Atrazine Concentrations Research Articles

Synthesis and characterization of magnetic aluminum metal-organic frameworks encapsulated with chitosan and carboxymethyl cellulose for effective elimination of atrazine from aqueous solutions: Adsorption evaluation, DFT calculations and Box-Behnken design optimization

The discharge of herbicides is a primary contributor to water contamination, presenting significant environmental and public health hazards. Encapsulating herbicides in a chemical compound called MAl-MOF/CS-CMC hydrogel bead (MACC) made from magnetic aluminum metal-organic frameworks (MAl-MOF) and crosslinked with chitosan (CS) and carboxymethyl cellulose (CMC) shows promise for potential use. The research successfully developed and examined MACC microspheres, utilizing various analytical techniques including PXRD, FESEM, TEM, FT-IR, and XPS. The efficiency of MACC in eliminating atrazine (ATZ) from wastewater was also simulated. Additionally, density functional theory (DFT) was employed to assess the electrical characteristics, reactivity, and arrangement of ATZ at a structural level. The results of the DFT analysis demonstrate a significant relationship between the locations of nucleophilic and electrophilic attacks and the molecular orbitals of the HOMO and LUMO. Using MACC as an adsorbent provides considerable advantages due to its expansive surface area of 860.92 m2/g and a pore size of 1.48 nm, meeting the mesoporous classification criteria outlined by IUPAC standards. In addition, it possesses a pore volume of 1.22 cm3/g. Nevertheless, following the adsorption procedure, the pore volume reduced to 0.78 cm3/g, and the surface area decreased to 650.42 m2/g. Several factors contributing to the capacity to attract and retain substances were analyzed. These factors encompass temperature, duration of contact, quantity of the attracting substance, initial atrazine (ATZ) concentration, and solution pH. The primary method of adsorption that was determined is chemisorption, as evidenced by the calculated adsorption energy of 29.3 kJ per mole. The thermodynamic analysis indicates that the adsorption of ATZ by the micropores of MACC occurs spontaneously and is characterized as endothermic, as evidenced by the positive ΔHo value and negative ΔGo value. It has been proposed that a range of adsorption mechanisms, including chemisorption, π-π interactions, pore filling, hydrogen bonding, and electrostatic interactions, may be responsible for removing the herbicide from the MACC material.

Occurrence and distribution of atrazine in groundwater from agricultural areas in China

There has been heavy application of chemical pesticides to farmland worldwide. As a state with a heavy emphasis on farming, China has extensively applied chemical pesticides to farmlands. Atrazine (ATZ), one of the most widely used herbicide in the world, has been used in large quantities in weed control in many crops, which poses a relatively large threat to groundwater utilization and agricultural safety. A nationwide sampling and analysis of ATZ in 8146 groundwater monitoring wells from 10 main grain producing areas were conducted during 2019. The results showed that the detection rate of ATZ in groundwater was 40.79 %, with detected concentrations up to 2.86 μg/L. ATZ detection rate was significantly higher in phreatic aquifers than confined aquifer. The concentration of ATZ decreased significantly with the depth increasing, the detected depth of ATZ in groundwater was varied from 5 to 1100 m, and 70.27 % of the detected ATZ was distributed in the depth of 0–51.8 m. The detection rate of ATZ in most north regions lower than south regions in China, and ATZ with high concentration was mainly occurred in southern regions. ATZ is more likely to migrate into the groundwater in the water resource rich areas. The concentration of ATZ decreased with TDS increasing, 74.39 % of the ATZ was detected in groundwater with TDS concentration <1 g/L. The hydrochemical type of groundwater in ATZ-enrichment environment were mainly Ca-HCO3 and Mixed type. According to classification and regression tree analysis, the high ATZ detection rate were closely related with groundwater depth (<51.8 m) and high organic matter content.

Occurrence of pesticide residues and associated ecological risks assessment in water and sediment from selected dams in northern Ghana.

