However, this effect was weak for the biochar mixed with biogas residues. Straw reduced water-extractable amounts due to increased biodegradation and formation of likely biogenic non-extractable residues of MCPA. In contrast, compost decelerated mineralization and increased the water solubility of the MCPA residues due to released dissolved organic matter. The amendments' effects were minor regarding 14C-metalaxyl-M, except for the fermented biochar which again reduced water-extractability and delayed degradation due to adsorption. Thus, the effects of the organic amendments differed for the two pesticide compounds with only the fermented biochar's effect being similar for both. However, this effect was no longer present in the mixed product containing 20% biochar. Our findings clearly show that biologically treated biochar-containing products can affect the fate of pesticides in soil very differently, also when compared to traditional organic amendments. Such impacts and their desirable and undesirable ecotoxicological implications need to be considered before the large-scale application of biochars to temperate arable soils.

When biochar is involved in rhizosphere dissipation and plant absorption of pesticides: A meta-analysis

Clarifying the influences of biochar input on the rhizosphere dissipation and plant absorption of pesticides is a crucial prerequisite for utilizing biochar in the restoration of pesticide-contaminated soils. Nevertheless, the application of biochar to pesticide-contaminated soils does not always achieve consistent results on the rhizosphere dissipation and plant absorption of pesticides. Under the new situation of vigorously promoting the application of biochar in soil management and carbon sequestration, a timely review is needed to further understand the key factors affecting biochar remediation of pesticide-contaminated soil. In this study, a meta-analysis was conducted utilizing variables from three dimensions of biochar, remediation treatment, and pesticide/plant type. The pesticide residues in soil and the pesticide uptake by plant were used as response variables. Biochar with high adsorption capacity can impede the dissipation of pesticides in soil and mitigate their absorption by plants. The specific surface area of biochar and the type of pesticide are critical factors that affect pesticide residues in soil and plant uptake, respectively. Applying biochar with high adsorption capacity, based on specific dosages and soil characteristics, is recommended for the remediation of continuously cultivated soil contaminated with pesticides. This article aims to provide a valuable reference and understanding for the application of biochar-based soil remediation technology and the treatment of pesticide pollution in soil.

2-Methyl-4-chlorophenoxyacetic acid (MCPA) sorption and desorption as a function of biochar properties and pyrolysis temperature

2-Methyl-4-chlorophenoxyacetic acid (MCPA) is a highly mobile herbicide that is frequently detected in global potable water sources. One potential mitigation strategy is the sorption on biochar to limit harm to unidentified targets. However, irreversible sorption could restrict bioefficacy thereby compromising its usefulness as a vital crop herbicide. This research evaluated the effect of pyrolysis temperatures (350, 500 and 800°C) on three feedstocks; poultry manure, rice hulls and wood pellets, particularly to examine effects on the magnitude and reversibility of MCPA sorption. Sorption increased with pyrolysis temperature from 350 to 800°C. Sorption and desorption coefficients were strongly corelated with each other (R2 = 0.99; P < .05). Poultry manure and rice hulls pyrolyzed at 800°C exhibited irreversible sorption while for wood pellets at 800°C desorption was concentration dependent. At higher concentrations some desorption was observed (36% at 50 ppm) but was reduced at lower concentrations (1-3% at < 5 ppm). Desorption decreased with increasing pyrolysis temperature. Sorption data were analyzed with Langmuir, Freundlich, Dubinin-Radushkevich and Temkin isotherm models. Freundlich isotherms were better predictors of MCPA sorption (R2 ranging from 0.78 to 0.99). Poultry manure and rice hulls when pyrolyzed at higher temperatures (500 and 800°C) could be used for remediation efforts (such as spills or water filtration), due to the lack of desorption observed. On the other hand, un-pyrolyzed feedstocks or biochars created at 350°C could perform superior for direct field applications to limit indirect losses including runoff and leaching, since these materials also possess the ability to release MCPA subsequently to potentially allow herbicidal action.

