Changes in atrazine speciation and the degradation pathway in red soil during the vermiremediation process

Advances in understanding and mitigating Atrazine's environmental and health impact: A comprehensive review

Atrazine is a widely used herbicide in agriculture, and it has garnered significant attention because of its potential risks to the environment and human health. The extensive utilization of atrazine, alongside its persistence in water and soil, underscores the critical need to develop safe and efficient removal strategies. This comprehensive review aims to spotlight atrazine's potential impact on ecosystems and public health, particularly its enduring presence in soil, water, and plants. As a known toxic endocrine disruptor, atrazine poses environmental and health risks. The review navigates through innovative removal techniques across soil and water environments, elucidating microbial degradation, phytoremediation, and advanced methodologies such as electrokinetic-assisted phytoremediation (EKPR) and photocatalysis. The review notably emphasizes the complex process of atrazine degradation and ongoing scientific efforts to address this, recognizing its potential risks to both the environment and human health.

Design of a multi-electrode dielectric barrier discharge reactor and experimental study on the degradation of atrazine in water

Atrazine (ATZ) is widely used in agriculture as a triazine herbicide, and its long-term use can cause serious environmental pollution. This paper independently designed a multi-electrode reactor, explored the output power and energy utilization efficiency of the dielectric barrier discharge reactor, and used the dielectric barrier discharge reactor to treat ATZ solution. The results showed that the degradation efficiency of ATZ was 96.39% at 30 min at an initial ATZ concentration of 14 mg/L, an input voltage of 34 kV, an input current of 1.38 mA, an aeration rate of 100 L/h, and a treatment water volume of 150 mL. The degradation of ATZ was significantly increased by the addition of persulfate (PS), Fe2+, and H2O2. After adding radical quenchers (EtOH, p-BQ, and FFA), the degradation efficiency of ATZ decreased, indicating that free radicals (•OH, •O2-, and 1O2) played a key role in the degradation process of ATZ.

Impact of microplastics on nicosulfuron accumulation and bacteria community in soil-earthworms system

Microplastics (MPs) widely co-occur with various pollutants in soils. However, the data related to the impacts of MPs on terrestrial animal and microbial properties in pesticide-contaminated soils are few. In this study, the influence of MPs (0.01%, 0.1%, and 1%) on nicosulfuron concentrations in soil (10 µg/g) and earthworms were investigated, moreover, microbial community structure and diversity in soil and earthworm gut were also measured. After 30 days, the concentration of nicosulfuron in soil decreased to 1.27 µg/g, moreover, the residual concentration of nicosulfuron in soil (1%MPs and nicosulfuron) was only 44.8% of that in the single nicosulfuron treatment group. The accumulation of nicosulfuron in earthworms (1%MPs and nicosulfuron) was 7.37 µg/g, which was 1.82 times of that in the single nicosulfuron treatment group. In addition, 1% MPs decreased the richness and diversity of the soil and gut bacterial community in earthworms as well as altered microbial community composition, leading to the enrichment of specific microbial community. Our findings imply that MPs may change the migration of pesticides to terrestrial animal and as well as microbial diversity in earthworms and soil.

Distribution Characteristics and Risk Assessment of 57 Pesticides in Farmland Soil and the Surrounding Water

To investigate the effect of pesticide use on surface water, the concentration and distribution characteristics of 57 pesticides and 3 degradation products were analyzed in the farmland soil and surface water in the Xingkai Lake area, including water from paddy fields, drainages and the Xingkai Lake, in Heilongjiang Province, China. Forty-three pesticides and three degradation products were detected in farmland soil. In dry field (corn and soybean field) soil, the main detected pesticides were atrazine and acetochlor with mean concentrations of 26.09 ng·g-1 and 49.08 ng·g-1, respectively. In paddy field soil, oxadiazon, mefenacet and chlorpyrifos were the main detected pesticides with mean concentrations of 14.32 ng·g-1, 78.60 ng·g-1 and 20.03 ng·g-1, respectively. In the surrounding water, including water from paddy fields, drainages and Xingkai Lake, the total concentrations of contaminants detected in the water samples ranged from 71.19 ng·L-1 to 10,145.76 ng·L-1. Of the three sampling periods, the mean concentration of contaminants in the water exhibited its peak during the vegetative period. In the analysis of the drainage water, the primary pesticides detected were atrazine, acetochlor and buprofezin with mean concentrations of 354.83 ng·L-1, 109.09 ng·L-1 and 254.56 ng·L-1, respectively. Atrazine, simetryn, buprofezin and isoprothiolane were the main pesticides detected in Xingkai Lake water, with the mean concentrations of 222.35 ng·L-1, 112.76 ng·L-1, 301.87 ng·L-1 and 138.02 ng·L-1, respectively. The concentrations of contaminants could be correlated with drainage, Da Xingkai Lake and Xiao Xingkai Lake water (ρ > 0.8) suggested that the source of these contaminants in drainage and Xingkai Lake water could be the same. The maximum potentially affected fraction (PAF) values of atrazine, chlorpyrifos and prometryn were higher than 5% in Xingkai Lake water, resulting in high ecological risks.

Stereoselective bioaccumulation and dissipation of four stereoisomers of cyproconazole in earthworm-soil microcosm

Cyproconazole is a representative and widely used triazole fungicide with four stereoisomers, which will bring some risks to non-target organisms. A fast analytical method on supercritical fluid chromatography-tandem mass spectrometry was established in 4 min, and the environmental hazards of chiral cyproconazole were studied in earthworm-soil microcosm, including stereoselective bioaccumulation and dissipation. In the process of bioaccumulation, the concentrations of cyproconazole stereoisomers in earthworms showed a trend of increasing first and then reaching a stable state at 6 mg/kg treatment, which was different from those at 0.6 mg/kg treatment (decease-increase-equilibrium). The concentration order was (2S,3R)- > (2S,3S)- > (2R,3R)- > (2R,3S)-cyproconazole and (2S,3S)- ≈ (2S,3R)- > (2R,3R)- > (2R,3S)-cyproconazole at 6 and 0.6 mg/kg treatments, respectively. The bioaccumulation factor (BAF) values were in the range of 0.018-0.55, showing weakly relative accumulation capacity. The dissipation of cyproconazole stereoisomers in artificial soil accorded with the first-order kinetics equation, and the half-lives were 20.1-23.6 and 7.66-8.28 days at 6 and 0.6 mg/kg treatments, respectively, without stereoselectivity and diastereoselectivity. In earthworms, the dissipation half-lives were 5.81-6.01 days with the preferential dissipation of (2R,3R)-cyproconazole. The study would help with the rational uses and risk assessments of cyproconazole.

ATR induces hepatic lipid metabolism disorder in rats by activating IRE1α/XBP1 signaling pathway

Atrazine (ATR) is a widely used herbicide and due to its persistence in environment and bioaccumulation, it can cause harmful impacts on human health. ATR exposure can lead to disorders of lipid metabolism in the liver, but its underlying mechanism is still unclear. 40 eight-week-old rats were given different doses of ATR (0, 0.5, 5 and 50 mg/kg/d) for 90 days. The liver tissue and serum were collected for histological observation and biochemical analysis. The levels of lipid and oxidative stress were assessed using colorimetry. Changes in MMP and ROS of liver cells were observed through flow cytometry. The expression of mRNA and protein was detected using Real-Time PCR and western blot. The results showed that TC and HDL-C levels in both the liver and serum were increased in the ATR-treated groups. The levels of MDA were accumulated, while the levels of SOD and GSH were depleted in the liver with ATR exposure. The expression of liver lipid metabolism related genes (SCD1, DGAT2, ACC1, PPARγ) was elevated. The liver ERS was activated and the gene expression of IRE1α/XBP1 signal pathway and GRP78, GRP94 in the liver was increased. There was a correlation between the levels of ERS and the levels of lipid metabolism. These results suggested that ATR can activate ERS and promote the expression of IRE1α/XBP1 signaling pathway, and further lead to lipid metabolism disorders in rat liver. This study can provide valuable insights as a reference for the prevention and control of hazards associated with agricultural residues.

