Atrazine Metabolites Research Articles

Environmental Stress-Induced Alterations in Embryo Developmental Morphokinetics.

The association between embryo morphokinetics and its developmental competence is well documented. For instance, early cleaved embryos are more competent in developing to blastocysts, whereas the proportion of abnormally cleaved embryos that further developed to blastocysts is low. Numerous factors, such as the parental age, lifestyle, health, and smoking habits have been reported to affect the embryo morphokinetics and, consequently, its development. However, less is known about the effect of environmental stressors on embryo morphokinetics. The current review discusses the effect of the most concerning environmental stressors on embryo morphokinetics. These stresses include heat stress and human-made chemicals such as phthalates (e.g., bis-(2-ethylhexyl phthalate, dibutyl phthalate, dimethyl phthalate, and their primary metabolites), herbicides (e.g., diaminochlorotriazine, the primary metabolite of atrazine), pharmaceutical compounds (e.g., carbamazepine, nocodazole) and pro-oxidant agents (cumene hydroperoxide, Triton X-100), as well as naturally occurring toxins such as mycotoxin (e.g., aflatoxin B1 and its metabolite, and ochratoxin A). In addition, this review discusses the effect of ionizing or non-ionizing radiation and viral infections (e.g., SARS-CoV-2, papillomavirus). Finally, it points out some potential mechanisms that underlie the impairment of embryo morphokinetics, and it suggests protective compounds, mainly the supplementation of antioxidants to improve the morphokinetics, and consequently, the embryo developmental competence.

Assessing plant pigmentation impacts: A novel approach integrating UAV and multispectral data to analyze atrazine metabolite effects from soil contamination

The objective of this study was to evaluate the levels of desethylatrazine (DEA), a hydrophilic metabolite of atrazine, and its impact on plant health. This was achieved by utilizing multispectral imagery captured by Unmanned Aerial Vehicles (UAVs) in combination with ground-measured data to assess photosynthetic pigment levels in Green Cos lettuce following atrazine application in agricultural soil. Strong correlations were found between DEA levels and chlorophyll a, chlorophyll b, and anthocyanin levels in lettuce (R² > 0.70), while the correlation with carotenoid levels was weaker (R² = 0.55). This disruption to the pigments could interfere with photosynthesis, potentially hindering the plant's growth and development, and ultimately leading to a reduction in yield. The Anthocyanin Reflectance Index (ARI) demonstrated a robust positive correlation with DEA, whereas the Normalized Difference Red Edge (NDRE), Leaf Chlorophyll Index (LCI), and Normalized Difference Vegetation Index (NDVI) displayed pronounced negative correlations. Incorporating ARI, LCI, and NDRE, with or without NDVI, provided the most accurate prediction of DEA levels, with an R² exceeding 0.96. NDRE emerged as the most efficient index for forecasting chlorophyll a and chlorophyll b levels. Modified Chlorophyll Absorption in Reflectance Index (MCARI) demonstrated the best fit for carotenoids, while ARI performed exceptionally well in describing actual measurements of anthocyanins (R² = 0.90). The best-performing VI models, developed from the selection of effective single variables, exhibited the best fit to actual pigment measurements (R² > 0.83). These findings underscore the role of UAV-derived multispectral imagery in assessing DEA levels and improving environmental monitoring, aiding in better planning for agriculture and environmental remediation to enhance ecosystem health and resilience.

Biochar modification accelerates soil atrazine biodegradation by altering bacterial communities, degradation-related genes and metabolic pathways

Atrazine is one of the most used herbicides, posing non-neglectable threats to ecosystem and human health. This work studied the performance and mechanisms of surface-modified biochar in accelerating atrazine biodegradation by exploring the changes in atrazine metabolites, bacterial communities and atrazine degradation-related genes. Among different types of biochar, nano-hydroxyapatite modified biochar achieved the highest degradation efficiency (85.13 %), mainly attributing to the increasing pH, soil organic matter, soil humus, and some enriched indigenous bacterial families of Bradyrhizobiaceae, Rhodospirillaceae, Methylophilaceae, Micrococcaceae, and Xanthobacteraceae. The abundance of 4 key atrazine degradation-related genes (atzA, atzB, atzC and triA) increased after biochar amendment, boosting both dechlorination and dealkylation pathways in atrazine metabolism. Our findings evidenced that biochar amendment could accelerate atrazine biodegradation by altering soil physicochemical properties, microbial composition and atrazine degradation pathways, providing clues for improving atrazine biodegradation performance at contaminated sites.

