Gotowa bibliografia na temat „Metal pesticide matrix”

River Kisat in Kenya is increasingly being polluted serving as a sink for waste receiving effluent from sewerage, industrial waste and agricultural pesticide residues leading to heavy metal contamination. This has led to the contamination of the aquatic ecosystem and water used by communities for consumption and farming. Little information is available on the bio-indicative aspects of water quality using bioaccumulation factor by macrophytes. This study aimed at determining concentrations of Zn, Pb and Cd in water, (Eichhornia crassipes (water hyacinth), Vossia cuspidata (hippo grass), Cyperus papyrus (papyrus reed) and bioaccumulation factors (BAF) in River Kisat, Kisumu County. This was determined following laboratory standard procedures using Atomic Absorption Spectrophotometer (AAS). Results showed mean concentrations (mg/L) of Cd (Below detectable limit), Zn (0.2 -0.15) and Pb (0.03-0.03) in water. Mean values were within allowable WHO drinking water limits except for Pb which was above acceptable limits. Zn recorded highest accumulated levels in E. crassipes (72.43mg/L), C. papyrus (70.13mg/L) and V. cuspidate (71.03mg/L). E. crassipes was observed to bioaccumulate the highest concentration of the heavy metals with C. papyrus bioaccumulating the lowest (E. crassipes > V. cuspidata> C. papyrus). Pearson matrix correlation analysis showed positive significant correlations (r = 0.621; p = 0.027) between Zn and Pb in water and the macrophytes which reflected a common source of pollution and indication of accumulation. BAF recorded for all macrophytes ranged from 2.45 to 6.85, above value of 1, indicating significant bioaccumulation for Zn and Pb. The findings from this study showed higher concentrations of Zn and Pb in the macrophytes in comparison to the water in River Kisat with BAF values >1 indicating bioaccumulation which represented poor water quality. The study recommends local authorities employ monitoring processes with incorporation of BAF as a water quality indicator where low metal concentrations in water are recorded, introduce penalties for polluters and sensitize local inhabitants on detrimental health effects of heavy metal and avoid use of River Kisat water for agricultural activities.

Metal nanoparticles are well known for their antimicrobial properties. The use of metalbased nanoparticles in the agricultural field has considerably increased globally by both direct and indirect means for the management of plant diseases. In this context, the development of controlled delivery systems for slow and sustained release of metal nanoparticles is crucial for prolonged antimicrobial activity. Polymers have emerged as a valuable carrier for controlled delivery of metal nanoparticles as agrochemicals because of their distinctive properties. The most significant benefits of encapsulating metal nanoparticles in a polymer matrix include the ability to function as a protector of metal nanoparticles and their controlled release with prolonged efficacy. This review focuses on loading strategies and releasing behavior of metal nanoparticles in the polymer matrix as antimicrobial agents for plant diseases. The Polymer-metal nanocomplexes (PMNs) comprise a biocompatible polymeric matrix and metal nanoparticles as active components of an antimicrobial agent, pesticides and plant growth regulators used to enhance the crop productivity.

Abstract Metal-organic frameworks aluminum terephthalate MIL-53 and Cu-benzene-1,3,5-tricarboxylate (BTC) were tested for extraction of pyrimethanil, ametryn, dichlofluanid, tetraconazole, flumetralin, kresoxim-methyl, and tebuconazole from the medicinal plant Hyptis pectinata, with analysis using GC/MS in the selected ion monitoring mode. Experiments carried out at different fortification levels (0.1, 0.5, and 1.0 μg/g) resulted in recoveries in the range 61 to 107% with RSD values between 3 and 12% for the metal-organic framework materials. Detection and quantification limits ranged from 0.02 to 0.07 and 0.05 to 0.1 μg/g, respectively, for the different pesticides studied. The method developed was linear over the range tested (0.04–20.0 μg/g), with correlation coefficients ranging from 0.9987 to 0.9998. Comparison of MIL-53 and Cu-BTC with C18-bonded silica showed good performance of the MIL-53 metal-organic framework as a sorbent for the pesticides tested.

Biofilms consisting of a matrix of exopolysaccharide and microorganisms developed over granular activated carbon (GAC) enhance metal uptake from solution several times more than that achieved by GAC alone. By specifically employing GAC, there is also the opportunity of developing biofilm/GAC systems that can both entrap metals and also adsorb, and ultimately degrade, polluting organic residues such as pesticides. Targets for this type of process could be dump site leachates, mine tailings and other industrial wastes. The conditions under which the biofilm is developed, including pH and temperature have, therefore, been studied in terms of subsequent influence on metal bisorption.

