Long-Term Effects of Copper Nanopesticides on Soil and Sediment Community Diversity in Two Outdoor Mesocosm Experiments

Insights from a Long-Term Outdoor Mesocosm Study: eDNA Metabarcoding Reveals Exacerbated but Transient Impacts from a Nanoenabled Pesticide Formulation (Nano-TiO2-Coated Carbendazim) on Freshwater Microbial Communities

Fungicides currently encompass the second-most-used class of agricultural pesticides globally. Residues are frequently detected in freshwater, leading to undesired ecological impacts. Nanoenabled pesticide formulations have recently gained prominence in the scientific literature and have been suggested to exhibit favorable properties over conventional pesticide formulations by facilitating reductions in emissions toward nontarget locations. However, data on unintended effects on nontarget aquatic communities are scarce, especially concerning microbial communities. In this study, long-term effects of nano titanium-dioxide- (nTiO2)-coated carbendazim and its constituents on (pelagic) freshwater microbial communities in simulated agricultural ditches were investigated over a period of 14 weeks using environmental DNA (eDNA) metabarcoding. Impacts on bacterial diversity (α and β) were observed 2 weeks after the treatment application and most pronounced in the nTiO2-coated carbendazim treatment, followed by its active substance, i.e., noncoated carbendazim. The observed patterns possibly imply that nTiO2-coated carbendazim imposed more pronounced and potentially delayed or extended effects compared to the noncoated form of carbendazim. Bacterial communities also proved to be resilient under the tested conditions as they returned to the control-state within 5 weeks after the treatment application. Overall, our data suggest that eDNA metabarcoding data on microbial communities can help uncover time-dependent effects of nanoformulated pesticides.

Functional gene array and non-target soil microorganisms in nanopesticides captan@ZnO35-45nm and captan@SiO2 20-30nm environmental risk assessment

Currently there are no widely recognized standards for assessing the environmental risk of nanopesticides. Therefore, whether they are safer than conventional pesticide products remains open to discussion. We used non-target soil microorganisms as indicators of environmental change and applied functional gene arrays (FGAs) using GeoChip 5.0S targeting 151 000 genes involved in ecologically relevant functions. We synthesized nanofungicides in which the active substance captan was bound to inorganic nanocarriers (ZnO and SiO2) to examine the functional capabilities of microbial communities. During a 100-day microcosm study, changes in soil were compared to the effect of pesticide and nanocarriers alone. Based on 72 functional gene diversity profiles, we conducted environmental risk assessment of nanopesticides. Nanoagrochemicals affected the alpha and beta diversity of microbial functional genes, and the most profound negative effect was detected for captan, impacting carbon cycling and the organic remediation process from day 30. Additionally, the effect of nanopesticides changed during the experiment. On day 42, the effect was nanocarrier-dependent, and an increase of genes involved in denitrification (nirS, norB), archaeal conversion of N2 to NH3 and fungal N-assimilation was observed, especially for SiO2-treated set-ups. After 100 days, the negative effect was mainly related to the active substance released from the nanocarrier impacting the nitrate reductase gene (narG) and genes from the denitrification and nitrogen fixation subcategory. Analysis of microarrays did not indicate a recovery process for carbon cycling. Moreover, pesticide and nanoagrochemicals affected arsenic detoxification (aoxB, arsM, arsC), which may lead to an elevation of toxic As(III) availability. Our study indicated that FGAs are a sensitive method, revealing long-term changes previously undetected by other methods, including next-generation sequencing (NGS). This is the first study to confirm the usefulness of GeoChips for the evaluation of microbial redundancy as an important factor for fair environmental risk assessment of nanopesticides.

The use of copper as plant protection product contributes to environmental contamination and resulting impacts on terrestrial and aquatic biodiversity and ecosystem functions

Copper-based plant protection products (PPPs) are widely used in both conventional and organic farming, and to a lesser extent for non-agricultural maintenance of gardens, greenspaces, and infrastructures. The use of copper PPPs adds to environmental contamination by this trace element. This paper aims to review the contribution of these PPPs to the contamination of soils and waters by copper in the context of France (which can be extrapolated to most of the European countries), and the resulting impacts on terrestrial and aquatic biodiversity, as well as on ecosystem functions. It was produced in the framework of a collective scientific assessment on the impacts of PPPs on biodiversity and ecosystem services in France. Current science shows that copper, which persists in soils, can partially transfer to adjacent aquatic environments (surface water and sediment) and ultimately to the marine environment. This widespread contamination impacts biodiversity and ecosystem functions, chiefly through its effects on phototrophic and heterotrophic microbial communities, and terrestrial and aquatic invertebrates. Its effects on other biological groups and biotic interactions remain relatively under-documented.