The Nrf2/ARE pathway as a potential target to ameliorate atrazine-induced endocrine disruption in granulosa cells

Atrazine (ATR) is widely used worldwide as a commercial herbicide, Diaminochlorotriazine (DACT) is the main metabolite of ATR in the organism. Both of them disrupt the production of steroids and induce abnormal reproductive development. The granulosa cells (GCs) are important for growth and reproduction of animals. However, the toxicity of ATR on the GCs of birds is not well clarified. To evaluate the effect of the environmental pollutant ATR on bird GCs. The quail GCs were allotted into 7 groups, C (The medium of M199), A20 (20 µM ATR), A100 (100 µM ATR), A250 (250 µM ATR), D20 (20 µM DACT), D100 (100 µM DACT) and D200 (200 µM DACT). The results demonstrated that ATR reduced the viability of GCs, disrupted mitochondrial structure (including mitochondrial cristae fragmentation and the mitochondrial morphology disappearance) and decreased mitochondrial membrane potential. Meanwhile, ATR interfered with the expression of key factors in the steroid synthesis pathway, inducing the secretion of the sex hormones E2 and P in GCs. which in turn induced apoptosis. Furthermore, the Nrf2/ARE pathway as a potential target to ameliorate ATR-induced endocrine disruption in GCs for proper reproductive functions. Our research provides a new perspective for understanding the effects of ATR on reproductive functions in birds.

Effect of biochar on soil microbial community, dissipation and uptake of chlorpyrifos and atrazine

For the application of biochar in restoring pesticide-contaminated soils and minimizing the risk associated with their uptake in plants, it is crucial to understand the biochar impact on soil biological activities and dissipation and accumulation of pesticides in plant and soil systems. In this study, the effect of Mentha-distilled waste-derived biochar was investigated on chlorpyrifos and atrazine contaminated sandy loam soil. The four application rates of atrazine (2, 4, 6, and 8 mg kg−1) and chlorpyrifos (2, 4, 6, and 12 mg kg−1) and a single application rate of biochar (4%) were used in this study. The degradation of pesticides, the diversity of the bacterial community, and enzymatic activities (alkaline phosphatase, dehydrogenase, arylsulfatase, phenol oxidase, urease activity and N-acetyl glucosaminidase) were examined in soil. The uptake of two pesticides and their effect on growth and stress parameters were also investigated in plants (A. paniculata). The dissipation of chlorpyrifos and atrazine followed simple first-order kinetics with a half-life of 6.6–74.6 and 21–145 days, respectively. The presence of deisopropyl atrazine desethyl atrazine (metabolites of atrazine) and 3,5,6-trichloro-2-pyridinol (a metabolite of chlorpyrifos) was observed in soil and plant tissues. Biochar application significantly (p = 0.001) enhanced the degradation rate of chlorpyrifos and atrazine leading to the lower half-life of chlorpyrifos and atrazine in soil. A significant reduction (p = 0.001) in the uptake of chlorpyrifos and atrazine and alteration in their binding affinity and uptake rate in plant tissues was observed in biochar treatments. The incorporation of biochar improved chlorpyrifos/atrazine degrader and plant growth-promoting bacterial genera such as Balneimonas, Kaistobacter, Rubrobacter, Ammoniphilus, and Bacillus. The upregulation of functional genes associated with nucleotide, energy, carbohydrate, amino acid metabolism, xenobiotic biodegradation, and metabolism: atrazine degradation was observed in biochar treatments. The biochar amendments significantly (p = 0.001) reduced the plant’s uptake velocity (Vmax) and affinity (Km) of chlorpyrifos and atrazine. These results delineated that Mentha-distilled waste-derived biochar can potentially remediate chlorpyrifos and atrazine contaminated soils and ensure the safety of plants for consumption.Graphical

Exposure to and Biomarker Responses From Legacy and Emerging Contaminants Along Three Drainages in the Milwaukee Estuary, Wisconsin, USA.

