Bioinformatics analysis of the potential mechanisms of Alzheimer's disease induced by exposure to combined triazine herbicides.

BACKGROUND: The development of Alzheimer's disease (AD) is promoted by a combination of genetic and environmental factors. Notably, combined exposure to triazine herbicides atrazine (ATR), simazine (SIM), and propazine (PRO) may promote the development of AD, but the mechanism is unknown. AIM: To study the molecular mechanism of AD induced by triazine herbicides. METHODS: Differentially expressed genes (DEGs) of AD patients and controls were identified. The intersectional targets of ATR, SIM, and PRO for possible associations with AD were screened through network pharmacology and used for gene ontology (GO) and Kyoto Encyclopaedia of Genes and Genomes (KEGG) enrichment analysis. The binding potentials between the core targets and herbicides were validated by molecular docking and molecular dynamics. RESULTS: A total of 1,062 DEGs were screened between the AD patients and controls, which identified 148 intersectional targets of herbicides causing AD that were screened by network pharmacology analysis. GO and KEGG enrichment analysis revealed that cell cycling and cellular senescence were important signalling pathways. Finally, the core targets EGFR, FN1, and TYMS were screened and validated by molecular docking and molecular dynamics. CONCLUSION: Our results suggest that combined exposure to triazine herbicides might promote the development of AD, thereby providing new insights for the prevention of AD.

Responses to herbicides of Arctic and temperate microalgae grown under different light intensities.

In aquatic ecosystems, microalgae are exposed to light fluctuations at different frequencies due to daily and seasonal changes. Although concentrations of herbicides are lower in Arctic than in temperate regions, atrazine and simazine, are increasingly found in northern aquatic systems because of long-distance aerial dispersal of widespread applications in the south and antifouling biocides used on ships. The toxic effects of atrazine on temperate microalgae are well documented, but very little is known about their effects on Arctic marine microalgae in relation to their temperate counterparts after light adaptation to variable light intensities. We therefore investigated the impacts of atrazine and simazine on photosynthetic activity, PSII energy fluxes, pigment content, photoprotective ability (NPQ), and reactive oxygen species (ROS) content under three light intensities. The goal was to better understand differences in physiological responses to light fluctuations between Arctic and temperate microalgae and to determine how these different characteristics affect their responses to herbicides. The Arctic diatom Chaetoceros showed stronger light adaptation capacity than the Arctic green algae Micromonas. Atrazine and simazine inhibited the growth and photosynthetic electron transport, affected the pigment content, and disturbed the energy balance between light absorption and utilization. As a result, during high light adaptation and in the presence of herbicides, photoprotective pigments were synthesized and NPQ was highly activated. Nevertheless, these protective responses were insufficient to prevent oxidative damage caused by herbicides in both species from both regions, but at different extent depending on the species. Our study demonstrates that light is important in regulating herbicide toxicity in both Arctic and temperate microalgal strains. Moreover, eco-physiological differences in light responses are likely to support changes in the algal community, especially as the Arctic ocean becomes more polluted and bright with continued human impacts.

Transition metal-doped germanium oxide nanozyme with enhanced enzyme-like activity for rapid detection of pesticide residues in water samples.

Designing highly active nanozymes for bioanalysis and environmental sensing remains a challenge. In this study, transition metal, palladium (Pd) and iron (Fe), doped germanium oxide (GeO2) nanozyme was designed and optimized. Compared with the pristine GeO2 nanozyme, the transition metal doped GeO2 nanozyme have lower Michaelis-Menten constants and higher catalytic activity, indicating that the Pd and Fe doped GeO2 nanozyme not only enhance their affinity for the substrate but also improve its catalytic activity. In addition, a colorimetric sensor based on the GeO2@Pd-H2O2-TMB system was constructed for the visual detection of simazine in water samples due to the good affinity between TMB and simazine. This sensor has good selectivity and sensitivity with a detection limit of 6.21 µM because of the highest catalytic performance of GeO2@Pd nanozyme. This study broadens the application of nanozymes in environmental field and other nanozymes can also be enhanced in activity by simple transition metal doping.