This paper focuses on evaluating the degree of three metal pollution (Cu, Zn and Pb) in the sediments of Béni Haroun dam, located in northeastern of Algeria. For this reason, the superficial sediments were sampled at five stations, and the samples were taken at different seasons of the year. The results show low Cu and Zn levels which reflect natural conditions in relation to the area of geological nature. It also highlights the presence of Pb contamination (2.29 to 91.86µg/g). This result was also confirmed by various indices, including the geoaccumulation index (Igeo) and the contamination factor (FC). The Igeo values for Pb show moderate contamination of the Bge2 and Bge3 stations. CF values indicate moderate to considerable contamination for most stations by Pb. However, low or absent of Zn contamination was noted in all stations except for the Bge5. The correlation matrix and the PCA between all metal elements indicates that they were derived from similar sources. The contamination sources would probably establish a significant relationship between runoff and the erosion of agricultural lands. It is therefore an anthropogenic metal pollution related to agricultural activity using fertilizers and pesticides.

The present level of development of agricultural science has led to the emergence of a new method of plant protection, it is based on improving the immune potential of plants using elicitors, but not on the destruction of pathogens using pesticides. We have studied the effect of disease resistance inducers based on chitosan, organic acids and other substances with elicitor activity, being part of (nano) chips of different composition (matrix carrier - modified natural minerals, activated carbons, nanotubes, graphene, etc..) for pre-sowing seed treatment and for foliar fertilizing. We have studied their influence on growth, development, the incidence of rape plants, the quantity and quality of their crop. We have also determined the efficiency of (nano) chips depending upon their nature and carrier matrix composition.