The ROS/SIRT1/STAR axis as a target for melatonin ameliorating atrazine-induced mitochondrial dysfunction and steroid disorders in granulosa cells

The granulosa cells (GCs) of birds are essential for the reproduction and maintenance of populations in nature. Atrazine (ATR) is a potent endocrine disruptor that can interfere with reproductive function in females and Diaminochlorotriazine (DACT) is the primary metabolite of ATR in the organism. Melatonin (MT) is an endogenous hormone with antioxidant properties that plays a crucial role in development of animal germ cells. However, how ATR causes mitochondrial dysfunction, abnormal secretion of steroid hormones, and whether MT prevents ATR-induced female reproductive toxicity remains unclear. Thus, the purpose of this study is to investigate the protective effect of MT against ATR-induced female reproduction. In the present study, the GCs of quail were divided into 6 groups, as follows: C (Serum-free medium), MT (10 µM MT), A250 (250 µM ATR), MA250 (10 µM MT+250 µM ATR), D200 (200 µM DACT) and MD200 (10 µM MT+200 µM DACT), and were cultured for 24 h. The results revealed that ATR prevented GCs proliferation and decreased cell differentiation. ATR caused oxidative damage and mitochondrial dysfunction, leading to disruption of steroid synthesis, which posed a severe risk to GC's function. However, MT supplements reversed these changes. Mechanistically, our study exhibited that the ROS/SIRT1/STAR axis as a target for MT to ameliorate ATR-induced mitochondrial dysfunction and steroid disorders in GCs, which provides new insights into the role of MT in ATR-induced reproductive capacity and species conservation in birds.

New mechanisms of biochar-assisted vermicomposting by recognizing different active di-(2-ethylhexyl) phthalate (DEHP) degraders across pedosphere, charosphere and intestinal sphere

Biochar-assisted vermicomposting can significantly accelerate soil DEHP degradation, but little information is known about the underlying mechanisms as different microspheres exist in soil ecosystem. In this study, we identified the active DEHP degraders in biochar-assisted vermicomposting by DNA stable isotope probing (DNA-SIP) and surprisingly found their different compositions in pedosphere, charosphere and intestinal sphere. Thirteen bacterial lineages (Laceyella, Microvirga, Sphingomonas, Ensifer, Skermanella, Lysobacter, Archangium, Intrasporangiaceae, Pseudarthrobacter, Blastococcus, Streptomyces, Nocardioides and Gemmatimonadetes) were responsible for in situ DEHP degradation in pedosphere, whereas their abundance significantly changed in biochar or earthworm treatments. Instead, some other active DEHP degraders were identified in charosphere (Serratia marcescens and Micromonospora) and intestinal sphere (Clostridiaceae, Oceanobacillus, Acidobacteria, Serratia marcescens and Acinetobacter) with high abundance. In biochar-assisted vermicomposting, the majority of active DEHP degraders were found in charosphere, followed by intestinal sphere and pedosphere. Our findings for the first time unraveled the spatial distribution of active DEHP degraders in different microspheres in soil matrices, explained by DEHP dynamic adsorption on biochar and desorption in earthworm gut. Our work highlighted that charosphere and intestinal sphere exhibited more contribution to the accelerated DEHP biodegradation than pedosphere, providing novel insight into the mechanisms of biochar and earthworm in improving contaminant degradation.

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.

Change of tetracycline speciation and its impacts on tetracycline removal efficiency in vermicomposting with epigeic and endogeic earthworms

Tetracycline pollution is common in Chinese arable soils, and vermicomposting is an effective approach to accelerate tetracycline bioremediation. However, current studies mainly focus on the impacts of soil physicochemical properties, microbial degraders and responsive degradation/resistance genes on tetracycline degradation efficiencies, and limited information is known about tetracycline speciation in vermicomposting. This study explored the roles of epigeic E. fetida and endogeic A. robustus in altering tetracycline speciation and accelerating tetracycline degradation in a laterite soil. Both earthworms significantly affected tetracycline profiles in soils by decreasing exchangeable and bound tetracycline but increasing water soluble tetracycline, thereby facilitating tetracycline degradation efficiencies. Although earthworms increased soil cation exchange capacity and enhanced tetracycline adsorption on soil particles, the significantly elevated soil pH and dissolved organic carbon benefited faster tetracycline degradation, attributing to the consumption of soil organic matter and humus by earthworms. Different from endogeic A. robustus which promoted both abiotic and biotic degradation of tetracycline, epigeic E. foetida preferently accelerated abiotic tetracyline degradation. Our findings described the change of tetracycline speciation during vermicompsiting process, unraveled the mechanisms of different earthworm types in tetracycline speciation and metabolisms, and offered clues for effective vermiremediation application at tetracycline contaminated sites.

A comprehensive and global evaluation of residual antibiotics in agricultural soils: Accumulation, potential ecological risks, and attenuation strategies

The occurrence of antibiotics in agricultural soils has raised concerns due to their potential risks to ecosystems and human health. However, a comprehensive understanding of antibiotic accumulation, distribution, and potential risks to terrestrial ecosystems on a global scale is still limited. Therefore, in this study, we evaluated the accumulation of antibiotics and their potential risks to soil microorganisms and plants, and highlighted the driving factors of antibiotic accumulation in agricultural soils based on 134 peer-reviewed studies (between 2000 and 2022). The results indicated that 56 types of antibiotics were detected at least once in agricultural soils with concentrations ranging from undetectable to over 7000 µg/kg. Doxycycline, tylosin, sulfamethoxazole, and enrofloxacin, belonging to the tetracyclines, macrolides, sulfonamides, and fluoroquinolones, respectively, were the most accumulated antibiotics in agricultural soil. The accumulation of TCs, SAs, and FQs was found to pose greater risks to soil microorganisms (average at 29.3%, 15.4%, and 21.8%) and plants (42.4%, 26.0%, and 38.7%) than other antibiotics. East China was identified as a hot spot for antibiotic contamination due to high levels of antibiotic concentration and ecological risk to soil microorganisms and plants. Antibiotic accumulation was found to be higher in vegetable fields (245.5 µg/kg) and orchards (212.4 µg/kg) compared to croplands (137.2 µg/kg). Furthermore, direct land application of manure resulted in a greater accumulation of TCs, SAs, and FQs accumulation in soils than compost fertilization. The level of antibiotics decreased with increasing soil pH and organic matter content, attributed to decreasing adsorption and enhancing degradation of antibiotics. In conclusion, this study highlights the need for further research on the impacts of antibiotics on soil ecological function in agricultural fields and their interaction mechanisms. Additionally, a whole-chain approach, consisting of antibiotic consumption reduction, manure management strategies, and remediation technology for soil contaminated with antibiotics, is needed to eliminate the potential environmental risks of antibiotics for sustainable and green agriculture.

Reinforced Bioremediation of Excessive Nitrate in Atrazine-Contaminated Soil by Biodegradable Composite Carbon Source

Bioremediation is a good alternative to dispose of the excessive nitrate (NO₃^-) in soil and alleviate the secondary salinization of soil, but the presence of atrazine in soil interferes with the bioremediation process. In the present study, the biodegradable composite carbon source with different dosages was added to the atrazine-contaminated soil to intensify the bioremediation of excessive NO₃^-. The atrazine-contaminated soil with a 25 g/kg composite carbon source achieved the optimal NO₃^- removal performance (92.10%), which was slightly higher than that with a 5 g/kg composite carbon source (86.15%) (p > 0.05). Unfortunately, the negative effects of the former were observed, such as the distinctly higher emissions of N₂O, CO₂ and a more powerful global warming potential (GWP). Microbial community analysis showed that the usage of the composite carbon source clearly decreased the richness and diversity of the microbial community, and greatly stimulated nitrogen metabolism and atrazine degradation (p < 0.05). To sum up, the application of a 5 g/kg composite carbon source contributed to guaranteeing bioremediation performance and reducing adverse environmental impacts at the same time.

