Redox-Responsive Nanopesticides Based on Natural Polymers for Environmentally Safe Delivery of Pesticides with Enhanced Foliar Dispersion and Washout Resistance.

Based on the modified cross-linking of the degradable natural polymers chitosan oligosaccharides (COS) and gelatin (GEL) via introduction of a functional bridge 3,3'-dithiodipropionic acid, this study constructed an environmentally responsive dinotefuran (DNF) delivery system (DNF@COS-SS-GEL). The introduction of the disulfide bond (-S-S-) endowed DNF@COS-SS-GEL with redox-responsive properties, allowing for the rapid release of pesticides when stimulated by glutathione (GSH) in the simulated insect. Compared with commercial DNF suspension concentrate (DNF-SC), DNF@COS-SS-GEL showed superior wet spreading and retention performance on cabbage leaves with a reduced contact angle (57°) at 180 s and 4-fold increased retention capacity after rainfall washout. Nanoencapsulation effectively improved the UV-photostability with only a 31.4% decomposition rate of DNF@COS-SS-GEL at 96 h. The small scale and large specific surface area resulted in excellent uptake and transportation properties in plants as well as higher bioactivity against Plutella xylostella larvae. This study will help promote sustainable agricultural development by reducing environmental pollution through improved pesticide utilization.

Impact of biochar on the degradation rates of three pesticides by vegetables and its effects on soil bacterial communities under greenhouse conditions.

A 28 days pesticide degradation experiment was conducted for broccoli (Brassica oleracea L. var. italica Planch) and pakchoi (Brassica chinensis L.) with three pesticides (chlorantraniliprole (CAP), haloxyfop-etotyl (HPM), and indoxacarb (IXB)) to explore the effects of biochar on pesticide environmental fate and rhizosphere soil diversity. Rice straw biochar (RB) was applied to soil at a 25.00 t ha-1 dosage under greenhouse conditions, and its effects on the degradation of three pesticides in vegetables and in soil were investigated individually. Overall, RB application effectively facilitated CAP and HPM degradation in broccoli by 13.51-39.42% and in broccoli soil by 23.80-74.10%, respectively. RB application slowed the degradation of CAP, HPM and IXB in pakchoi by 0.00-57.17% and slowed the degradation of CAP in pakchoi by 37.32-43.40%. The results showed that the effect of RB application on pesticide degradation in crops and soil was related to biochar properties, pesticide solubility, plant growth status, and soil characteristics. Rhizosphere soil microorganisms were also investigated, and the results showed that biochar application may be valuable for altering bacterial richness and diversity. The effect of biochar application on pesticide residues in crops and soil was influenced by the vegetable variety first, and the second was pesticide characteristics. RB applied to soil at a 25.00 t ha-1 dosage under greenhouse conditions is recommended for broccoli production to ensure food safety. Our results suggested that biochar application in soil could reduce pesticide non-point source pollution, especially for highly soluble pesticides, and could affect soil microorganisms.

Biodegradation of chemical contamination by lactic acid bacteria: A biological tool for food safety.

Chemical pollutants such as mycotoxins and pesticides exert harmful effects on human health such as inflammation, oxidative stress, and cancer. Several strategies were applied for food decontamination, including physicochemical and biological strategies. The present review comprehensively discussed the recent efforts related to the biodegradation of eight food chemical contaminants, including mycotoxins, acrylamide, biogenic amines, N-nitrosamines, polycyclic aromatic hydrocarbons, bisphenol A, pesticides, and heavy metals by lactic acid bacteria (LAB). Biological detoxification by LAB such as Lactobacillus is a promising approach to remove the risks related to the presence of chemical and environmental pollutants in foodstuffs. It is a safe, efficient, environmentally friendly, and low-cost strategy to remove hazardous compounds. LAB can directly decrease these chemical pollutants by degradation or adsorption. Also, it can indirectly reduce the content of these pollutants by reducing their precursors. Hence, LAB can contribute to reducing chemical pollutants in contaminated foods and enhance food safety.

Temporal Dynamics of Copper-Based Nanopesticide Transfer and Subsequent Modulation of the Interplay Between Host and Microbiota Across Trophic Levels.