Malgré la prise de conscience écologique et sanitaire, la consommation mondiale de pesticides est en augmentation. Étant donné que ces produits chimiques présentent de nombreux effets néfastes sur la santé humaine et l'environnement, des mesures doivent être prises afin de limiter leurs effets. Les produits de biocontrôle sont proposés comme une solution alternative aux produits synthétiques. En effet, ces « biopesticides » sont présumés être moins nocifs et relativement moins persistants. Toutefois, cet a priori doit être examiné et une évaluation stricte des risques de ces nouvelles substances doit être envisagée.Le développement de solutions de biocontrôle passe d'abord par les protocoles proposés pour étudier leur activité, leur devenir et leur impact environnemental. Actuellement, le temps de demi-vie (t½) est utilisé pour évaluer le devenir environnemental des pesticides synthétiques. Cependant, l'approche t½ ne donne que des informations sur la persistance des pesticides dans l'environnement, mais aucune indication concernant la formation de produits de dégradation ou son impact sur la biodiversité n'est apportée. De plus, les produits de biocontrôle sont des mélanges (bio)chimiques complexes. La t½ n'est pas applicable pour ces produits complexes. Par conséquent, de nouvelles approches analytiques doivent être envisagées afin de surmonter ces difficultés.Une nouvelle approche basée sur la méta-métabolomique et la Spectrométrie de Masse; « Empreinte Métabolique Environnementale » (EMF), a été récemment introduite. Elle offre un nouveau proxy universel et intégratif; le « temps de résilience », dédié à l'évaluation du devenir environnemental et de l'impact des (bio)pesticides complexes dans des matrices environnementales (ex. sol, sédiments). Néanmoins, le développement d'une telle approche de méta-métabolomique non ciblée basée sur la Spectrométrie de Masse doit être étudié en profondeur. Plusieurs tâches doivent alors être abordées: 1) les protocoles d'extraction performants et les méthodes analytiques basées sur la GC/LC-(HR)MS doivent être mis en place, 2) le traitement de données et les outils chimiométriques appropriés doivent être développés pour maitriser la complexité des ensembles des données générées, 3) l'impact de la complexité du xénométabolome sur les analyses basées sur la MS doit être évalué, et 4) l'étude des résidus volatiles doit être envisagée et nécessite donc le développement de nouvelles méthodologies analytiques.Le travail a été mené sur 3 axes principaux. Le premier axe portait sur 1) le développement de protocoles d'extraction et des méthodes LC-HRMS pour analyser à la fois les xénométabolites des pesticides et les endométabolites du sol, et 2) le développement d'une nouvelle approche chimiométrique pour évaluer les performances d'extraction. De nouveaux protocoles d'extraction se sont avérés optimaux pour l'EMF, et l'approche chimiométrique a donc été validée. Le deuxième axe a évalué l'impact de la complexité du xénométabolome sur la détermination des biomarqueurs environnementaux. La suppression d'ion a été révélée et une stratégie pragmatique a donc été élaborée pour surmonter son influence. Le troisième axe visait à mettre en place une nouvelle méthodologie pour analyser les résidus volatils de pesticides complexes. Des analyses HS-SPME-GC-MS ont été couplées à la chimiométrie afin de réaliser des études cinétiques et de suivre la transformation des résidus volatils. Le workflow chimiométrique a prouvé sa fiabilité pour expliquer la transformation du pesticide et de nouveaux xénométabolites et sous-produits ont été identifiés.En conclusion, une avancée significative a été apportée à l’EMF. Elle a été consolidée pour les applications en laboratoire et sur le terrain qui doivent être étudiées afin d'améliorer le proxy et de le valider comme une approche fiable pour l'évaluation des risques des pesticides
Despite the ecological and sanitary awareness, worldwide consumption of pesticides is increasing. As these chemical products represent several adverse effects on human health and environment, measures should be taken in order to limit their impacts. Biocontrol products are proposed as an alternative solution of the synthetic products. In fact, these “biopesticides” are presumed to be less harmful and relatively less persistent. However, this a priori must be examined and strict risk assessment of those new substances should be considered.The development of biocontrol solutions proceeds first of all through the proposed protocols to study their activity and their environmental fate and impact. Currently, half-life (DT50) is used in order to evaluate the environmental fate of synthetic pesticides. However, DT50 approach gives only information about pesticides' persistence in the environment, but no indications concerning the formation of degradation products or its impact on biodiversity are provided. Furthermore, biocontrol products are complex (bio)chemical mixes. The DT50 is not applicable for such complex products. Therefore, novel analytical approaches should be considered in order to overcome these difficulties.A novel approach based on meta-metabolomics and Mass Spectrometry; the “Environmental Metabolic Footprinting” (EMF), was recently introduced. It affords a novel universal and integrative proxy; the “resilience time”, dedicated to assess the environmental fate and impact of complex (bio)pesticides in environmental matrices (e.g. soil, sediment). Nonetheless, the development of such Mass Spectrometry-based untargeted meta-metabolomics approach needs to be in-depth studied. Several tasks should be addressed: 1) performant extraction protocols and GC/LC-(HR)MS-based analytical methods should be set up, 2) suitable data processing and chemometric tools should be developed to deal with the complexity of the generated datasets, 3) the impact of xenometabolome complexity on MS-based analyses should be assessed, and 4) the study of the volatile residues should be considered and thus needs new analytical methodologies to be developed.The work was carried out following 3 main axes. The first axis addressed 1) the development of extraction protocols and LC-HRMS methods to analyze both pesticides xenometabolites and soil endometabolites, and 2) the development of a novel chemometric approach to assess the extraction performance. Novel extraction protocols have been proven optimal for the EMF, and the chemometric approach was thus validated. The second axis assessed the impact of xenometabolome complexity on the determination of environmental biomarkers. Ion suppression was revealed and thus a pragmatic strategy has been developed to overcome its influence. The third axis aimed to set-up a novel methodology in order to analyze the volatile residues of complex pesticides. HS-SPME-GC-MS analyses were coupled to chemometrics in order to perform kinetics studies and to follow the transformation of the volatile residues. The chemometric workflow proved its reliability to explain pesticide’s transformation and novel xenometabolites and by-products were identified.In conclusion, significant advances were carried to the EMF. It has been consolidated for laboratory and field applications that must be investigated in order to improve the proxy and to validate it as a reliable approach for pesticides risk evaluation

Nanocomposites offer an exclusive advantage over bulk materials in terms of efficiency on account of their greater surface area, higher reactivity, ease of modification, good dispersion, and hence, multi-faceted applications. The various forms of nanocomposites derived from low-cost resources, especially carbon-based materials, are of unique interest. Activated carbons offer the unique advantage as the matrix for nanocomposites synthesis due to their graphite structure, thereby providing strength and the ease of modification on the surface of nanocomposites while introducing desired functional groups. Apart from this, they are widely popular for their large surface area and porosity. Therefore, carbon-based nanocomposites offer vivid applications in various fields, such as environmental remediation as adsorbents, suitable sorbents in the analytical determination of organics, targeted drug delivery, diagnostic agents, fuel cells and sensors, to name a few. Amongst these, the role of nanocomposites as sensors and environmental remediation tools has been studied extensively. The varied modes of action include adsorption, nano-catalysis, membrane filtration, etc ., for pollutants ranging from inorganic ions, heavy metals, pesticides, dyes, anti-bacterials, oil spills, and many more. However, there are constraints in their stability, cost, storage and disposal triggered by varying environmental conditions.This chapter presents a review of the synthesis, application and challenges of nanostructured composite materials in environmental remediation.