Different phenanthrene degraders between free-cell mediated and biochar-immobilization assisted soil bioaugmentation as identified by RNA-based stable isotope probing (RNA-SIP)

Bioaugmentation (BA) is an effective approach to remove polycyclic aromatic hydrocarbons (PAHs) from contaminated soils, and biochar is frequently used to enhance PAH degradation performance. In this study, phenanthrene (PHE) degradation behavior and active degraders in a petroleum-contaminated soil were investigated and compared between free-cell mediated and biochar-immobilization assisted bioaugmentation. Biochar-immobilization assisted bioaugmentation (BA-IPB) introduced PHE degraders immobilized on biochar and effectively promoted PHE degradation, achieving higher PHE removal efficiencies within 24 h (~58 %) than free-cell mediated bioaugmentation (BA-FPB, ~39 %). Soil microbial community structure significantly changed in both BA-FPB and BA-IPB treatments. Through RNA-stable isotope probing (SIP), 14 and 11 bacterial lineages responsible for in situ PHE degradation were identified in BA-FPB and BA-IPB treatments, respectively. ASV_17 in BA-FPB treatment was Rhodococcus in the exogenous bacterial mixture; in contrast, none of exogenous bacteria were involved in PHE degradation in BA-IPB treatment. Methylobacterium (ASV_186), Xanthomonas (ASV_41), Kroppenstedtia (ASV_205), Scopulibacillus (ASV_243), Bautia (ASV_356), and Lactobacillus (ASV_376) were identified as PHE degraders for the first time. Our findings expanded the knowledge of the active PHE degraders and underlying mechanisms in bioaugmentation process, and suggested biochar-immobilization assisted bioaugmentation as a promising strategy for the bioremediation of PAH contaminated soils.

Performance and mechanisms of biochar-assisted vermicomposting in accelerating di-(2-ethylhexyl) phthalate biodegradation in farmland soil

Biochar and earthworms can accelerate di-(2-ethylhexyl) phthalate (DEHP) degradation in soils. However, little is known regarding the effect of biochar-assisted vermicomposting on soil DEHP degradation and the underlying mechanisms. Therefore, the present study investigated DEHP degradation performance and bacterial community changes in farmland soils using earthworms, biochar, or their combination. Biochar-assisted vermicomposting significantly improved DEHP degradation through initial physical adsorption on biochar and subsequent rapid biodegradation in the soil, earthworm gut, and charosphere. Burkholderiaceae, Pseudomonadaceae, and Flavobacteriaceae were the potential DEHP degraders and were enriched in biochar-assisted vermicomposting. In particularly, Burkholderiaceae and Sphingomonadaceae were enriched in the earthworm gut and charosphere, possibly explaining the mechanism of accelerated DEHP degradation in biochar-assisted vermicomposting. Soil pH, soil organic matter, and humus (humic acid, fulvic acid, and humin) increased by earthworms or biochar enhanced DEHP degradation. These findings imply that biochar-assisted vermicomposting enhances DEHP removal not only through rapid physical sorption but also through the improvement of soil physicochemical characteristics and promotion of degraders in the soil, earthworm gut, and charosphere. Overall, biochar-assisted vermicomposting is a suitable method for the remediation of organic-contaminated farmland soils.

Immobilization of bacterial mixture of Klebsiella variicola FH-1 and Arthrobacter sp. NJ-1 enhances the bioremediation of atrazine-polluted soil environments

In this study, the effects of the immobilized bacterial mixture (IM-FN) of Arthrobacter sp. NJ-1 and Klebsiella variicola strain FH-1 using sodium alginate-CaCl₂ on the degradation of atrazine were investigated. The results showed that the optimal ratio of three types of carrier materials (i.e., rice straw powder, rice husk, and wheat bran) was 1:1:1 with the highest adsorption capacity for atrazine (i.e., 3774.47 mg/kg) obtained at 30°C. On day 9, the degradation efficiency of atrazine (50 mg/L) reached 98.23% with cell concentration of 1.6 × 10⁸  cfu/ml at pH 9 and 30°C. The Box-Behnken method was used to further optimize the culture conditions for the degradation of atrazine by the immobilized bacterial mixture. The IM-FN could be reused for 2-3 times with the degradation efficiency of atrazine maintained at 73.0% after being stored for 80 days at 25°C. The population dynamics of IM-FN was explored with the total soil DNA samples specifically analyzed by real-time PCR. In 7 days, the copy numbers of both PydC and estD genes in the IM-FN were significantly higher than those of bacterial suspensions in the soil. Compared with bacterial suspensions, the IM-FN significantly accelerated the degradation of atrazine (20 mg/kg) in soil with the half-life shortened from 19.80 to 7.96 days. The plant heights of two atrazine-sensitive crops (wheat and soybean) were increased by 14.99 and 64.74%, respectively, in the soil restored by immobilized bacterial mixture, indicating that the IM-FN significantly reduced the phytotoxicity of atrazine on the plants. Our study evidently demonstrated that the IM-FN could significantly increase the degradation of atrazine, providing a potentially effective bioremediation technique for the treatment of atrazine-polluted soil environment and providing experimental support for the wide application of immobilized microorganism technology in agriculture.

One-pot synthesis of porous N-doped hydrochar for atrazine removal from aqueous phase: Co-activation and adsorption mechanisms

KOH-activated N-doped hydrochar (KHCN) was synthesized via co-activation method to eliminate atrazine (AT) in water efficiently. Compared to primitive HC, KHCN had advantages of splendid specific surface area (1205.82 m2/g) and developed microsphere structures on the surface. Specially for KHCN, the extra melamine added strengthened and preserved partial structure of polar oxygen-containing groups that were decomposed in the process of pore making. Besides, the estimated uptake amount of AT onto KHCN (216.50 mg/g) was remarkably superior to KHC (114.25 mg/g). KHCN exhibited the pH-dependence for AT removal, and presented excellent uptake capacity at a relatively neutral environment. Notably, the proposed mechanisms for AT removal by KHCN included electrostatic attraction, pore filling, π-π EDA, H-bond as well as hydrophilic effect. Hence, the porous N-doped hydrochar was a kind of adsorbent which was easy to prepare and had the application prospect for AT removal in natural water.

Toxicological effects, environmental behaviors and remediation technologies of herbicide atrazine in soil and sediment: A comprehensive review

Atrazine has become one of the most popular applied triazine herbicides in the world due to its high herbicidal efficiency and low price. With its large-dosage and long-term use on a global scale, atrazine can cause widespread and persistent contamination of soil and sediment. This review systematically evaluates the toxicological effects, environmental risks, environmental behaviors (adsorption, transport and transformation, and bioaccumulation) of atrazine, and the remediation technologies of atrazine-contaminated soil and sediment. For the adsorption behavior of atrazine on soil and sediment, the organic matter content plays an extremely important role in the adsorption process. Various models and equations such as the multi-media fugacity model and solute transport model are used to analyze the migration and transformation process of atrazine in soil and sediment. It is worth noting that certain transformation products of atrazine in the environment even have stronger toxicity and mobility than its parent. Among various remediation technologies, the combination of microbial remediation and phytoremediation for atrazine-contaminated soil and sediment has wide application prospects. Although other remediation technologies such as advanced oxidation processes (AOPs) can also efficiently remove atrazine from soil, some potential problems still need to be further clarified. Finally, some related challenges and prospects are proposed.