Adsorption-desorption characteristics of atrazine on soil and vermicompost prepared with different ratios of raw materials

In this work, vermicompost was prepared with maize stover and cattle dung in ratios of 60:40 (VC1), 50:50 (VC2) and 40:60 (VC3), and the physicochemical properties of the vermicompost were related to the ratio of the raw materials used. The effect of the vermicomposts on the adsorption kinetics, adsorption isotherms and desorption of atrazine were investigated in unamended soil (S) and soil amended with 4% (w/w) of VC1(S-VC1), VC2(S-VC2) and VC3(S-VC3). The total organic carbon (TOC) content of VC1, VC2 and VC3 was 38.46, 37.33 and 34.47%, the HA content was 43.50, 42.22 and 39.28 g/kg, and the HA/FA ratios was 1.47, 0.44 and 0.83, respectively. The adsorption of atrazine on the soil, on the vermicompost and on soils amended with vermicompost followed a pseudo-second-order kinetic model. The Freundlich equation better fitted the adsorption isotherm of atrazine. The vermicomposts enhanced atrazine adsorption and decreased atrazine desorption. Correlation analysis showed that the TOC and HA were significantly positively correlated with Kf, which indicated that TOC and HA of the vermicomposts contributed significantly to the adsorption and desorption of atrazine. This study demonstrated that vermicomposts have great potential in the bioremediation of atrazine pollution and that their role is related to the raw materials used to prepare them.

Potential of fluorescent tracers to appraise biochar amendment strategies for pesticide mitigation - insights from comparative sorption

Mitigation of pesticide dispersion in soil and water is required to protect ecosystem health and the anthropic uses of water bodies. Biochar amendments have been suggested to reduce pesticide dispersion due to their high sorption potentials. Nevertheless, appraisals at different scales have been limited by the costs of pesticide analyses. The aim of this study was to evaluate the potential of two fluorescent tracers, uranine (UR) and sulforhodamine B (SRB), for use as pesticide proxies in the context of biochar amendments used for mitigation purposes. Therefore, we compared the sorption processes of both fluorescent tracers and those of three pesticides, glyphosate, 2,4-D, and difenoconazole for soils; three wood biochars (pine, oak, and beech/charm blend); and soil/biochar mixtures representing agricultural usages. The results showed that the sorption of glyphosate by soil was unaffected by amendment with the tested pine, oak, and wood blend biochars. In contrast, the sorption coefficients of UR, SRB, 2,4-D, and difenoconazole were significantly increased with these biochar amendments. SRB, in particular, exhibited sorption behavior similar to that of the hydrophobic fungicide difenoconazole. This indicates promise for the use of SRB as a proxy for hydrophobic pesticides, in testing biochar amendments.

Pyrolysis Temperature vs. Application Rate of Biochar Amendments: Impacts on Soil Microbiota and Metribuzin Degradation

Biochar-amended soils influence the degradation of herbicides depending on the pyrolysis temperature, application rate, and feedstock used. The objective of this study was to evaluate the influence of sugarcane straw biochar (BC) produced at different pyrolysis temperatures (350 °C, 550 °C, and 750 °C) and application rates in soil (0, 0.1, 0.5, 1, 1.5, 5, and 10% w/w) on metribuzin degradation and soil microbiota. Detection analysis of metribuzin in the soil to find time for 50% and 90% metribuzin degradation (DT₅₀ and DT₉₀) was performed using high-performance liquid chromatography (HPLC). Soil microbiota was analyzed by respiration rate (C-CO₂), microbial biomass carbon (MBC), and metabolic quotient (qCO₂). BC350 °C-amended soil at 10% increased the DT₅₀ of metribuzin from 7.35 days to 17.32 days compared to the unamended soil. Lower application rates (0.1% to 1.5%) of BC550 °C and BC750 °C decreased the DT₅₀ of metribuzin to ~4.05 and ~5.41 days, respectively. BC350 °C-amended soil at high application rates (5% and 10%) provided high C-CO₂, low MBC fixation, and high qCO₂. The addition of low application rates (0.1% to 1.5%) of sugarcane straw biochar produced at high temperatures (BC550 °C and BC750 °C) resulted in increased metribuzin degradation and may influence the residual effect of the herbicide and weed control efficiency.