Catchment sourcing urban pesticide pollution using constructed wetlands in Melbourne, Australia.

A survey of 111 urban constructed stormwater wetlands (median watershed area = 86.8 ha) was conducted to identify the major pesticides present and to determine their major catchment sources (residential, industrial, commercial, sporting ovals) and associations with catchment imperviousness. Melbourne, Australia, has separate stormwater and sewerage systems and these wetlands are designed to treat urban stormwater. To maximise the pesticides that could be detected, three types of passive samplers (POCIS, Chemcatcher® SDB-XC and Chemcatcher® C18) were deployed, along with collection of fine sediments. A total of 231 pesticides were screened using these methods. Pesticides that were detected in >5 % of wetlands were checked to determine their registered use in urban areas using an Australian government database (PubCris). Twenty-five pesticides were detected in >5 % of wetlands: 4 pesticides were associated with non-urban land uses (agriculture and forests), another 4 pesticides had no known registered use in urban areas and 17 were associated with urban areas. The pesticides associated with urban areas were the herbicides simazine, diuron, metolachlor, bromacil, propyzamide and paclobutrazol, the fungicides tebuconazole, propiconazole, metalaxyl, trifloxystrobin, iprodione and carbendazim and the insecticides fipronil, bifenthrin, chlorantraniliprole, thiamethoxam and permethrin. Atrazine was also detected in 59 % of wetlands but has not been registered for urban uses in Australia since 2010. It's presence in Melbourne may be due to legacy issues or aerial transportation from rural areas where it's still widely used in crop cultivation. Generally, the major urban catchment source of pesticides is from residential areas (particularly fipronil and simazine), most likely in wood preservatives, paints and from weed or insect control. Many of these widely used pesticides were correlated with increased catchment imperviousness. Some pesticides (bromacil and imidacloprid) were correlated with commercial premises and chlorantraniliprole was correlated with the presence of sporting ovals in the catchment. No pesticides were specifically correlated with industrial areas. The use of passive samplers and fine sediments, in conjunction with detailed land use mapping of stormwater wetland catchments is very effective and efficient in monitoring and sourcing pesticide contamination in urban environments.

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 (Ru) 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, Ru 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 Ru of the moderately polar compounds (i.e., simazine) was about a decade, and their degradation products showed even longer Ru. 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 Ru 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.

Surface water contamination from pesticide mixtures and risks to aquatic life in a high-input agricultural region of Brazil.

The environmental risks of pesticides found in surface waters of an important agricultural basin in Brazil were estimated by adopting two approaches: individual pesticides risk quotients (RQ) and concentration addition model for pesticide mixtures (∑RQs) contained in each water sample. Monitoring was carried out in the Mogi Guaçu River basin, Brazil, from October 2017 to May 2018. Four sampling points were selected in the Mogi Guaçu River and seven in its tributaries A multiresidue method with solid-phase extraction and subsequent analysis by UPLC-ESI-QqQ-MS/MS was developed to quantify 19 pesticides. Herbicides, except for simazine, presented the highest detection frequencies with values above 70%. Tebuthiuron was found in all 55 analyzed samples, presenting the highest concentration (6437 ng L-1) over the monitoring period. Fungicides and insecticides showed similar detection frequency (DF) values, ranging from 1.8% to 21.8%. Tebuconazole and carbofuran were the fungicides and insecticides most frequently detected, respectively. January 2018 sampling showed the highest total concentration of pesticides, differing from March 2018 and May 2018 (p < 0.05). The MG2 > TMG8 > MG1 > TMG6 sites showed the highest concentration total of pesticides while MG4 > TMG4 > TMG3 (p < 0.05) sites showed the lowest values: MG4 > TMG4 > TMG3 (p < 0.05). Most pesticide occurrences presented no risks to aquatic organisms. Only 19 out of the 175 pesticide occurrences > LOQ presented individual risks to aquatic biota. Contrary to the results obtained by the individual risk assessment, most pesticide mixtures presented risks to aquatic biota. In 36 out of the 55 samples analyzed during monitoring, pesticide mixtures presented risks to aquatic life.

