A nationwide study of the occurrence and distribution of atrazine and its degradates in tap water and groundwater in China: Assessment of human exposure potential

Migration mechanism of atrazine in the simulated lake icing process at different freezing temperatures based on density function theory

Atrazine causes concern due to its resistant to biodegradation and could be accumulated in aquatic organisms, causing pollution in lakes. This study measured the concentration of atrazine in ice and the water under ice through a simulated icing experiment and calculated the distribution coefficient K to characterize its migration ability in the freezing process. Furthermore, density functional theory (DFT) calculations were employed to expatiate the migration law of atrazine during icing process. According to the results, it could release more energy into the environment when atrazine staying in water phase (-15.077 kcal/mol) than staying in ice phase (-14.388 kcal/mol), therefore it was beneficial for the migration of atrazine from ice to water. This explains that during the freezing process, the concentration of atrazine in the ice was lower than that in the water. Thermodynamic calculations indicated that when the temperature decreases from 268 to 248 K, the internal energy contribution of the compound of atrazine and ice molecule (water cluster) decreases at the same vibrational frequency, resulting in an increase in the free energy difference of the compound from -167.946 to -165.390 kcal/mol. This demonstrated the diminished migratory capacity of atrazine. This study revealed the environmental behavior of atrazine during lake freezing, which was beneficial for the management of atrazine and other pollutants during freezing and environmental protection.

Annual atrazine residue estimation in Chinese agricultural soils by integrated modeling of machine learning and mechanism-based models

This study presents a comprehensive approach to estimating annual atrazine residues in China's agricultural soils, integrating machine learning algorithms and mechanism-based models. First, machine learning was used to predict essential parameters influencing atrazine's adsorption, degradation, and dispersivity of solute transport. The results demonstrated that soil organic matter was the most important input variable for predicting adsorption and degradation; clay content was the primary variable for predicting dispersivity. The SHapley Additive exPlanations (SHAP) contribution of various soil properties on target variables were also analyzed to reveal whether each input variable has a positive, negative, or complex effect. Subsequently, these parameters inform the construction of a detailed model across 23,692 subregions of China, with a 20 km × 20 km resolution. The model considered regional variations and soil layer heterogeneity, including rainfall, soil depth-specific properties, and parameters for adsorption, degradation, and dispersivity. Utilizing the convection-dispersion equations and the Phydrus, the model simulated atrazine's transport and degradation patterns across diverse soil environments after applying 250 mL of atrazine (40%) per Chinese mu. The outcomes provided a spatially explicit distribution of atrazine residues, specifying that the arid areas have the highest residual risk, followed by the Northeast, Southwest, and Southeast. Atrazine levels may exceed national drinking water standards at 50 cm depth in Inner Mongolia, the Qinghai-Tibet Plateau, and the Jungar Basin. This study's integrative approach may also offer valuable insights and tools for evaluating residues of various pesticides and herbicides in agricultural soils.

Long-term vinasse application enhanced the initial dissipation of atrazine and ametryn in a sugarcane field in Tucumán, Argentina

The production of sugarcane bioethanol generates large volumes of vinasse, an effluent whose final disposal can produce an environmental impact that is of concern. The long-term disposal of vinasse in sugarcane fields could challenge crop management, such as the performance of traditional herbicides, by changing soil properties. This study aimed to evaluate the effect of long-term vinasse application on the field and the dissipation of atrazine and ametryn herbicides in a subtropical sugarcane agroecosystem, and to discuss the potential processes involved in it. Vinasse affected soil properties by increasing pH (12%), electrical conductivity (160%), and soil organic carbon (25%) at 0-10 cm depth of soil. Differences in the herbicide calculated sorption coefficient (Kd) varied according to the pedotransfer function applied and the herbicide type (atrazine or ametryn). During the first seven days after herbicide application, the soil underwent long-term vinasse application and increased atrazine and ametryn dissipation 45% and 33%, respectively, compared with the conventional fertilization scheme (control). The Pesticide Root Zone Model revealed that dissipation was mediated mainly by the degradation process rather than transport or other processes. The long-term application of vinasse in a typical sugarcane field of Tucumán, Argentina decreased the potential groundwater pollution of triazines and, adversely, reduced their bioavailability for weed control. For this, the present study presents original information about how long-term treatment with vinasse may require an adaptation of conventional management practices such as the application of herbicides in Argentina and other sugarcane-producing regions. Integr Environ Assess Manag 2024;20:1075-1086. © 2023 SETAC.

Simulated climate change and atrazine contamination can synergistically impair zebrafish testicular function

Elements that interfere with reproductive processes can have profound impacts on population and the equilibrium of ecosystems. Global warming represents the major environmental challenge of the 21st century, as it will affect all forms of life in the coming decades. Another coexisting concern is the persistent pollution by pesticides, particularly the herbicide Atrazine (ATZ), which is responsible for a significant number of contamination incidents in surface waters worldwide. While it is hypothesized that climate changes will significantly enhance the toxic effects of pesticides, the actual impact of these phenomena remain largely unexplored. Here, we conducted a climate-controlled room experiment to assess the interactive effects of the projected 2100 climate scenario and environmentally realistic ATZ exposures on the reproductive function of male zebrafish. The gonadosomatic index significantly decreased in fish kept in the extreme scenario. Cellular alterations across spermatogenesis phases led to synergic decreased sperm production and increased germ cell sloughing and death. ATZ exposure alone or combined with climate change effects, disrupted the transcription levels of key genes involved in steroidogenesis, hormone signaling and spermatogenesis regulation. An additive modulation with decreased 11-KT production and increased E2 levels was also evidenced, intensifying the effects of androgen/estrogen imbalance. Moreover, climate change and ATZ independently induced oxidative stress, upregulation of proapoptotic gene and DNA damage in post-meiotic germ cell, but the negative effects of ATZ were greater at extreme scenario. Ultimately, exposure to simulated climate changes severely impaired fertilization capacity, due to a drastic reduction in sperm motility and/or viability. These findings indicate that the future climate conditions have the potential to considerably enhance the toxicity of ATZ at low concentrations, leading to significant deleterious consequences for fish reproductive function and fertility. These may provide relevant information to supporting healthcare and environmental managers in decision-making related to climate changes and herbicide regulation.

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.

Endocrine toxicity of atrazine and its underlying mechanisms

Atrazine (ATR) is one of the most widely utilized herbicides globally and is prevalent in the environment due to its extensive use and long half-life. It can infiltrate the human body through drinking water, ingestion, and dermal contact, and has been recognized as an environmental endocrine disruptor. This study aims to comprehensively outline the detrimental impacts of ATR on the endocrine system. Previous research indicates that ATR is harmful to various bodily systems, including the reproductive system, nervous system, adrenal glands, and thyroi d gland. The toxic effects of ATR on the endocrine system and its underlying molecular mechanisms are summarized as follows: influencing the expression of kisspeptin in the HPG axis, consequently affecting steroid synthesis; disrupting DNA synthesis and meiosis, as well as modifying DNA methylation levels, leading to reproductive and developmental toxicity; impacting dopamine by altering Nurr1, VMAT2, and DAT expression, consequently affecting dopamine synthesis and transporter expression, and influencing other neurotransmitters, resulting in neurotoxicity; and changing adipose tissue synthesis and metabolism by reducing basal metabolism, impairing cellular oxidative phosphorylation, and inducing insulin resistance. Additionally, a compilation of natural products used to mitigate the toxic effects of ATR has been provided, encompassing melatonin, curcumin, quercetin, lycopene, flavonoids, vitamin C, vitamin E, and other natural remedies. It is important to note that existing research predominantly relies on in vitro and ex vivo experiments, with limited population-based empirical evidence available.

Assessment of drinking water quality and health risk using water quality index and multiple computational models: a case study of Yangtze River in suburban areas of Wuhan, central China, from 2016 to 2021

Water quality, increasingly recognized for its significant impact on health, is garnering heightened attention. Previous studies were limited by the number of water quality indicators and the duration of analysis. This study assessed the drinking water quality and its associated health risk in suburban areas of Wuhan, a city in central China, from 2016 to 2021. We collected 368 finished water samples and 1090 tap water samples and tested these for 37 different indicators. The water quality was evaluated using the water quality index, with trends over time analyzed via the Mann-Kendall test. Furthermore, an artificial neural network model was employed for future water quality prediction. Our findings indicated that the water quality in rural Wuhan was generally good and had an improvement from 2016 to 2021. The qualification and excellent rates were 98.91% and 86.81% for finished water, and 97.89% and 78.07% for tap water, respectively. The drinking water quality was predicted to maintain satisfactory in 2022 and 2023. Additionally, principal component analysis revealed that the primary sanitary issues in the water were poor sensory properties, elevated metal contents, high levels of dissolved solids, and microbial contamination. These issues were likely attributable to domestic and industrial waste discharge and aging water pipelines. The health risks associated with the long-term consumption of this water have been steadily decreasing over the years, underscoring the effectiveness of Wuhan's ongoing water management efforts.