During agricultural production, significant quantities of copper-based nanopesticides (CBNPs) may be released into terrestrial ecosystems through foliar spraying, thereby posing a potential risk of biological transmission via food chains. Consequently, we investigated the trophic transfer of two commonly available commercial CBNPs, Reap2000 (RP) and HolyCu (HC), in a plant-caterpillar terrestrial food chain and evaluated impacts on host microbiota. Upon foliar exposure (with 4 rounds of spraying, totaling 6.0 mg CBNPs per plant), leaf Cu accumulation levels were 726 ± 180 and 571 ± 121 mg kg-1 for RP and HC, respectively. HC exhibited less penetration through the cuticle compared to RP (RP: 55.5%; HC: 32.8%), possibly due to size exclusion limitations. While caterpillars accumulated higher amounts of RP, HC exhibited a slightly higher trophic transfer factor (TTF; RP: 0.69 ± 0.20; HC: 0.74 ± 0.17, p > 0.05) and was more likely to be transferred through the food chain. The application of RP promoted the dispersal of phyllosphere microbes and perturbed the original host intestinal microbiota, whereas the HC group was largely host-modulated (control: 65%; RP: 94%; HC: 34%). Integrating multiomics analyses and modeling approaches, we elucidated two pathways by which plants exert bottom-up control over caterpillar health. Beyond the direct transmission of phyllosphere microbes, the leaf microbiome recruited upon exposure to CBNPs further influenced the ingestion behavior and intestinal microbiota of caterpillars via altered leaf metabolites. Elevated Proteobacteria abundance benefited caterpillar growth with RP, while the reduction of Proteobacteria with HC increased the risk of lipid metabolism issues and gut disease. The recruited Bacteroidota in the RP phyllosphere proliferated more extensively into the caterpillar gut to enhance stress resistance. Overall, the gut microbes reshaped in RP caterpillars exerted a strong regulatory effect on host health. These findings expand our understanding of the dynamic transmission of host-microbiota interactions with foliar CBNPs exposure, and provide critical insight necessary to ensure the safety and sustainability of nanoenabled agricultural strategies.

Understanding pyrethrin biosynthesis: toward and beyond natural pesticide overproduction.

Pyrethrins are natural insecticides biosynthesised by Asteraceae plants, such as Tanacetum cinerariifolium and have a long history, dating back to ancient times. Pyrethrins are often used as low-persistence and safe insecticides to control household, horticultural, and agricultural insect pests. Despite its long history of use, pyrethrin biosynthesis remains a mystery, presenting a significant opportunity to improve yields and meet the growing demand for organic agriculture. To achieve this, both genetic modification and non-genetic methods, such as chemical activation and priming, are indispensable. Plants use pyrethrins as a defence against herbivores, but pyrethrin biosynthesis pathways are shared with plant hormones and signal molecules. Hence, the insight that pyrethrins may play broader roles than those traditionally expected is invaluable to advance the basic and applied sciences of pyrethrins.

A baseline assessment of contamination in the Sacramento deep water ship channel.

The Sacramento Deep Water Ship Channel (SDWSC) in the San Francisco Estuary, which is an active commercial port, is critical habitat for pelagic fish species including delta smelt (Hypomesus transpacificus), longfin smelt (Spirinchus thaleichthys), and Sacramento perch (Archoplites interruptus). Pelagic organism decline has been attributed to covarying factors such as manipulation of habitat, introduction of invasive species, decrease in food production, and contaminant exposure. Quantification of bioavailable toxicant loads in the SDWSC is limited despite previous surveys that have detected elevated contaminant concentrations in the sediments. Therefore, the focus of the present study was to characterize the bioavailability of the contaminants in the SDWSC from six sites along the channel. At each site, organochlorine pesticides (OCPs), pyrethroid insecticides, polyaromatic hydrocarbons (PAHs), and polychlorinated biphenyls (PCBs) were quantified in sediment, zooplankton, and suspended solids. In addition, Tenax extraction was used to measure the bioaccessible fraction of sediment-associated contaminants freely dissolved in the water. Bioaccessible contaminants in the sediment provided an uptake route for these stressors into invertebrates and fish with bioaccessible OCPs being found at all sites, particularly 4,4'-dichlorodiphenyldichloroethylene (DDE). Bifenthrin was the only pyrethroid detected in the chosen matrices and it was found at concentrations below levels of concern. Bioaccessible PAHs were found at all sites, with highest detections for phenanthrene and pyrene. No PCBs were detected in sediments, but were detected in both suspended solids and zooplankton. Contaminant concentrations overall were significantly higher in suspended solids, followed by zooplankton and sediments. The highest sediment concentrations of DDE, fluoranthene, pyrene, and dibenzo[a,h]anthracene exceeded sediment quality benchmarks indicating potential risk to sediment-dwelling species. Finally, elevated contaminant levels were found in both suspended solids and zooplankton, suggesting additional risk to pelagic species in the SDWSC.

