Bottom-up proteomics analysis for adduction of the broad-spectrum herbicide atrazine to histone

Histones are the major proteinaceous components of chromatin in eukaryotic cells and an important part of the epigenome. The broad-spectrum herbicide atrazine (2-chloro-4-[ethylamino]-6-[isopropylamino]-1, 3, 5-triazine) and its metabolites are known to form protein adducts, but the formation of atrazine-histone adducts has not been studied. In this study, a bottom-up proteomics analysis method was optimized and applied to identify histone adduction by atrazine in vitro. Whole histones of calf thymus or human histone H3.3 were incubated with atrazine. After solvent-based protein precipitation, the protein was digested by trypsin/Glu-C and the resulting peptides were analyzed by high-resolution mass spectrometry using an ultra-high-performance liquid chromatograph interfaced with a quadrupole Exactive-Orbitrap mass spectrometer. The resulting tryptic/Glu-C peptide of DTNLCAIHAK from calf thymus histone H3.1 or human histone H3.3 was identified with an accurate mass shift of  +179.117 Da in atrazine incubated samples. It is deduced that a chemical group with an elemental composition of C8H13N5 (179.1171 Da) from atrazine adducted with calf thymus histone H3.1 or human histone H3.3. It was confirmed by MS/MS analysis that the adduction position was at its cysteine 110 residue. Time- and concentration-dependent assays also confirmed the non-enzymatic covalent modification of histone H3.3 by atrazine in vitro. Thus, the potential exists that atrazine adduction may lead to the alteration of histones that subsequently disturbs their normal function.

Electron transfer enhancing the Mn(II)/Mn(III) cycle in MnO/CN towards catalytic ozonation of atrazine via a synergistic effect between MnO and CN

In this study, manganese oxide (MnO) dispersed on CN (Mn-nCN) was fabricated as a catalyst in heterogeneous catalytic ozonation (HCO), achieving excellent catalytic performance on refractory organic pollutant degradation via the synergistic effects between MnO and CN. The study demonstrated that the C-N-Mn and C-O-Mn bonds constructed in the catalyst linking MnO and CN created the synergistic effects which could overcome typical problems, such as metal leaching etc. The C-N-Mn and C-O-Mn bonds could promote electron transfer from cation-π reactions to form electron-rich Mn(II) sites and electron-poor CN sites. The electron-rich Mn(II) sites as active sites supplied electrons to ozone which then further evolved into reactive oxygen species (ROS). The electron-poor CN sites captured electrons from the pollutant intermediate radicals to electron-rich Mn(II) sites via cation-π reactions with the help of C-N-Mn and C-O-Mn bonds, which promote the redox reactions of Mn. The surface hydroxyl groups also participated in ozone decomposition and ROS production. Additionally, ^•OH was the dominant ROS of the Mn-nCN HCO processes. This study presents the excellent HCO performance of Mn-nCN, as well as provides views on the electron transfer route between the catalyst, pollutant and ozone, which is crucial for the design of the catalyst.

Evaluation of a graphitic porous carbon modified with iron oxides for atrazine environmental remediation in water by adsorption

In the last decades, the growth of world agricultural activity has significantly contributed to the increased presence of emerging pollutants such as atrazine (ATZ) in aquatic ecosystems. Due to its high stability to the natural or artificial degradation processes, the ATZ environmental remediation by adsorption has been investigated. In this study, a graphitic-porous-carbon- (GPC) based material with magnetic domains was applied to remove ATZ from aqueous solution. ATZ high adsorption efficiency in a reduced time was achieved in the presence of the GPC adsorbent, leading to a detailed investigation of the mechanisms involved in the adsorption processes. Pseudo-first-order (PFO), pseudo-second-order (PSO), Ritchie, Elovich, and Weber-Morris models were applied to calculate the kinetic process efficiency. Likewise, adsorption isotherms based on Langmuir, Freundlich, Temkin, and Redlich-Peterson models were applied for a detailed understanding of the adsorption mechanisms. GPC was successfully applied for ATZ remediation in natural waters, confirming its high potential for treating natural waters contaminated by ATZ using adsorption process. The material can also be recovered and reused for up to 4 application cycles due to its magnetic properties, showing that in addition to ATZ adsorption efficiency, its sustainable use can be achieved.