Sustainable permeable biobarriers for atrazine removal in packed bed biofilm reactors

The synergy between two supported bacterial biofilms of S. equisimilis and P. putida and a sustainable biocarrier (raw pine) was studied, working both as biobarriers for the treatment of water contaminated with atrazine. Firstly, the effects of ATZ exposure on bacterial growth were evaluated, with Gram-positive S. equisimilis being a more tolerant bacterium to higher amounts of the herbicide. The bioremoval of ATZ by S. equisimilis concentrated biomass was then assessed, reaching around 83.5% after 15 days due to the potential degradation by the biomass and biosorption by the solids, with overlapping of both mechanisms. The optimization of bacterial biofilm attachment onto raw pine prior to bioremoval assays in lab-scale packed bed biofilm reactors was performed by varying initial biomass concentration, inocula growth time and hydrodynamic conditions. Lastly, the optimized biosystems were tested as sustainable remediation designs to treat water contaminated with the selected herbicide. Results reveal an added beneficial effect towards the bioremoval of atrazine using supported biofilms onto raw pine, reaching 90.42% and 79.71% by S. equisimilis and P. putida biofilms, respectively, over 58.31% increase when compared to sorption on fixed bed of pine. The coupling of biosorption/biodegradation favors the bioremoval process significantly.

Boosted Photocatalytic Degradation of Atrazine Using Oxygen-Modified g-C3N4: Investigation of the Reactive Oxygen Species Interconversion

Elaborating the specific reactive oxygen species (ROS) involved in the photocatalytic degradation of atrazine (ATZ) is of great significance for elucidating the underlying mechanism. This study provided conclusive evidence that hydroxyl radicals (·OH) were the primary ROS responsible for the efficient photocatalytic degradation of ATZ, thereby questioning the reliability of widely adopted radical quenching techniques in discerning authentic ROS species. As an illustration, oxygen-modified g-C3N4 (OCN) was prepared to counteract the limitations of pristine g-C3N4 (CN). Comparative assessments between CN and OCN revealed a remarkable 10.44-fold improvement in the photocatalytic degradation of ATZ by OCN. This enhancement was ascribed to the increased content of C-O functional groups on the surface of the OCN, which facilitated the conversion of superoxide radicals (·O2-) into hydrogen peroxide (H2O2), subsequently leading to the generation of ·OH. The increased production of ·OH contributed to the efficient dealkylation, dechlorination, and hydroxylation of ATZ. Furthermore, toxicity assessments revealed a significant reduction in ATZ toxicity following its photocatalytic degradation by OCN. This study sheds light on the intricate interconversion of ROS and offers valuable mechanistic insights into the photocatalytic degradation of ATZ.

Health effects of herbicides and its current removal strategies

The continually expanding global population has necessitated increased food supply production. Thus, agricultural intensification has been required to keep up with food supply demand, resulting in a sharp rise in pesticide use. The pesticide aids in the prevention of potential losses caused by pests, plant pathogens, and weeds, but excessive use over time has accumulated its occurrence in the environment and subsequently rendered it one of the emerging contaminants of concern. This review highlights the sources and classification of herbicides and their fate in the environment, with a special focus on the effects on human health and methods to remove herbicides. The human health impacts discussion was in relation to toxic effects, cell disruption, carcinogenic impacts, negative fertility effects, and neurological impacts. The removal treatments described herein include physicochemical, biological, and chemical treatment approaches, and advanced oxidation processes (AOPs). Also, alternative, green, and sustainable treatment options were discussed to shed insight into effective treatment technologies for herbicides. To conclude, this review serves as a stepping stone to a better environment with herbicides.

Concepts on Accumulation of Pesticides and Veterinary Drugs in Fish: A Review with Emphasis in Tilapia

The quality of the aquatic environment can be compromised by the practice of intensive use of pesticides in agriculture and by the misuse of veterinary drugs. Therefore, organisms that live in aquatic ecosystems may be affected due to the presence of these chemicals, through runoff, leaching and other processes. Exposure of aquatic organisms to these xenobiotics could pose health risks. Consequently, there is a growing interest in predicting the bioaccumulation of these substances in aquatic biota from experiments conducted under laboratory conditions. Studies on fish have been performed due to its importance as human food and their wide distribution in most of the aquatic environment. Thus, this article reviews the concepts on determining the accumulation of pesticides and veterinary drugs in fish. The risk regarding the consumption of fish containing residues of these chemical agents, the acceptable daily intake, the testing protocols and the analytical techniques used to determine the residues of these substances in fish tissues are discussed. An emphasis on studies involving tilapia as the test organism was included because, according to Food and Agricultural Organization (FAO), this species is one of the most cultivated in the world.

Combinational exposure to hydroxyatrazine increases neurotoxicity of polystyrene nanoparticles on Caenorhabditis elegans

Using Caenorhabditis elegans as an animal model, we investigated combinational effect between 2-hydroxyatrazine (HA) and polystyrene nanoparticle (PS-NP) on function and development of D-type motor neurons. Exposure to HA (10 and 100 μg/L) alone caused decreases in body bend, head thrash, and forward turn and increase in backward turn. Exposure to 100 μg/L HA also caused neurodegeneration of D-type motor neurons. Moreover, combinational exposure to HA (0.1 and 1 μg/L) induced enhancement in PS-NP (10 μg/L) toxicity in inhibiting body bend, head thrash, and forward turn, and in increasing backward turn. In addition, combinational exposure to HA (1 μg/L) could result in neurodegeneration of D-type motor neurons in PS-NP (10 μg/L) exposed nematodes. Combinational exposure to HA (1 μg/L) and PS-NP (10 μg/L) increased expressions of crt-1, itr-1, mec-4, asp-3, and asp-4, which govern the induction of neurodegeneration. Moreover, combinational exposure to HA (0.1 and 1 μg/L) strengthened PS-NP (10 μg/L)-induced decreases in glb-10, mpk-1, jnk-1, and daf-7 expressions, which encode neuronal signals regulating response to PS-NP. Therefore, our results demonstrated the effect of combinational exposure to HA and nanoplastics at environmentally relevant concentrations in causing toxic effect on nervous system in organisms.

Triazine herbicides exposure, natural immunoglobulin M antibodies, and fasting plasma glucose changes: Association and mediation analyses in general Chinese urban adults

The effects of triazine herbicides on glucose metabolism remain unclear. In this study, we aimed to assess the associations between serum triazine herbicides and glycemia-related risk indicators in general adults, and to evaluate the mediating role of natural immunoglobulin M antibodies (IgM) in the above associations among uninfected participants. We measured the concentrations of atrazine, cyanazine, and IgM in serum, as well as fasting plasma glucose (FPG), and fasting plasma insulin in 4423 adult participants from the Wuhan-Zhuhai cohort baseline population, enrolled in 2011-2012. Generalized linear models were used to evaluate the associations of serum triazine herbicides with glycemia-related risk indicators, and mediation analyses were performed to evaluate the mediating role of serum IgM in the above associations. The median levels of serum atrazine and cyanazine were 0.0237 μg/L and 0.0786 μg/L, respectively. Our study found significant positive associations of serum atrazine, cyanazine, and Σtriazine with FPG levels, risk of impaired fasting glucose (IFG), abnormal glucose regulation (AGR), and type 2 diabetes (T2D). Additionally, serum cyanazine and Σtriazine were found to be significant positive associated with the homeostatic model assessment of insulin resistance (HOMA-IR) levels. Significant negative linear relationships were observed in associations of serum IgM with serum triazine herbicides, FPG, HOMA-IR levels, the prevalence of T2D, and AGR (P < 0.05). Furthermore, we observed a significant mediating role by IgM in the associations of serum triazine herbicides with FPG, HOMA-IR, and AGR, with the proportions ranging from 2.96% to 7.71%. To ensure the stability of our findings, we conducted sensitivity analyses in normoglycemic participants and found that the association of serum IgM with FPG and the mediating role by IgM remained stable. Our results suggest that triazine herbicides exposure is positively associated with abnormal glucose metabolism, and decreasing serum IgM may partly mediate these associations.