Unveiling the earthworm-associated preferential remediation of emerging organic pollutants and heavy metals in MSW-based vermicomposting systems: Insights through the lens of multivariate techniques and novel empirical models.

Studies on the efficacies of vermicomposting and composting in countering the toxic impacts of pollutant cocktails in municipal solid waste (MSW) are scarce. Moreover, further research is needed to explore earthworms' remediation preferences for various pollutants in heterogeneous vermicomposting feedstocks, such as MSW. Therefore, removal dynamics of pesticides (chlorpyrifos, cypermethrin, and carbofuran), pharmaceuticals (diclofenac and carbamazepine), and heavy metals (Pb, Zn, Cu, and Mn) in MSW-based vermicomposting (Eisenia fetida and Eudrilus eugeniae) and composting systems were evaluated through multivariate analytical techniques (principal component (PCA) and multi-factor (MFA)) on the R-platform. Both earthworms satisfactorily increased their population and augmented NPK (nitrogen, phosphorous, and potassium) availability, cation exchange, microbial biomass C&N, and their metabolic activity 2-3 folds more than composting, accompanied by a 3-4 folds reduction of organic C, pH, and bulk density. Correspondingly, heavy metals, pesticides, and pharmaceuticals decreased by 8-10-folds via earthworm's significant pollutant removal efficiencies that subsided MSW-driven ecological risks by 60-90%. PCA and MFA revealed that N, P, and K-availability, organic C, and microbial activity were the indicative attributes for heavy metal and emerging organic micropollutant (EOMP)-removal during biocomposting; however, earthworms remove pesticides faster than pharmaceuticals and heavy metals. PCA-based novel empirical models demonstrated that in MSW-only feedstock, earthworm-mediated pollutant detoxification followed the order of pesticides > pharmaceuticals > heavy metals. However, in MSW combined with cow dung (1:1 ratio) feedstock, the detoxification order shifted to pharmaceuticals > heavy metals > pesticides. Therefore, this study provides fresh insights into pollutant-focused feedstock optimization for vermicomposting through model-based approaches, advancing the eco-friendly valorization of toxic MSW.

Bioremediation strategies against pesticides: An overview of current knowledge and innovations.

Pesticides pose significant risks to both human health, such as cancer, neurological disorders, and endocrine disruption, and ecosystems, through the destruction of beneficial insects, contamination of soil and water, and impact on non-target species. In the face of escalating pesticide pollution, there is an urgent need for multifaceted approaches to address the issue. Bioremediation emerges as a potent tool in the environmental pollution mitigation arsenal. Ideally aiming for the complete decomposition of pesticides into harmless molecules, bioremediation encompasses diverse approaches - from bioabsorption, bioadsorption, and biotransformation using enzymes and nanoenzymes to comprehensive degradation facilitated by microorganisms such as bacteria, fungi, macro- and microalgae, or phytoremediation. Exploring nature's biodiversity offers a promising avenue to find solutions to this pressing human-induced problem. The acceleration of biodegradation necessitates identifying and developing efficient organisms, achieved through bioprospection and targeted modifications. Specific strategies to enhance process efficiency and throughput include optimizing biomass production, strategic inoculation in diverse environments, and employing bioreactor systems for processing heavily contaminated waters or soils. This comprehensive review presents various bioremediation approaches, emphasizing the importance of microorganisms' exploration and new technologies development, including current innovations and patents to effectively combat pesticide pollution. Furthermore, challenges regarding the effective implementation of these technologies are also addressed.

Chlorophyll fluorescence in sentinel plants for the surveillance of chemical risk.