Use of wood and cork in biofilters for the simultaneous removal of nitrates and pesticides from groundwater

About 13% and 7% of monitored groundwater stations in Europe exceed the permitted levels of nitrates (50 mg NO₃^- L^-1) or pesticides (0.1 μg L^-1), respectively. Although slow sand filtration can remove nitrates via denitrification when oxygen is limited, it requires an organic carbon source. The present study evaluates the performance of the use of wood pellets and granulated cork as carbon sources in bench-scale biofilters operated under water-saturated and water-unsaturated conditions for more than 400 days. The biofilters were monitored for nitrate (200 mg L^-1) and pesticide (mecoprop, diuron, atrazine, and bromacil, each at a concentration of 5 μg L^-1) attenuation, as well as for the formation of nitrite and pesticide transformation products. Microbiological characterization of each biofilter was also performed. The water-saturated wood biofilter achieved the best nitrate removal (>99%), while the cork biofilters lost all denitrification power over time (from 38% to no removal). The unsaturated biofilter columns were not effective for removing nitrates (20-30% removal). As for pesticides, all the biofilters achieved high removal rates of mecoprop and diuron (>99% and >75%, respectively). Atrazine removal was better in the wood-pellet biofilters than the cork ones (68-96% vs. 31-38%). Bromacil was only removed in the water-unsaturated cork biofilter (67%). However, a bromacil transformation product was formed there. The water-saturated wood biofilter contained the highest number of denitrifying microorganisms, with Methyloversatilis as the characteristic genus. Microbial composition could explain the high removal of pesticides and nitrates achieved in the wood-pellet biofilter. Overall, the results indicate that wood-pellet biofilters operated under water-saturated conditions are a good solution for treating groundwater contaminated with nitrates and pesticides.

Identifying unusual human exposures to pesticides: Qilu Lake Basin as an overlooked source

Although common exposure pathways of pesticides (e.g., crop consumption) have been intensively studied, we noticed that some unusual occupational exposures to pesticides were overlooked and could lead to unacceptable health risks. In this study, we presented information on the occurrence of 5 triazine pesticides (TRIs) and 3 neonicotine pesticides (NEOs) detected in water samples of Qilu Lake Basin in China. We identified the unusual occupational exposure scenarios as (i) adult females washing the harvested vegetables, and (ii) adult males catching fish in Qilu Lake; next, the health risk assessment was conducted using collected data. The results showed that the mean Σ5 TRI concentrations ranged from 505.87 ng/L in spring to 864.04 ng/L in summer, and the river water samples around Qilu Lake had the highest concentrations. The mean concentrations of Σ3 NEOs ranged from 885.86 ng/L in winter to 2593.04 ng/L in summer. Occupational exposed populations were bearing one to two orders of magnitude higher exposure doses than local adults. Although the carcinogenic risks caused by atrazine in water were at acceptable levels for local residents, all the occupational exposed males were at moderate risks, and 15.78 %-43.50 % of occupational exposed females in different seasons were even at high risks. The non-carcinogenic risks caused by pesticides in water were all at negligible levels, but the occupational exposed population were facing up to two orders of magnitude higher risks than local residents. This study established a sound basis for further decision-making to take necessary action on protection of sensitive population groups.

Impact of Eastern Redcedar encroachment on water resources in the Nebraska Sandhills

Worldwide, tree or shrub dominated woodlands have encroached into herbaceous dominated grasslands. While very few studies have evaluated the impact of Eastern Redcedar (redcedar) encroachment on the water budget, none have analyzed the impact on water quality. In this study, we evaluated the impact of redcedar encroachment on the water budget in the Nebraska Sand Hills and how the decreased streamflow would increase nitrate and atrazine concentrations in the Platte River. We calibrated a Soil and Water Assessment Tool (SWAT model) for streamflow, recharge, and evapotranspiration. Using a moving window with a dilate morphological filter, encroachment scenarios of 11.9 %, 16.1 %, 28.0 %, 40.6 %, 57.5 %, 72.5 % and 100 % were developed and simulated by the calibrated model. At 11.9 % and 100 % encroachment, streamflow was reduced by 4.6 % and 45.5 %, respectively in the Upper Middle Loup River, a tributary to the Platte River. Percolation and deep aquifer recharge increased by 27 % and 26 % at 100 % encroachment. Streamflow in the Platte River, a major water source for Omaha and Lincoln, would decrease by 2.6 %, 5.5 % and 10.5 % for 28 %, 57.5 %, and 100 % encroachment of the Loup River watershed, respectively. This reduction in streamflow could increase nitrate and atrazine concentrations in the Platte River by 4 to 15 % and 4 to 30 %, respectively. While the density of redcedar is minimal, it is important to manage their encroachment to prevent reductions in streamflow and potential increases in pollutant concentrations.