Water a major source of endocrine-disrupting chemicals: An overview on the occurrence, implications on human health and bioremediation strategies

Endocrine disrupting chemicals (EDCs) are toxic compounds that occur naturally or are the output of anthropogenic activities that negatively impact both humans and wildlife. A number of diseases are associated with these disruptors, including reproductive disorders, cardiovascular disorders, kidney disease, neurological disorders, autoimmune disorders, and cancer. Due to their integral role in pharmaceuticals and cosmetics, packaging companies, agro-industries, pesticides, and plasticizers, the scientific awareness on natural and artificial EDCs are increasing. As these xenobiotic compounds tend to bioaccumulate in body tissues and may also persist longer in the environment, the concentrations of these organic compounds may increase far from their original point of concentrations. Water remains as the major sources of how humans and animals are exposed to EDCs. However, these toxic compounds cannot be completely biodegraded nor bioremediated from the aqueous medium with conventional treatment strategies thereby requiring much more efficient strategies to combat EDC contamination. Recently, genetically engineered microorganism, genome editing, and the knowledge of protein and metabolic engineering has revolutionized the field of bioremediation thereby helping to breakdown EDCs effectively. This review shed lights on understanding the importance of aquatic mediums as a source of EDCs exposure. Furthermore, the review sheds light on the consequences of these EDCs on human health as well as highlights the importance of different remediation and bioremediation approaches. Particular attention is paid to the recent trends and perspectives in order to attain sustainable approaches to the bioremediation of EDCs. Additionally, rigorous restrictions to preclude the discharge of estrogenic chemicals into the environment should be followed in efforts to combat EDC pollution.

Microbial hydrolysis of atrazine in contaminated groundwater

Degradation of the widespread herbicide atrazine has been intensively studied in soils, while its degradation in groundwater has received less attention. This work studied atrazine degradation in contaminated groundwater adjacent to its production plant. The degradation potential was first explored in groundwater enrichment cultures. A broad potential for microbial atrazine degradation was observed when atrazine served as the sole nitrogen source, even when incubated with nitrate. Hydroxyatrazine was formed by the cultures, while desethylatrazine and desisopropylatrazine were not detected. Both the atzA and the trzN genes were identified by quantitative PCR analysis, with a clear dominance of atzA. Carbon isotope enrichments throughout the degradation process varied between the different cultures, with ε values ranging from -0.6 to -5.5‰. This implies corresponding uncertainties when using compound-specific isotope analysis to estimate degradation extents. In the field samples, in-situ degradation was reflected by a high percentage of metabolites, with hydroxyatrazine accounting for >95% of the metabolites in most wells. Both atzA and trzN were detected in the groundwater at quantities of ≈10² to 10⁶ copies mL^-1, with a dominance of atzA over trzN. These results provide evidence of the high potential for atrazine hydrolysis in the contaminated groundwater.

A systematic review of the toxic effects of a nanopesticide on non-target organisms: Estimation of protective concentrations using a species sensitivity distribution (SSD) approach - The case of atrazine

Nanopesticides, such as nanoencapsulated atrazine (nATZ), have been studied and developed as eco-friendly alternatives to control weeds in fields, requiring lower doses. This review contains a historical and systematic literature review about the toxicity of nATZ to non-target species. In addition, the study establishes protective concentrations for non-target organisms through a species sensitivity distribution (SSD) approach. Through the systematic search, we identified 3197 publications. Of these, 14 studies addressed "(nano)atrazine's toxicity to non-target organisms". Chronological and geographic data on the publication of articles, characterization of nATZ (type of nanocarrier, size, polydispersity index, zeta potential), experimental design (test species, exposure time, measurements, methodology, tested concentrations), and toxic effects are summarized and discussed. The data indicate that cell and algal models do not show sensitivity to nATZ, while many terrestrial and aquatic invertebrates, aquatic vertebrates, microorganisms, and plants have high sensitivity to nAZT. The SSD results indicated that D. similis is the most sensitive species to nATZ, followed by C. elegans, E. crypticus, and P. subcapitata. However, the limitations in terms of the number of species and endpoints available to elaborate the SSD reflect gaps in knowledge of the effects of nATZ on different ecosystems.

Occurrence, fate, seasonal variability, and risk assessment of twelve triazine herbicides and eight related derivatives in source, treated, and tap water of Wuhan, Central China

Triazine herbicides have been widely used, are frequently detected in aqueous environments and soils, and can cause acute or chronic toxicity to living organisms. We collected source water samples (n = 20) originating from the Hanshui River and the Yangtze River of Wuhan section, treated water samples (n = 20), and tap water samples (n = 169) in Wuhan, Central China during 2019 for determination of twelve triazine herbicides and their eight derivatives (collectively defined as TZs) and characterizing their fate during water treatment. Eighteen of the twenty TZs were detected in the source water. Atrazine (ATZ) had the highest concentrations (median: 22.4 ng/L) in the source water samples while DACT had the highest concentrations (median: 31.4 ng/L) in the treated water. "Tryns" (ametryn, prometryn, simetryn, terbutryn) were efficiently removed by conventional water treatment, while other target analytes were not; interestingly, hydroxypropazine and prometon increased significantly accompanied by prometryn disappearance, which implicated potential transformation pathways. In addition, "tryns" might be transformed into "tons" (atraton, prometon, secbumeton, terbumeton) by ozonation. In the tap water samples, diaminochlorotriazine had the highest concentrations (median: 34.9 ng/L) among the target analytes, followed by ATZ (18.3 ng/L), hydroxyatrazine (5.17 ng/L), deethylatrazine (5.00 ng/L), hydroxypropazine (3.20 ng/L), deisopropylatrazine (2.05 ng/L), hydroxydesethylatrazine (1.68 ng/L), and others. The TZs had the highest cumulative concentration in July in the tap water samples (median: 89.7 ng/L). This study found that ozonation in combination with activated carbon was more efficient in removing triazine herbicides, although "tryns" could also be transformed during conventional treatment. Ecological risk assessment showed moderate risks posed by hydroxyterbuthylazine, prometryn, and simetryn; the Hanshui River had higher risks than the Yangtze River, and July had higher risks than February. Human exposure to the TZs via water ingestion was low compared to the reference doses. This study characterized the occurrence of some new emerging TZs in the source water, their fate during drinking water treatment, and their seasonal variability in the tap water.

Atrazine induces phagocytotic dysfunction of microglia depends on nucleocytoplasmic translocation of acetylated HMGB1

Atrazine (ATR) is a widely applied herbicide which was named an environmental endocrine disrupting chemical (EDC). Increasing evidence indicates ATR causes neurotoxic effects resulting in central nervous system (CNS) disease. As the primary immunocytes in the CNS, microglia cells carry out their phagocytosis to maintain the CNS microenvironment by preventing damage from healthy cells. However, the mechanism in which ATR affects the phagocytic function of microglia remains unclear. The present study was designed to investigate the effect of ATR on the phagocytosis of microglia. BV-2 cells and primary microglia selected as microglial models in which BV-2 cells were administrated by ATR at different concentrations (0, 4, 8, 16 μM) for 24 h. Results demonstrated ATR dose-dependently increased the expression of ionized calcium binding adapter molecule 1 (Iba-1), indicating that microglia were activated. Microglial phagocytotic activity induced by ATR fluctuated at the different time points, accompanied by fluctuations in membrane receptor MERTK and cytoplasmic lysosomal marker LAMP1 (two markers related to cell phagocytosis). In this period, the expression of iNOS gradually increased. A mechanistic study further demonstrated that the translocation of High Mobility Group Protein-B1 (HMGB1) from nucleus to cytoplasm in the BV-2 and primary microglial cells induced by ATR, and the process showed a positive correlation with phagocytosis activity of BV-2 cells induced by ATR (r = 0.8030, P = 0.05; α = 0.1). ATR was also shown to spur the acetylation of HMGB1 by breaking the balance between acetylase P300 and deacetylase SIRT1. Unexpectedly, the inhibition of acetylating HMGB1 by resveratrol (Res) was effectively retained by HMGB1 in the nucleus, reversed the SIRT1 and MERTK expression, and enhanced the phagocytosis activity in BV-2 cells. Our results suggested that ATR exposure influenced microglial phagocytosis by acetylating HMGB1 further translocated it in the nucleoplasm.