This research aimed to develop natural plant systems to serve as biological sentinels for the detection of organophosphate pesticides in the environment. The working hypothesis was that the presence of the pesticide in the environment caused changes in the content of pigments and in the photosynthetic functioning of the plant, which could be evaluated non-destructively through the analysis of reflected light and emitted fluorescence. The objective of the research was to furnish in vivo indicators derived from spectroscopic parameters, serving as early alert signals for the presence of organophosphates in the environment. In this context, the effects of two pesticides, Chlorpyrifos and Dimethoate, on the spectroscopic properties of aquatic plants (Vallisneria nana and Spathyfillum wallisii) were studied. Chlorophyll-a variable fluorescence allowed monitoring both pesticides' presence before any damage was observed at the naked eye, with the analysis of the fast transient (OJIP curve) proving more responsive than Kautsky kinetics, steady-state fluorescence, or reflectance measurements. Pesticides produced a decrease in the maximum quantum yield of PSII photochemistry, in the proportion of PSII photochemical deexcitation relative to PSII non photochemical decay and in the probability that trapped excitons moved electrons into the photosynthetic transport chain beyond QA-. Additionally, an increase in the proportion of absorbed energy being dissipated as heat rather than being utilized in the photosynthetic process, was notorious. The pesticides induced a higher deactivation of chlorophyll excited states by photophysical pathways (including fluorescence) with a decrease in the quantum yields of photosystem II and heat dissipation by non-photochemical quenching. The investigated aquatic plants served as sentinels for the presence of pesticides in the environment, with the alert signal starting within the first milliseconds of electronic transport in the photosynthetic chain. Organophosphates damage animals' central nervous systems similarly to certain compounds found in chemical weapons, thus raising the possibility that sentinel plants could potentially signal the presence of such weapons.

Pesticides and the Gut Microbiota: Implications for Parkinson's Disease.

Parkinson's disease (PD) affects more people worldwide than just aging alone can explain. This is likely due to environmental influences, genetic makeup, and changes in daily habits. The disease develops in a complex way, with movement problems caused by Lewy bodies and the loss of dopamine-producing neurons. Some research suggests Lewy bodies might start in the gut, hinting at a connection between these structures and gut health in PD patients. These patients often have different gut bacteria and metabolites. Pesticides are known to increase the risk of PD, with evidence showing they harm more than just dopamine neurons. Long-term exposure to pesticides in food might affect the gut barrier, gut bacteria, and the blood-brain barrier, but the exact link is still unknown. This review looks at how pesticides and gut bacteria separately influence PD development and progression, highlighting the harmful effects of pesticides and changes in gut bacteria. We have examined the interaction between pesticides and gut bacteria in PD patients, summarizing how pesticides cause imbalances in gut bacteria, the resulting changes, and their overall effects on the PD prognosis.

Applications of Microbial Organophosphate-Degrading Enzymes to Detoxification of Organophosphorous Compounds for Medical Countermeasures against Poisoning and Environmental Remediation.

Mining of organophosphorous (OPs)-degrading bacterial enzymes in collections of known bacterial strains and in natural biotopes are important research fields that lead to the isolation of novel OP-degrading enzymes. Then, implementation of strategies and methods of protein engineering and nanobiotechnology allow large-scale production of enzymes, displaying improved catalytic properties for medical uses and protection of the environment. For medical applications, the enzyme formulations must be stable in the bloodstream and upon storage and not susceptible to induce iatrogenic effects. This, in particular, includes the nanoencapsulation of bioscavengers of bacterial origin. In the application field of bioremediation, these enzymes play a crucial role in environmental cleanup by initiating the degradation of OPs, such as pesticides, in contaminated environments. In microbial cell configuration, these enzymes can break down chemical bonds of OPs and usually convert them into less toxic metabolites through a biotransformation process or contribute to their complete mineralization. In their purified state, they exhibit higher pollutant degradation efficiencies and the ability to operate under different environmental conditions. Thus, this review provides a clear overview of the current knowledge about applications of OP-reacting enzymes. It presents research works focusing on the use of these enzymes in various bioremediation strategies to mitigate environmental pollution and in medicine as alternative therapeutic means against OP poisoning.

Insights into the uptake, translocation, and accumulation dynamics of cyantraniliprole and thiamethoxam seed coating pesticides in maize plants.