Deciphering key nano-bio interface descriptors to predict nanoparticle-induced lung fibrosis

BACKGROUND

The advancement of nanotechnology underscores the imperative need for establishing in silico predictive models to assess safety, particularly in the context of chronic respiratory afflictions such as lung fibrosis, a pathogenic transformation that is irreversible. While the compilation of predictive descriptors is pivotal for in silico model development, key features specifically tailored for predicting lung fibrosis remain elusive. This study aimed to uncover the essential predictive descriptors governing nanoparticle-induced pulmonary fibrosis.

METHODS

We conducted a comprehensive analysis of the trajectory of metal oxide nanoparticles (MeONPs) within pulmonary systems. Two biological media (simulated lung fluid and phagolysosomal simulated fluid) and two cell lines (macrophages and epithelial cells) were meticulously chosen to scrutinize MeONP behaviors. Their interactions with MeONPs, also referred to as nano-bio interactions, can lead to alterations in the properties of the MeONPs as well as specific cellular responses. Physicochemical properties of MeONPs were assessed in biological media. The impact of MeONPs on cell membranes, lysosomes, mitochondria, and cytoplasmic components was evaluated using fluorescent probes, colorimetric enzyme substrates, and ELISA. The fibrogenic potential of MeONPs in mouse lungs was assessed by examining collagen deposition and growth factor release. Random forest classification was employed for analyzing in chemico, in vitro and in vivo data to identify predictive descriptors.

RESULTS

The nano-bio interactions induced diverse changes in the 4 characteristics of MeONPs and had variable effects on the 14 cellular functions, which were quantitatively evaluated in chemico and in vitro. Among these 18 quantitative features, seven features were found to play key roles in predicting the pro-fibrogenic potential of MeONPs. Notably, IL-1β was identified as the most important feature, contributing 27.8% to the model's prediction. Mitochondrial activity (specifically NADH levels) in macrophages followed closely with a contribution of 17.6%. The remaining five key features include TGF-β1 release and NADH levels in epithelial cells, dissolution in lysosomal simulated fluids, zeta potential, and the hydrodynamic size of MeONPs.

CONCLUSIONS

The pro-fibrogenic potential of MeONPs can be predicted by combination of key features at nano-bio interfaces, simulating their behavior and interactions within the lung environment. Among the 18 quantitative features, a combination of seven in chemico and in vitro descriptors could be leveraged to predict lung fibrosis in animals. Our findings offer crucial insights for developing in silico predictive models for nano-induced pulmonary fibrosis.

Interaction of heavy metals and polycyclic aromatic hydrocarbons in soil-crop systems: The effects and mechanisms

In natural environments, the removal and degradation of two major pollutants, heavy metals (HMs) and polycyclic aromatic hydrocarbons (PAHs), are explored through targeted experimental investigations. However, these endeavors reveal that outcomes in situ may significantly diverge from the idealized effects observed in laboratory settings due to the complex interaction between HMs and PAHs, underscoring a pressing need for thorough research into their mutual impacts. This review examines the origins and migratory pathways of compound pollution stemming from HMs and PAHs. Concurrently, it provides an overview of the farmland ecosystem's response to combined HMs-PAHs pollution. This encompassed the assessments of changes in the soil's physical and chemical properties, the intricacies of the migration and transformation processes of the combined pollution within plants, and the consequential impact on the physiological functions of soil microorganisms. The varying concentration ratios of HMs and PAHs can modulate the permeability of plant root cell membranes, thereby influencing the translocation of these substances within the plant via symplastic and apoplastic pathways. Recent research has uncovered the mechanisms underlying cation-π interactions between HMs and PAHs. This review aims to offer a comprehensive overview of the current state of HMs-PAHs co-pollution, offering both qualitative and quantitative insights into their interaction patterns within the farmland ecosystem. The ultimate goal is to establish a robust theoretical foundation to support the in-situ remediation of these pollutants in agricultural practices and to provide a theoretical basis for soil health management in agricultural production.