Pesticides are chemicals used to enhance crop production. However, their residues can persist and accumulate in various environmental settings. This study assessed the occurrence of pesticide residues and ecological risks in surface water and sediment from the Libga and Builpela dams in northern Ghana. A total of 42 pesticides were analysed. Toxic units were used to assess the acute risk to sediment-dwelling organisms and aquatic biota. Risk quotients were employed to assess the chronic risk to aquatic organisms. Chlorpyrifos, atrazine, profenofos, and chlorfenvinphos were the main chemicals found in surface water. The concentrations were highest near the Builpela dam (0.413μg/L, 2.927μg/L, 0.304μg/L, 0.692μg/L, 0.073μg/L, 0.290μg/L, 0.06μg/L, and absent in the Libga dam). In the sediment, the organophosphates pyrimiphos-methyl and chlorpyrifos were found at high concentrations. They were found in higher quantities in the Libga dam (0.554mg/kg and 0.052mg/kg, respectively) and Builpela dam (0.051mg/kg and 0.043mg/kg, respectively). For organochlorines, p,p'-DDE and p,p'-DDD were the main residues detected at high concentrations. However, concentrations were higher for p,p'-DDD at Builpela than for p,p'-DDE. Additionally, high concentrations of atrazine were detected in this study. The toxic units showed a high acute risk for organisms that live in sediment as a result of chlorpyrifosfos and chlorfenvinphos residues. Similarly, pirimiphos-methyl and chlorfenvinphos, followed by chlorpyrifos, contributed to high acute risk in aquatic invertebrates. Risk quotients showed that both dams had a high long-term risk for aquatic life; however, the risk was higher at the Builpela dam due to Pirimiphos-methyl and Chlorfenvinphos. Ghana's pesticide regulations are less comprehensive and enforcement is often weaker in protecting aquatic organisms. It is recommended to enforce strict limits on pesticide residues. Additionally, there is a need to regularly review and update these regulations based on new scientific data to protect aquatic ecosystems.

Atrazine dependence in cultivated fungal communities.

The isolation and study of fungi within specific contexts yield valuable insights into the intricate relationships between fungi and ecosystems. Unlike culture-independent approaches, cultivation methods are advantageous in this context because they provide standardized replicates, specific species isolation, and easy sampling. This study aimed to understand the ecological process using a microcosm system with pesticide concentrations similar to those found in the soil, in contrast to high doses, from the isolation of the enriched community. The atrazine concentrations used were 0.02mg/kg (control treatment), 300ng/kg (treatment 1), and 3000ng/kg (treatment 2), using a 28-day microcosm system. Ultimately, the isolation resulted in 561 fungi classified into 76 morphospecies. The Ascomycota phylum was prevalent, with Purpureocillium, Aspergillus, and Trichoderma being consistently isolated, denoting robust and persistent genera. Diversity analyses showed that the control microcosms displayed more distinct fungal morphospecies, suggesting the influence of atrazine on fungal communities. Treatment 2 (higher atrazine concentration) showed a structure comparable to that of the control, whereas treatment 1 (lower atrazine concentration) differed significantly, indicating that atrazine concentration impacted community variance. Higher atrazine addition subtly altered ligninolytic fungal community dynamics, implying its potential for pesticide degradation. Finally, variations in atrazine concentrations triggered diverse community responses over time, shedding light on fungal resilience and adaptive strategies against pesticides.

Degradation of Atrazine in Water by Dielectric Barrier Discharge Combined with Periodate Oxidation: Enhanced Performance, Degradation Pathways, and Toxicity Assessment.