Transcriptome analysis reveals the mechanisms of hepatic injury caused by long-term environmental exposure to atrazine in juvenile common carp (Cyprinus carpio L.)

Atrazine (ATZ) is the second most commonly used herbicide worldwide, resulting in the pollution of water bodies and affecting the economic benefits of aquaculture. ATZ is known to cause liver damage in the common carp, Cyprinus carpio L., one of the most widely cultivated fish in China, but the underlying mechanisms are poorly understood. In this study, juvenile common carp Cyprinus carpio L. were exposed to three different environmental levels (0.4, 0.8, and 1.2 μg/L) of ATZ for 12 weeks and changes in the liver transcriptomes between the high-dose group and the control group were analyzed. The data showed that different levels of ATZ exposure caused hepatotoxicity in juvenile carp, shown by biochemical parameters and histopathological changes. Comparative transcriptomics showed that high-dose ATZ exposure led to alterations in the expression of various lipid metabolism-related gene changes, including genes associated with metabolic pathways, fatty acid metabolism, and fatty acid elongation. Furthermore, a connection network analysis of the top 100 differentially expressed genes (DEGs) showed a variety of associations between high-dose ATZ-induced liver damage and the principal DEGs, indicating the complexity of hepatotoxicity induced by ATZ. In conclusion, the molecular mechanisms underlying ATZ-triggered hepatotoxicity in juvenile carp are primarily related to impaired lipid metabolism.

Catalytic ozonation for imazapic degradation over kelp-derived biochar: Promotional role of N- and S-based active sites

It is a feasible strategy to prepare reliable biochar catalysts for heterogeneous catalytic ozonation (HCO) processes by using inexpensive, high quality, and easily available raw materials. Here, an environmentally friendly, simple, and green biochar catalyst rich in nitrogen (N) and sulfur (S) has been prepared by the pyrolysis of kelp. Compared with directly carbonized kelp biomass (KB), acid-activated KB (KBA) and base-activated KB (KBB) have higher specific surface areas and more extensive porous structures, although only KBB displays effective ozone activation. Imazapic (IMZC), a refractory organic herbicide, was chosen as the target pollutant, which has apparently not hitherto been investigated in the HCO process. Second-order rate constants (k) for the reactions of IMZC with three different reactive oxygen species (ROS), specifically kO3, IMZC, kOH, IMZC, and k1O2, IMZC, have been determined as 0.974, 2.48 × 109, and 6.23 × 105 M-1 s-1, respectively. The amounts of graphitic N and thiophene S derived from the intrinsic N and S showed good correlations with the IMZC degradation rate, implicating them as the main active sites. OH and O2- and 1O2 were identified as main ROS in heterogeneous catalytic ozonation system for IMZC degradation. This study exemplified the utilization of endogenous N and S in biological carbon, and provided more options for the application of advanced oxidation processes and the development of marine resources.

Urinary concentrations of fungicide carbendazim's metabolite and associations with oxidative stress biomarkers in young children

Carbendazim (CBDZ) is the most widely used fungicide in China. It is ubiquitous in environment and can induce oxidative stress in mammals, while data on occurrence of its metabolite in human urine are scarce, and the relationship between CBDZ and oxidative stress biomarkers (OSBs) in young children has not been examined. The aim of this study was to measure the concentrations of methyl 5-hydroxy-2-benzimidazolecarbamate (5-HBC, the main metabolite of CBDZ in urine) in 390 urine samples collected from 130 healthy young (< 6.6 years old) children from Shenzhen and Wuhan, in south and central China, respectively, and to evaluate the associations of 5-HBC with three selected OSBs (4-HNEMA, 8-OHG, and 8-OHdG, for lipid, RNA, and DNA, respectively). 5-HBC was found in 99.2% of the urine samples at concentrations ranging from below the method detection limit (< 0.005 ng/mL) to 10.9 ng/mL (median: 0.11 ng/mL). Moderate inter-day reproducibility was found for specific gravity-adjusted 5-HBC concentrations (intraclass correlation coefficient: 0.50). The urinary 5-HBC concentrations were significantly and positively associated with 4-HNEMA (p < 0.01). An interquartile range increase in urinary 5-HBC concentrations was associated with a 42.1% increase in 4-HNEMA, which implied that CBDZ exposure might be associated with lipid peroxidation in young children without occupational exposure. As far as we know, this pilot study is the first to report urinary 5-HBC and its associations with OSBs in children.

Comparison of Two Estrogen Chemically Activated Luciferase Expression Cell Bioassays to Liquid Chromatography-Mass Spectrometry for Quantifying Estrone in Water Samples

Chemically activated luciferase expression (CALUX) cell bioassays are popular tools for assessing endocrine activity of chemicals such as certain environmental contaminants. Although activity equivalents can be obtained from CALUX analysis, directly comparing these equivalents to those obtained from analytical chemistry methods can be problematic because of the complexity of endocrine active pathways. We explored the suitability of two estrogen CALUX bioassays (the Organisation for Economic Co-operation and Development-approved VM7Luc4E2 cell bioassay and the VM7LucERβc9 cell bioassay) for quantitation of estrogen. Quadrupole-time of flight ultraperformance liquid chromatography-mass spectrometry (LC/MS) was selected as a comparative method. Regression analysis of measured estrone (E1) calibration samples showed all three methods to be highly predictive of nominal concentrations (p ≤ 7.5 × 10^-51 ). Extracts of water sampled from laboratory dilutor tanks containing E1 at 0, 20, and 200 ng/L alone and in combination with atrazine were selected to test the quantitative capabilities of the CALUX assays. Process controls (0 and 100 ng E1/L) and a separate E1 standard (10 ng/ml, used to prepare the E1 process control) were also tested. Levels of E1 determined by LC/MS analysis and bioanalytical equivalents (ng E1/L) determined by CALUX analyses were comparable except in certain instances where the samples required dilution prior to CALUX analyses (e.g., the E1 process control and E1 standard). In those instances, measurements by CALUX were slightly but significantly decreased relative to LC/MS. Atrazine had no effect on the ability of either LC/MS or the CALUX bioassays to quantify E1. The present study illustrates the CALUX bioassays as successful in quantifying an estrogen in simple water samples and further characterizes their utility for screening. Environ Toxicol Chem 2023;42:333-339. Published 2022. This article is a U.S. Government work and is in the public domain in the USA.

Identification of high-concern organic pollutants in tap waters from the Yangtze River in China based on combined screening strategies

Recently, numerous organic pollutants have been detected in water environment. The safety of our drinking water has attracted widespread attention. Effective methods to screen and identify high-concern substances are urgently needed. In this study, the combined workflow for the detection and identification of high-concern organic chemicals was established and applied to tap water samples from the Yangtze River Basin. The solid phase extraction (SPE) sorbents were compared and evaluated and finally the HLB cartridge was selected as the best one for most of the contaminants. Based on target, suspect and non-target analysis, 3023 chemicals/peaks were detected. Thirteen substances such as diundecyl phthalate (DUP), 2-hydroxyatrazine, dioxoaminopyrine and diethyl-2-phenylacetamide were detected in drinking water in the Yangtze River Basin for the very first time. Based on three kinds of prioritization principles, 49 ubiquitous, 103 characteristic chemicals and 13 inefficiently removed chemicals were selected as high-concern substances. Among them, 8, 31, 9, 3, 4 substances overlapped with the toxic, risky or high-concern chemicals lists in China, America, European Union, Japan, Korea, respectively. Specific management and removal strategies were further recommended. The workflow is efficient for identification of key pollutants.