Legacy contaminants and contaminants of emerging concern (CECs) were assessed in tree swallow (Tachycineta bicolor) tissue and diet samples from three drainages in the Milwaukee estuary, Wisconsin, USA, to understand exposures and possible biomarker responses. Two remote Wisconsin lakes were assessed for comparative purposes. Bioaccumulative classes of contaminants, such as polybrominated diphenyl ethers and per- and polyfluoroalkyl substances, while at higher concentrations than the reference lakes, did not vary significantly among sites or among the three drainages. Polycyclic aromatic hydrocarbons were assessed in diet and sediment and were from primarily pyrogenic sources. Ten biomarkers were assessed relative to contaminant exposure. Polychlorinated biphenyls (PCBs) were elevated above reference conditions at all Milwaukee sites but did not correlate with any measured biomarker responses. Only one site, Cedarburg, just downstream from a Superfund site, had elevated PCBs compared to other sites in the Milwaukee estuary. Few non-organochlorine insecticides or herbicides were detected in tree swallow liver tissue, except for the atrazine metabolite desethylatrazine. Few pharmaceuticals and personal care products were detected in liver tissue except for N,N-diethyl-meta-toluamide, iopamidol, and two antibiotics. The present study is one of the most comprehensive assessments to date, along with the previously published Maumee River data, on the exposure and effects of a wide variety of CECs in birds. Environ Toxicol Chem 2024;43:856-877. © 2024 SETAC. This article has been contributed to by U.S. Government employees and their work is in the public domain in the USA.

Degradation of atrazine, glyphosate, and 2,4-D in soils collected from two contrasting crop rotations in Southwest Chaco, Argentina

Argentina stands as one of the leading consumers of herbicides. In a laboratory incubation experiment, the persistence and production of degradation metabolites of Atrazine, 2,4-D, and Glyphosate were investigated in a loamy clay soil under two contrasting agricultural practices: continuous soybean cultivation (T1) and intensified rotations with grasses and legumes (T2). The soils were collected from a long-term no-till trial replicating the influence of the meteorological conditions in the productive region. The soil was enriched with diluted concentrations of 6.71, 9.95, and 24 mg a.i./kg-1 of soil for the respective herbicides, equivalent to annual doses commonly used in the productive region. Samples were taken at intervals of 0, 0.5, 1, 2, 4, 6, 8, 16, 32, and 64 days, and analysis was conducted using high-resolution liquid chromatography UPLC MS/MS. An optimal fit to the first-order kinetic model was observed for each herbicide in both rotations, resulting in relatively short half-lives. Intensified crop sequences favored the production of biotic degradation metabolites. The impact of the high frequency of soybean cultivation revealed a trend of soil acidification and a reduced biological contribution to attenuation processes in soil contamination.

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.

Degradation of co-applied Atrazine and Fipronil in Phanerochaete Chrysosporium Augmented Biobeds.

White rot fungi possess an enzymatic system that is non-specific to any pesticide and can be used for pesticide detoxification in biobeds. The present study evaluated potential of Phanerochaete chrysosporium to degrade co-applied atrazine and fipronil in ash or biochar biomixtures. Five biomixtures were prepared by partially replacing compost in rice straw-compost biomixture (BM) with 10% rice husk ash (RHA), 10% sugarcane bagasse ash (SBA), and 1 and 5% wheat straw biochar (WBC). Results suggested that after 30 days P. chrysosporium augmented biobeds resulted in 60.52-72.72% atrazine and 69.57-72.52% fipronil degradation. Hydroxyatrazine and fipronil sulfone were detected as the only metabolite of atrazine and fipronil, respectively, and were further degraded. Although, SBA significantly enhanced atrazine degradation, RHA or SBA had no significant effect on fipronil degradation. WBC (5%) slowed down degradation of both pesticides.

Metabolic insights into how multifunctional microbial consortium enhances atrazine removal and phosphorus uptake at low temperature

Agricultural soils in the black soil region of northeast China often face negative stress due to low temperatures, pesticide contamination, and inadequate nutrient supply. In this study, a new cold-tolerant strain of Peribacillus simplex C1 (C1) was selectively isolated from atrazine contaminated soil. The artificially constructed microbial consortium (CPD) [C1, phosphorus-solubilizing bacterium Enterobacter sp. P1, and atrazine-degrading bacterium Acinetobacter lwoffii DNS32] demonstrated the most effective performance in enhancing atrazine degradation and phosphorus-solubilizing capacity when the initial inoculation ratio of 5:1:2 at 15 °C. CPD enhanced energy-related metabolic pathways and increased choline production to regulate bacterial adaptation to temperature decrease. Additionally, the strains could selectively utilize carbon sources (low molecular weight organic acids) or nitrogen sources (some metabolites of atrazine) provided by each other to enhance growth. Furthermore, strain C1 enhanced membrane fluidity through increased expression of the unsaturated fatty acids. Pot experiments demonstrated that CPD assisted soybean seedlings in resisting dual stresses of low temperature and atrazine contamination by inducing the expression of genes related to photosynthesis, membrane permeability, phosphorus response, and cold tolerance.