The widespread occurrence of atrazine (ATZ) in water environments presents a considerable risk to human health and ecosystems. Herein, the performance of dielectric barrier discharge integrated with periodate (DBD/PI) for ATZ decomposition was evaluated. Results demonstrated that the DBD/PI system improved ATZ decomposition efficiency by 18.2-22.5% compared to the sole DBD system. After 10 min treatment, the decomposition efficiency attained 82.4% at a discharge power of 68 W, a PI dosage of 0.02 mM, and an initial ATZ concentration of 10 mg/L. As the PI dosage increased, the decomposition efficiency exhibited a trend of initially increasing, followed by a decrease. Acidic conditions were more favorable for ATZ removal compared to alkaline and neutral conditions. Electron paramagnetic resonance (EPR) was adopted for characterizing the active species produced in the DBD/PI system, and quenching experiments revealed their influence on ATZ decomposition following a sequence of 1O2 > O2-• > IO3• > OH•. The decomposition pathways were proposed based on the theoretical calculations and intermediate identification. Additionally, the toxic effects of ATZ and its intermediates were assessed. This study demonstrates that the DBD/PI treatment represents an effective strategy for the decomposition of ATZ in aquatic environments.

Diatomite with gold nanoparticles for atrazine adsorption

Atrazine is a commonly used herbicide worldwide, and it has significant environmental concerns due to its toxic ecological effects. This work uses diatomite decorated with gold nanoparticles to evaluate its capacity for atrazine adsorption. The structural characterization was studied by Fourier transform infrared spectroscopy (FTIR), Raman spectroscopy, Transmission Electron Microscopy (TEM), Scanning Electron Microscopy (SEM), Energy Dispersive spectroscopy (EDX), Fluorescence microscopy and X-ray photoelectron spectroscopy (XPS). Our findings reveal that diatomite decorated with gold nanoparticles with an average particle size of 10 nm enhances the Raman signal and fluorescence intensity for atrazine detection. Experimental conditions, such as atrazine concentration, pH, contact time, and diatomite mass, have been optimized to quantify the maximum removal conditions using ultraviolet–visible spectroscopy, reaching a maximum adsorption of 2.5 mg/g in 4 h. FTIR and XPS evidence the interaction of the amine groups of the atrazine with the diatomite-decorated surface. The impact of this work relies on environmental remediation using naturally available diatomite decorated with gold nanoparticles and understanding the binding interactions for the removal of atrazine.

Degradation and mineralization of atrazine by ozonation: A toxicological prediction by QSAR toolbox

This work aims to investigate the atrazine (ATZ) mitigation by an advanced oxidative process. Atrazine is one an effective herbicide which has been detected in water sources, causing contamination problems. To address the persistent issue of contamination, ATZ degradation and mineralization were studied by ozonation. In addition, the eco-toxicity of the possible degradation byproducts was also evaluated by the Quantitative Structure-Activity Relationship (QSAR) OECD toolbox. To evaluate the influence and predict the optimum conditions of the ozonation process and the reaction time on the degradation of ATZ, as well as, the percentage of mineralization, an experimental design was performed based on factorial design 23 methodology with center-point analysis. Total organic carbon (TOC) analyses and High-Performance Liquid Chromatography (HPLC) were employed to evaluate the efficiency of ATZ mitigation. The optimal conditions were achieved at an ozone flow rate of 0.4 mL/min, oxidation time = 30 min, and pH=8 where 100 % of ATZ was degraded and the highest percentage of mineralization was obtained (25.61 %). The potential toxicity of the residual concentration of ATZ was obtained by comparing with the values predicted by the QSAR tool, by comparing the outcomes. It was possible to come to the conclusion that the approach had positive implications for environmental safety. The values obtained are below the values considered toxic in aquatic environments, in almost all experiments. Low-concentration byproduct formation suggests that the degradation routes lead to low-hazardous concentrations of compounds for the environment. This implies the ozone treatment strategy might offer a long-term remedy for the ATZ.

Comprehensive Assessment of Herbicide Toxicity on Navicula sp. Algae: Effects on Growth, Chlorophyll Content, Antioxidant System, and Lipid Metabolism.