Seed coating with pesticides is used extensively for the protection of both seeds and plants against pests. In this study, the uptake and transport of seed-coating pesticides (insecticides), including cyantraniliprole (CYN) and thiamethoxam (THX), were investigated. The translocation of these pesticides from the soil to the plant and their accumulation in different plant parts were also calculated. After sowing the seeds with seed coating pesticides, soil and plant samples were taken across the study area. These samples were extracted and analyzed in liquid chromatography with tandem mass spectrometry (LC-MS/MS). CYN and THX were used in maize plants for the first time to observe soil degradation kinetics, and CYN showed a higher half-life than THX in soil. Both pesticides have been taken up by the corn maize plant and transferred and accumulated to the upper parts of the plant. Although the THX concentration was between 2.240 and 0.003 mg/kg in the root, between 3.360 and 0.085 mg/kg in the stem, it was between 0.277 and 3.980 mg/kg in the leaf, whereas CYN was detected at higher concentrations. The concentration of CYN was 1.472 mg/ kg and 0.079 mg/kg in the roots and stems of the maize plant, respectively. However, the bioconcentration factor (BCF) indicates the soil-to-plant accumulation of CYN from 28 to 34.6 and that of 12.5 to 4567.1 for THX on different sampling days. The translocation factor (TFstem) represents the ratio of pesticides absorbed from the stem and transported to the roots. For CYN, TFstem ranges from 3.6 to 20.5, while for THX, it varies between 1.5 and 26.8, indicating a higher translocation rate for THX. The ratio of leaf to root concentration are 3.6 to 20.5 for CYN and 1.8 to 87.7 for THX, demonstrating effective translocation for both pesticides. The TF values for both pesticides are above 1, signifying successful root-to-stem-to-leaf movement. Notably, THX exhibits a notably higher transport rate compared to CYN.

A User-Friendly Kinetic Model Incorporating Regression Models for Estimating Pesticide Accumulation in Diverse Earthworm Species Across Varied Soils.

Existing models for estimating pesticide bioconcentration in earthworms exhibit limited applicability across different chemicals, soils and species which restricts their potential as an alternative, intermediate tier for risk assessment. We used experimental data from uptake and elimination studies using three earthworm species (Lumbricus terrestris, Aporrectodea caliginosa, Eisenia fetida), five pesticides (log Kow 1.69-6.63) and five soils (organic matter content = 0.972-39.9 wt %) to produce a first-order kinetic accumulation model. Model applicability was evaluated against a data set of 402 internal earthworm concentrations reported from the literature including chemical and soil properties outside the data range used to produce the model. Our models accurately predict body load using either porewater or bulk soil concentrations, with at least 93.5 and 84.3% of body load predictions within a factor of 10 and 5 of corresponding observed values, respectively. This suggests that there is no need to distinguish between porewater and soil exposure routes or to consider different uptake and elimination pathways when predicting earthworm bioconcentration. Our new model not only outperformed existing models in characterizing earthworm exposure to pesticides in soil, but it could also be integrated with models that account for earthworm movement and fluctuating soil pesticide concentrations due to degradation and transport.

Earthworm injury test for in-situ biomonitoring of pesticides in biobeds.

Biobeds are presented as an alternative for good pesticide wastewater management on farms. This work proposes a new test for in-situ biomonitoring of pesticide detoxification in biobeds. It is based on the assessment of visually appreciable injuries to Eisenia fetida. The severity of the injury to each exposed individual is assessed from the morphological changes observed in comparison with the patterns established in seven categories and, an injury index is calculated. A linear relationship between the proposed injury index and the pesticide concentration was determined for each pesticide sprayed individually in the biomixture. The five pesticides used were atrazine, prometryn, clethodim, haloxyfop-P-methyl and dicamba. In addition, a multiple linear regression model (i.e., a multivariate response surface) was fitted, which showed a good generalization capacity. The sensitivity range of the injury test was tested from 0.01 to 630 mg kg-1 as the total pesticide concentration. This index is then used to monitor the detoxification of these pesticides in a biomixture (composed of wheat stubble, river waste, and soil, 50:25:25% by volume) over 210 days. The results are compared with standardized tests (Eisenia fetida avoidance test and Lactuca sativa seed germination test) carried out on the same biomixture. The results are also compared with data on the removal of pesticides. The injury test showed a better correlation with the removal of pesticides than the avoidance test and seed germination test. This simple and inexpensive test has proved to be useful for decontamination in-situ monitoring in biobeds.

An investigation of some persistent organic pollutants in loggerhead sea turtles (Caretta caretta).