Co-exposure of Monensin Increased the Risks of Atrazine to Earthworms

Antibiotics could enter farmlands through sewage irrigation or manure application, causing combined pollution with pesticides. Antibiotics may affect the environmental fate of pesticides and even increase their bioavailability. In this study, the influence of monensin on the degradation, toxicity, and availability of atrazine in soil-earthworm microcosms was investigated. Monensin inhibited the degradation of atrazine, changed the metabolite patterns in soil, and increased the bioavailability of atrazine in earthworms. Atrazine and monensin had a significant synergistic effect on earthworms in the acute toxic test. In long-term toxicity tests, co-exposure of atrazine and monensin also led to worse effects on earthworms including oxidative stress, energy metabolism disruption, and cocoon production compared to single exposure. The expression of tight junction proteins was down-regulated significantly by monensin, indicating that the intestinal barrier of earthworms was weakened, possibly causing the increased bioavailability of atrazine. The expressions of heat shock protein 70 (Hsp70) and reproductive and ontogenetic factors (ANN, TCTP) were all downregulated in binary exposure, indicating that the resilience and cocoon production of earthworms were further weakened under combined pollution. Monensin disturbed the energy metabolism and weakened the intestinal barrier of earthworms. These results showed that monensin increased the risks of atrazine in agricultural areas.

Quantitative relationship between earthworms' sensitivity to organic pollutants and the contaminants' degradation in soil: A meta-analysis

Using earthworms to remove soil organic pollutants is a common bioremediation method. However, it remains challenging to evaluate and predict their effect on removing soil organic pollutants based on earthworm toxicology and pollutant degradation rates. Peer-reviewed journal articles on ecotoxicology and bioremediation from the years 1974-2020 (cutoff date September 2020) were selected for meta-analysis to quantify the effect size of earthworms on organic pollutant degradation. The meta-analysis shows that the average effect size of earthworms on organic pollutant degradation is 128.5% (p < 0.05). Soils with high soil organic matter or clay textures are more conducive to earthworm-mediated removal of organic pollutants. Structural equation modeling reveals that earthworms' sensitivity to contaminant exposure may be a greater limiting factor on pollutant degradation than environmental factors. In addition, the quantitative relationship existed between LC50 and the pollutants' degradation that an elevated LC50 threshold resulted in at least 1.5 times increase in the pollutants' degradation size. This correlation was dually confirmed via meta-analysis and the validation trial. The results of this study contribute to a more profound understanding of the potential to use earthworms to mitigate organic pollution in soils and develop earthworm-based soil remediation techniques on a global scale.

Impacts of earthworm casts on atrazine catabolism and bacterial community structure in laterite soil

Atrazine accumulation in agricultural soil is prone to cause serious environmental problems and pose risks to human health. Vermicomposting is an eco-friendly approach to accelerating atrazine biodegradation, but the roles of earthworm cast in the accelerated atrazine removal remains unclear. This work aimed to investigate the roles of earthworm cast in promoting atrazine degradation performance by comprehensively exploring the change in atrazine metabolites and bacterial communities. Our results showed that earthworm cast amendment significantly increased soil pH, organic matters, humic acid, fulvic acid and humin, and achieved a significantly higher atrazine removal efficiency. Earthworm cast addition also remarkably changed soil microbial communities by enriching potential soil atrazine degraders (Pseudomonadaceae, Streptomycetaceae, and Thermomonosporaceae) and introducing cast microbial degraders (Saccharimonadaceae). Particularly, earthworm casts increased the production of metabolites deethylatrazine and deisopropylatrazine, but not hydroxyatrazine. Some bacterial taxa (Gaiellaceaea and Micromonosporaceae) and humus (humic acid, fulvic acid and humin) were strongly correlated with atrazine metabolism into deisopropylatrazine and deethylatrazine, whereas hydroxyatrazine production was benefited by higher pH. Our findings verified the accelerated atrazine degradation with earthworm cast supplement, providing new insights into the influential factors on atrazine bioremediation in vermicomposting.

Earthworm Eisenia fetida potential for sewage sludge amended soil valorization by heavy metal remediation and soil quality improvement

Sewage sludge reuse in agriculture is increasing, however it can be an important route for contaminants to enter the environment. The aim of this study was to evaluate earthworm Eisenia fetida capability to reduce heavy metal content in the sewage sludge (SS) amended soil and increase soil fertility in terms of soil nutrients content. Adult earthworms were introduced into aged SS amended soil (0-200 Mg ha^-1) and left for 65 days. Earthworms have stabilized soil pH and accelerated organic matter mineralization. The concentrations of most heavy metals during the vermiremediation sharply decreased, K and Mg decreased to a moderate extent, whereas Ca content has increased. The highest removal efficiency was detected for Ni, Co and Mn (> 80%), bioconcentration factors were as follows Zn > Co > Cu > Ni > Mn > Cr. The content of major nutrients (S, P) was substantially higher compared to the initial values. The most efficient remediation and soil quality improvement was achieved under the doses of 25-50 Mg ha^-1. Higher (≥ 100 Mg ha^-1) doses might restrict this technique application because of earthworm mortality and retarded growth. Overall, the study shows that vermiremediation might be a sustainable technique for ecological stabilization of SS amended soil and converting to usable for agricultural needs.

Minimized Atrazine Risks to Crop Security and Its Residue in the Environment by a Rice Methyltransferase as a Regulation Factor

Atrazine (ATZ) is an agricultural pesticide for controlling field weeds. ATZ accumulates in many crops, posing high risks to crop production and food safety. Characterizing one of the novel rice MT genes named Oryza sativa atrazine-responsive methyltransferase (OsARM) showed that the expression of OsARM was associated with DNA demethylation (hypomethylation) in its promoter region. The enhancement of OsARM expression was manifested by the attenuated symptoms of ATZ toxicity including better growth and lower ATZ accumulation in plants. The promoted capacity of detoxification was confirmed by transgenic rice overexpression OsARM lines and also functionally proved by CRISPR-Cas9 knockout mutants. The transgenic lines accumulate more ATZ metabolites in rice and lower concentrations in the growth environment, pointing out that ATZ metabolism or degradation can be intensified. The ATZ-induced DNA demethylation is an important hallmark representing the epigenetic mechanism, which is required for the extra OsARM expression to facilitate ATZ disappearance in rice and the environment.

Vermiremediation and comparative exploration of physicochemical, growth parameters, nutrients and heavy metals content of biomedical waste ash via ecosystem engineers Eisenia fetida

Vermicomposting of Biomedical waste ash (BA) by the earthworm Eisenia fetida was studied with cow dung (CD) as nutrient medium. For 105 days, experiment was carried out in seven vermireactors containing varying ratios of BA and CD. Earthworm activity significantly reduced the pH (8.61-7.24), Electrical conductivity (EC) (4.1-1.62), Total organic carbon (TOC) (38.6-14.92), and Carbon and nitrogen (C/N ratios) (145.4-8.2) of all BA ratios. Levels of Total kjeldahl nitrogen (TKN) (0.26-1.82), Total available phosphorus (TAP) (0.22-0.64), Total potassium (TK) (2.05-12.08), and Total sodium (TNa) (47.53-92.26) were found to be increasing in the postvermicompost mixture. Although heavy metals content decreased from initial to final, it becomes below the permissible limits in the end product. The results showed that earthworm growth and fecundity were best in vermireactors containing 10-25% of BA. The best reproduction and growth of earthworms, demonstrate the vermicomposting's ability to manage hazardous solid wastes like BA. Use of vermitechnology to manage BA has not been performed yet in any kind of the research. Finally, it was determined that vermicomposting can be incorporated into overall plan for BA management. Thus nutrient-rich, detoxified, and physiochemically stable product may be used safely in agricultural processes.

The effect of atrazine on intestinal histology, microbial community and short chain fatty acids in Pelophylax nigromaculatus tadpoles

The intestine is the main organ for nutrient absorption in amphibians. It is sensitive to atrazine, which is a herbicide widely used in agricultural areas. At present, there is a lack of systematic research on the effect of atrazine on the amphibian intestine. In this study, we evaluated the effects of atrazine exposure (0, 50 μg/L, 100 μg/L, and 500 μg/L) for 20 days on intestinal histology, microbiota and short chain fatty acids in Pelophylax nigromaculatus tadpoles. Our research showed that 500 μg/L atrazine exposure significantly decreased the height of microvilli and epithelial cells, and altered the composition and diversity of intestinal microbiota in P. nigromaculatus tadpoles compared to the control. At the phylum level, the abundance of Bacteroidetes and Fusobacteria increased significantly, while that of Verrucomicrobia and Firmicutes decreased significantly in the 500 μg/L atrazine treatment group. At the genus level, Akkermansia and Lactococcus had significantly lower abundance in the 100 μg/L and 500 μg/L atrazine exposure group, while Cetobacterium was only detected in the 100 μg/L and 500 μg/L atrazine treated group. Also, function prediction of intestinal microbiota showed that atrazine treatment significantly changed the metabolism pathways of P. nigromaculatus tadpoles. In addition, 500 μg/L atrazine exposure changed the content of short chain fatty acids by significantly increasing the content of total SFCAs, butyric acid, and valeric acid, and decreasing the content of isovaleric acid in the intestine. Taken together, atrazine exposure could affect the intestinal histology and induce intestinal microbiota imbalance and metabolic disorder in amphibian tadpoles.