Characterization of Arsenic and Atrazine Contaminations in Drinking Water in Iowa: A Public Health Concern.

Arsenic and atrazine are two water contaminants of high public health concern in Iowa. The occurrence of arsenic and atrazine in drinking water from Iowa's private wells and public water systems was investigated over several decades. In this study, the percentages of detection and violation of regulations were compared over region, season, and water source, and factors affecting the detection and concentration of arsenic and atrazine were analyzed using a mixed-effects model. Atrazine contamination in drinking water was found to vary by region, depending on agricultural usage patterns and hydrogeological features. The annual median atrazine levels of all public water systems were below the drinking water standard of 3 ppb in 2001-2014. Around 40% of public water systems contained arsenic at levels > 1 ppb in 2014, with 13.8% containing arsenic at levels of 5-10 ppb and 2.6% exceeding 10 ppb. This unexpected result highlights the ongoing public health threat posed by arsenic in drinking water in Iowa, emphasizing the need for continued monitoring and mitigation efforts to reduce exposure and associated health risks. Additionally, an atrazine metabolite, desethylatrazine, should be monitored to obtain a complete account of atrazine exposure and possible health effects.

Influence of temperature on the biomarker responses of bullfrog tadpoles (Lithobates catesbeianus) to 2-hydroxyatrazine exposure

The influence of temperature (25 and 32 °C) on the biomarker responses of bullfrog tadpoles (Lithobates catesbeianus) to different concentrations of the atrazine metabolite 2-hydroxyatrazine (2-HA, 0, 10, 50 and 200 ng.L−1, 16 days), was evaluated. Temperature affected the activities of superoxide dismutase, glutathione S-transferase and acetylcholinesterase. The activities of catalase, glutathione peroxidase, glucose-6-phosphate dehydrogenase and carboxylesterase presented no alterations. Frequencies of micronuclei and nuclear abnormalities were also not altered. 2-HA decreased SOD activity at 25 °C and caused histopathological changes in the liver and the kidney at both temperatures, with the kidney being more affected by the combination of higher temperature and 2-HA exposure, presenting glomerular shrinkage and an increase in Bowman's space. Our results indicate that at environmentally relevant concentrations, 2-HA can cause changes in biomarker responses as well as in the morphology of liver and kidney in L. catesbeianus tadpoles. Temperature has an important influence on biomarker response and histopathological alterations.

Enhanced phytoremediation of atrazine-contaminated soil by vetiver (Chrysopogon zizanioides L.) and associated bacteria.

The intensive and long-term use of atrazine (ATZ) has led to the contamination of agricultural soils and non-target organisms, posing a series of threats to human health through the transmission of the food chain. In this study, a 60-day greenhouse pot experiment was carried out to explore the phytoremediation by Chrysopogon zizanioides L. (vetiver). The uptake, accumulation, distribution, and removal of ATZ were investigated, and the degradation mechanisms were elucidated. The results showed that the growth of vetiver was inhibited in the first 10 days of the incubation; subsequently, the plant recovered rapidly with time going. Vetiver grass was capable of taking up ATZ from the soil, with root concentration factor ranging from 2.36 to 15.55, and translocating to the shoots, with shoot concentration factor ranging from 7.51 to 17.52. The dissipation of ATZ in the rhizosphere soil (97.51%) was significantly higher than that in the vetiver-unplanted soil (85.14%) at day 60. Metabolites were identified as hydroxyatrazine (HA), deethylatrazine (DEA), deisopropylatrazine (DIA), and didealkylatrazine (DDA) in the samples of the shoots and roots of vetiver as well as the soils treated with ATZ. HA, DEA, DIA, and DDA were reported first time as metabolites of ATZ in shoots and roots of vetiver grown in soil. The presence of vetiver changed the formation and distribution of the dealkylated products in the rhizosphere soil, which remarkably enhanced the occurrence of DEA, DIA, and DDA. Arthrobacter, Bradyrhizobium, Nocardioides, and Rhodococcus were the major atrazine-degrading bacterial genera, which might be responsible for ATZ degradation in the rhizosphere soil. Our findings suggested that vetiver grass can significantly promote ATZ degradation in the soil, and it could be a strategy for remediation of the atrazine-contaminated agricultural soil.