Prospects and challenges of nanopesticides in advancing pest management for sustainable agricultural and environmental service

The expanding global population and the use of conventional agrochemical pesticides have led to the loss of crop yield and food shortages. Excessive pesticide used in agriculture risks life forms by contaminating soil and water resources, necessitating the use of nano agrochemicals. This article focuses on synthesis moiety and use of nanopesticides for enhanced stability, controlled release mechanisms, improved efficacy, and reduced pesticide residue levels. The current literature survey offered regulatory frameworks for commercial deployment of nanopesticides and evaluated societal and environmental impacts. Various physicochemical and biological processes, especially microorganisms and advanced oxidation techniques are important in treating pesticide residues through degradation mechanisms. Agricultural waste could be converted into nanofibers for sustainable composites production, new nanocatalysts, such as N-doped TiO2 and bimetallic nanoparticles for advancing pesticide degradation. Microbial and enzyme methods have been listed as emerging nanobiotechnology tools in achieving a significant reduction of chlorpyrifos and dimethomorph for the management of pesticide residues in agriculture. Moreover, cutting-edge biotechnological alternatives to conventional pesticides are advocated for promoting a transition towards more sustainable pest control methodologies. Application of nanopesticides could be critical in addressing environmental concern due to its increased mobility, prolonged persistence and ecosystem toxicity. Green synthesis of nanopesticides offers solutions to environmental risks associated and using genetic engineering techniques may induce pest and disease resistance for agricultural sustainability. Production of nanopesticides from biological sources is necessary to develop and implement comprehensive strategies to uphold agricultural productivity while safeguarding environmental integrity.

Three-year field study on the temporal response of soil microbial communities and functions to PFOA exposure

Contamination of per- and polyfluoroalkyl substances (PFAS) poses a significant threat to soil ecosystem health, yet there remains a lack of understanding regarding the responses of soil microbial communities to prolonged PFAS exposure in field conditions. This study involved a three-year field investigation to track changes in microbial communities and functions in soil subjected to the contamination of a primary PFAS, perfluorooctanoic acid (PFOA). Results showed that PFOA exposure altered soil bacterial and fungal communities in terms of diversity, composition, and structure. Notably, certain bacterial communities with a delayed reaction to PFOA contamination showed the most significant response after one year of exposure. Fungal communities were sensitive to PFOA in soil, exhibiting significant responses within just four months of exposure. After two years, the impact of PFOA on both bacterial and fungal communities was lessened, likely due to the long-term adaptation of microbial communities to PFOA. Moreover, PFOA exposure notably inhibited alkaline phosphatase activity and reduced certain phosphorus cycling-related functional genes after three years of exposure, suggesting potential disruptions in soil fertility. These new insights advance our understanding of the long-term effects of PFOA on soil microbial communities and functions at a field scale.

Pioneer plants enhance soil multifunctionality by reshaping underground multitrophic community during natural succession of an abandoned rare earth mine tailing

Spontaneous natural succession in metal mine tailings is fundamental to the rehabilitation of bare tailing. Here, an abandoned rare earth element (REE) mine tailing with spontaneous colonisation by pioneer plants with different functional traits was selected. Soil nutrient cycling, fertility, organic matter decomposition as well as underground organismal communities and their multitrophic networks were investigated. Compared with the bare tailing, the colonisation with Lycopodium japonicum, Miscanthus sinensis, and Dicranopteris dichotoma increased soil multifunction by 222%, 293%, and 525%, respectively. This was accompanied by significant changes in soil bacterial and protistan community composition and increased soil multitrophic network complexity. Rhizospheres of different plant species showed distinct microbial community composition compared to that of bare tailing. Some WPS-2, Chloroflexi, and Chlorophyta were mainly present in the bare tailing, while some Proteobacteria and Cercozoa were predominantly seen in the rhizosphere. Pearson correlation and Random Forest revealed the biotic factors driving soil multifunction. Structural equation modelling further revealed that pioneer plants improved soil multifunction primarily by decreasing the microbial biodiversity and increasing the multitrophic network complexity. Overall, this highlights the importance of subterrestrial organisms in accelerating soil rehabilitation during natural succession and provides options for the ecological restoration of degraded REE mining areas.