Accelerated atrazine degradation and altered metabolic pathways in goat manure assisted soil bioremediation

The intensive and long-term use of atrazine in agriculture has resulted in serious environmental pollution and consequently endangered ecosystem and human health. Soil microorganisms play an important role in atrazine degradation. However, their degradation efficiencies are relatively low due to their slow growth and low abundance, and manure amendment as a practice to improve soil nutrients and microbial activities can solve these problems. This study investigated the roles of goat manure in atrazine degradation performance, metabolites and bacterial community structure. Our results showed that atrazine degradation efficiencies in un-amended soils were 26.9-35.7% and increased to 60.9-84.3% in goat manure amended treatments. Hydroxyatrazine pathway was not significantly altered, whereas deethylatrazine and deisopropylatrazine pathways were remarkably enhanced in treatments amended with manure by encouraging the N-dealkylation of atrazine side chains. In addition, goat manure significantly increased soil pH and contents of organic matters and humus, explaining the change of atrazine metabolic pathway. Nocardioides, Sphingomonas and Massilia were positively correlated with atrazine degradation efficiency and three metabolites, suggesting their preference in atrazine contaminated soils and potential roles in atrazine degradation. Our findings suggested that goat manure acts as both bacterial inoculum and nutrients to improve soil microenvironment, and its amendment is a potential practice in accelerating atrazine degradation at contaminated sites, offering an efficient, cheap, and eco-friendly strategy for herbicide polluted soil remediation.

The radical and non-radical oxidation mechanism of electrochemically activated persulfate process on different cathodes in divided and undivided cell

Electrochemically activated persulfate (PS) employing stainless steel (SS), carbon felt (CF) and carbon black modified CF (CB-CF) as the cathode, in the divided and undivided cell, respectively, for degradation of atrazine (ATZ) was first investigated using novel B, Co-doped TiO₂ nanotubes (B, Co-TNT) anode. In undivided cell, ATZ degradation was followed the order of CF<CB-CF<SS. The main radical for ATZ removal in SS and CF system was ^•OH, while on CB-CF cathode, it was the comprehensive contribution of ^•OH and SO₄^•-. ^•OH in SS system was more inclined to free ^•OH, while in CF and CB-CF systems it was more likely to be surface ^•OH. In divided anode cell, ^•OH was responsible for ATZ degradation in all three cathodes system. However, in divided cathode cell, ^•OH played a major role for ATZ degradation in SS cathode system. In CF and CB-CF cathode systems, the ATZ degradation was the comprehensive effect of ^•OH and SO₄^•- with the contribution of ^•OH and SO₄^•- was 91.7%, 8.3%, and 96.3%, 3.6%, respectively. The quenching studies showed that non-radical oxidation occurred in anode chamber in the presence of PS. Besides, the intermediates in divided and undivided cell were detected by LC-MS, and the possible degradation pathway was proposed.

Removal of chlortetracycline and antibiotic resistance genes in soil by earthworms (epigeic Eisenia fetida and endogeic Metaphire guillelmi)

The impacts of two ecological earthworms on the removal of chlortetracycline (CTC, 0.5 and 15 mg kg^-1) and antibiotic resistance genes (ARGs) in soil were explored through the soil column experiments. The findings showed that earthworm could significantly accelerate the degradation of CTC and its metabolites (ECTC) in soil (P < 0.05), with epigeic Eisenia fetida promoting degradation rapidly and endogeic Metaphire guillelmi exhibiting a slightly better elimination effect. Earthworms alleviated the abundances of tetR, tetD, tetPB, tetG, tetA, sul1, TnpA, ttgB and intI1 in soil, with the total relative abundances of ARGs decreasing by 35.0-44.2% in earthworm treatments at the 28th day of cultivation. High throughput sequencing results displayed that the structure of soil bacteria community was modified apparently with earthworm added, and some possible CTC degraders, Aeromonas, Flavobacterium and Luteolibacter, were promoted by two kinds of earthworms. Redundancy analysis demonstrated that the reduction of CTC residues, Actinobacteria, Acidobacteria and Gemmatimonadetes owing to earthworm stimulation was responsible for the removal of ARGs and intI1 in soil. Additionally, intI1 declined obviously in earthworm treatments, which could weaken the risk of horizontal transmission of ARGs. Therefore, earthworm could restore the CTC-contaminated soil via enhancing the removal of CTC, its metabolites and ARGs.

Effects of two ecological earthworm species on tetracycline degradation performance, pathway and bacterial community structure in laterite soil

This study explored the change of tetracycline degradation efficiency, metabolic pathway, soil physiochemical properties and degraders in vermiremediation by two earthworm species of epigeic Eisenia fetida and endogeic Amynthas robustus. We found a significant acceleration of tetracycline degradation in both earthworm treatments, and 4-epitetracycline dehydration pathway was remarkably enhanced only by vermiremediation. Tetracycline degraders from soils, earthworm intestines and casts were different. Ralstonia and Sphingomonas were potential tetracycline degraders in soils and metabolized tetracycline through direct dehydration pathway. Degraders in earthworm casts (Comamonas, Acinetobacter and Stenotrophomonas) and intestines (Pseudomonas and Arthrobacter) dehydrated 4-epitetracycline into 4-epianhydrotetracycline. More bacterial lineages resisting tetracycline were found in earthworm treatments, indicating the adaptation of soil and intestinal flora under tetracycline pressure. Earthworm amendment primarily enhanced tetracycline degradation by neutralizing soil pH and consuming organic matters, stimulating both direct dehydration and epimerization-dehydration pathways. Our findings proved that vermicomposting with earthworms is effective to alter soil microenvironment and accelerate tetracycline degradation, behaving as a potential approach in soil remediation at tetracycline contaminated sites.

Coexisting antibiotic changes the persistence and metabolic profile of atrazine in the environment

Pesticides are widely used in agriculture to control weeds, pests and plant diseases. Antibiotics may be introduced to the agricultural environment by manure fertilizer or wastewater irrigation. Co-existence of antibiotics in field may lead to profound impacts on pesticide residue. In this study, the impacts of oxytetracycline on the environmental fate and metabolic profile of atrazine was investigated, and the disturbance of oxytetracycline on functional genes related to atrazine degradation in soils was also studied. Oxytetracycline could inhibit the degradation of atrazine significantly and prolong the half-life to 1.27 and 1.59 times longer at 5 mg/kg and 50 mg/kg. Also, oxytetracycline altered the composition of atrazine metabolites, including three chloro-s-triazine metabolites (DEA, DIA, DDA) and three hydroxyl metabolites (OH-ATZ, OH-DEA, OH-DIA). Oxytetracycline decreased the ratio of hydroxyl metabolites, while increased the chloro-s-triazine metabolites which had higher toxicity and were easily leached in soil. Atrazine hydrolase genes atzA and trzN were down-regulated by oxytetracycline, which might decrease the hydroxyl metabolite formation and detoxification of atrazine. Oxytetracycline changed the degradation of atrazine and the composition of the metabolites probably by altering the soil microorganisms. The increased persistence and the percentage of the chloro-s-triazine metabolites induced by oxytetracycline might result in increased environmental problems.