Combination of microwave-assisted solvent extraction and effervescence-assisted deep eutectic solvent-based in-syringe dispersive liquid-liquid microextraction and its application in the extraction of triazine pesticides from apple samples.

In the current study, a combination of microwave-assisted solvent extraction combined with effervescence-assisted deep eutectic solvent-based in-syringe dispersive liquid-liquid microextraction has been developed as a new sample pretreatment method. The offered method was used for the extraction of five triazine pesticides (atrazine, propazine, cyanazine, ametryn, and simazine) from apple samples before their determination by gas chromatography-flame ionization detection. For this purpose, briefly, the apple sample was contacted with a suitable acidified extraction solvent and the mixture was exposed to microwave irradiations. Then, the supernatant was taken and mixed with a few microliters of a low-density deep eutectic solvent. The supernatant phase containing the extracted analytes was injected into a sodium bicarbonate solution filled into a syringe. Consequently, the effervescence reaction occurs and the analytes were extracted into the fine droplets of extractant dispersed throughout the solution. Afterward, an aliquot of this phase was analyzed by the chromatographic system. Satisfactory outcomes include high enrichment factors (228-261) and extraction recoveries (67-87%), good repeatability (relative standard deviations equal to or less than 3.2% and 5.3% for intra- and inter-day precisions), and low limits of detection (0.4-0.7 ng/g) and quantification (1.4-2.3 ng/g) were acquired under the best experimental situations.

Synthesis and application of new silver and sulfur decorated S-doped reduced graphene oxide in ultra-trace analysis of pesticides by ion mobility spectrometry.

In this research study, a novel, facile, and affordable method is presented for the synthesis of a Ag/S/S-RGO nanocomposite. The resulting new nanocomposite was identified by FT-IR, XRD, FESEM, XPS, BET and EDX and employed as a rapid and effective adsorbent with acceptable absorption capacity for the analysis of various pesticides by dispersive solid-phase microextraction combined with ion mobility spectrometry. The main experimental parameters of the method were optimized such as the type of desorption solvent, pH of the sample solution, type of buffer, amount of the sorbent (Ag/S/S-RGO), sorption/desorption time, etc. Under the optimized conditions, linear dynamic ranges of 0.5-110.0, 1.0-110.0, and 0.8-90.0 ng mL-1 were achieved, with limits of detection of 0.25, 0.35, and 0.25 ng mL-1 for simazine, alachlor, and haloxyfop, respectively. The relative standard deviations (RSD%) were obtained as <5.0%. Eventually, the method was utilized for the simultaneous determination of simazine, alachlor, and haloxyfop in environmental and agricultural samples with recoveries between 95.0 and 104.6%.

Tracing water-soluble, persistent substances in the Black Sea.

We apply a tracer model linked with a 3D circulation model to simulate transport and fate of water-soluble persistent substances in the Black Sea that do not bioaccumulate to a considerable extent. The model uses specified degradation time and identical concentrations in the rivers to build a correlation between average concentration in the basin and half-life (DT50). The average concentration in certain sub-regions of the Black Sea can be estimated using an exponential dependence of DT50, if DT50 and concentration in rivers are known. Averaging is performed on the simulations from 2000 to 2019 with real atmospheric forcing and river runoff. A well-defined seasonal cycle is evident for the average shelf concentration, while the average concentration in the deep region does not show a pronounced seasonal cycle or inter-annual variations. With the help of the existing observational data, we estimate DT50 and concentration in the rivers for carbamazepine, sulfamethoxazole and terbuthylazine. Atrazine and simazine are believed to have accumulated in the basin for a long time due to their widespread use in the past and the slow rate of degradation in the marine environment.