Process analysis of asymmetric interaction between copper and atrazine in a system of macrophytes

To clarify the mutual influence and inner processes between heavy-metal and pesticide pollutants, single copper and atrazine as well as binary mixtures were spiked in a system of aquatic Acorus tatarinowi Schott. The results show that: the total copper amount in roots was 23.31 and 41.46 times as much as those in leaves in single and co-contaminated copper pollution. In the solution, the copper removal reached equilibrium in 3 days. Atrazine raised plant-mediated copper removal by 20.69 % by calculating mass balance, and the increase in pH value and organic matter and the decrease of nitrate in solutions were key factors driving it. Correlation analysis demonstrated that the pH increase was mainly caused by the decline of nitrate and increases in organic matter in the solution. Hydroxyl units on the surface of organic matter in solutions provided binding sites for Cu²⁺, which was demonstrated by CO and OH peak position alterations in Fourier Transform Infrared Spectrometer. In turn, the root contained 2.56 and 2.04 times as much as atrazine in leaves in single and co-contaminated atrazine treatments. In the solution, atrazine removal became stable after 7 days. Cu²⁺ inhibited the total accumulation of atrazine in plants by 12.5 %. Copper-induced biological phenol-like components in solution decreased the total atrazine accumulation in A. tatatinowii.

FeOCl-confined activated carbon for improving intraparticle Fenton-like oxidation regeneration

Highly efficient oxidation, as non-thermal regeneration technology, is a promising method to solve the regeneration problem of spent activated carbon (AC) in wastewater treatment. In this study, FeOCl was confined into activated carbon (FeOCl/AC) for catalytic oxidation of contaminants on AC during the regeneration process. The characterization results of FeOCl/AC showed that amorphous FeOCl was distributed in micropores, mesopores and macropores of AC. The methylene blue (MB)-adsorbed FeOCl/AC had a regeneration efficiency of 93.7 % at neutral pH in the presence of H₂O₂, much higher than 46.9 % by Fenton oxidation and 33.7 % by H₂O₂ oxidation. Meanwhile, the spent FeOCl/AC after the adsorption of atrazine, 2,4-dichlorophenol, and ofloxacin had the regeneration efficiencies of 71.5 %, 86.4 %, and 100 %, respectively. Moreover, the regeneration efficiency still reached 87 % in the fifth adsorption-regeneration cycle, and was linearly decreased with the increase of adsorbed amounts of MB. During 6 h regeneration of spent FeOCl/AC, 97 % of adsorbed MB was degraded. Electron paramagnetic resonance and radical trapping experiments indicated that both superoxide and hydroxyl radicals were involved in MB oxidation during the regeneration process.

Citrate and glutathione capped gold nanoparticles for electrochemical immunosensing of atrazine: Effect of conjugation chemistry

Recently, the exposure of pesticides/herbicides to the living organisms is increased especially due to agricultural malpractices and industrial processes. In particular, the exposure of pesticides/herbicides (e.g., atrazine) can impart several harsh effects on the human health. The development of efficient detection systems can be crucial in monitoring the atrazine in water and food/plant products, which can be decisive in controlling the deadly exposures of atrazine. Herein, we have developed electrochemical immunosensors for atrazine by employing monoclonal anti-atrazine antibody conjugated gold nanoparticles. Two types of gold nanoparticles (i.e., citrate and glutathione (GSH)-capped AuNPs) were used to modify gold working electrode and utilized for the development of atrazine immunosensors. The conjugation of immunoprobe on working electrode was especially designed to obtain stable and efficient sensing signals. The nanosensing immunoprobes fabricated using citrate-AuNPs and GSH-AuNPs exhibited comparable responses for a wide linear working range of 50 ng/L- 30 μg/L with limit of detection (LOD) values of 0.08 and 0.06 ng/L for atrazine, respectively.

A novel g-C3N4/g-C3N4-x homojunction with efficient interfacial charge transfer for photocatalytic degradation of atrazine and tetracycline

The abuse of pesticides and antibiotics and their harm to the environment are the disadvantages of modern agriculture and breeding industry. g-C₃N₄ has shown great potential in photocatalytic water pollution purification under visible light irradiation, however, the conventional g-C₃N₄ suffers from the disadvantage of limited optical absorption and serious charge recombination, resulting in inefficient light energy conversion and pollutant degradation. This study provides a strategy of combining defect engineering with a built-in electric field to prepare homojunction a photocatalyst with high optical absorption rate and charge separation efficiency. Experiments and DFT simulation revealed the mechanism of significant improvement in the photocatalytic performance of the prepared catalyst, and proposed the pollutant degradation pathway. In addition, the photocatalytic effects of the prepared catalysts on different natural water bodies, natural light, and various water conditions were investigated, revealing the applicability of the catalysts in the purification of pollutants in various water environments.