Ecogenotoxicity of environmentally relevant atrazine concentrations: A threat to aquatic bioindicators

Atrazine (ATZ) is a herbicide that is frequently present in surface waters and may result in damage to the health of various organisms, including humans. However, most scientific literature reports injuries caused by ATZ at high concentrations, which are not found in the environment. Therefore, the scope of this study was to investigate the impacts of realistic concentrations of ATZ found in surface waters (1, 2, 5, 10, 15 and 20 μg/L) using the bioindicators Allium cepa, Daphnia magna and zebrafish (Danio rerio). ATZ elicited a genotoxic effect in A. cepa, manifested by the induction of chromosomal aberrations, and a mutagenic effect with increased incidence of micronuclei formation, promotion of cell death and reduction in nuclear size revealed by flow cytometry analysis. D. magna exposed to 10, 15 and 20 μg/L of ATZ showed significant reduction in body size after 21 days, delayed first-brood release, decreased egg production and total offspring, as well as swimming behavioral changes. ATZ exposure promoted physiological and developmental alterations in zebrafish embryos, including an increased spontaneous movement rate, which led to premature hatching at all concentrations investigated. Increase in total body length, decrease of the yolk sac area, pericardial edema and higher heart rate were also detected in ATZ-treated zebrafish. In summary, environmentally relevant concentrations of ATZ can induce substantial alterations in the three bioindicators investigated. This study evidences the deleterious effects of ATZ on three aquatic bioindicators employing established and current techniques, and may contribute to elucidate the risks caused by this widely used herbicide even at low concentrations and short-to-medium-term exposure.

Atrazine pollution in groundwater and raw bovine milk: Water quality, bioaccumulation and human risk assessment

Atrazine herbicide can bioaccumulate over time and thus affect humans for generations to come. However, scarce studies have evaluated its bioaccumulation potential in bovine milk, a nutritional staple for children and the elderly both domestically and internationally. This study aimed to determine its concentration in groundwater and bovine milk, as well as the risks it is likely to pose for human health. Eighteen dairy farms in the Pampean plain of Argentina were analyzed. A strong correlation was found between the chemical composition and the geomorphological characteristics of the plain. In addition, increased salinity was observed in the groundwater at greater distances from the aquifer's recharge area. Atrazine was quantified in 50 % of the groundwater samples (at values ranging from 0.07 to 1.40 μg/L), and in 89 % of the bovine milk samples (from 2.51 to 20.97 μg/L). Moreover, atrazine levels in 44.4 % of the groundwater samples and 11.1 % of the bovine milk samples (n = 18) exceeded the limits internationally established as safe for human consumption. The hazard quotient (HQ) values of the compound were negligible for children and adults, both in groundwater (child = 9.7E-4, adult = 4.5E-4) and in milk (child = 1.0E-2, adult = 1.6E-3). The estimated cancer risk (CR) values need further evaluation (child = 7.8E-6, adult = 3.6E-6 in groundwater; child = 6.6E-5, adult = 1.3E-5 in milk). In both types of samples, the HQ and CR of residual atrazine were higher for children than for adults. Nevertheless, bioaccumulation factors suggest that dairy cows have a moderate capacity to incorporate atrazine from abiotic matrices. This is the first report on residual atrazine in bovine milk in Argentina. The results presented here indicate that the status of atrazine contamination in the area should continue to be monitored in order to assess its long-term impact on public health.

Anxiety-related behavior and associated brain transcriptome and epigenome alterations in adult female zebrafish exposed to atrazine during embryogenesis

Atrazine often contaminates drinking water sources, exceeding the maximum contaminant level established by the US Environmental Protection Agency at 3 parts per billion (ppb; μg/L). Atrazine is linked to endocrine disruption, neurotoxicity, and cancer, with delayed health effects observed after developmental exposure in line with the developmental origins of health and disease (DOHaD) hypothesis. To test the hypothesis that embryonic atrazine exposure induces delayed neurotoxicity in adult female zebrafish (Danio rerio), embryos were exposed to 0, 0.3, 3, or 30 ppb atrazine during embryogenesis (1-72 h post fertilization (hpf)) and raised to adults with no additional atrazine exposure. Behavioral outcomes were tested through a novel tank test, light-dark box, and open field test and indicated female zebrafish had more anxious phenotypes at 9 months post fertilization (mpf). Female brain transcriptomic analysis at 9 mpf found altered gene expression pathways related to organismal injury and cancer with beta-estradiol and estrogen receptor as top upstream regulators. These results were compared to 9 mpf male and 6 mpf female groups with the same atrazine embryonic exposures and showed differences in specific genes that were altered, but similarities in top molecular pathways. Molecular pathways associated with behavior were observed only in the 6 mpf transcriptomic profiles, suggesting prediction of observed behavioral outcomes at 9 mpf. The expression of genes associated with serotonin neurotransmission was also evaluated at 14 mpf to determine persistence; however, no significant changes were observed. Brain global methylation in 12 mpf zebrafish observed an increased percent 5 mC in females with embryonic 0.3 ppb atrazine exposure. Finally, the body length, body weight, and brain weight were determined at 14 mpf and were altered in all treatment groups. These results indicate that embryonic atrazine exposure does cause delayed neurotoxicity within the DOHaD framework, which is significant given atrazine's presence and persistence in the environment.

A deep learning-based method for classification, detection, and localization of weeds in turfgrass

BACKGROUND

Precision spraying of synthetic herbicides can reduce herbicide input. Previous research demonstrated the effectiveness of using image classification neural networks for detecting weeds growing in turfgrass, but did not attempt to discriminate weed species and locate the weeds on the input images. The objectives of this research were to: (i) investigate the feasibility of training deep learning models using grid cells (subimages) to detect the location of weeds on the image by identifying whether or not the grid cells contain weeds; and (ii) evaluate DenseNet, EfficientNetV2, ResNet, RegNet and VGGNet to detect and discriminate multiple weed species growing in turfgrass (multi-classifier) and detect and discriminate weeds (regardless of weed species) and turfgrass (two-classifier).

RESULTS

The VGGNet multi-classifier exhibited an F₁ score of 0.950 when used to detect common dandelion and achieved high F₁ scores of ≥0.983 to detect and discriminate the subimages containing dallisgrass, purple nutsedge and white clover growing in bermudagrass turf. DenseNet, EfficientNetV2 and RegNet multi-classifiers exhibited high F₁ scores of ≥0.984 for detecting dallisgrass and purple nutsedge. Among the evaluated neural networks, EfficientNetV2 two-classifier exhibited the highest F₁ scores (≥0.981) for exclusively detecting and discriminating subimages containing weeds and turfgrass.

CONCLUSION

The proposed method can accurately identify the grid cells containing weeds and thus precisely locate the weeds on the input images. Overall, we conclude that the proposed method can be used in the machine vision subsystem of smart sprayers to locate weeds and make the decision for precision spraying herbicides onto the individual map cells. © 2022 Society of Chemical Industry.

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.

Quality assessment and prediction of municipal drinking water using water quality index and artificial neural network: A case study of Wuhan, central China, from 2013 to 2019

The sanitary security of drinking water is closely related to human health, but its quality assessment mainly focused on limited types of indicators and relatively restricted time span. The current study was aimed to evaluate the long-term spatial-temporal distribution of municipal drinking water quality and explore the origin of water contamination based on multiple water indicators of 137 finished water samples and 863 tap water samples from Wuhan city, China. Water quality indexes (WQIs) were calculated to integrate the measured indicators. WQIs of the finished water samples ranged from 0.24 to 0.92, with the qualification rate and excellent rate of 100 % and 96.4 %, respectively, while those of the tap water samples ranged from 0.09 to 3.20, with the qualification rate of 99.9 %, and excellent rate of 95.5 %. Artificial neural network model was constructed based on the time series of WQIs from 2013 to 2019 to predict the water quality thereafter. The predicted WQIs of finished and tap water in 2020 and 2021 qualified on the whole, with the excellent rate of 87.5 % and 92.9 %, respectively. Except for three samples exceeding the limits of free chlorine residual, chloroform and fluoride, respectively, the majority of indicators reached the threshold values for drinking. Our study suggested that municipal drinking water quality in Wuhan was generally stable and in line with the national hygiene standards. Moreover, principal component analysis illustrated that the main potential sources of drinking water contamination were inorganic salts and organic matters, followed by pollution from distribution systems, the use of aluminum-containing coagulants and turbidity involved in water treatment, which need more attention.