Alfalfa’s response to atrazine stress and its secreted atrazine metabolites

Although listed as endocrine disruptor compounds, atrazine (ATZ) is still used in large quantities in agricultural production. Here, alfalfa seedling was cultivated in hydroponic media to investigate the toxic effects of ATZ on alfalfa and accumulation of ATZ in tissues of different plant parts. Alfalfa had a strong upward translocation ability to ATZ. The stress response of alfalfa under ATZ stress was studied using metabolomic and transcriptomic techniques. S-adenosylmethionine, glutathione, 3-mercaptopyruvic acid, ornithine, and aminopropylcadaverine were significantly increased by ATZ in pathways mtr00270 and mtr00480. Several genes of cysteine synthase and spermidine synthase were significantly up-regulated by ATZ induction. They may be markers and genes with potential physiological functions of alfalfa in response to ATZ stress. In addition, using high resolution mass spectrometry, a total of five ATZ metabolites secreted from alfalfa roots were detected. Among them, acetylated deisopropylated ATZ was discovered for the first time. Hydroxylated ATZ and acetylated deethylated ATZ were more readily excreted by the root system. This study not only provides potential genes for the construction of engineering plants to remediate ATZ-contaminated soil, but also provides monitoring objects for the ecological research of ATZ metabolites.

Ash and biochar mixed biomixtures to degrade co-applied atrazine and fipronil in bio-augmented biobeds

ABSTRACT Retention and degradation of co-applied atrazine and fipronil was studied in laboratory constructed bio-augmented biobeds containing rice straw-compost (BM) and compost replaced with 10% rice husk ash [RHABM(10%)] or 1% wheat straw biochar [WBCBM(1%)] biomixtures. Atrazine (5000 µg, 50% WP) and fipronil (5000 µg, 0.3 G) were co-applied in 100 mL water. After 30 days, 7.31, 4.65, and 11.21 µg g−1 atrazine and 21.59, 7.41, and 37.20 µg g−1 fipronil remained undegraded in the top 3–4 cm of BM, RHABM(10%), WBCBM(1%) biobeds, respectively, suggesting that degradation of both pesticides significantly varied (p < 0.05) among the three biobeds. After 60 days 94.5%–98.3% of initially applied atrazine and 80.3%–86.9% fipronil degradation was observed. Hydroxyatrazine and sulphone were detected as the metabolites of atrazine and fipronil, respectively. Out of 5000 µg of initially applied pesticides, BM, RHABM(10%), and WBCBM(1%) biobeds accounted for 95.2%, 93.1%, and 95.2% of atrazine + hydroxyatrazine and 62.8%, 67.0%, and 71.5% of fipronil + sulphone degradation, respectively. Maximum amounts of recovered atrazine (68.8%–81.1%) and fipronil (89.8%–94.6%) were retained in the 0–5 cm sections of the biobeds. No significant effect of co-applied atrazine + fipronil was evident on the microbial parameters. This study suggested that RHA/WBC-mixed rice straw-compost biomixtures can be exploited for the detoxification of these pesticides in bio-purification systems.

Determination of atrazine and propazine metabolites deemed endocrine disruptors in human seminal plasma by LC\u2013ESI-MS/MS