Melatonin promotes the recovery of apple plants after waterlogging by shaping the structure and function of the rhizosphere microbiome

The dynamics of the physiological adaptability of plants and the rhizosphere soil environment after waterlogging remain unclear. Here we investigated the mechanisms regulating plant condition and shaping of the rhizosphere microbiome in a pot experiment. In the experiment, we added melatonin to waterlogged plants, which promoted waterlogging relief. The treatment significantly enhanced photosynthesis and the antioxidant capacity of apple plants, and significantly promoted nitrogen (N) utilization efficiency by upregulating genes related to N transport and metabolism. Multiperiod soil microbiome analysis showed the dynamic effects of melatonin on the diversity of the microbial community during waterlogging recovery. Random forest and linear regression analyses were used to screen for potential beneficial bacteria (e.g., Azoarcus, Pseudomonas and Nocardioides) specifically regulated by melatonin and revealed a positive correlation with soil nutrient levels and plant growth. Furthermore, metagenomic analyses revealed the regulatory effects of melatonin on genes involved in N cycling in soil. Melatonin positively contributed to the accumulation of plant dry weight by upregulating the expression of nifD and nifK (N fixation). In summary, melatonin positively regulates physiological functions in plants and the structure and function of the microbial community; it promoted the recovery of apple plants after waterlogging stress.

Interactions shape aquatic microbiome responses to Cu and Au nanoparticle treatments in wetland manipulation experiments

In natural systems, organisms are embedded in complex networks where their physiology and community composition is shaped by both biotic and abiotic factors. Therefore, to assess the ecosystem-level effects of contaminants, we must pair complex, multi-trophic field studies with more targeted hypothesis-driven approaches to explore specific actors and mechanisms. Here, we examine aquatic microbiome responses to long-term additions of commercially-available metallic nanoparticles [copper-based (CuNPs) or gold (AuNPs)] and/or nutrients in complex, wetland mesocosms over 9 months, allowing for a full growth cycle of the aquatic plants. We found that both CuNPs and AuNPs (but not nutrient) treatments showed shifts in microbial communities and populations largely at the end of the experiment, as the aquatic plant community senesced. we examine aquatic microbiomes under chronic dosing of NPs and nutrients Simplified microbe-only or microbe + plant incubations revealed that direct effects of AuNPs on aquatic microbiomes can be buffered by plants (regardless of seasonal As mesocosms were dosed weekly, the absence of water column accumulation indicates the partitioning of both metals into other environmental compartments, mainly the floc and aquatic plants photosynthetically-derived organic matter. Overall, this study identifies the potential for NP environmental impacts to be either suppressed by or propagated across trophic levels via the presence of primary producers, highlighting the importance of organismal interactions in mediating emerging contaminants' ecosystem-wide impacts.

Impacts of nano-acetamiprid pesticide on faba bean root metabolic response and soil health

The associated benefits and potential environmental risks of nanopesticides on plant and soil health, particularly in comparison with traditional pesticides, have not been systematically elucidated. Herein, we investigated the impacts of the as-synthesized nano-acetamiprid (Nano-Ace, 20 nm) at low (10 mg/L), medium (50 mg/L), high (100 mg/L) doses and the corresponding high commercial acetamiprid (Ace, 100 mg/L) on the physiological and metabolic response of faba bean (Vicia faba L.) plants, as well as on rhizosphere bacterial communities and functions over short-, medium- and long-term exposures. Overall, Nano-Ace exposure contributed to basic metabolic pathways (e.g., flavonoids, amino acids, TCA cycle intermediate, etc.) in faba bean roots across the whole exposure period. Moreover, Nano-Ace exposure enriched rhizosphere beneficial bacteria (e.g., Streptomyces (420.7%), Pseudomonas (33.8%), Flavobacterium (23.3%)) and suppressed pathogenic bacteria (e.g., Acidovorax (44.5%)). Additionally, Nano-Ace exposure showed a trend of low promotion and high inhibition of soil enzyme activities (e.g., invertase, urease, arylsulfatase, alkaline phosphatase) involved in soil C, N, S, and P cycling, while the inhibition was generally weaker than that of conventional Ace. Altogether, this study indicated that the redox-responsive nano-acetamiprid pesticide possessed high safety for host plants and soil health.