Selenium alleviates biological toxicity of thiamethoxam (TMX): Bioaccumulation of TMX, organ damage, and antioxidant response of red swamp crayfish (Procambarus clarkii)

Pesticides are important for agricultural development; however, animals involved in rice-fish farming absorb the pesticides used during the farming process. Thiamethoxam (TMX) is extensively used in agriculture and is gradually occupying the market for traditional pesticides. Therefore, this study aimed to investigate whether selenomethionine (SeMet) could affect the survival rate, bioaccumulation of TMX, serum biochemical parameters, lipid peroxidation, antioxidants in the hepatopancreas, and expression of stress genes after exposure of red swamp crayfish to 10 ppt TMX for 7 days. The results showed that the survival rate significantly increased and the bioaccumulation of TMX significantly decreased with SeMet administration (P < 0.05). Furthermore, severe histological damage to the hepatopancreas of red crayfish was observed after exposure to TMX; however, this damage was alleviated after SeMet administration. SeMet also significantly reduced the TMX-induced changes in serum biochemical parameters, malondialdehyde content, and antioxidant enzyme activity in crayfish hepatopancreas (P < 0.05). Notably, analysis of the expression of 10 stress response genes showed that 0.5 mg/kg SeMet might decrease cell damage in the hepatopancreas. Consequently, our findings suggest that higher levels of TMX in crayfish may cause hepatopancreatic cell toxicity, which can be harmful to human health; however, SeMet could mitigate these effects, providing an understanding of pesticide compounds and food safety.

Metabolic Degradation and Bioactive Derivative Synthesis of Phenazine-1-Carboxylic Acid by Genetically Engineered Pseudomonas chlororaphis HT66

Phenazine-1-carboxylic acid (PCA) secreted by Pseudomonas chlororaphis has been commercialized and widely employed as an antifungal pesticide. However, it displays potential hazards to nontarget microorganisms and the environment. Although the PCA degradation characteristics have received extensive attention, the biodegradation efficiency is still insufficient to address the environmental risks. In this study, an engineered Pseudomonas capable of degrading PCA was constructed by introducing heterologous PCA 1,2-dioxygenase (PcaA1A2A3A4). By integrating the PCA degradation module in the chemical mutagenesis mutant P3, 7.94 g/L PCA can be degraded in 60 h, which exhibited the highest PCA degradation efficiency to date and was 35.4-fold higher than that of the PCA natural degraders. Additionally, PCA was converted to 1-methoxyphenazine through structure modification by introducing the functional enzymes PhzS_Pa and PhzM_La, which has good antifungal activity and environmental compatibility. This work demonstrates new possibilities for developing PCA-derived biopesticides and enables targeted control of the impact of PCA in diverse environments.

Validation and Simultaneous Monitoring of 311 Pesticide Residues in Loamy Sand Agricultural Soils by LC-MS/MS and GC-MS/MS, Combined with QuEChERS-Based Extraction

Soil can be contaminated by pesticide residues through agricultural practices, by direct application or through spray-drift in cultivations. The dissipation of those chemicals in the soil may pose risks to the environment and human health. A simple and sensitive multi-residue analytical method was optimized and validated for the simultaneous determination of 311 active substances of pesticides in agricultural soils. The method involves sample preparation with QuEChERS-based extraction, and determination of the analytes with a combination of GC-MS/MS and LC-MS/MS techniques. Calibration plots were linear for both detectors over the range of five concentration levels, using matrix-matched calibration standards. The obtained recoveries from fortified-soil samples ranged from 70 to 119% and from 72.6 to 119% for GC-MS/MS and LC-MS/MS, respectively, while precision values were <20% in all cases. As regards the matrix effect (ME), signal suppression was observed in the liquid chromatography (LC)-amenable compounds, which was further estimated to be negligible. The gas chromatography (GC)-amenable compounds showed enhancement in the chromatographic response estimated as medium or strong ME. The calibrated limit of quantification (LOQ) value was 0.01 μg g^-1 dry weight for most of the analytes, while the corresponding calculated limit of determination (LOD) value was 0.003 μg g^-1 d.w. The proposed method was subsequently applied to agricultural soils from Greece, and positive determinations were obtained, among which were non-authorized compounds. The results indicate that the developed multi-residue method is fit for the purpose of analyzing low levels of pesticides in soil, according to EU requirements.