Highly selective molecularly imprinted-electrochemiluminescence sensor based on perovskite/Ru(bpy)32+ for simazine detection in aquatic products.

A novel molecularly imprinted electrochemiluminescence (MIECL) sensor based on the luminescence of molecularly imprinted polymer-perovskite (MIP-CsPbBr3) layer and Ru(bpy)32+ was fabricated for simazine detection. MIP-CsPbBr3 layers were immobilized onto the surface of glassy carbon electrode as the capture and signal amplification probe, and Ru(bpy)32+ and co-reactant tripropylamine exhibited stronger electrochemiluminescence (ECL) emission. Under optimal conditions, the ECL signal of the MIECL sensor was linearly quenched, with the logarithm of simazine concentration ranging from 0.1 µg/L to 500.0 µg/L, correlation coefficient of 0.9947, and limit of detection of 0.06 µg/L. The practicality of the developed MIECL sensor method for simazine determination in aquatic samples was validated. Excellent recoveries of 86.5 %-103.9 % with relative standard deviation below 1.6 % were obtained for fish and shrimp samples at three different spiked concentrations. The MIECL sensor exhibited excellent selectivity, sensitivity, reproducibility, accuracy, and precision for simazine determination in actual aquatic samples.

Isolation and characterization of cyromazine degrading Acinetobacter sp. ZX01 from a Chinese ginger cultivated soil.

Cyromazine, a symmetrical triazine insecticide, is used to control dipteran larvae in chicken manure by feeding to the poultry, flies on animals, and leafminers in vegetables. Its extensive use has resulted in the widespread contamination in the environment. In the current study, a cyromazine degrading bacterium (designated strain ZX01) was isolated and characterized from a Chinese ginger cultivated soil by selective enrichment culture method. On the basis of morphological, biochemical characteristics, and 16S rRNA gene sequence, this bacterium showed strong similarity to the Pseudomonadales members and was closely related to the Acinetobacter baumannii group. Spectrophotometric and HPLC analyses revealed that strain ZX01 degraded cyromazine and utilized it as the sole carbon source for its growth. This process hydrolyzes cyromazine to melamine. Strain ZX01 degraded most of the cyromazine in 60 h. Besides, its substrate specificity against four symmetrical triazine herbicides, one triazinone herbicide, as well as 10 insecticides and its antibiotic sensitivity towards eight commercial antibiotics were also tested. At the concentration of 100 µg/mL for 60 h, it could effectively degrade a variety of different pesticides, including atrazine, prometon, simazine, prometryn, enitrothion, diazinon, cypermethrin, and acetamiprid, and the degradation was in the range of 71-87%. In particular, melamine, the main degradation product of cyromazine, was degraded by 47.3%. This microorganism was sensitive to chloramphenicol and tetracycline and intermediate to amoxicillin and trimethoprim. These results highlight that strain ZX01 can be used as a potential biological agent for the remediation of soil, water, or crop contaminated with cyromazine and other symmetrical triazine insecticides.

Unraveling the occurrence of contaminants of emerging concern in groundwater from urban setting: A combined multidisciplinary approach and self-organizing maps.

In recent decades, changes in human behavior and new technologies have introduced thousands of new compounds into the environment called "contaminants of emerging concern" (CEC). These compounds have been detected in different environmental compartments such as soil, surface water, air, and groundwater. The presence of these contaminants in groundwater may pose risks to human health when used as potable water. In some urban areas in Brazil, groundwater is normally consumed without previous treatment. This study aimed to use statistical analysis by self-organizing maps (SOM) to evaluate the trends of CEC in urban groundwater systems. A total of 23 CEC compounds including pesticides, pharmaceuticals, and hormones were determined in groundwater samples using solid phase extraction and liquid chromatography-mass spectrometry. The CEC most frequently detected were atrazine and degradation products, fipronil, simazine, tebuconazole, hexazinone, and caffeine in concentrations up to 300 ng L-1. All studied compounds were detected in groundwater at least in one sample. Patterns in the data through SOM have shown a strong positive correlation between atrazine, hexazinone, simazine, tebuthiuron, 2-hydroxyatrazine, and 17ß-estradiol. The hormones estrone and testosterone also show a positive correlation due to their similar chemical properties. On the other hand, caffeine was detected in 90% of the samples, likely due to a population habit of taking daily a hot drink made of yerba mate associated with low rates of treated domestic sewage in the study area.