This study investigated the effects of herbicide exposure on Navicula sp. (MASCC-0035) algae, focusing on growth density, chlorophyll content, antioxidant system, and lipid metabolism. Navicula cultures were exposed to different concentrations of atrazine (ATZ), glyphosate (Gly), and acetochlor (ACT) for 96 h. Results showed a significant decrease in cell numbers, with higher herbicide concentrations having the most noticeable impacts. For instance, Gly-G2 had reduced cell populations by 21.00% at 96 h. Chlorophyll content varied, with Gly having a greater impact on chlorophyll a compared to ATZ and ACT. Herbicide exposure also affected the antioxidant system, altering levels of soluble sugar, soluble protein, and reactive oxygen species (ROS). Higher herbicide rates increased soluble sugar content (e.g., ATZ, Gly, and ACT-G2 had increased by 14.03%, 19.88%, and 19.83%, respectively, at 72 h) but decreased soluble protein content, notably in Gly-G2 by 11.40%, indicating cellular stress. Lipid metabolism analysis revealed complex responses, with changes in free proline, fatty acids, and lipase content, each herbicide exerting distinct effects. These findings highlight the multifaceted impacts of herbicide exposure on Navicula algae, emphasizing the need for further research to understand ecological implications and develop mitigation strategies for aquatic ecosystems.

Does the atrazine increase animal mortality: Unraveling through a meta-analytic study

Atrazine is one of the most used herbicides in the world, although it is banned in several countries. Pollution of terrestrial and aquatic ecosystems represents a threat to non-target organisms, with various damages already reported in different species. However, there is controversy in studies on atrazine. The question of whether atrazine increases animal mortality is not yet clearly resolved. In this context, this study aimed to carry out a meta-analytic review, focusing on studies on environmental concentrations of the herbicide atrazine to evaluate its lethal effects on various animal species. We identified and analyzed 107 datasets through a selection process that used the Scopus, PubMed, and Web of Science (WoS) databases. A significant increase in the mortality rate of animals exposed to environmental concentrations of atrazine was observed. Nematodes, amphibians, molluscs, insects, and fish showed increased mortality after exposure to atrazine. Animals in the larval and juvenile stages showed greater susceptibility when exposed to different concentrations of atrazine. Furthermore, both commercial and pure formulations resulted in high mortality rates for exposed animals. Atrazine and other pesticides had a synergistic effect, increasing the risk of mortality in animals. There are still many gaps to be filled, and this study can serve as a basis for future regulations involving atrazine.

Nanobiosensors based on tyrosinase with alkanethiols for detection commercial formulation of atrazine in artesian water samples applied in agriculture crop

This study aims to develop cantilever nanobiosensors functionalized with commercial tyrosinase enzymes and alkanethiols for the detection of a commercial formulation of atrazine in artesian water samples used in agricultural crops. Functionalization was carried out using the self-assembled monolayer (SAM) technique with different alkanethiols, namely, 16-mercaptohexadecanoic acid (16-MHDA) and 11-mercaptoundecanoic acid (11-MUA), in conjunction with commercial tyrosinase enzymes. Surface characterization techniques confirm the successful deposition of the sensing layer. The nanobiosensors exhibited the capability to detect various concentrations of atrazine in water, achieving high sensitivity with detection and quantification limits in the µg/L range, while maintaining 100 % reversibility. The enzyme retained 87 % and 80 % of its activity when immobilized on 16-MHDA and 11-MUA linkages, respectively. The response of cantilever nanobiosensors was stable after 13 min, with deflection values showing a direct proportional relationship with atrazine concentrations ranging from 0.001 to 100 µg/L. Both cantilever nanobiosensors demonstrated promising responses, with 11-MUA differing statistically (P<0.05) from 16-MHDA. The rapid detection of commercial atrazine was successfully conducted in real water samples collected directly during its application in crop fields. Consequently, the developed devices hold significant potential for practical use in the detection of atrazine in water, contributing to assessments of environmental quality.