Combined use of biochar and alternative management systems for imazamox induced pollution control in rice growing environments

Imazamox (IMZX) is a persistent herbicide having probable risks for non-target organisms in the environment and water contamination. Alternatives to conventional flooding rice production, including biochar amendment, may induce changes in soil properties which can greatly modify the environmental fate of IMZX. This two-year study is the first to evaluate how tillage and irrigation practices, with or without fresh or aged biochar (Bc), that are alternatives to conventional rice production impact IMZX's environmental fate. The treatments were: conventional tillage and flooding irrigation (CTFI), conventional tillage and sprinkler irrigation (CTSI), no-tillage and sprinkler irrigation (NTSI), and the corresponding Bc-amendment treatments (CTFI-Bc, CTSI-Bc, and NTSI-Bc). Fresh and aged Bc amendment decreased IMZX's sorption onto the soil in tillage treatments, with K_f values decreasing 3.7 and 4.2-fold (fresh case) and 1.5 and 2.6-fold (aged case) for CTSI-Bc and CTFI-Bc, respectively. The transition to sprinkler irrigation reduced IMZX persistence. Overall, Bc amendment also reduced chemical persistence with half-life values decreasing 1.6 and 1.5-fold for CTFI and CTSI (fresh year) and 1.1, 1.1, and 1.3-fold for CTFI, CTSI, and NTSI (aged year), respectively. Sprinkler irrigation reduced IMZX leaching by up to a factor of 2.2. The use of Bc as amendment led to a significant decrease in IMZX leaching only under tillage conditions, but notable in particular for the CTFI case where leaching losses were reduced in the fresh year from 80% to 34% and, in the aged year, from 74% to 50%. Hence the change in irrigation from flooding to sprinkler either alone or in combination with the use of Bc (fresh or aged) amendment could be considered an effective way to sharply mitigate IMZX contamination of water in environments where rice is grown, particularly in those managed with tillage.

Exposure to cypermethrin pesticide disturbs the microbiome and disseminates antibiotic resistance genes in soil and the gut of Enchytraeus crypticus

Worldwide, pyrethroids, such as cypermethrin, are the second most applied group of insecticides, however, their effects on the soil microbiome and non-target soil fauna remain largely unknown. Herein, we assessed the change of bacterial communities and antibiotic resistance genes (ARGs) of soil and in the gut of the model soil species Enchytraeus crypticus using a combination of 16S rRNA gene amplicon sequencing, and high-throughput qPCR of ARGs. Results indicate that cypermethrin exposure enriches potential pathogens (e.g. Bacillus anthracis) in the soil and gut microbiome of E. crypticus, heavily disrupting the latter's microbiome structure, and even disrupts activities of the E. crypticus immune system. The co-occurrence of potential pathogens (e.g. Acinetobacter baumannii), ARGs, and mobile genetic elements (MGEs) revealed the increased risk of pathogenicity as well as antibiotic resistance in potential pathogens. Moreover, structural equation modeling demonstrated that the dissemination of ARGs was not only promoted by MGEs, but also by the ratio of the core to non-core bacterial abundance. Collectively, these results provide an in-depth view of the previously unappreciated environmental risk of cypermethrin on the dissemination of ARGs in the soil and non-target soil fauna.