Household herbicide use as a source of simazine contamination in urban surface waters.

Contamination of urban surface waters by herbicides is an increasing concern; however, sources of contamination are poorly understood, hindering the development of mitigation and regulatory strategies. Impervious surfaces, such as concrete in driveways and paths are considered an important facilitator for herbicide runoff to urban surface waters following applications by residential homeowners. This study assessed the transferability of a herbicide from concrete pavers treated with an off-the-shelf product, containing simazine as the active herbicide, marketed for residential homeowner application to impervious surfaces. Commercially available pavers were treated according to label directions and the effects of exposure time prior to irrigation, repeated irrigations, and dry time between irrigations on transferability of simazine to runoff were assessed. Simazine transferability was greatest when receiving an initial irrigation 1 h after application, with concentrations in runoff reduced by half when exposure times prior to the first irrigation were >2 days. Concentrations remained stable for repeated irrigations up to 320 days and exposures to outdoor conditions of 180 days prior to a first irrigation. Dry time between irrigations significantly influenced simazine transfer to runoff. Dry periods of 140 days resulted in approximately a 4-times increase in simazine transferability to runoff. These results suggest that herbicides used by homeowners, or any other users, on impervious surfaces are available to contaminate runoff for prolonged time periods following application at concentrations that may pose risks to aquatic life and for reuse of harvested runoff on parks and gardens. Regulators should consider the potential of hard surfaces to act as reservoirs for herbicides when developing policies and labelling products.

Ionic Liquid Modified Porous Polymer as a Dispersive Filter Extraction Adsorbent for Simple, Sensitive, and Efficient Determination of Chlorotriazine Herbicides in Irrigation Water.

Triazine herbicides (TRZHs) are widely used in agricultural production, but their improper use can threaten the environment and organisms. Herein, rapid extraction of four chlorotriazine herbicides (Cl-TRZHs) in irrigation water was achieved using an ionic liquid modified porous m-aminophenol formaldehyde resin (IL-MAPFR) as a dispersive filter extraction (DFE) adsorbent. The IL-MAPFR shows excellent adsorption performance for four Cl-TRZHs (simazine, cyanazine, atrazine, and terbuthylazine), with a large specific surface area (158.1 m2 g-1) and fast mass transfer (2 min). The adsorption process conforms to the pseudo-second-order kinetics and Freundlich isotherm models. The four Cl-TRZHs were concentrated 12-16-fold after the IL-MAPFR-DFE method. Coupled with high-performance liquid chromatography, an accurate and sensitive determination method for four Cl-TRZHs in irrigation water was established, with low detection limit (0.11-0.20 ng mL-1), high recoveries (91.5-110%), and excellent precision (relative standard deviations (RSDs) ≤ 8.4%). This method provides technical support for agricultural irrigation water quality monitoring and has great application potential in water safety, especially pesticide residues.

Autonomic behavioral impairment induced by simazine exposure during early life of male mouse is mediated by Lmx1a/Wnt1 pathway.