Groundwater quality and vulnerability in farms from agricultural-dairy basin of the Argentine Pampas

Agricultural and livestock activities strongly influence groundwater quality and conditioning its use as water supply in rural areas. The aim was to determine the quality and suitability of the groundwater supply used in dairy farms of an agricultural area of Pampa plain of Córdoba (Argentina). Piper's diagram showed that the groundwater types were sodium bicarbonate, sodium bicarbonate-chloride, sodium chloride-sulfate, and sodium sulfate. Physicochemical parameters revealed that cations and anions showed a high and significant correlation in water samples, indicating a strong water-rock interaction. Nitrate (NO₃^-) content was significantly correlated with pH, water well depth, and distance from contamination sources. A high positive correlation between arsenic (As) and bicarbonate, sulfate, sodium, and chloride (p < 0.05) indicates a similar origin. Among the pesticides monitored, 2,4-D was detected in 25% of groundwater samples (0.4 to 0.8 µg/L) coinciding with the ordinary application practices. In general, most of the groundwater samples did not comply with national and international regulations for drinking water and dairy hygiene, due to the high content of As, NO₃^-, bacteria, and the presence of 2,4-D herbicide. However, the quality of water was suitable for livestock drink. The data obtained in this study contribute to a better understanding of the contamination processes taking place and improve the agricultural and livestock management for an efficient use of this resource by dairy farmers.

Removal of micropollutants by UASB reactor and post-treatment by Fenton and photo-Fenton: Matrix effect and toxicity responses

Literature is scarce on the performance of Fenton-based processes as post-treatment of municipal wastewater treated by upflow anaerobic sludge blanket (UASB) reactor. This study aims to perform Fenton and photo-Fenton from UASB influent and effluent matrices to remove micropollutants (MPs) models: atrazine (ATZ), rifampicin (RIF), and 17α-ethynylestradiol (EE2). A UASB reactor at bench-scale (14 L) was operated with these MPs, and the AOPs experiments at bench-scale were performed on a conventional photochemical reactor (1 L). A high-pressure vapor mercury lamp was used for photo-Fenton process (UVA-Vis) as a radiation source. Microcrustacean Daphnia magna (acute toxicity) and seeds of Lactuca sativa (phytotoxicity) were indicator organisms for toxicity monitoring. The UASB reactor showed stability removing 90% of the mean chemical oxygen demand, and removal efficiencies for ATZ, RIF, and EE2 were 16.5%, 45.9%, and 15.7%, respectively. A matrix effect was noted regarding the application of both Fenton and photo-Fenton in UASB influent and effluent to remove MPs and toxicity responses. The pesticide ATZ was the most recalcitrant compound, yet the processes carried out from UASB effluent achieved removal >99.99%. The post-treatment of the UASB reactor by photo-Fenton removed acute toxicity in D. magna for all treatment times. However, only the photo-Fenton conducted for 90 min did not result in a phytotoxic effect in L. sativa.

Residue level, occurrence characteristics and ecological risk of pesticides in typical farmland-river interlaced area of Baiyang Lake upstream, China

Baiyang Lake is the largest freshwater lake in North China, playing an important role in aquatic products production and eco-environment improvement. Traditional organochlorine pesticides were not enough to reflect ecological risk. We performed the high-throughput and non-targeted screening to identify the high-residue and wide-distribution pesticides at farmland-river interlaced area. We firstly reported the residue level and spatio-temporal distribution of typical pesticides in soils and waters (SP1–SP13) near Fuhe river in 2020–2021. The mean recoveries of eight pesticides ranged from 79.4 to 129%. The residues were 0.250–3530 ng/L (water) and 2.79 × 10⁻³–647 μg/kg dw (soil), respectively. Thiamethoxam was dominant with the high-residue proportion (HRP) of 53–95% (water, HRP > 50%) and 63–97% (soil, HRP > 60%), respectively. Most of pesticides almost have no significant season-change. The risk quotient (RQ) model results showed that although most pesticides have no aquatic risk (RQ < 0.01), carbendazim and propionazole deserved attention. The individual thiamethoxam at nearly half of the sites exhibited high terrestrial risk (RQ, 1.070–1.682), while propiconazole was at medium risk (SP1, SP2, SP8, and SP9) and high risk (SP12). The RQ_all were in the range of 0.4541–3.327 (earthworm), 0.0239–0.4552 (algae), 0.1094–1.103 (aquatic invertabrates), and 0.1657–1.923 (fish), respectively, so co-residue caused joint toxic effect to aquatic invertebrates.

Preparation of novel N-doped biochar and its high adsorption capacity for atrazine based on π-π electron donor-acceptor interaction

Novel nitrogen (N)-doped cellulose biochar (NC1000-10) with large adsorption capacity (103.59 mg g^-1) for atrazine (ATZ) was synthesized through the one-pot method. It has the best adsorption efficiency than N-doped biochars prepared from hemicellulose and lignin. The adsorption behaviors of ATZ by N-doped biochars with different N doping ratios (NC1000-5, NC1000-10, NC1000-20 and NC1000-30) were significantly different, which was attributed to the difference of sp² conjugate C (I_D/I_G = 0.99-1.18) and doped heteroatom N (pyridinic N, pyrrolic N and graphitic N). Adsorption performance of ATZ on NC1000-10 conformed to the pseudo-second-order kinetic and Langmuir adsorption isotherm model. Thermodynamic calculations showed that adsorption performance was favorable. Besides, wide pH adaptability (pH = 2-10), good resistance to ionic strength and excellent recycling efficiency make it have extensive practical application potential. Further material characterizations and the density functional theory (DFT) calculations indicated that good adsorption performance of NC1000-10 for ATZ mainly depended on chemisorption, and π-π electron donor-acceptor (EDA) interaction contributed the most due to high graphitization degree. Specifically, pyridinic N and graphitic N further promoted adsorption performance by hydrophobic effect and π-π EDA interaction between ATZ and NC1000-10, respectively. Pyrrolic N and other surface functional groups (-COOH, -OH) facilitated the hydrogen bond effect.

Do commonly used herbicides (atrazine and glyphosate) have the potential to impair the contractions, prostaglandin releasing and conducting of oxytocin signal at the bovine cervix in vitro?

Glyphosate (Gly) and atrazine (Atr) are among the most commonly used herbicides in global agriculture. It was previously shown that both Atr and Gly impair the ovarian and uterine secretion of regulators of myometrial motility (oxytocin (OT) or prostaglandins (PGs)) in cows, and Atr can also decrease the force of contractions in strips from the uterine horn. Hence, the aim of this study was to compare the effects of Atr and Gly on the motor and secretory function of the bovine cervix in vitro as well as receptivity and signal transduction in cervical cell cultures. Cervical strips or cells obtained from cows before ovulation were treated with environmental doses of Atr or Gly (0.1-10 ng/ml) since these herbicides exerted no cytotoxic effect at a dose of 100 ng/ml. Only Atr increased the force of cervical contractions, while both Atr and Gly decreased the secretion of prostaglandins (PGs) without disturbing their synthesis. Moreover, Atr decreased the mRNA expression and protein level of oxytocin receptor (OTR), while Gly increased OTR protein levels. Both Atr and Gly decreased the contents of gap junction proteins (GAPs), Atr decreased the contents of second messengers (diacylglycerol - DAG, inositol-tris-phosphate - IP3), and Gly decreased the level of myosin light chain kinase (MLCK) but increased DAG levels. Atr directly enhanced the cervical strips contractions. Both herbicides disturbed cellular signalling and inhibited PGs secretion. It suggest that Atr and Gly have the potential to impair the activity of cervical cells in vitro, which might be followed by failure of maintenance with gestation.

Integrated metabolomics and transcriptomics analysis reveals new biomarkers and mechanistic insights on atrazine exposures in MCF‑7 cells

Atrazine (ATZ) is a widely used herbicide worldwide and is a long-suspected endocrine-disrupting chemical. However, most endocrine-disrupting toxicity studies on ATZ have been based on animal models and those investigating inner mechanisms have only focused on a few genes. Therefore, the possible link between ATZ and endocrine-disrupting toxicity is still unclear. In this study, multi-omics and molecular biology techniques were used to elucidate the possible molecular mechanisms underlying the effect of ATZ exposure on MCF-7 proliferation at environmentally relevant concentrations. Our study is the first report on ATZ-induced one carbon pool by folate metabolic disorder in MCF-7 cells. A concentration of 1 μM ATZ yielded the highest cell viability and was selected for further mechanistic studies. A total of 34 significantly changed metabolites were identified based on metabolomic analysis, including vitamins, amino acids, fatty acids, and corresponding derivatives. Folate and pyridoxal have potential as biomarkers of ATZ exposure. One carbon pool by folate metabolic pathway was identified based on metabolic pathway analysis of the significantly altered pathways. Moreover, FTCD and MTHFD related to this pathway were further identified based on transcriptomic analysis and protein assays. Folate and different forms of 5,6,7,8-tetrahydrofolate, which participate in purine synthesis and associate with methyl groups (SOPC, arachidonic acid, and L-tryptophan) in one carbon pool by the folate metabolic pathway, potentially promote MCF-7 cell proliferation. These findings on the key metabolites and regulation of the related differentially expressed genes in folate metabolism will shed light on the mechanism of MCF-7 cell proliferation after ATZ exposure. Overall, this study provides new insights into the mechanistic understanding of toxicity caused by endocrine-disrupting chemicals.