BackgroundThe increasing prevalence of male infertility and the declining trend in sperm quality has been associated to compounds known as “endocrine-disruptors”. The proven endocrine-disrupting effects of atrazine and propazine herbicides led us to conduct long-term research based on highly accurate specific analytical methods with a view to confirming the suspected association. Among the proposed developments was a sensitive analytical method for the simultaneous determination of three metabolites of atrazine and propazine.ResultsIn this work, the method was for first time used for the chromatographic separation and determination of deethyl- and deisopropyl-atrazine (DEA and DIA, respectively) and propazine-2-hydroxy (PP-2OH) in human seminal plasma by LC–ESI-MS/MS using deuterated atrazine (d5-AT) as internal standard (IS). Chromatographic and mass spectrometric conditions such as the mobile phase composition and flow-rate, injected volume, dry gas source temperature and flow-rate, nebulizer pressure and capillary voltage were all carefully optimized. Analytes were identified and quantified by using the multiple reaction monitoring (MRM) mode as applied to positive ions ([M + H]+). Transitions at three different m/z values for each analyte were selected from precursor ions, and the 212.1 → [128]+, 188.1 → [146]+ and 174.1 → [68.1]+ transitions for PP-2OH, DEA and DIA, respectively, were found to be quantitative. The proposed method was validated in terms of precision (repeatability and reproducibility), linear range (10–240 ng mL–1), limit of detection (150–210 pg mL–1), and quantification (500–700 pg mL–1), recovery, accuracy and matrix effects on extracts from variably treated seminal plasma samples. The overall analytical method was successfully applied to human seminal plasma samples from volunteers. PP-2OH was found at concentrations from 1.10 to 11.3 ng mL–1 in four of the six samples, and so was DIA at 9.60 ng mL–1 in one.ConclusionsThese results are suggestive of bioaccumulation of the target analytes in humans. Untargeted analytes including suspected parent molecules (atrazine and propazine) and other ions [viz., deethyldeisopropyl-atrazine (DD) and diamino-s-chlorotriazine (DACT)] were also detected under the working conditions used. These results may open up new prospects for as yet very incipient research into the bioaccumulation of endocrine disruptors in seminal plasma.Graphical

Simultaneous detection of topramezon, atrazine, and atrazine metabolite residues in environmental water by large-volume SPE-UPLC-MS/MS

ABSTRACT An analytical method that combined large-volume solid-phase (Cleanert-PEP) extraction with ultra-performance liquid chromatography-tandem mass spectrometry (SPE-UPLC-MS/MS) was established for the detection of atrazine, atrazine metabolites, and topramezon residues in environmental water. The results showed that atrazine, its metabolites, and topramezon had a good linear relationship within the linear range of 0.5–50 μg/L, and the linear correlation coefficients of all compounds were r2 ≥ 0.9989. At three spiked levels of 10, 100, and 1000 ng/L, the relative recoveries rate was between 77.1% and 114.1%, with relative standard deviations (RSDs) between 0.9% and 6.8%. The limits of detection (LODs) and limits of quantification (LOQs) of all target compounds were between 0.4 and 3.0 ng/L, and between 1.2 and 10.0 ng/L, respectively. After optimisation, Cleanert-PEP was selected for pretreatment of environmental water, and its elution curve was studied, and the optimal elution volume was 6 mL. The analysis method was applied to surface water bodies around Tai’an City in Shandong Province, China, and none of the target metabolites were detected. This method has the advantages of high sensitivity, good stability, simple operation, and high efficiency. It can be used to quantify topramezon, atrazine, and atrazine metabolite residual in water samples and to investigate their behaviour in environmental water.

Optimal design of experiments to improve the characterisation of atrazine degradation pathways in soil

AbstractContamination of soils with pesticides and their metabolites is a global environmental threat. Deciphering the complex process chains involved in pesticide degradation is a prerequisite for finding effective solution strategies. This study applies prospective optimal design (OD) of experiments to identify laboratory sampling strategies that allow model‐based discrimination of atrazine (AT) degradation pathways. We simulated virtual AT degradation experiments with a first‐order model that reflects a simple reaction chain of complete AT degradation. We added a set of Monod‐based model variants that consider more complex AT degradation pathways. Then, we applied an extended constraint‐based parameter search algorithm that produces Monte‐Carlo ensembles of realistic model outputs, in line with published experimental data. Differences between‐model ensembles were quantified with Bayesian model analysis using an energy distance metric. AT degradation pathways following first‐order reaction chains could be clearly distinguished from those predicted with Monod‐based models. As expected, including measurements of specific bacterial guilds improved model discrimination further. However, experimental designs considering measurements of AT metabolites were most informative, highlighting that environmental fate studies should prioritise measuring metabolites for elucidating active AT degradation pathways in soils. Our results suggest that applying model‐based prospective OD will maximise knowledge gains on soil systems from laboratory and field experiments.Highlights Bayesian model analysis can help to distinguish the active degradation pathway of pesticides. Information on degradation metabolites is crucial to understand pesticide fate. Measurements of specific guilds improve the distinction of active pesticide pathways. Prospective optimal design maximizes information gain in soil sciences.

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.

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.