Simazine is a widely used herbicide and known as an environmental estrogen. Multiple studies have proved simazine can induced the degeneration of dopaminergic neuron resulting in a degenerative disease-like syndrome. Herein, we explored the neurotoxicity of simazine on the dopaminergic nervous system of embryos and weaned offspring during the maternal gestation period or the maternal gestation and lactation periods. We found that simazine disturbed the crucial components expression involved in Lmx1a/Wnt1 pathway of dopaminergic neuron in embryonic and weaned offspring. Furthermore, morphological and behavioral tests performed on weaned male offspring treated by simazine suggested that the grip strength, autonomic exploring, and the space sense ability were weakened, as well as the pathological damage of dopaminergic neuron was clearly observed. But, the same neurotoxicity of simazine is less significantly observed in female offspring. Our findings will provide reliable reference for the determination of environmental limits and new insight into the pathogenesis of nonfamilial neurodegenerative diseases related to environmental risk factors.

Fe2.5Co0.3Zn0.2O4/CuCr-LDH as a visible-light-responsive photocatalyst for the degradation of caffeine, bisphenol A, and simazine in pure water and real wastewater under photo-Fenton-like degradation process.

This paper outlines the synthesis and application of a sustainable composite for the photo-Fenton-like degradation of caffeine, bisphenol A, and simazine. The phase, morphology, optical and magnetic properties of the samples were evaluated by different characterization techniques. The composite of Fe2.5Co0.3Zn0.2O4 and copper-chromium layered double hydroxide (CuCr-LDH) was determined to be the most favorable photocatalyst in the photo-Fenton-like process when compared with Fe3O4, Fe2.5Co0.3Zn0.2O4, CuCr-LDH, and Fe3O4/CuCr-LDH composite. Studying the efficiency of the photo-Fenton-like degradation process in the presence of the Fe2.5Co0.3Zn0.2O4/CuCr-LDH composite revealed a degradation rate constant of caffeine twice more than the sum of those obtained for the individual processes. This ascribes to the synergistic effect by which the photo-generated electron-hole from the catalyst and the efficient reduction of Fe3+, Cu2+, etc. during the photo-Fenton-like reaction is accelerated. Moreover, under the optimal condition and after 120 min of heterogenous photo-Fenton-like process at natural pH, > 90% of pollutants mixture was decomposed. The experiments fulfilled in near-real conditions demonstrated I) the high stability and magnetically recoverability of the photocatalyst and II) the proper degradation performance of the applied heterogenous photo-Fenton-process in the removal of pollutant mixture in different water bodies and in the presence of chloride and bicarbonate ions.

Isolation of 2 simazine-degrading bacteria and development of a microbial agent for bioremediation of simazine pollution.

Simazine was one of the most commonly used herbicides and was widely used to control broadleaf weeds in agriculture and forestry. Its widespread use had caused wide public concern for its high ecological toxicity. In order to remove simazine residues, 2 strains capable of effectively degrading simazine were isolated from the soil and named SIMA-N5 and SIMA-N9. SIMA-N5 was identified as Bacillus licheniformis by 16SrRNA sequence analysis, and SIMA-N9 was Bacillus altitudinis. According to the degradation ratio of simazine in a certain period of time, the degradation ability of different strains was evaluated. The degradation efficiency of simazine (5 mg/L) by SIMA-N9 could reach about 98% in 5d, and the strain SIMA-N5 could reach 94% under the same conditions. In addition, the addition of Pennisetum rhizosphere soil during the process of degrading simazine by strain SIMA-N9 could effectively improve the degradation efficiency. The strain SIMA-N9 has been developed as a microbial agent for the bioremediation of simazine contamination in soil. The new microbial agent developed by using SIMA-N9 has achieved satisfactory application effects. Based on the research results already obtained in this study, it was considered that strain SIMA-N9 and its live bacterial agent could play an important role in bioremediation of simazine pollution. This study could not only provide a set of solutions to the simazine pollution, but also provide a reference for the treatment of other pesticide pollution.

Estimating simazine-treated area in watersheds based on annual stream loads.