Lanthanum-modified polydopamine loaded Acinetobacter lwoffii DNS32 for phosphate and atrazine removal: Insights into co-adsorption and biodegradation mechanisms

A novel biobased composite was developed for the removal of phosphate (P) and atrazine from agricultural wastewater. A composite with strong P affinity and good biocompatibility, synthesized from La³⁺ and polydopamine (PDA), was immobilized onto an atrazine-degrading bacterium Acinetobacter lwoffii DNS32 (La/PDA/DNS32). Following Box-Behnken design optimization, the maximum removal rate of P (500 mg L^-1) and atrazine (100 mg L^-1) by La/PDA/DNS32 reached 28 % and 100 %, respectively. Density functional theory calculations revealed that La/PDA had more negative adsorption energy (-5.90 eV) than PDA alone and exhibited prominent electrophilic sites. Additionally, La/PDA-induced sorption of atrazine improved transmembrane transport and enhanced expression of degradation-associated genes in strain DNS32. La/PDA nanoparticles surrounding strain DNS32 provided a shielding effect and exhibited desirable biostability, thermal stability, and acid-alkaline resistance under contamination stress. This study demonstrates the promising potential of La/PDA/DNS32 in reducing the P and atrazine pollution caused by agricultural production.

Electrochemical quantification of atrazine-fulvic acid and removal through bismuth tungstate photocatalytic hybrid membranes

Herbicides such as atrazine and humus substances such as fulvic acid are widely used in agricultural sector. They can be traced in surface and groundwater around the agriculture field at concentrations beyond the approved limit due to their mobility and persistence. Bismuth-based photocatalysts activated by visible light are potential materials for removing various organic pollutants from water bodies. These photocatalysts can also be suitable candidates for developing a hybrid membrane with anti-fouling properties. In this study, Bi2WO6 nanoparticles were synthesized via the hydrothermal method and integrated into the cellulose acetate (CA), polyetherimide (PEI), polysulfone (PSF) and polyvinylidene fluoride (PVDF) polymers via physical blending approach. The hybrid membranes were then characterized by FTIR, XPS and FESEM to confirm the chemical bonding, chemical composition and surface morphology of Bi2WO6. Thus, the pure water flux of CA (35.6 L m-2 h-1), PEI (46.56 L m-2 h-1), PSF (6.84 L m-2 h-1), and PVDF (68.47 L m-2 h-1) hybrid membranes has significantly enhanced than the pristine CA, PEI, PSF and PVDF membranes. The significant rejection of atrazine-fulvic acid was observed with hybrid membranes in the order of CA (84.1%) > PVDF (72.7%) > PEI (47.8%) > PSF (37.2%), and these membranes have shown an excellent flux recovery ratio than pristine membranes. Further, electrochemical quantification studies were performed to analyze the removal efficiency of atrazine-fulvic acid from water. In this present work, GO-modified SPE was employed for electrochemical sensing studies. The resultant CA hybrid membrane achieved removal efficiency of 84.08% for atrazine. It was observed that the Bi2WO6 established strong bonding with CA, and PVDF membranes, thus showing a significant removal efficiency and FRR than other hybrid and pristine membranes.

Azocalixarene-Based Supramolecular System for the Detection of Paraquat via an Improved Indicator Displacement Assay

In view of the lethal toxicity of paraquat (PQ) on human health, herein, a simple indicator displacement assay (IDA) based on an azo-modified calixarene host (azoCX[4]) and a fluorophore guest (p-DPD) were elaborately constructed for PQ detection in environmental water samples and plant surfaces. The fluorescent signal of p-DPD in the probe can be quenched by azoCX[4] through a photon-induced electron transfer process and recovered upon the addition of PQ within 10 s. The detection range of the p-DPD@azoCX[4] probe was calculated to be 0.35-8 μM in the Tris-HCl buffer solutions (pH = 7.4). Moreover, this probe exhibited excellent detection selectivity toward PQ over five herbicides (glyphosate, bispyribac, atrazine, ametryn, and bensulfuron methyl), together with anti-interference abilities in the presence of inorganic ions (K⁺, Na⁺, Zn²⁺, Ni²⁺, Li⁺, F^-, Cl^-, Br^-, CO₃^2-, HCO₃^-, and NO₃^-) and amino acids (Asp, Arg, Glu, Ala, and Cys). Particularly, the probe was successfully used to detect PQ in real water samples with acceptable accuracy and showed potential applications for on-site detection with paper-based test strips and on the leaf surface. We believe that this simplified IDA-based probe provided an effective detecting tool for PQ, and the design strategy would guide the further development of new IDA sensing systems.