Copper-based nanomaterials: Opportunities for sustainable agriculture

The exponential growth of the global population has resulted in a significant surge in the demand for food worldwide. Additionally, the impact of climate change has exacerbated crop losses caused by pests and pathogens. The transportation and utilization of traditional agrochemicals in the soil are highly inefficient, resulting in significant environmental losses and causing severe pollution of both the soil and aquatic ecosystems. Nanotechnology is an emerging field with significant potential for market applications. Among metal-based nanomaterials, copper-based nanomaterials have demonstrated remarkable potential in agriculture, which are anticipated to offer a promising alternative approach for enhancing crop yields and managing diseases, among other benefits. This review firstly performed co-occurrence and clustering analyses of previous studies on copper-based nanomaterials used in agriculture. Then a comprehensive review of the applications of copper-based nanomaterials in agricultural production was summarized. These applications primarily involved in nano-fertilizers, nano-regulators, nano-stimulants, and nano-pesticides for enhancing crop yields, improving crop resistance, promoting crop seed germination, and controlling crop diseases. Besides, the paper concluded the potential impact of copper-based nanomaterials on the soil micro-environment, including soil physicochemical properties, enzyme activities, and microbial communities. Additionally, the potential mechanisms were proposed underlying the interactions between copper-based nanomaterials, pathogenic microorganisms, and crops. Furthermore, the review summarized the factors affecting the application of copper-based nanomaterials, and highlighted the advantages and limitations of employing copper-based nanomaterials in agriculture. Finally, insights into the future research directions of nano-agriculture were put forward. The purpose of this review is to encourage more researches and applications of copper-based nanomaterials in agriculture, offering a novel and sustainable strategy for agricultural development.

Responses of soil microbiome to copper-based materials (nano and bulk) for agricultural applications: An indoor-mesocosm experiment

The foreseen increasing application of copper-based nanomaterials (Cu-NMs), replacing or complementing existing Cu-agrochemicals, may negatively impact the soil microbiome. Thus, we studied the effects on soil microbiome function and composition of nano copper oxide (nCuO) or copper hydroxide NMs in a commercial (Kocide®3000) or a lab-synthetized formulation (nCu(OH)2) or bulk copper hydroxide (Cu(OH)2-B), at the commonly recommended Cu dose of 50 mg(Cu)kg-1 soil. Microbial responses were studied over 28 days in a designed indoor mesocosm. On day-28, in comparison to non-treated soil (CT), all Cu-treatments led to a reduction in dehydrogenase (95% to 68%), arylsulfatase (41% to 27%), and urease (40% to 20%) activity. There was a 32% increase in the utilization of carbon substrates in the nCuO-treatment and an increased abundance of viable bacteria in the nCu(OH)2-treatment (75% of heterotrophic and 69% of P-solubilizing bacteria). The relative abundance of Acidobacteria [Kocide®3000, nCuO, and Cu(OH)2-B treatments] and Flavobacteriia [nCu(OH)2-treatment] was negatively affected by Cu exposure. The abundance of Cu-tolerant bacteria increased in soils treated with Kocide®3000 (Clostridia) and nCu(OH)2 (Gemmatimonadetes). All Cu-treated soils exhibited a reduced abundance of denitrification-related genes (0.05% of nosZ gene). The DTPA-extractable pool of ionic Cu(II) varied among treatments: Cu(OH)2-B > Kocide®3000 ∼ nCuO>nCu(OH)2, which may explain changes on the soil microbiome composition, at the genera and OTU levels. Thus, our study revealed that Cu-materials (nano and bulk) influence the soil microbiome with implications on its ecological role. It highlights the importance of assessing the impact of Cu-materials under dynamic and complex exposure scenarios and emphasizes the need for specific regulatory frameworks for NMs.

Actinomycetota, a central constituent microbe during long-term exposure to diazinon, an organophosphorus insecticide

Microbial biodegradation is a primary pesticide remediation pathway. Despite diazinon is one of the most frequently used organophosphate insecticides worldwide, its effect on soil microbial community remains obscure. We hypothesize that diazinon exposure reshapes microbial community, among them increased microbes may play a crucial role in diazinon degradation. To investigate this, we collected soil from an organic farming environment, introduced diazinon, cultivated it in a greenhouse, and then assessed its effects on soil microbiomes at three distinct time points: 20, 40, and 270 days after treatment (DAT). Results from HPLC showed that the level of diazinon was gradually degraded by 98.8% at 270 DAT when compared with day zero, whereas 16S rRNA gene analysis exhibited a significant reduction in the bacterial diversity, especially at the early two time points, indicating that diazinon may exert selection pressure to the bacteria community. Here, the relative abundance of phylum Actinomycetota increased at 20 and 40 DATs. In addition, the bacterial functional gene profile employing PICRUSt2 prediction also revealed that diazinon exposure induced the genomic function related to xenobiotics biodegradation and metabolism in soil, such as CYB5B, hpaC, acrR, and ppkA. To validate if bacterial function is caused by increased relative abundance in diazinon enriched soil, further bacteria isolation resulted in obtaining 25 diazinon degradation strains out of 103 isolates. Notably, more than 70% (18 out of 25) isolates are identified as phylum Actinomycetota, which empirically confirms and correlates microbiome and PICRUSt2 results. In conclusion, this study provides comprehensive information from microbiome analysis to obtaining several bacteria isolates responsible for diazinon degradation, revealing that the phylum Actinomycetota is as a key taxon that facilitates microbial biodegradation in diazinon spoiled soil. This finding may assist in developing a strategy for microbial detoxification of diazinon, such as using an Actinomycetota rich synthetic community (SynCom).