Existing data in the United States are insufficient for estimating pesticide-treated crop areas at the watershed scale. The objective of this research was to evaluate an approach for estimating simazine usage on corn (Zea mays L.) based on its transport to streams of the Salt River Basin (SRB) of Missouri, USA. Annual loads of total simazine and atrazine (parent + metabolites) were quantified for seven SRB watersheds from 2005 to 2017. Simazine-treated corn area was computed as the total simazine load (g) divided by total atrazine load (g ha-1 ) on a treated area basis; atrazine was used as surrogate in the absence of treated area simazine load data. From 2005 to 2010, an estimated 3.8-31% of the corn area within SRB watersheds was treated with simazine, and four of six watersheds had <10% of corn treated. In contrast, Long Branch Creek (2005-2017) and its sub-watersheds (2012-2017) had ≥20% of corn area treated with simazine. Key sources of variation in treated area estimates included extremely dry years with little simazine transport and disparities between spring-applied atrazine and fall-applied simazine transport. However, compared with national estimates for the SRB, these results estimated simazine usage that was generally one to two orders of magnitude greater and showed far more spatial and temporal variation among watersheds. These results demonstrated that this broadly applicable output-based method is a significant improvement over existing input-based national data for estimating pesticide usage in watersheds.

A comparison of visible-light photocatalysts for solar photoelectrocatalysis coupled to solar photoelectro-Fenton: Application to the degradation of the pesticide simazine.

Three different visible-light photocatalysts (hematite (α-Fe2O3), bismuth vanadate (BiVO4) and Mo-doped bismuth vanadate (BiMoVO4)) deposited on transparent fluorine-doped SnO2 (FTO) were evaluated for the solar-driven photoelectrocatalytic treatment of emerging pollutants. BiMoVO4 was found to be the most effective photoanode, yielding the fastest degradation rate constant and highest mineralization efficiency using phenol as the oxidation probe. The BiMoVO4 photoanode was then used to degrade the herbicide simazine in a photoelectrolytic cell combining photoelectrocatalysis (PEC) with photoelectron-Fenton (PEF) under solar light (SPEC-SPEC). Total simazine removal was achieved within 1 min of treatment (kapp = 4.21 min-1) at the optimum electrode potential of 2.5 V vs Ag/AgCl, with complete TOC removal in 2 h. The analysis of anionic species in solution during treatment showed that most of the nitrogen heteroatoms in the simazine structure were converted into NO3- following •OH addition to organic N. This innovative process combining BiMoVO4-PEC with PEF using solar light as a sustainable source of energy (SPEC-SPEF) achieved the highest degradation/mineralization efficiency ever reported for simazine treatment. Besides, this is the first work reporting the photo(electrochemical) degradation of this toxic herbicide.

Bioassays to assess the ecotoxicological impact of polyethylene microplastics and two organic pollutants, simazine and ibuprofen.

Research on the environmental impact of plastics, especially on the effect of microplastics (MPs), has become a priority issue in recent years, mainly in terrestrial ecosystems where there is a lack of studies. This work aims to assess the impact of two types of polyethylene MPs, white microbeads (W) and fluorescent blue microbeads (FB), and their interactions with two contaminants, ibuprofen (Ib) and simazine (Sz), on different organisms. A set of bioassays for Vibrio fischeri, Caenorhabditis elegans and Lactuca sativa was carried out, which helped to establish the ecotoxicological impact of those pollutants. C. elegans showed the least sensitivity, while V. fischeri and L. sativa showed a high toxicological response to MPs alone. We found that W and FB induced an inhibition of 27% and 5.79%, respectively, in V. fischeri, and the growth inhibition rates were near 70% in L. sativa for both MPs. MPs exhibited a potential role as contaminant vectors in V. fischeri since the inhibition caused by W-Ib or W-Sz complexes was near 39%. The W-Sz complex significantly reduced leaf development in L. sativa, and a reduction of 30% in seed germination was detected when the complex FB-Sz was tested. This study reveals the importance of designing a complete set of analyses with organisms from different trophic levels, considering the great variability in the effects of MPs and the high number of relevant factors.