Assessing global-warming induced soil organic matter and iron oxides depletion: Empirical insights into sorption and uptake of atrazine by plants

Recent pesticide use is alarmingly high and unregulated in several parts of the world. Pesticide fate in soil is controlled by sorption processes which affect the subsequent transport and chemical reactivity in the environment, as well as uptake by plants. Sorption processes are dependent on soil composition and properties, but these are beginning to be affected by global warming-linked factors leading to soil depletion. Thus, it is vital to decipher soils’ response, especially in the sub-Sahara (SS), to the depletion of some inherent components in the presence of pesticides. This was ascertained by monitoring a model pesticide (atrazine) sorption and desorption on whole SS soil (WS), and the same soil whose organic matter (OMR) and iron oxides (IOR) were substantially depleted, as well as studying atrazine uptake from these soils by fast-growing vegetables. Organic matter depletion enhanced equilibrium in OMR. Sorption was enhanced at lower ambient pH, higher initial atrazine concentration, and higher temperature. Hysteresis was low resulting in high desorption. Overall, atrazine desorption of ≥65 % was observed; it was higher in OMR (≥95 %) since SOM enhanced hysteresis. Though sub-Saharan soils are rich in iron oxides, SOM played a significantly higher role in sorption than iron oxides in this soil. This result suggests a high potential for atrazine to leach into the aquifer in the sub-Saharan. Atrazine uptake experiment by waterleaf and spinach showed that it could be detected in soil after 63 d, and its presence significantly affected the growth of both vegetables especially in soils with depleted SOM and iron oxides, and at high (100 µg/kg) atrazine spiking. Spinach may be a higher atrazine accumulator than waterleaf. It may be concluded that waterleaf and spinach grown on atrazine-contaminated soils, especially on SOM/iron oxide-depleted soils, are likely to accumulate atrazine.

Efficiency and mechanism of high surface area mesoporous nanocast NC-LaCoO3 for activating peroxymonosulfate to degrade atrazine in water

A highly active perovskite is needed to activate peroxymonosulfate (PMS) into reactive oxygen species (ROS) to degrade organic pollutants in wastewater. High surface area LaCoO3 was fabricated via nano-casting employing mesoporous silica KIT-6 (a 3D material, first fabricated in Korea Advanced Institute of Science and Technology number 6) as the hard template. The NC-LaCoO3 showed a higher surface area (81.33 m2·g−1), pore volume (0.21 cm3·g−1) and pore diameter (7.78 nm), abundant acidic/basic sites, rich oxygen vacancies (OVs), and easily accessible active sites, as well as higher catalytic efficiency to degrade atrazine than uncast/citric acid-assisted perovskite (CA-LaCoO3), CA-La2O3 and Co3O4. Under the specific experimental condition (PMS concentration: 4.30 mM; catalyst dosage: 0.60 g·L−1; pH: 8.20; atrazine concentration: 10 mg·L−1; and room temperature), in 6.0 min, approximately 19.02 %, 56 %, 29.38 %, and 39.21 % of atrazine were degraded by sole PMS, CA-LaCoO3/PMS, CA-La2O3/PMS and Co3O4/PMS respectively, while it was completely degraded in 4.0 min in NC-LaCoO3/PMS. Moreover, 0.06 mg/L leaching of cobalt was detected during oxidation in the NC-LaCoO3 /PMS process. The NC-LaCoO3 depicted stable catalytic efficiency after six recycling terms. Radical scavengers depicted that SO4•− and •OH were produced as the main reactive species at the initial phase of the catalytic reaction, and subsequently, O2•− and 1O2 were generated as the secondary oxidative species. A comparatively dominant inhibitory effect of methanol compared to TBA suggested that SO4•− was mainly involved in atrazine degradation. XPS, EPR, in-situ ATR-FTIR, EIS, LSV, and chronoamperometric measurements were employed to explore the catalytic reaction mechanism. High catalytic efficiency was ascribed to better textural properties, diffusion-friendly structure, rich oxygen vacancies, and radical species. This research suggests that perovskites with a range of A and B metals can be synthesized by nanocasting using high surface area templates for advanced oxidation processes, especially PMS activation, to remediate organic wastewater.