The study assessed persistent organic pollutants (POPs) in Caretta caretta turtles along Turkish coasts, analyzing bioaccumulation in accessible organs and discerning sex-related differences. Ten adult turtles (5 males, 5 females) from Mugla province were sampled post-mortem. Various tissues were analyzed for organochlorine pesticides (OCPs), polychlorinated biphenyls (PCBs), polybrominated diphenyl ethers (PBDEs), and polycyclic aromatic hydrocarbons (PAHs) using gas chromatography-mass spectrometry. DDT distribution showed no sex-based difference, with concentrations highest in fat tissue followed by liver, kidney, muscle, spleen, and heart. Male PCB concentrations ranked highest in fat, followed by kidney, liver, spleen, muscle, and heart, while females showed a similar trend. PAH concentrations were highest in fat for both sexes, followed by various organs. Limited PBDE concentrations hindered comprehensive evaluation. Overall, C. caretta act as effective bioindicators for monitoring environmental pollution, with certain POPs exhibiting sex and organ-based variations.

Near-infrared fluorescent probe for ultrasensitive detection of organophosphorus pesticides and visualization of their interaction with butyrylcholinesterase in living cells.

The toxicity of organophosphorus pesticides (OPs) can catastrophically cause liver cell damage and inhibit the catalytic activity of cholinesterase. We designed and synthesized a near-infrared fluorescent probe HP-LZB with large Stokes shift which can specifically identify and detect butyrylcholinesterase (BChE) and visually explore the interaction between OPs and endogenous BChE in living cells. Fluorescence was turned on when HP-LZB was hydrolyzed into HP-LZ in the presence of BChE, and OPs could inhibit BChE's activity resulting in a decrease of fluorescence. Six OPs including three oxon pesticides (paraoxon, chlorpyrifos oxon and diazoxon) and their corresponding thion pesticides (parathion, chlorpyrifos and diazinon) were investigated. Both in vitro and cell experiments indicated that only oxon pesticides could inhibit BChE's activity. The limits of detection (LODs) of paraoxon, chlorpyrifos oxon and diazoxon were as low as 0.295, 0.007 and 0.011 ng mL-1 respectively and the recovery of OPs residue in vegetable samples was satisfactory. Thion pesticides themselves could hardly inhibit the activity of BChE and are only toxic when they are converted to their corresponding oxon form in the metabolic process. However, in this work, thion pesticides were found not be oxidized into their oxon forms in living HepG2 cells due to the lack of cytochrome P450 in hepatoma HepG2 cell lines. Therefore, this probe has great application potential in effectively monitoring OPs in real plant samples and visually exploring the interaction between OPs and BChE in living cells.

Soil microbial communities and degradation of pesticides in greenhouse effluent through a woodchip bioreactor.

Pesticides, including insecticides and fungicides, are major contaminants in the effluent from intensive agricultural systems, such as greenhouses. Because of their constant use and persistence, some pesticides can accumulate in soil and/or run off into adjacent waterways. Microbial communities in soil can degrade some pesticides, and bioreactors with enhanced microbial communities have the potential to facilitate decontamination before the effluent is released into the environment. In this study, we sampled the soil along a gradient from immediately below greenhouses, into, through and below a bioreactor. Multi-analyte pesticide screening was undertaken along with shotgun metagenomic sequencing, to assess microbial community taxonomic profiles and metabolic pathway responses for functional analysis. Two insecticides (imidacloprid and fipronil) and nine fungicides were identified in the soil samples, with a general decrease in most pesticides with increasing distance from the greenhouses. Diversity indexes of taxonomic profiles show changes in the microbial community along the gradient. In particular, microbial communities were significantly different in the bioreactor, with lower Shannon diversity compared to immediately below the greenhouses, in the channels leading into the bioreactor and further downstream. Metabolic pathway analysis revealed significant changes in a wide range of core housekeeping genes such as protein/amino acid synthesis and lipid/fatty acid biosynthesis among the sampling sites. The result demonstrates that the composition and potential functional pathways of the microbial community shifted towards an increased tendency for phytol and contaminant degradation in the bioreactor, facilitated by high organic matter content. This highlights the potential to use enhanced microbial communities within bioreactors to reduce contamination by some pesticides in sediment receiving run-off from greenhouses.

How bioaugmentation for pesticide removal influences the microbial community in biologically active sand filters.