Aquaculture-derived distribution, partitioning, migration, and transformation of atrazine and its metabolites in seawater, sediment, and organisms from a typical semi-closed mariculture bay

Atrazine (ATR) is one of the most commonly used herbicides that could directly impair the growth and health of organisms in mariculture areas and adversely affect human health through the food chain. This study investigated the contaminant occurrence, migration, and transformation of ATR and three of its chlorinated metabolites, namely deethylatrazine (DEA), deisopropylatrazine (DIA), and didealkylatrazine (DDA), in surface seawater, sediment, and aquatic organisms from the Xiangshan Harbor. ATR was detected in all samples, while DIA and DDA were only respectively detected in aquatic and seawater samples. The distribution of ATR and its metabolites presented different patterns depending on the geographic location and showed a higher level in the aquaculture area than that in the non-aquaculture area. The bioaccumulation of ATR in aquaculture organisms showed that benthic organisms, such as Ditrema, and Sinonovacula constricta (Sin), had increased levels. The ecological risks indicated that ATR posed medium or high risks to algae in the water phase of the study area. The microcosm experiment showed that the main fate of ATR in the simulated microenvironment was sedimentation, which followed the first-order kinetic equation. The ATR in the sediment could be enriched 3-5 times in Sin, and its major metabolites were DEA and DIA.

The changes of antioxidant system and intestinal bacteria in earthworms (Metaphire guillelmi) on the enhanced degradation of tetracycline

Tetracycline (TC) in soil severely imperils food security and ecosystem function. Metaphire guillelmi is a common species in farmland. It could impact the degradation of antibiotics. However, how it affects is rarely unknown. Hence, the present study aimed to investigate the effects of M. guillelmi on the TC degradation in soil and the changes of the antioxidant system and intestinal bacteria in M. guillelmi. The treatments that M. guillelmi was inoculated on soil contaminated with different TC concentrations were contrasted with those without M. guillelmi. After 21 days, the degradation rate of TC significantly increased by 13.70%, 18.14% and 29.01% at 10, 50 and 100 mg kg ^-1 TC dose, respectively, due to the inoculation of M. guillelmi. The half-life of TC was also shortened nearly by 1/3 to 2/3. Superoxide dismutase (SOD) increased in a dose-dependent manner with the increase of TC concentration on the 7th and 14th day. Catalase (CAT) and glutathione S-transferase (GST) presented an inverted U-shaped dose response on the 7th day, and the peak of enzyme activities occurred at TC concentration of 0.1, 1 mg kg ^-1 (CAT) and 0.1 mg kg ^-1 (GST). Malondialdehyde (MDA) contents did not change significantly. At the phylum level, only Verrucomicrobia significantly decreased under 1 mg kg ^-1 and 100 mg kg ^-1 TC dose. Genus Paracoccus, Singulisphaera, Acinetobacter and Bacillus significantly increased and became the dominant bacterium during the TC degradation. Overall, the antioxidant system and intestinal bacteria of M. guillelmi were affected by the different concentrations of TC pollution, which provided new ideas for the research of mechanism of TC degradation by earthworms in the future.

Preparation, Performances and Mechanisms of Co@AC Composite for Herbicide Atrazine Removal in Water

In this study, a high-performance adsorbent Co@AC was prepared by loading cobalt ions (Co2+) on activated carbon (AC) via solution impregnation and high-temperature calcination technology, and was used to remove atrazine in water. The preparation factors on the adsorbent properties were studied, and the characteristics were analyzed by scanning electron microscopy (SEM), energy dispersive spectroscopy (EDS), and Fourier transform infrared spectrometer (FTIR). The results showed that Co@AC possessed the best performance when the factors were 7.0% of Co2+ (w/v), 7.0 h of immersing time, 500 °C of calcination temperature and 4.0 h of calcination time. The adsorption conditions and mechanisms for atrazine removal by Co@AC were also studied scientifically. As the conditions were pH 4.0, reaction time 90 min and temperature 25 °C, Co@AC had the largest adsorption capacity, which was 92.95 mg/g, and the maximum removal rate reached 94.79%. The correlation coefficient of the Freundlich isotherm was better than that of the Langmuir isotherm, and the adsorption process followed the pseudo-second-order kinetic model. Cycle experiments showed that the removal efficiency of atrazine by Co@AC remained above 85% after five repeated experiments, indicating that Co@AC showed a strong stable performance and is a promising material for pesticides removal.

Simultaneously enhanced removal and stepwise recovery of atrazine and Pb(II) from water using β-cyclodextrin functionalized cellulose: Characterization, adsorptive performance and mechanism exploration

Heavy metals and pesticides often coexist in contaminated water, while their potential competition behaviors make the adsorptive removal more challenging. Thus, decorating an adsorbent with independent functional sites could be a promising alternative to radically prevent the competitive process for improving the adsorption performance. Herein, β-cyclodextrin functionalized rice husk-based cellulose (β-CD@RH-C) was designed and applied for synchronous removal of atrazine and Pb(II). The characterization results supported the successful grafting of β-cyclodextrin onto the cellulose. The β-CD@RH-C presented a pH-dependent adsorption performance for Pb(II) with a theoretical monolayer adsorption capacity of 283.00 mg/g, while was mostly unrelated to pH for atrazine adsorption with a heterogeneous uptake of 162.21 mg/g in the mono-component system. Most importantly, the β-CD@RH-C could efficiently achieve simultaneous removal of atrazine and Pb(II) via avoiding their competitive behaviors, which was due to the different adsorption mechanisms for atrazine (i.e. host-guest interaction) and Pb(II) (i.e. complexation and electrostatic interaction). Moreover, the adsorbed atrazine and Pb(II) could be sequentially desorbed with slight decrease in the adsorption performance of β-CD@RH-C even after four cycles in the atrazine-Pb(II) multi-component system. All these results suggested β-CD@RH-C to be a tailored adsorbent with high-performance elimination of co-existing heavy metals and organic pollutants in water.

Spatial and Temporal Distribution Characteristics of Triazine Herbicides in Typical Agricultural Regions of Liaoning, China

The aim of the current study was to track the composition, spatial and temporal distribution charactistics of triazine herbicides in arable soils and corns in typical agricultural regions of Liaoning Province, China. All samples were analyzed using high performance liquid chromatography-tandem mass spectrometry (HPLC-MS/MS). Twelve kinds of triazine herbicides were found including atrazine, simazine, prometryn, propazine, ametryn, metribuzin, simetryn, aziprotryne, cyanizine, atrazine-desethyl, atrazine-desisopropyl and atrazine-desethyl-desisopropyl in the soil samples, of which atrazine, simazine, prometryn, atrazine-desethyl and atrazine-desethyl-desisopropyl were proved to be the predominant species with a high incidence though relatively low contamination level. The maximum concentration of atrazine in the soils was 73.80 µg·kg^-1. Five kinds of triazine herbicides were found in corns in the region including atrazine, simazine, prometryn, atrazine-desethyl and atrazine-desethyl-desisopropyl with the detection rate 96.4%, 17.8%, 14.3%, 60.7% and 46.4%, respectively. The maximum contaminant level of atrazine in corns was 12.52 µg·kg^-1, which is lower than that regulated in the National Standard of the People's Republic of China (GB2763-2012).

Responsiveness change of biochemistry and micro-ecology in alkaline soil under PAHs contamination with or without heavy metal interaction

Co-presence of organic pollutants and heavy metals in soil is causing increasing concerns, but the lack of knowledge of relation between soil ecology and pollutant fate is limiting the developing of specific control strategy. This study investigated soil change under pyrene stress and its interaction with cadmium (Cd). Soil physicochemical properties were not seriously influenced. However, pollutants' presence easily varied soil microbial activity, quantity, and diversity. Under high-level pyrene, Cd presence contributed to soil indigenous microorganisms' adaption and soil microbial community structure stability. Soils with both pyrene and Cd presented 7.11-12.0% higher pyrene degradation compared with single pyrene treatment. High-throughput sequencing analysis indicated the proportion of Mycobacterium sp., a commonly known PAHs degrader, increased to 25.2-48.5% in treatments from 0.52% in control. This phenomenon was consistent with the increase of PAHs probable degraders (the ratio increased to 2.86-6.57% from 0.24% in control). Higher Cd bioavailability was also observed in soils with both pollutants than that with Cd alone. And Cd existence caused the elevation of Cd resistant bacterium Limnobacter sp. (increased to 12.2% in CdCK from 2.06% in control). Functional gene prediction also indicated that abundance of genes related to nutrient metabolism decreased dramatically with pollutants, while the abundances of energy metabolism, lipid metabolism, secondary metabolites biosynthesis-related genes increased (especially for aromatic compound degradation related genes). These results indicated the mutual effect and internal-interaction existed between pollutants and soils resulted in pollutants' fate and soil microbial changes, providing further information regarding pollutants dissipation and transformation under soil microbial response.