INFLUENCE OF SOME SELECTED ENVIRONMENTAL FACTORS ON THE NATURAL ATTENUATION OF ATRAZINE IN TROPICAL AGRICULTURAL SOILS

Understanding environmental factors that help to optimize the natural attenuation of atrazine in agricultural soils is necessary to minimize contamination risks and human health risks, as well as support a healthy soil ecosystem. This study, therefore, investigated the influence of pH, temperature, soil organic matter content, often measured as total organic carbon (TOC), and moisture content on atrazine attenuation by soil microbes. Agricultural soil with a history of atrazine application was spiked with the herbicide. The effects of pH (3, 7, 10), moisture content (10%, 15%, 25%), total organic carbon (TOC, 2%, 3%, 4%), and temperature (15°C, 25°C, 45°C) on atrazine attenuation and bacterial count were evaluated at the interval of 30 days each for 60 days of incubation in nutrient agar. The residual concentrations of atrazine attenuation were determined using GC-MS analysis at the interval of 30 days each for 60 days of incubation. The results indicate that higher bacterial counts (Arthrobacter sp.) were observed at neutral pH (7.0) and moderate moisture (10%). At a neutral pH (7), only 52.1% of the initial atrazine concentration remained after 60 days due to attenuation processes. Also, Atrazine natural attenuation increased with increasing TOC where only 25.8% attenuation residual concentration was left at 4% TOC and reached a maximum of 15% moisture content with a residual concentration of 20.13% after 60 days. Similarly, the concentration of atrazine decreased as the temperature increased, with only 29.01% of the residual concentration remaining at 45ºC treatment after 60 days. Statistical analysis revealed significant differences in natural attenuation between 30 and 60 days, but not after 30 days. These findings suggest that natural attenuation was favoured by higher organic matter content and moderate moisture levels, highlighting the importance of soil properties for atrazine fate in tropical soils and emphasizing the importance of studying natural attenuation processes as a viable strategy, particularly in tropical agricultural settings to minimize unnecessary contamination of soil to ensure a healthy and safe agricultural environment.

Biochar prevents soybean seedling injury caused by atrazine residue by regulating the concentration of this herbicide in soil pore water

The residue of atrazine in field soils poses a major threat to crop growth in the rotation system, raising concerns about grain security and food safety. Current agricultural production requires more efficient and cost-effective mitigation measures in response to the emerging threat. This study reported the critical concentration (0.1 mg L−1) of atrazine injury to soybean seedlings in soil pore water and how biochar amendment could influence the distribution of atrazine in different soil environments. The results showed that biochar significantly reduced the concentration of atrazine in soil pore water, for example, 0.5% biochar in red (cinnamon, fluvo-aquic, paddy, black) soil reduced atrazine concentration from 0.31 (0.20, 0.18, 0.12, 0.03) mg L−1 to 0.004 (0.002, 0.005, 0.013, 0.011) mg L−1 in pore water (P < 0.01). On the basis of these, a reliable mathematical model was developed to predict the atrazine concentration in soil pore water under (or without) biochar amendment conditions. The verification results showed that the mean absolute percentage error of the model was 14.1%, indicating that the prediction error was within a reasonable range. Our work provides a precise solution to crop injury caused by soil residual herbicides with the aid of biochar, which reduces the bioavailability of atrazine in soybean seedlings. This method not only maximizes the use of biochar but also provides effective crop protection and environmental benefits.Graphical

Concomitant determination of pesticides in soil and drainage water over a potato cropping season reveal dissipations largely in accordance with respective models

Pesticides are widely used in agriculture where they do not only reach their targets but also distribute to other environmental compartments and negatively affect non-target organisms. To prospectively assess their environmental risk, several tools and models using pesticide persistence (DT50) and leaching potential (groundwater ubiquity score (GUS), EXPOSIT) have been developed. Here, we simultaneously quantified 18 pesticides in soil and drainage water during a conventionally grown potato culture at field scale with high temporal resolution and compared our findings with predictions of the above models. Overall dissipations of all freshly applied compounds in soil were in line with published DT50 field values and their occurrences in drainage water were generally consistent with GUS and EXPOSIT models, respectively. In contrast, soil concentrations of the legacy pesticide atrazine and one of its transformation products (atrazine-2-hydroxy) were constant during the entire sampling campaign. Moreover, during peak discharge atrazine concentrations in drainage water were diluted whereas those of freshly applied pesticides were maximal. This difference demonstrates that the applied risk assessment tools were capable of predicting environmental concentrations and dissipation of pesticides at the short and medium time scale of a few half-lives after application, but fell short of capturing long-term trace residues.