Nanopesticides in comparison with agrochemicals: Outlook and future prospects for sustainable agriculture

Agrochemicals are products of advanced technologies that use inorganic pesticides and fertilizers. Widespread use of these compounds has adverse environmental effects, leading to acute and chronic exposure. Globally, scientists are adopting numerous green technologies to ensure a healthy and safe food supply and a livelihood for everyone. Nanotechnologies significantly impact all aspects of human activity, including agriculture, even if synthesizing certain nanomaterials is not environmentally friendly. Numerous nanomaterials may therefore make it easier to create natural insecticides, which are more effective and environmentally friendly. Nanoformulations can improve efficacy, reduce effective doses, and extend shelf life, while controlled-release products can improve the delivery of pesticides. Nanotechnology platforms enhance the bioavailability of conventional pesticides by changing kinetics, mechanisms, and pathways. This allows them to bypass biological and other undesirable resistance mechanisms, increasing their efficacy. The development of nanomaterials is expected to lead to a new generation of pesticides that are more effective and safer for life, humans, and the environment. This article aims to express at how nanopesticides are being used in crop protection now and in the future. This review aims to shed some light on the various impacts of agrochemicals, their benefits, and the function of nanopesticide formulations in agriculture.

Dissipation kinetics of chlorpyrifos and 3,5,6 trichloro-2-pyridinol under vegetation of different aromatic grasses: Linkage with enzyme kinetics and microbial community of soil

The dissipation of chlorpyrifos (CP) and its hydrolytic metabolite 3,5,6-trichloro-2-pyridinol (TCP) in the soil is crucial for safe agriculture. However, there is still lacking relevant information about its dissipation under different vegetation for remediation purposes. In the present study, evaluation of dissipation of CP and TCP in non-planted and planted soil with different cultivars of three types of aromatic grass viz Cymbopogon martinii (Roxb. Wats), Cymbopogon flexuosus, and Chrysopogon zizaniodes (L.) Nash was examined in light of soil enzyme kinetics, microbial communities, and root exudation. Results revealed that the dissipation of CP was well-fitted into a single first-order exponential model (SFO). A significant reduction in the half-life (DT₅₀) of CP was observed in planted soil (30-63 days) than in non-planted soil (95 days). The presence of TCP in all soil samples was observed. The three types of the inhibitory effect of CP i.e. linear mixed inhibition (increase in enzyme-substrate affinity (Km) and decrease in enzyme pool (Vmax), un-competitive inhibition (decrease in Km and Vmax), and simple competitive inhibition were observed on soil enzymes involved in mineralization of carbon, nitrogen, phosphorus, and sulfur. The improvement in the enzyme pool (Vmax) was observed in planted soil. Streptomyces, Clostridium, Kaistobacter, Planctomyces, and Bacillus were the dominant genera in CP stress soil. CP contamination in soil demonstrated a reduction of richness in microbial diversity and enhancement of functional gene family related to cellular process, metabolism, genetic, and environmental information processing. Among all the cultivars, C. flexuosus cultivars demonstrated a higher dissipation rate of CP along with more root exudation.

Impact of atrazine on soil microbial properties: A meta-analysis

Atrazine is a biotoxic long-residing herbicide whose toxic effects on soil microorganisms have attracted widespread attention. However, previous studies on the effects of atrazine on soil microorganisms have yielded highly variable results. Therefore, a meta-analysis using a database containing 1141 data points from 39 peer-reviewed papers was conducted to illustrate the response of soil microorganisms to the application of atrazine. The results showed that the application of atrazine significantly increased soil microbial biomass and respiration by 8.9% and 26.77%, respectively, and decreased soil microbial diversity and enzyme activity by 4.87% and 24.04%, respectively. In addition, mixed-effect models were used to explain the influence of moderator variables, including water holding capacity, temperature, pH, organic carbon content, atrazine concentration, duration, and soil texture, on the results to help account for inconsistent conclusions. It was found that soil microbial biomass was significantly positively correlated with temperature, organic carbon content, atrazine concentration, clay content and silt content, while it was negatively correlated with pH and sand content. Soil microbial respiration was negatively correlated with pH and positively correlated with atrazine concentration. Soil microbial diversity was positively correlated with water holding capacity, pH, silt content and sand content, and negatively correlated with organic carbon content and clay content. Soil enzyme activity, the indicator that showed the largest decrease after atrazine application, was significantly positively correlated with water holding capacity, temperature, organic carbon content, and herbicide concentration; it was negatively correlated with soil pH. On the basis of these analysis results, we recommend that atrazine should not be allowed to persist in alkaline sandy soil for long periods of time, as this can result in atrazine having a significant negative impact on soil microorganisms.