Analytical method for sequential determination of persistent herbicides and their metabolites in fish tissues by UPLC-MS/MS

A novel and accurate liquid chromatography-tandem mass spectrometry method was developed to sequentially determine three persistent herbicides (atrazine (ATZ), acetochlor (ACE), and metolachlor (MET)) and seven characteristic metabolites (desethylatrazine (DEA), deisopropylatrazine (DIA), diaminochlorotriazine (DACT), MET-oxanilic acid (MET-OA), MET-ethanesulfonic acid (MET-ESA), ACE-ESA, and ACE-OA) in fresh fish tissues from six fish species. A modified QuEChERS method was conducted to extract the target compounds from fish tissues. Matrix-matched calibrations of the target analytes were carried out at spiking levels of 1, 10, 100, and 1000 ng g^-1. The method was validated in accordance with Codex guidelines (CAC/GL 71-2009). Recoveries for the target analytes were 67-120% with relative standard deviations below 20%, and the matrix effects ranged from -58.7% to 59.3%. The limits of detection and quantitation were 0.01-1.90 and 0.02-6.35 ng g^-1, respectively. Moreover, the method was successfully applied to analyze the concentrations of the target chemicals in fresh tissue samples of six fish species (n = 67) collected from four markets in Nanning City, Guangxi Province, China. The concentrations in all samples were 1.1-140.5 ng g^-1. Interestingly, this study was the first to measure DEA and DIA in fish liver, and their highest concentrations were 10.7 and 14.2 ng g^-1, respectively. This method provides a basis for studying the pathways of biotransformation, bioaccumulation, detoxification, and exposure patterns of ACE, ATZ, MET, and their metabolites in aquatic environments.

Integrating network pharmacology and in vitro model to investigate hippocampal neurotoxicity induced by atrazine

Atrazine (ATR), a commonly applied herbicide in agriculture, has been found to cause hippocampal injury in rodents. However, the underlying toxicological targets and mechanisms are unclear. In this study, network pharmacology analysis and in vitro model were integrated to investigate the effect and mechanism of ATR-induced hippocampal neurotoxicity. In total, 71 targets of hippocampal neurotoxicity induced by ATR were predicted. Gene Ontology (GO) and Kyoto Encyclopedia of Genes and Genomes enrichment (KEGG) enrichment analysis suggested that these targets were related to multiple GO terms and signaling pathways. To further investigate the underlying mechanisms, the top 10 hub targets were screened and included tumor protein p53 (Tp53), caspase 3 (Casp3), prostaglandin-endoperoxide synthase 2 (Ptgs2), cAMP-responsive element-binding protein 1 (Creb1), estrogen receptor 1 (Esr1), Jun proto-oncogene (Jun), brain-derived neurotrophic factor (Bdnf), catalase (Cat), sirtuin 1 (Sirt1) and Fos proto-oncogene (Fos). Moreover, the cell counting kit-8 (CCK8) and lactate dehydrogenase (LDH) assay showed that ATR had time and dose-dependent cytotoxicity on H19-7 cells. TUNEL staining revealed that ATR increased the apoptotic ratio. In addition, Real-time quantitative polymerase chain reaction (RT-qPCR) results indicated that the mRNA expression levels of all hub targets showed significant changes, except Esr1 and Jun. Our study demonstrated that ATR mainly acted on multiple targets and signaling pathways to exert its hippocampal neurotoxicity. These results provided initial evidence for the further exploration of the toxicological mechanism of ATR.

Anthropogenic Organic Pollutants in Groundwater Increase Releases of Fe and Mn from Aquifer Sediments: Impacts of Pollution Degree, Mineral Content, and pH

In many aquifers around the world, there exists the issue of abnormal concentrations of Fe and Mn in groundwater. Although it has been recognized that the main source of this issue is the release of Fe and Mn from aquifer sediments into groundwater under natural environmental conditions, there lacks enough reliable scientific evidence to illustrate whether the pollutants imported from anthropogenic activities, such as organics, can increase this natural release. On the basis of time series analysis and comparative analysis, the existence of an increasing effect was verified through laboratorial leaching test, and the impacts of aquatic chemical environment conditions, such as pH, on the effect were also identified. The results showed that the increase of organics in groundwater made the release of Fe and Mn more thorough, which was favorable for the increase of groundwater concentrations of Fe and Mn. The higher the contents of Fe- and Mn-bearing minerals in aquifer sediments, the higher the concentrations of Fe and Mn in groundwater after the release reaches kinetic equilibrium. Lower pH can make the leaching more thorough, but the neutral environment also increases the amount of Mn. It can be deduced that the pollutants such as organics imported by anthropogenic activities can indeed increase the releases of Fe and Mn from aquifer sediments into groundwater, thus worsening the issue of groundwater Fe and Mn pollution. The findings provide a deeper insight into the geochemical effects of Fe and Mn in the natural environment, especially in the groundwater system.

The use of different sublethal endpoints to monitor atrazine toxicity in nematode Caenorhabditis elegans

In this work, Caenorhabditis elegans was employed as an in vivo model to determine the toxic effects of atrazine at different concentrations. After the exposure period from the larval stage L1 to adulthood day 1, atrazine (10 mg/L) significantly decreased the body length and lifespan of nematodes. In addition, exposure to ≥0.01 mg/L atrazine remarkably increased the intestinal reactive oxygen species (ROS) levels and reduced locomotion behavior of nematodes, while exposure to ≥ 1 mg/L atrazine decreased the brood size of nematodes. Moreover, atrazine (0.001-0.1 mg/L) upregulated the expression levels of hsp-6::GFP and hsp-6/60 in nematodes, indicating the activation of mitochondrial unfolded protein response (mtUPR). On the contrary, atrazine (1-10 mg/L) downregulated the expression levels of hsp-6::GFP and hsp-6/60 in nematodes. Furthermore, mtUPR induction governed by the RNAi knockdown of atfs-1 could increase the vulnerability of nematodes against atrazine toxicity. Overall, our findings highlighted the dynamic responses of nematodes toward different concentrations of atrazine, which could be monitored using different sublethal endpoints as bioindicators.

Meta-analysis and experimental validation identified atrazine as a toxicant in the male reproductive system

Atrazine (ATZ), as a widely used triazine herbicide, is an environmental endocrine disruptor (EDC) that can cause many health problems. Therefore, we conducted this study based on the evidence of rats and mice to figure out the characteristics of ATZ damage to the reproductive system and further evaluate its health effects on the human. PRISMA's guidelines were followed according to the principles recommended by the Cochrane Handbook for Systematic Review. Health assessment was performed using the OHAT approach. Our new data were obtained from randomized controlled trials in rats designed in accordance with toxicological guidelines. Exposure to ATZ was significantly associated with decreased testosterone production (SMD = - 0.90, 95% CI - 1.27 to - 0.53), and reduced absolute weights of testis (SMD = - 0.41, 95% CI - 0.61 to - 0.22) and other reproductive organs. The damaging effect of sperm quality was also observed clearly, which included reduction of sperm count both in epididymis (SMD = - 2.32, 95% CI - 2.83 to - 1.81) and testis (SMD = - 1.01, 95% CI - 1.37 to - 0.64), decrease in sperm motility (SMD = - 8.86, 95% CI - 10.88 to - 6.83), and increase in sperm abnormality. Subgroup analysis revealed consistency across different species, life stage, and dosage. In addition, we found that ATZ exposure at a daily dose of 120 mg/kg during adolescence could cause decrease in weight gain and histological damage to the testis. The gene expression levels of Nrf2/HO-1 and Bcl-2/caspase signaling pathways in testis tissues were changed significantly. The results of this SR indicated that exposure to ATZ was associated with impairment of male reproductive system in rodents regardless of species, exposure life stage, and dosage. It is believed that ATZ exposure may have similar effects on male reproductive system of human beings. Pathways related to oxidative stress and apoptosis may be the mechanism leading to testicular damage in rats treated with ATZ.