Removing pesticides from biological drinking water filters is challenging due to the difficulty in activating pesticide-degrading bacteria within the filters. Bioaugmented bacteria can alter the filter's microbiome, affecting its performance either positively or negatively, depending on the bacteria used and their interaction with native microbes. We demonstrate that adding specific bacteria strains can effectively remove recalcitrant pesticides, like metaldehyde, yielding compliance to regulatory standards for an extended period. Our experiments revealed that the Sphingobium CMET-H strain was particularly effective, consistently reducing metaldehyde concentrations to levels within regulatory compliance, significantly outperforming Acinetobacter calcoaceticus E1. This success is attributed to the superior acclimation and distribution of the Sphingobium strain within the filter bed, facilitating more efficient interactions with and degradation of the pesticide, even when present at lower population densities compared to Acinetobacter calcoaceticus E1. Furthermore, our study demonstrates that the addition of pesticide-degrading strains significantly impacts the filter's microbiome at various depths, despite these strains making up less than 1% of the total microbial community. The sequence in which these bacteria are introduced influences the system's ability to degrade pesticides effectively. This research shows the potential of carefully selected and dosed bioaugmented bacteria to improve the pesticide removal capabilities of water filtration systems, while also highlighting the dynamics between bioaugmented and native microbial communities. Further investigation into optimizing bioaugmentation strategies is suggested to enhance the resilience and efficiency of drinking water treatment systems against pesticide contamination.

PGPR-Enabled bioremediation of pesticide and heavy metal-contaminated soil: A review of recent advances and emerging challenges.

The excessive usage of agrochemicals, including pesticides, along with various reckless human actions, has ensued discriminating prevalence of pesticides and heavy metals (HMs) in crop plants and the environment. The enhanced exposure to these chemicals is a menace to living organisms. The pesticides may get bioaccumulated in the food chain, thereby leading to several deteriorative changes in the ecosystem health and a rise in the cases of some serious human ailments including cancer. Further, both HMs and pesticides cause some major metabolic disturbances in plants, which include oxidative burst, osmotic alterations and reduced levels of photosynthesis, leading to a decline in plant productivity. Moreover, the synergistic interaction between pesticides and HMs has a more serious impact on human and ecosystem health. Various attempts have been made to explore eco-friendly and environmentally sustainable methods of improving plant health under HMs and/or pesticide stress. Among these methods, the employment of PGPR can be a suitable and effective strategy for managing these contaminants and providing a long-term remedy. Although, the application of PGPR alone can alleviate HM-induced phytotoxicities; however, several recent reports advocate using PGPR with other micro- and macro-organisms, biochar, chelating agents, organic acids, plant growth regulators, etc., to further improve their stress ameliorative potential. Further, some PGPR are also capable of assisting in the degradation of pesticides or their sequestration, reducing their harmful effects on plants and the environment. This present review attempts to present the current status of our understanding of PGPR's potential in the remediation of pesticides and HMs-contaminated soil for the researchers working in the area.

Biochemical responses of Echinochloa polystachya inoculated with a Trichoderma consortium during the removal of a pyrethroid-based pesticide.

The biochemical response of plants exposed to pesticides and inoculated with microorganisms is of great importance to explore cleaning up strategies for contaminated sites with pyrethroid-based pesticides. We evaluated the effects of a Trichoderma consortium on the biochemical responses of Echinochloa polystachya plants during the removal of a pyrethroid-based pesticide. Plants were inoculated or not with the Trichoderma consortium and exposed to commercial pesticide H24®, based on pyrethroids. Pesticide application resulted in significant reduction in root protein content (58%), but enhanced content of malondialdehyde (MDA) in shoots, superoxide dismutase (SOD) activity in shoots and roots, and catalase (CAT) activity in roots. Inoculation of Trichoderma consortium in E. polystachya exposed to the pesticide resulted in increased protein content in roots and MDA content in shoots (2-fold). Trichoderma consortium improved protein content and SOD activity (140-fold) in plants. Fungal inoculation increased the removal (97.9%) of the pesticide in comparison to the sole effect of plants (33.9%). Results allow further understanding about the responses of the interaction between plants and root-associated fungi to improving the assisted-phytoremediation of solid matrices contaminated with organic pesticides.

This original paper describes the positive role of the Trichoderma sp. consortium on favoring the removal of a pyretrhoid-based pesticide. This is one of first reports on analyzing the influence of a Trichoderma consortium on the oxidative stress and antioxidant response of Echinochloa polystachya in presence of the pesticide. This experimental approach provides a new alternative for further fungal assisted-phytoremediation of a pyretrhoid-based pesticide.