Atrazine adsorption and desorption on functionalized montmorillonite: aluminum-pillared and lithium saturated

Atrazine is an herbicide used worldwide, and it is considered a severe environmental contaminant. The present study aims to evaluate the atrazine adsorption in aqueous media in montmorillonite samples which were either in natural state or functionalized through saturation with lithium and pillarization with aluminum by different methods. Montmorillonite saturated with lithium adsorbed significantly more atrazine than the natural montmorillonite sample. Among the samples obtained through the three aluminum-pillarization methods, the mass percentage of adsorbed atrazine was very similar. However, the best combination was the aluminum-pillarization (due to the maintenance of the open interlayer region) and saturation with lithium (due to the significant reduction of the cation exchange capacity of the mineral), because both processes facilitate the interaction of atrazine with the montmorillonite. Another advantage was that the adsorption of atrazine in the pillared and lithium saturated samples had small desorption, which is desirable in the environmental perspective. It is recommended to build filters with aluminum-hydroxy pillared, lithium saturated montmorillonite as an alternative method to rapidly remove atrazine from aqueous media. In addition to the shorter production time, this process resulted in montmorillonite with high occupancy rate and stability of the aluminum-hydroxy pillars.

TiO2/C coated Co3O4 nanocages for peroxymonosulfate activation towards efficient degradation of organic pollutants

Developing new catalysts for efficient degradation of micropollutants in water is of significant importance in advanced oxidation processes (AOPs). Herein, TiO₂/C coated Co₃O₄ nanocages (Co₃O₄@TiO₂/C) were synthesized and their performance on micropollutants degradation was evaluated. Specifically, cobalt-based Zeolitic imidazolate framework (ZIF-67) coated by a thin layer of titanium species and polydopamine (PDA) was used as a precursor for the preparation of Co₃O₄@TiO₂/C by two-step calcination. The catalytic performance of peroxymonosulfate (PMS) activation towards the degradation of organic pollutants was investigated by using atrazine (ATZ) and Bisphenol A (BPA) as typical micropollutants. The efficiency and the effect of TiO₂/C shell on the as-synthesized catalyst were analyzed by comparing Co₃O₄ derived from ZIF-67 and Co₃O₄/C derived from ZIF-67/PDA. ATZ degradation results showed that the Co₃O₄@TiO₂/C catalyst was the most efficient for catalytic oxidation when 99.5% of ATZ was removed within 4 min, which is 57.5% and 74.6% faster than that of Co₃O₄@C and Co₃O₄, respectively. The enhanced performance of Co₃O₄@TiO₂/C is attributed to their unique nanocages structure and improved specific surface area. The catalysis mechanisms and ATZ degradation pathways were presented based on the results of electron paramagnetic resonance (EPR), XPS, and LC-MS analysis. Our results might have added to the design of heterogeneous catalysts of large surface area for efficient PMS activation in AOPs.

PWC-based evaluation of groundwater pesticide pollution in the Júcar River Basin

Predicting pesticides' behavior in the environment is necessary to anticipate and minimize their adverse effects. Despite the use of pesticides in Spain is increasing, the implementation and use of predictive mathematical models is seldomly done in practice due to the lack of available data. In this original work, the Pesticide Root Zone Model version 5 (PRZM 5) mathematical model under the Pesticide in Water Concentration 1.52 (PWC) interface has been applied to model pesticide behavior in nine groundwater bodies located inside the Júcar River Basin (JRB) in Spain. Mathematical modeling allowed calculating the maximum concentration of pesticides after completing the calibration process. Bromacil, terbuthylazine, atrazine, desethyl-terbuthylazine, and terbumeton concentrations in groundwater were simulated between 2006 and 2019. Results show that the maximum pesticide concentration value on every well exceeds the current Spanish Maximum Concentration Limit (0.1 μg/L). PRZM 5 was able to reproduce pesticide concentration observations over time despite the limited amount of available data. This study contributes to assessing environmental risks caused by the use of pesticides inside the JRB and can potentially be applied in other areas of interest.