Integrated occurrence of contaminants of emerging concern, including microplastics, in urban and agricultural watersheds in the State of São Paulo, Brazil

Contaminants of emerging concern (CECs), including microplastics, have been the focus of many studies due to their environmental impact, affecting biota and human health. The diverse land uses and occupation of watersheds are important parameters driving the occurrence of these contaminants. CECs such as pesticides, drugs, hormones, and industrial-origin substances were analyzed in urban/industrial (Atibaia) and agricultural (Preto/Turvo) watersheds located in São Paulo state, Brazil. A total of 24 CECs were investigated, and, as a result, only 5 (caffeine, carbendazim, atrazine, ametrine and 2-hydroxytrazine) were responsible for 81.73 % of the statistical difference between watersheds contamination profile. The Atibaia watershed presented considerable concentrations of caffeine (ranging from 75 to 2025 ng L−1), while carbendazim (44 to 1144 ng L−1) and atrazine (3 to 266 ng L−1) presented highest levels in Preto/Turvo watershed. In all sampling points, the cumulative potential aquatic life risk assessed by the NORMAN database indicates some level of environmental concern associated to pesticides and caffeine (risk quotient >1). Microplastics had been analyzed in both watersheds, being the white/transparent fragments in size between 100 and 250 μm the most detected in this study. The estimated abundance in the Atibaia watershed ranged from 349 to 2898 items m−3 presenting some influence of pluviosity, while in Rio Preto/Turvo ranged from 169 to 6370 items m−3, being more abundant in the dam area without a clear influence of pluviosity. In both basins, polyethylene and polypropylene were the most detected polymers, probably due to the intense use of single-use plastics in urban areas. Possibly, due to the distinct physic-chemical properties of microplastics and organic CECs, no correlations were observed between their occurrence, which makes us conclude that they have different transport mechanism, behavior, and fate in the environment.

Quantitative image analysis for assessing extracellular polymeric substances in activated sludge under atrazine exposure

Extracellular polymeric substances (EPS) play a vital role in biological wastewater treatment systems. This study investigates the impact of herbicide atrazine (ATZ) on the overall performance, EPS yield, composition, and sludge morphology in an activated sludge (AS) system operated in a sequencing batch reactor (SBR). Since conventional methods for analyzing EPS are time-consuming and releases residues, a new approach was developed in this work to evaluate the EPS fractions and components, based on the morphological characterization of the biomass using quantitative image analysis (QIA) technique coupled with multivariate statistics.Results showed that exposure to ATZ inhibit biomass activity in terms of organic matter (COD) and nitrogen removal. Moreover, both tightly bound EPS (TB-EPS) and loosely bound EPS (LB-EPS) increased under ATZ, indicating that microorganisms release EPS as a defense mechanism against environmental changes. The PN/PS ratio also increases, indicating likely increased hydrophobicity in ATZ phases. Furthermore, ATZ phases exhibit a predominance of large aggregates compared to intermediate and small ones, indicating a change in aggregate morphological structure associated with EPS production. The new approach using QIA coupled with partial least squares (PLS) modeling provides accurate predictions of EPS content. The increase in TB-EPS is closely related to the rise of large aggregates in phases exposed to higher ATZ concentrations. The PLS models demonstrate high accuracy for EPS prediction (coefficients of determination, R2 above 0.86), showcasing the feasibility of using QIA for EPS assessment in AS systems. This approach offers significant potential for regular process monitoring and management, providing a more environmentally friendly methodology by eliminating the need for chemical usage.