Adsorption, mobility, and degradation of the pesticide propaquizafop in five agricultural soils in China

Propaquizafop is a fatty acid synthetic herbicide used to control annual and perennial grasses. To understand the potential environmental risks of propaquizafop to crops and food safety, the adsorption, mobility, and degradation of propaquizafop in five different soils were studied. At an initial concentration of 5 mg L^-1 propaquizafop, its adsorption equilibrium was reached within 24 h, and the adsorption rates were between 46.98 and 57.76%. The Elovich kinetic model provided the best fit for the kinetic model, with R² values between 0.9882 and 0.9940. For the isothermal adsorption tests, the Freundlich model was used to better fit the adsorption characteristics of propaquizafop in different soils, with R² values between 0.9748 and 0.9885. Increasing the concentration of Ca²⁺ was beneficial for propaquizafop adsorption. In the soil thin-layer chromatography tests, the R_f of propaquizafop in the five soil samples ranged from 0.076 to 0.123. The results of the soil column leaching tests showed that propaquizafop did not migrate in the five soil columns; it was not detected in the leachate of each soil column, and propaquizafop in the soil columns only existed in the 0-5 cm soil layer. The results of soil thin-layer chromatography and soil column leaching tests showed that propaquizafop is a pesticide with a weak migration ability. Under the same environmental conditions, the degradation rate of propaquizafop in different soils followed the order LF fluvo-aquic soil (T_1/2 = 1.41 d) > CS red loam (T_1/2 = 2.76 d) > SX paddy soil (T_1/2 = 3.52 d) > CC black soil (T_1/2 = 5.74 d) > BS ginseng soil (T_1/2 = 7.75 d). Considering the effects of soil moisture, incubation temperature, and microorganisms on propaquizafop degradation in the soil, temperature was found to have the greatest influence on its degradation rate.

Immediate effects of atrazine application on soil organic carbon and selected macronutrients and amelioration by sawdust biochar pretreatment

Increasing use of herbicides has contributed immensely to current soil and water degradation in the tropics. Published works on effects of herbicides on soil organic carbon (SOC) – a major indicator for soil health and macronutrients and their enhancement by biochar are scarce for soils in Africa despite heavy herbicide applications every cropping season. This incubation trial evaluated immediate effects of atrazine application on SOC and selected soil macronutrients. The potential of sawdust (SD) biochar to mitigate associated SOC and macronutrients depletion was also assessed. A total of 950 g soil was placed in each leaching column (20 cm length and 7 cm diameter). The experiment was a factorial combination of four SD biochar types: SD + poultry manure (PM) pyrolyzed at 350 °C, SD-PM at 350 °C, SD + PM at 450 °C and SD-PM at 450 °C applied at two rates of 5 and 10 t/ha equivalent to 2.38 and 4.76 g/950 g soil, respectively. Atrazine alone and absolute control (AC) that received neither biochar nor atrazine were included for comparison. The treatments were replicated thrice in completely randomized design. Appropriate biochar was applied within 5 cm soil depth, moistened to field capacity, and left to equilibrate for 2 weeks. Thereafter, 20 mL atrazine solution was applied at 2.5 kg a.i/ha (achieved through 6.75 g atrazine powder/l of distilled water). Basal NPK 15:15:15 fertilizer mixed with urea at 0.1 and 0.03 g/900 g soil, respectively, was applied to mimic farmers’ practice on atrazine treated fields. Maize seeds were thereafter sown in the treated soils and nurtured for 2 weeks. Data taken on soil pH, SOC, exchangeable bases, available phosphorus, and dry biomass weight (DBW) of maize seedlings at the expiration of the trial were subjected to two-way analysis of variance using Genstat Statistical Package with means separated using LSD at 5% probability level. There were significant reductions in soil pH (5.8%), SOC (31%), and Ex. Ca (27%) in atrazine alone soil compared to AC. Contrarily, similar atrazine treated soil pretreated with SD biochar had increased soil pH, SOC, exchangeable Ca, available P, and DBW by 5.6 (in SD + PM@450 °C), 73.6 (SD-PM@450 °C), 84 (SD + PM@450 °C), 2,338.4 (SD + PM@450 °C), and 154.8% (SD + PM@350 °C), respectively, dominantly at 10 t/ha compared to AC. Sole atrazine treated soil was, however, higher in soil available P (23.8 mg/kg) and TDBW (0.56 g) against 5.42 mg/kg and 0.42 g from AC, respectively. Biochar pH and organic carbon were the most influential biochar properties contributing significantly to SOC sequestration and macronutrient enrichment in the atrazine treated soil. Pretreatment of soils with sawdust biochar prior to atrazine application is, therefore, recommended for mitigating associated organic carbon and macronutrient depletion in the soils for enhanced maize production.