Coupling field-scale and watershed models for regulatory modeling of pesticide aquatic exposures in streams

Estimating exposure in receiving waterbodies is a key step in the regulatory process to evaluate potential ecological risks posed by the use of agricultural pesticides. The United States Environmental Protection Agency (USEPA) currently uses the Variable Volume Water Model (VVWM) to predict environmental concentrations of pesticides in static waterbodies (ponds) that receive edge-of-field runoff inputs from the Pesticide Root Zone Model (PRZM). This regulatory model, however, does not adequately characterize potential pesticide concentrations in flowing water systems (streams and rivers) drained from watershed areas. This study aims at addressing this gap by coupling the regulatory PRZM model with a watershed-level hydrological model, the Soil and Water Assessment Tool (SWAT), to predict pesticide concentrations in flowing water habitats for aquatic organisms. This coupled PRZM-SWAT model was applied in a test watershed (~HUC12), a headwater watershed of Goodwater Creek in Missouri, and simulation results at the outlet of this watershed were compared to daily and near-daily measured streamflow and atrazine concentration data from a decade-long sampling campaign. Overall, the PRZM-SWAT model captured (1) the general magnitude and temporal trend of daily atrazine concentrations, (2) the observed high-end of exposure levels (>3 ppb) of atrazine concentrations, and (3) the 90^th centile annual maximum for various exposure durations (1-, 4-, 7-, 21-, and 60-day rolling average), which are important exposure metrics used in assessing the potential ecological risks posed by the application of pesticides. The PRZM-SWAT model is expected to expand the utility of the field-scale regulatory model to include pesticide exposure prediction capability in flowing waterbodies from agricultural watersheds. Integr Environ Assess Manag 2022;18:1678-1693. © 2022 SETAC.

Synthesis of a biobased resin and its screening as an alternative adsorbent for organic and inorganic micropollutant removal

The sol-gel route was used to synthesize a biophenolic resin from a blend of Kraft black liquor and condensed tannin. The biobased resin has an amorphous structure and diversified surface functional groups. The biomaterial thermal stability was improved by Kraft black liquor, which increased the fixed carbon yield by 19.78% in an oxidant medium and 9.07% in an inert medium. Moreover, the presence of fixed carbon and char is positively related to the material flame retardant property. Additionally, impedance measurements were used to understand the physical phenomena occurring at the polymeric matrix's interface and the material's final properties. The biobased resin characterization and the considerable increase in the presence of micropollutants in surface and water bodies suggest the new biomaterial application in the adsorption process. Thus, its adsorption capacity toward several organic and inorganic micropollutants and its effectiveness in complex water matrices were evaluated. Methylene blue was used as a model compound to assess the influence of the resin composition on the adsorption capacity, and the type H isotherm indicates the high affinity of the biobased resin toward the micropollutant. The adsorption occurs in multilayer by intermolecular interaction and electrostatic forces. The amount of Kraft black liquor favored the adsorption, and the adsorption capacity was greater than 1250 mg g^-1. When inorganic compounds were evaluated, the carboxyl and phenol groups favor the biomaterial affinity toward metal ions. Cu²⁺ and Ni²⁺ were completely removed from the contaminated water, and the adsorption capacity of the other inorganic compounds was: Pb²⁺ (36.97 mg g^-1), Al³⁺ (22.17 mg g^-1), Ba²⁺ (12.76 mg g^-1), Ag¹⁺ (33.85 mg g^-1), and Fe²⁺ (19.44 mg g^-1). In contrast, the adsorption capacity of the organic micropollutants was: 2,4-D (3.09 mg g^-1), diuron (5.89 mg g^-1), atrazine (2.71 mg g^-1), diclofenac (2.04 mg g^-1), caffeine (5.79 mg g^-1), acetaminophen (4.80 mg g^-1), methylene Blue (106.66 mg g^-1), and methyl orange (30.48 mg g^-1). The results pointed that the adsorption efficiency of organic micropollutants increases with the distribution coefficient (logD), indicating the biobased resin affinity toward more lipophilic compounds and ionized species.

National Assessment of Long-Term Groundwater Response to Pesticide Regulation

Quantitative assessments of long-term, national-scale responses of groundwater quality to pesticide applications are essential to evaluate the effectiveness of pesticide regulations. Retardation time in the unsaturated zone (R_u) was estimated for selected herbicides (atrazine, simazine, and bentazon) and degradation products (desethylatrazine (DEA), desisopropylatrazine (DIA), desethyldesisopropylatrazine (DEIA), and BAM) using a multidecadal time series of groundwater solute chemistry (∼30 years) and herbicide sales (∼60 years). The sampling year was converted to recharge year using groundwater age. Then, R_u was estimated using a cross-correlation analysis of the sales and the frequencies of detection and exceedance of the drinking water standard (0.1 μg/L) of each selected compound. The results showed no retardation of the highly polar, thus mobile, parent compounds (i.e., bentazon), while R_u of the moderately polar compounds (i.e., simazine) was about a decade, and their degradation products showed even longer R_u. The temporal trends of the degradation products did not mirror those of the sale data, which were attributed to the various sale periods of the parent compounds, sorption of the parent compounds, and complex degradation pathways. The longer R_u in clayey/organic sediments than in sandy sediments further confirmed the role of soil-specific retardation as an important factor to consider in groundwater protection.