Insights into the mechanisms underlying the remediation potential of earthworms in contaminated soil: A critical review of research progress and prospects

In recent years, soil pollution is a major global concern drawing worldwide attention. Earthworms can resist high concentrations of soil pollutants and play a vital role in removing them effectively. Vermiremediation, using earthworms to remove contaminants from soil or help to degrade non-recyclable chemicals, is proved to be an alternative, low-cost technology for treating contaminated soil. However, knowledge about the mechanisms and framework of the vermiremediation various organic and inorganic contaminants is still limited. Therefore, we reviewed the research progress of effects of soil contaminants on earthworms and potential of earthworm used for remediation soil contaminated with heavy metals, polychlorinated biphenyls (PCBs), polybrominated diphenyl ethers (PBDEs), polycyclic aromatic hydrocarbons (PAHs), pesticides, as well as crude oil. Especially, the possible processes, mechanisms, advantages and limitations, and how to boost the efficiency of vermiremediation are well addressed in this review. Finally, future prospects of vermiremediation soil contamination are listed to promote further studies and application of vermiremediation in contaminated soils.

Hazardous wastes treatment technologies

A review of the literature published in 2019 on topics related to hazardous waste management in water, soils, sediments, and air. The review covered treatment technologies applying physical, chemical, and biological principles for the remediation of contaminated water, soils, sediments, and air. PRACTICAL POINTS: This report provides a review of technologies for the management of waters, wastewaters, air, sediments, and soils contaminated by various hazardous chemicals including inorganic (e.g., oxyanions, salts, and heavy metals), organic (e.g., halogenated, pharmaceuticals and personal care products, pesticides, and persistent organic chemicals) in three scientific areas of physical, chemical, and biological methods. Physical methods for the management of hazardous wastes including general adsorption, sand filtration, coagulation/flocculation, electrodialysis, electrokinetics, electro-sorption ( capacitive deionization, CDI), membrane (RO, NF, MF), photocatalysis, photoelectrochemical oxidation, sonochemical, non-thermal plasma, supercritical fluid, electrochemical oxidation, and electrochemical reduction processes were reviewed. Chemical methods including ozone-based, hydrogen peroxide-based, potassium permanganate processes, and Fenton and Fenton-like process were reviewed. Biological methods such as aerobic, anoxic, anaerobic, bioreactors, constructed wetlands, soil bioremediation and biofilter processes for the management of hazardous wastes, in mode of consortium and pure culture were reviewed. Case histories were reviewed in four areas including contaminated sediments, contaminated soils, mixed industrial solid wastes and radioactive wastes.

Biodegradation of Atrazine by Mixed Bacteria of Klebsiella variicola Strain FH-1 and Arthrobacter sp. NJ-1

The purpose of this study is to enhance the biodegradability of atrazine with FH-1 and NJ-1 alone by selecting the mixing ratio, optimizing the culture medium and conditions. The results showed that FH-1 and NJ-1 have the best biodegradation effect on atrazine being mixed in a volume ratio of 3:2. In a single factor experiment, sucrose and NH₄Cl provided carbon and nitrogen sources for the mixed bacteria. Subsequently, composition of fermentation medium was further optimized using Box-Behnken design of response surface methodology. Based on the results, growth of mixed bacteria and biodegradation of atrazine performed best effects with a biodegradation rate of 85.6% when sucrose and NH₄Cl amounts were 35.30 g/L and 10.28 g/L. The optimal medium condition was 10% inoculum of mixed bacteria, with initial atrazine concentration of 50 mg/L, neutral or weakly alkaline pH value, 30°C. The biodegradation rate reached 97.4%, 11.8% higher than the unoptimized condition.

Synergistic effect of Klebsiella sp. FH-1 and Arthrobacter sp. NJ-1 on the growth of the microbiota in the black soil of Northeast China

The application of Atrazine in soil has always been a main problem in agriculture because its residuals may maintain in the soil for a long term. In this paper, two strains of Atrazine degrading bacteria (Klebsiella sp. FH-1 and Arthrobacter sp. NJ-1) were used to make biological compound microbial inoculum to repair the Atrazine contaminated typical black soil in Northeast China. Grain chaff was chosen as the optimal carrier material for microbial inoculum. The dynamic changes of Atrazine were detected by gas chromatography. The half-life of Atrazine in soil containing microbial inoculum was shortened from 9.8 d to 4.2 d. The Atrazine sensitive crops grown in the repaired soil showed increased stem length, root length, and emergence rate. The effects of microbial remediation on the original bacterial and fungal biota in the typical black soil in Northeast China were analyzed using the metagenomic approach. Results showed that Atrazine inhibited the original bacteria and fungi populations. The total numbers of bacterial and fungal species in the soil were partially recovered by adding the microbial inoculum. Two genera (Sphingosinicella and Sphingomonas) were the dominant bacteria. The beneficial bacterial biota was recovered and the number of species of the beneficial bacteria was higher than that in the original soil after adding the microbial inoculum. The dominant fungi included genera Guehomyces and Chaetomella. There was a total of 113 unclassified fungal genera (22.6% of 499), indicating the potential utility of the unclassified fungal species in the assessment of the soil contamination by Atrazine.

Bioremediation by earthworms on soil microbial diversity and partial nitrification processes in oxytetracycline-contaminated soil

A large proportion (60-90%) of ingested tetracyclines are released to slurry, soils, surface waters and ground water, which has raised extensive concerns and may pose a risk to the soil ecosystem. A 56-day experiment was conducted to study the bioremediation by earthworms on soil microbial diversity and partial nitrification processes in oxytetracycline (OTC)-contaminated soil. The results showed that high OTC concentration significantly decreased the activity of soil bacteria, ammonia-oxidizing bacteria (AOB) and archaea (AOA). Earthworms were found to accelerate the degradation efficiency and rate of OTC, and its main metabolites were 4-epi-oxytetracycline (EOTC) and 2-acetyl-2-decarboxamido-oxytetracycline (ADOTC). Earthworms had an important role in the bioremediation of soil microbial diversity by degrading OTC and its metabolite (EOTC), especially in the high OTC condition. Additionally, the results indicated that the effects of earthworms on the degradation of OTC could remediate the abundances of 16S rRNA and AOB amoA genes and the NO₃^- content in both low and high OTC-contaminated soils. The structural equation model suggested that earthworms could remediate the microbial diversity, the abundances of 16s rRNA and AOB amoA genes by accelerating the degradation of OTC, which contributed to the bioremediation by earthworms on soil microbial diversity and partial nitrification processes in oxytetracycline-contaminated soil.