Evaluation of atrazine neurodevelopment toxicity in vitro-application of hESC-based neural differentiation model

Atrazine is one of the widely used herbicides in the world and most of the current researches on atrazine neurodevelopment toxicity have focused on rodents or zebrafish models in vivo, resulting in relatively high cost, time consumption, and lower translational value to identify its hazard for the developing brain. Major international initiatives have pushed forward to convert the traditional animal-based developmental toxicity tests to in vitro assays using human cells to detect and predict chemical health hazards. In this study, we presented a human neural differentiation model based on human embryonic stem cells (hESC) that can be used to test toxicity at different stages of neural differentiation in vitro. hESC were differentiated into neural stem cells (NSC) and then terminally differentiated towards mixed neurons and glial cells for 21 days. Cell survival, proliferation, cell cycle, apoptosis, and gene expression levels were examined. Our results demonstrated that atrazine inhibited the proliferation of hESC and NSC, and showed different toxic sensitivity on these two kinds of cells. Also, atrazine blocked the NSC cell cycle G1 phase via down-regulating CCND1, CDK2, and CDK4, with no obvious effect on apoptosis. In addition, atrazine curbed EB spontaneous differentiation and NSC-induced neurons and glia cells differentiation. Atrazine altered genes expression levels of PAX6, TUBB3, NCAM1, GFAP, TH, NR4A1, and GRIA1. From the data we obtained, we recognized that the dopaminergic system was not the only target of atrazine neurotoxicity, glutamatergic neurons and astrocytes were also adversely affected.

Efficacy of atrazine pesticide reduction in aqueous solution using activated carbon, ozone and a combination of both

In this study, the reduction of the emerging organic contaminant atrazine in water, was investigated by adsorption, oxidation and a combination of both technologies. Adsorption tests were performed using method ASTM D3860-98 with two types of activated carbon: powdered activated carbon and granular activated carbon. For the oxidation tests, advanced ozone oxidation technology was used. Finally, in the combined tests, firstly adsorption treatment was applied followed by oxidation and then the order was reversed. We studied the contaminant removal percentage using different treatments at various reaction times. Results for the different treatments under study showed that, for an initial atrazine concentration of 0.7 mg L^-1 and a dose of 16 mg L^-1 of powdered activated carbon, with contact times of 60 min, 24 h and 48 h, percentage reductions of the contaminant of 81%, 92% and 94% respectively were obtained. For the same concentration of contaminant, but instead using granular activated carbon, the percentage reduction of atrazine at 60 min was 2%, this percentage rising to 34% and 35% after 24 and 48 h of contact time, respectively. For the same initial contaminant concentration, when ozone was applied at a dose of 19.7 mg L^-1, and with a reaction time of 18 min, a reduction of atrazine of 93% was obtained, but oxidation by-products were also produced. For the combined treatments, with the same initial concentration of contaminant and the same doses of carbon and ozone as previously indicated, better contaminant reductions were obtained when the treatment started with activated carbon followed by ozone, achieving a 90% reduction of atrazine observing a 17 minute contact time with powdered activated carbon and a 3 day contact time using the granulated carbon. When the order was reversed by starting with ozone, the contact time was 52 min and 4 days, respectively.

Monitoring of pesticides in drinking water: finding the right balance between under- and over-monitoring - experience from the Czech Republic

The modern, risk-based approach requires that only those pollutants which are likely to be present in a given water supply should be monitored in drinking water. From this perspective, defining an adequate approach to the monitoring of pesticides in areas with intensive agriculture is currently one of the greatest issues of regulation. This article shows the development and detailed results of pesticide monitoring in drinking water in the Czech Republic (CR). More than 4000 water supply zones serving around a 9.5 million population are routinely monitored, with nearly 250 thousand analyses of over 200 different pesticides and their metabolites being performed every year, with a non-compliance rate of ca. 0.3%. In 2017, pesticides accounted for most derogations in the CR, concerning a total of 64 water supply systems serving more than a 250 thousand population. A representative survey targeting 21 selected chemicals showed that 75% of water supply systems contained up to 11 pesticides per sample. The most commonly found were metabolites of the herbicides used to protect oilseed rape, maize, and sugar beet: acetochlor ESA, alachlor ESA, metazachlor OA, and chloridazon-desphenyl. The health risk assessment did not reveal any risks from these chemicals, even at the highest levels detected or in the most abundant mixtures, to the most vulnerable population (infants). Nevertheless, the increased presence of pesticides undermines the public's trust in drinking water safety.

Neonicotinoids, fipronil, chlorpyrifos, carbendazim, chlorotriazines, chlorophenoxy herbicides, bentazon, and selected pesticide transformation products in surface water and drinking water from northern Vietnam

Studies on the occurrence of emerging pesticides in surface and drinking water in Vietnam are limited. In this study, lake water (n = 7), river water (n = 1), tap water (n = 46), and bottled water (n = 3) collected from Hanoi and other four provinces in northern Vietnam were analyzed for selected pesticides (including insecticides such as neonicotinoids, fipronil, and chlorpyrifos; fungicide carbendazim; herbicides such as atrazine, terbuthylazine, simazine, 2,4-dichlorophenoxyacetic acid, 2-methyl-4-chlorophenoxyacetic acid, and bentazon) and some of their degradates by liquid chromatography-tandem mass spectrometry. Carbendazim (median: 86.7 ng/L) and triazines (49.3 ng/L) were the major pesticides found in lake water samples, followed by neonicotinoids and their degradation products (15.1 ng/L), chlorpyrifos and its degradate (13.4 ng/L), fipronil and its degradates (3.76 ng/L), chlorophenoxy acid herbicides (2.10 ng/L), and bentazon (0.62 ng/L). Triazines (164 ng/L) were the major pesticides in river water. Higher concentrations (median: 39.3 ng/L; range: 1.20-127) of selected pesticides were found in tap water from Hanoi than those from four other provinces studied (5.49 ng/L; 4.73-66.8 ng/L). Bottled water samples collected from Hanoi contained lower concentrations of pesticide residues (median: 3.54 ng/L, range: 2.18-8.09) than those of tap water samples. The calculated risks from pesticide exposure through ingestion of tap water by the general populations were low. However, fipronil concentrations in lake water exceeded the benchmark value recommended for freshwater in the United States or the Netherlands. Degradation of acetamiprid into desmethyl-acetamiprid was found in lake water.

Spatial variation of 2,4-D and MCPA in tap water and groundwater from China and their fate in source, treated, and tap water from Wuhan, Central China

Data on chlorophenoxy herbicides (CPHs) in drinking water from China are scarce. This study was designed to describe the occurrence of CPHs in drinking water in China. In June 2019, drinking water samples including 789 tap water and 95 groundwater samples were collected from 31 provinces in mainland China and Hong Kong. Raw source, treated, and tap water samples (n = 20, 20, and 170, respectively) in Wuhan, Central China were also analyzed. 2,4-dichlorophenoxyacetic acid (2,4-D) and 2-methyl-4-chlorophenoxyacetic acid (MCPA) were found in 71.2% and 74.9% of the samples nationwide, respectively. The cumulative concentration of CPHs (ΣCPHs) in tap water in China was up to 125 ng/L (median: 1.38 ng/L), and regional variations were found for ΣCPHs. The highest median ΣCPHs (3.95 ng/L) was found in Northeast China, followed by Central (3.40), South (2.71), East (2.43), Southwest (1.58), North (0.42), and Northwest China (0.30). The median ΣCPHs in groundwater was approximately five times lower than that in tap water. In addition, ΣCPHs were found in all the raw source water samples collected in Wuhan, Central China (median: 6.69 ng/L, range: 2.66-43.1 ng/L). The removal of 2,4-D and MCPA during conventional drinking water treatment was not efficient, removing approximately 0.91% and 17.4%, respectively. In a water plant with advanced treatment, they were efficiently removed. Seasonal variations were found in ΣCPHs in tap water from Wuhan, with the highest found in July (median: 21.2 ng/L), and the lowest in October (1.96 ng/L). The intake of CPHs via water ingestion was estimated as below 5 ng/kg-bw/day, much lower than the reference doses for 2,4-D (5 μg/kg-bw/day) and MCPA (4 μg/kg-bw/day). This is the first study to demonstrate the fate of CPHs during drinking water treatment and seasonal variations of CPHs in water from Wuhan, China. Moreover, this study provides an overview of ΣCPHs in tap water for many areas in China.