High-efficient peroxymonosulfate activation for rapid atrazine degradation by FeSx@MoS2 derived from MIL-88A(Fe)

FeS_x@MoS₂-x (FM-x, x implied real Mo/Fe content ratios) in which FeS_x derived from MIL-88A deposited on the surface of MoS₂ with a tight heterogeneous interface were synthesized for peroxymonosulfate (PMS) activation to degrade atrazine (ATZ). The catalytic performance of FM-0.96 was greatly improved due to the rapid regeneration of Fe²⁺ resulting from the interfacial interaction. FM-0.96 could completely degrade 10.0 mg/L ATZ within 1.0 min, and the toxicities for most of its intermediates were greatly reduced. The k value of FM-0.96 was 320 and 40 times higher than that of the MoS₂ and FeS_x, respectively. The SO₄·^-, ·OH and ¹O₂ were mainly responsible for ATZ degradation in FM-0.96/PMS system, and the conversion pathway of ¹O₂ was analyzed. Furthermore, the long-term continuous operation for ATZ degradation was achieved using a fixed membrane reactor. This work provides deep insights into metal sulfide composites derived from metal-organic frameworks for removing pollutants by activating PMS.

Fluorescent Detection of Two Pesticides Based on CRISPR-Cas12a and Its Application for the Construction of Four Molecular Logic Gates

An intelligent detection platform was developed through molecular logic gate operation based on CRISPR-Cas12a and signal amplification circuits using two kinds of pesticides [acetamiprid (ACE) and atrazine (ATR)] as inputs. The pesticide-aptamer bindings activate the signal amplification process to produce numerous double-stranded DNA, which can be identified by CRISPR-Cas12a. Under the optimal assay conditions, the sensor exhibits excellent analytical performance, with the detection limits for ACE and ATR of 2.5 and 0.2 pM, respectively. The practicality of the platform was verified by testing pesticide concentrations in food samples. Several molecular logic gates (OR, AND, XOR, and INHIBIT) were constructed using "0" and "1" to encode the target pesticides and the fluorescence readout. The logic detection platform with simple operation, high sensitivity, and multiple logic functions is promising to become a powerful sensing system for the intelligent assay of different pesticides in food samples.

The spatial-temporal chemical footprint of pesticides in China from 1999 to 2018

The massive use of pesticides brings considerable environmental and human health impacts. This study conducted an overall assessment of the ecological impact of the extensive pesticide use in China from 1999 to 2018 through the Chemical Footprint (ChF) calculation. The results demonstrated that the primary ecological impacts caused by pesticides occurred in the most central and eastern regions in China, e.g., provinces of Shandong, Henan, Hubei, Anhui, and Jiangsu. The northeastern, some southern and central provinces, e.g., Heilongjiang, Jilin, Liaoning, Yunnan, Guangxi, Guangdong, Ningxia, and Shaanxi, got moderate impacts, whereas the northwest regions, e.g., Qinghai, Xinjiang, and Tibet, had much lighter impacts relatively. The agricultural soil in inland areas and surface sea waters in coastal provinces bore the major impacts of the pesticide pollution in China, shared above 80% of the ChF across all environmental compartments. Chlorpyrifos, pymetrozine, fenpropathrin, pyridaben, atrazine, etc., were the pesticides that had the greatest impacts on the ecosystem, which contributed over 95% of the total ChF of pesticides used in China, although the use amount of these pesticides accounted for less than 10% of the total use amount of all pesticides annually. The study also indicated that the overall ChF of pesticide use in China has been declining since 2010, which was corresponding with the control actions of highly hazardous pesticides, especially the elimination of high toxic organophosphorus insecticides during the past decade.