Recent advances in biochar amendments for immobilization of heavy metals in an agricultural ecosystem: A systematic review

Over the last several decades, extensive and inefficient use of contemporary technologies has resulted in substantial environmental pollution, predominantly caused by potentially hazardous elements (PTEs), like heavy metals that severely harm living species. To combat the presence of heavy metals (HMs) in the agrarian system, biochar becomes an attractive approach for stabilizing and limiting availability of HMs in soils due to its high surface area, porosity, pH, aromatic structure as well as several functional groups, which mostly rely on the feedstock and pyrolysis temperature. Additionally, agricultural waste-derived biochar is an effective management option to ensure carbon neutrality and circular economy while also addressing social and environmental concerns. Given these diverse parameters, the present systematic evaluation seeks to (i) ascertain the effectiveness of heavy metal immobilization by agro waste-derived biochar; (ii) examine the presence of biochar on soil physico-chemical, and thermal properties, along with microbial diversity; (iii) explore the underlying mechanisms responsible for the reduction in heavy metal concentration; and (iv) possibility of biochar implications to advance circular economy approach. The collection of more than 200 papers catalogues the immobilization efficiency of biochar in agricultural soil and its impacts on soil from multi-angle perspectives. The data gathered suggests that pristine biochar effectively reduced cationic heavy metals (Pb, Cd, Cu, Ni) and Cr mobilization and uptake by plants, whereas modified biochar effectively reduced As in soil and plant systems. However, the exact mechanism underlying is a complex biochar-soil interaction. In addition to successfully immobilizing heavy metals in the soil, the application of biochar improved soil fertility and increased agricultural productivity. However, the lack of knowledge on unfavorable impacts on the agricultural systems, along with discrepancies between the use of biochar and experimental conditions, impeded a thorough understanding on a deeper level.

A critical review on biochar-assisted free radicals mediated redox reactions influencing transformation of potentially toxic metals: Occurrence, formation, and environmental applications

Potentially toxic metals have become a viable threat to the ecosystem due to their carcinogenic nature. Biochar has gained substantial interest due to its redox-mediated processes and redox-active metals. Biochar has the capacity to directly adsorb the pollutants from contaminated environments through several mechanisms such as coprecipitation, complexation, ion exchange, and electrostatic interaction. Biochar's electron-mediating potential may be influenced by the cyclic transition of surface moieties and conjugated carbon structures. Thus, pyrolysis configuration, biomass material, retention time, oxygen flow, and heating time also affect biochar's redox properties. Generally, reactive oxygen species (ROS) exist as free radicals (FRs) in radical and non-radical forms, i.e., hydroxyl radical, superoxide, nitric oxide, hydrogen peroxide, and singlet oxygen. Heavy metals are involved in the production of FRs during redox-mediated reactions, which may contribute to ROS formation. This review aims to critically evaluate the redox-mediated characteristics of biochar produced from various biomass feedstocks under different pyrolysis conditions. In addition, we assessed the impact of biochar-assisted FRs redox-mediated processes on heavy metal immobilization and mobility. We also revealed new insights into the function of FRs in biochar and its potential uses for environment-friendly remediation and reducing the dependency on fossil-based materials, utilizing local residual biomass as a raw material in terms of sustainability.