Sensitivity and antioxidant response of forest species seedlings to the atrazine under simulated conditions of subsurface water contamination

Atrazine is an herbicide with a high soil leaching capacity, contaminating subsurface water sources. Once the water table is contaminated, riparian species can be exposed to atrazine. In this way, understanding the impacts of this exposure must be evaluated for planning strategies that minimize the effects of this herbicide on native forest species. We aimed to evaluate forest species' sensitivity and antioxidant response to exposure to subsurface waters contaminated with atrazine, as well the dissipation this herbicide. The experiment was conducted in a greenhouse in a completely randomized design, with three replications and one plant per experimental unit. The treatments were arranged in a 2 × 10 factorial. The first factor corresponded to the presence or absence (control) of the atrazine in the subsurface water. The second factor comprised 10 forest species: Amburana cearensis, Anadenanthera macrocarpa, Bauhinia cheilantha, Enterolobium contortisiliquum, Hymenaea courbaril, Libidibia ferrea, Mimosa caesalpiniifolia, Mimosa tenuiflora, Myracrodruon urundeuva, and Tabebuia aurea. The forest species studied showed different sensitivity levels to atrazine in subsurface water. A. cearensis and B. cheilantha species do not have efficient antioxidant systems to prevent severe oxidative damage. The species A. macrocarpa, E. contortisiliquum, L. ferrea, and M. caesalpiniifolia are moderately affected by atrazine. H. courbaril, M. urundeuva, and T. aurea showed greater tolerance to atrazine due to the action of the antioxidant system of these species, avoiding membrane degradation events linked to the production of reactive oxygen species (ROS). Among the forest species, H. courbaril has the most significant remedial potential due to its greater tolerance and reduced atrazine concentrations in the soil.

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

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

Screening of Atrazine Tolerant Aquatic Plant and Roles of Plant Growth Regulators on Plant Growth and Atrazine Tolerance

The extensive use of atrazine to control weeds in agricultural areas has contaminated atrazine in surface water and groundwater. Atrazine contamination in water resources causes human health concerns. Thus, this study investigated the possible use of aquatic plants for removing atrazine from contaminated water. The experiment was performed under plant nursery conditions and divided into two parts: (1) the atrazine-tolerant plants were screened, and (2) the most atrazine-tolerant plant was used for atrazine phytoremediation stimulated by plant growth regulators. The results showed that atrazine was toxic to all aquatic plants, as the dry weight of the plants was significantly decreased when exposed to 20 mg/L of atrazine (P&lt;0.05). Based on five aquatic plants grown under 2.5–20 mg/L atrazine-contaminated water, &lt;i&gt;Azolla microphylla&lt;/i&gt; Kaulf. was the most tolerant aquatic plant and was more suitable for use in atrazine phytoremediation than the other aquatic plants (&lt;i&gt;Ceratophyllum demersum&lt;/i&gt; L., &lt;i&gt;Eichhornia crassipes&lt;/i&gt; (Mart.) Solms, &lt;i&gt;Hydrilla verticillata&lt;/i&gt; (L. f.) Royle, and &lt;i&gt;Salvinia cucullata&lt;/i&gt; Roxb. ex Bory). The total chlorophyll, carotenoid, and proline contents in the biomass of &lt;i&gt;A. microphylla&lt;/i&gt; cultured in 2.5–20 mg/L of atrazine did not significantly differ between the atrazine concentrations (P&gt;0.05). Meanwhile, the proline contents in the other four aquatic plants increased with increasing atrazine concentrations, and the chlorophyll content significantly decreased with an increase in the atrazine concentration. However, &lt;i&gt;A. microphylla&lt;/i&gt; could not remove atrazine from contaminated water, and the application of plant growth regulators (6-benzyladenine, gibberellic acid, indole-3-butyric acid, and salicylic acid) did not improve the atrazine removal from water. Atrazine in the water was around 21–26 mg/L on day five of &lt;i&gt;A. microphylla&lt;/i&gt; cultivation compared to the initial concentration (25 mg/L). Using a plant growth regulator was ineffective for stimulating growth and atrazine removal by &lt;i&gt;A. microphylla&lt;/i&gt;. Future research should explore other potential mechanisms for enhancing atrazine removal by &lt;i&gt;A. microphylla&lt;/i&gt;.