Community structure and function of microbiomes in polluted stretches of river Yamuna in New Delhi, India, using shotgun metagenomics

The large population residing in the northern region of India surrounding Delhi mostly depends on water of River Yamuna, a tributary of mighty Ganga for agriculture, drinking and various religious activities. However, continuous anthropogenic activities mostly due to pollution mediated by rapid urbanization and industrialization have profoundly affected river microflora and their function thus its health. In this study, potential of whole-genome metagenomics was exploited to unravel the novel consortia of microbiome and their functional potential in the polluted sediments of the river at Delhi. Analysis of high-quality metagenome data from Illumina NextSeq500 revealed substantial differences in composition of microbiota at different sites dominated by Proteobacteria, Bacteroidetes, Firmicutes, Actinobacteria and Chloroflexi phyla. The presence of highly dominant anaerobic bacteria like Dechloromonas aromatica (benzene reducing and denitrifying), Rhodopseudomonas palustris (organic matter reducing), Syntrophus aciditrophicus (fatty acid reducing) and Syntrophobacter fumaroxidans (sulphate reducing) in the polluted river Yamuna signifies the impact of unchecked pollution in declining health of the river ecosystem. A decline in abundance of phages was also noticed along the downstream river Yamuna. Mining of mycobiome reads uncovered plethora of fungal communities (i.e. Nakaseomyces, Aspergillus, Schizosaccharomyces and Lodderomyces) in the polluted stretches due to the availability of higher organic carbon and total nitrogen (%) could be decoded as promising bioindicators of river trophic status. Pathway analysis through KEGG revealed higher abundance of genes involved in energy metabolism (nitrogen and sulphur), methane metabolism, degradation of xenobiotics (Nitrotoluene, Benzoate and Atrazine), two-component system (atoB, cusA and silA) and membrane transport (ABC transporters). Catalase-peroxidase and 4-hydroxybenzoate 3-monooxygenase were the most enriched pollution degrading enzymes in the polluted study sites of river Yamuna. Overall, our results provide crucial insights into microbial dynamics and their function in response to high pollution and could be insightful to the ongoing remediation strategies to clean river Yamuna.

Assessing the Impact of Atrazine on the Availability of Arsenic in Soils Using DGT Technique

Arsenic (As) has been observed to co-exist with atrazine (ATR) in soils worldwide. ATR, as an organic chemical, may affect the availability of As and further influence its uptake by organisms. Here we used a novel passive sampling technique, DGT (diffusive gradients in thin-films), to compare with other two conventional sampling approaches (soil solution extraction and 'Olsen As' measurement) to investigate the influence of ATR addition (normal recommended level and contaminated level) on the availability of As in soils, to further interpret the potential risk of As in soil environment. The effect of adding ATR on the behaviour of As in soils was limited. When the concentration of ATR was much higher, the availability of As in soils was supressed, the labile pool size was also affected, but the R value did not change much. The properties of the soils also played an important role by affecting the states of the compounds.

Control of organic contaminants in groundwater by passive sampling and multivariate statistical analysis

Organic contaminants in groundwater are among the most challenging chemical compound contaminants today, particularly when it comes to understanding their occurrence, origin, and relations in groundwater, as well as the transport processes, fate, and environmental impacts involved. This paper presents the use of active carbon fibre (AFC) passive sampling and multivariate statistical processing of the results to predict the possible occurrence of organic compounds (OCs) in groundwater and to determine the origin of various anthropogenic activity. This study aims to deepen our knowledge on the control of OCs in groundwater by introducing a multi-analytical and multi-elemental holistic approach, using the Dravsko polje aquifer, the largest intergranular aquifer in Slovenia, as an example. The occurrence of OCs in groundwater was determined by means of ACFs and compared against the characteristics of the recharge area and the type of compounds detected. We combined hierarchical cluster analysis (HCA) and principal component analysis (PCA) to identify the relationship between different OCs in groundwater. The relationships between their occurrence, environmental setting and type of compound were determined using multiple linear regression (MLR). From the total of 343 organic compounds detected using passive sampling, 47 were included in further statistical analysis. MLR shows that the environmental setting is one of the most important factors affecting the different types of pollutants in groundwater. MLR models were calculated for different sources of pollution (agricultural, urban, and industrial) based on the environmental setting, land use, agglomeration, infrastructure networks, and hydrogeological characteristics of the aquifer. By means of HCA and PCA, we identified the relationships between different OCs in groundwater. As expected, the strongest correlations were found between primary compounds and their degradation products (e.g. atrazine and desethylatrazine) and compounds of similar use (e.g. atrazine and propazine, also desethylatrazine and propazine, atrazine and simazine). Some of them were also found to have a similar molecular structure (e.g. palmitic and stearic acid, 5-methoxygramine and 5-methoxytryptamine). The use of the same substances in different environments (agricultural/urban) makes them markers of both (different) origins. Therefore, it is particularly important to determine the combination of markers of different origin using multivariate statistical methods, especially in the case of mixed land use. This study identifies the main factors influencing the distribution of groundwater OCs and thus contributes to a more comprehensive understanding of the vulnerability of shallow groundwater to surface-derived contamination in similar environments.