Application of Simplicillium chinense for Cd and Pb biosorption and enhancing heavy metal phytoremediation of soils

Phytoremediation is an effective approach to control soil heavy metal pollution. This study isolated a fungus strain from soils contaminated by cadmium (Cd) and lead (Pb) in Zhalong Wetland (China), which was identified as Simplicillium chinense QD10 via both genotypic and phenotypic analysis. The performance and mechanism of S. chinense QD10 in Cd and Pb adsorption was unraveled by morphological analysis and biosorption test, and its roles in ameliorating phytoremediation by Phragmites communis were tested in pot-experiments. Cd biosorption was attributed to the formation of Cd-chelate, whereas Pb was predominantly adsorbed by extracellular polymeric substances. Metal biosorption followed Langmuir isotherm, and the maximum biosorption capacity was 88.5 and 57.8 g/kg for Cd and Pb, respectively. Colonized in soils, such biosorption behavior of S. chinense QD10 can generate gradients of available Cr or Pb and drive their enrichment. Accordingly, S. chinense QD10 amendment significantly enhanced the phytoextraction of Cd and Pb by P. communis, possibly attributing to rhizospheric enrichment of Cd or Pb and defending effects on plants, explained by the significant removal of acid-extractable and reducible metals in soils and the increase of Cd and Pb content in P. communis tissues. The present study explored the mechanisms of S. chinense QD10 in Cd and Pb biosorption and proved its potential in ameliorating the phytoremediation performance at metal contaminated sites.

A Review on Recent Treatment Technology for Herbicide Atrazine in Contaminated Environment

Atrazine is a kind of triazine herbicide that is widely used for weed control due to its good weeding effect and low price. The study of atrazine removal from the environment is of great significance due to the stable structure, difficult degradation, long residence time in environment, and toxicity on the organism and human beings. Therefore, a number of processing technologies are developed and widely employed for atrazine degradation, such as adsorption, photochemical catalysis, biodegradation, etc. In this article, with our previous research work, the progresses of researches about the treatment technology of atrazine are systematically reviewed, which includes the four main aspects of physicochemical, chemical, biological, and material-microbial-integrated aspects. The advantages and disadvantages of various methods are summarized and the degradation mechanisms are also evaluated. Specially, recent advanced technologies, both plant-microbial remediation and the material-microbial-integrated method, have been highlighted on atrazine degradation. Among them, the plant-microbial remediation is based on the combined system of soil-plant-microbes, and the material-microbial-integrated method is based on the synergistic effect of materials and microorganisms. Additionally, future research needs to focus on the excellent removal effect and low environmental impact of functional materials, and the coordination processing of two or more technologies for atrazine removal is also highlighted.

Enantioselective degradation of chiral fungicides triticonazole and prothioconazole in soils and their enantioselective accumulation in earthworms Eisenia fetida

Triticonazole and prothioconazole are widely used systemic agricultural triazole fungicides both with a chiral center. In this work, the enantioselective degradation of triticonazole and prothioconazole in three types of soils were investigated under native conditions using reversed phase liquid chromatography-tandem mass spectrometry with a Chiralcel OD-RH column. The results indicated that the enantioselective degradation was observed with S-triticonazole and R-prothioconazole preferentially degraded and the degradation rate was fast with a half-life within 6 days. It was also found that the presence of earthworms can accelerate the degradation and further enhance degradation enantioselectivity of triticonazole and prothioconazole in soils. Moreover, the enantioselective of triticonazole and prothioconazole in earthworms were studied. The results showed that the bioaccumulation was enantioselective with R-triticonazole and S-prothioconazole preferentially accumulated, which was similar to the soil. Our findings suggest that the enantioselective toxicity and potential effects of the metabolites should be considered for more accurate assessment of ecological risks of triticonazole and prothioconazole to target and non-target species.

Nuclear receptor AHR-mediated xenobiotic detoxification pathway involves in atrazine-induced nephrotoxicity in quail (Coturnix C. coturnix)

Atrazine (ATR), one of the most widely used pesticides in agricultural production, are gradually concerned due to potential ecosystem and health risks. Further, the induction of ATR nephrotoxicity and detoxification response is still unknown. To evaluate ATR-induced nephrotoxicity, quails were treated with 0, 50, 250 or 500 mg/kg ATR by gavage administration for 45 days. Histopathology indicated that ATR exposure caused renal tubular epithelial cell swelling and endoplasmic reticulum degeneration, suggesting that ATR exposure causes renal impairment even renal diseases. Notably, ATR interfered cytochrome P450 system (CYP450s) homeostasis by enhancing contents or activities of CYP450s (total CYP450, Cyt b5, AH, APND, NCR and ERND) and the expression of CYP450 isoforms (CYP1A, CYP1B, CYP2C and CYP3A). ATR triggered phase II detoxifying reaction, reflected by the elevated GSH level, GST activity and the up-regulation of GST isoforms (GSTa, GSTa3 and GSTt1) and GSH synthetase (GCLC). Moreover, ABC transporters were activated to expel ATR from the body by increasing expression of MRP1 and P-GP gene. Accompanying these alterations, the nuclear receptors (AHR, CAR and PXR) were activated by ATR in a dose-dependent manner. Analysis results of present study demonstrated that the induction of phase II detoxifying enzyme system and ABC transporters could be modulated by nuclear receptors response and CYP450s disturbance in low-dose ATR-treated quail. In conclusion, all data suggested that nuclear receptors AHR-mediated detoxification pathway was involved in ATR-induced nephrotoxicity. These results provided new evidence about the nephrotoxic effects of ATR on the response of biotransformation and detoxification system.

Biodegradation of Atrazine by the Novel Klebsiella variicola Strain FH-1

Bacterial strain FH-1 with high efficiency of degrading Atrazine is separated by means of enrichment culture from the soil applied with Atrazine for many years. FH-1, recognized as Klebsiella variicola based on phylogenetic analysis of 16S rDNA sequences, can grow with Atrazine which is the sole nitrogen source. In fluid inorganic salt medium, the optimal degradation temperature, pH value, and initial concentration of Atrazine are 25°C, 9.0, and 50 mg L^–1, respectively, and the degradation rate of Atrazine by strain FH-1 reached 81.5% in 11 d of culture. The degrading process conforms to the kinetics equation of pesticide degradation. Among the metal ions tested, Zn²⁺ (0.2 mM) has the most significant effect of facilitation on the degradation of Atrazine. In the fluid medium with Zn²⁺, the degradation rate of Atrazine is increased to 72.5%, while the Cu²⁺ (0.2 mM) inhibits the degradation of Atrazine. The degradation products of Atrazine by strain FH-1 were identified as HEIT (2-hydroxyl-4-ethylamino-6-isopropylamino-1,3,5-triazine), MEET (2-hydroxyl-4,6-bis(ethylamino)-1,3,5-triazine), and AEEO (4,6-bis(ethylamino)-1,3,5-triazin-2(1H)-one) by HPLC-MS/MS. Three genes (atzC, trzN, and trzD) encoding for Atrazine degrading enzymes were identified by PCR and sequencing in strain FH-1. This study provides additional theoretical support for the application of strain FH-1 in bioremediation of fields polluted by Atrazine.

Activation of peroxymonosulfate by magnetic catalysts derived from drinking water treatment residuals for the degradation of atrazine

Magnetic catalysts (MCs) derived from iron-rich drinking water treatment residuals (WTRs) were prepared through pyrolysis treatment and introduced as activators of peroxymonosulfate (PMS) for refractory atrazine (ATZ) degradation. Comprehensive characterization analysis indicated that pyrolytic temperature could manipulate the crystalline structure evolution of the MCs and influence their physicochemical and catalytic properties. The catalytic performances of the as-prepared samples pyrolyzed at 600 °C (MC-600) and 1000 °C (MC-1000) were evaluated, and MC-1000 exhibited far more excellent catalytic reactivity than MC-600 in PMS oxidation system. Such difference was mainly attributed to that Fe₃O₄ and Fe° are the dominant active ingredients of MC-600 and MC-1000, respectively. The electron spin resonance (ESR) tests and radical quenching experiments revealed that hydroxyl radical (^•OH) and sulfate radical (SO₄^•-) predominated in the MC-600/PMS and MC-1000/PMS systems, respectively. The mechanisms of the MCs-mediated PMS activation process were elucidated, among which the role of iron mineral phase was emphatically explored. Furtherly, possible degradation by-products were identified by LC-MS, and potential degradation pathways were proposed. Ultimately, the effects of pivotal parameters (i.e. MC-1000 dosage, PMS concentration, initial pH, and water matrix species) on ATZ degradation were investigated to assess the applicability of the MC-1000/PMS system.