DNA metabarcoding reveals the impact of Cu2+ on soil cercozoan diversity

Although copper (Cu2+) is a micronutrient, the metal may be toxic if present in high concentrations in soil ecosystems and subsequently affect various organisms, ranging from microorganisms to earthworms. We performed a microcosm study with an array of Cu2+ concentrations, with a specific focus on Cercozoa, an important protozoan group in most soil food webs. Research on Cercozoa is still scarce in terms of both diversity and ecology; hence, to explore this group in more depth, we used high-throughput sequencing to detect Cu2+ induced community changes. Increased levels of Cu2+ caused a shift in the cercozoan community, and we observed decreased cercozoan relative abundance across the majority of orders, families and genera. Due to their key role in soil food webs, especially as bacterial predators and providers of nutrients to plants, the reduction of cercozoan abundance and diversity may seriously affect soil functionality. Our results indicate that the increase of Cu2+ concentrations in the soil could potentially have this effect and the consequences need exploration.

Nanoparticle applications in agriculture: overview and response of plant-associated microorganisms

Globally, food security has become a critical concern due to the rise in human population and the current climate change crisis. Usage of conventional agrochemicals to maximize crop yields has resulted in the degradation of fertile soil, environmental pollution as well as human and agroecosystem health risks. Nanotechnology in agriculture is a fast-emerging and new area of research explored to improve crop productivity and nutrient-use efficiency using nano-sized agrochemicals at lower doses than conventional agrochemicals. Nanoparticles in agriculture are applied as nanofertilizers and/or nanopesticides. Positive results have been observed in terms of plant growth when using nano-based agricultural amendments. However, their continuous application may have adverse effects on plant-associated rhizospheric and endospheric microorganisms which often play a crucial role in plant growth, nutrient uptake, and disease prevention. While research shows that the application of nanoparticles has the potential to improve plant growth and yield, their effect on the diversity and function of plant-associated microorganisms remains under-explored. This review provides an overview of plant-associated microorganisms and their functions. Additionally, it highlights the response of plant-associated microorganisms to nanoparticle application and provides insight into areas of research required to promote sustainable and precision agricultural practices that incorporate nanofertilizers and nanopesticides.

Environmental behaviors and toxic mechanisms of engineered nanomaterials in soil

Engineered nanomaterials (ENMs) are inevitably released into the environment with the exponential application of nanotechnology. Parts of ENMs eventually accumulate in the soil environment leading to potential adverse effects on soil ecology, crop production, and human health. Therefore, the safety application of ENMs on soil has been widely discussed in recent years. More detailed safety information and potential soil environmental risks are urgently needed. However, most of the studies on the environmental effects of metal-based ENMs have been limited to single-species experiments, ecosystem processes, or abiotic processes. The present review formulated the source and the behaviors of the ENMs in soil, and the potential effects of single and co-exposure ENMs on soil microorganisms, soil fauna, and plants were introduced. The toxicity mechanism of ENMs to soil organisms was also reviewed including oxidative stress, the release of toxic metal ions, and physical contact. Soil properties affect the transport, transformation, and toxicity of ENMs. Toxic mechanisms of ENMs include oxidative stress, ion release, and physical contact. Joint toxic effects occur through adsorption, photodegradation, and loading. Besides, future research should focus on the toxic effects of ENMs at the food chain levels, the effects of ENMs on plant whole-lifecycle, and the co-exposure and long-term toxicity effects. A fast and accurate toxicity evaluation system and model method are urgently needed to solve the current difficulties. It is of great significance for the sustainable development of ENMs to provide the theoretical basis for the ecological risk assessment and environmental management of ENMs.

Neurotoxicity of the Cu(OH)2 Nanopesticide through Perturbing Multiple Neurotransmitter Pathways in Developing Zebrafish

The copper hydroxide [Cu(OH)2] nanopesticide is an emerging agricultural chemical that can negatively impact aquatic organisms. This study evaluated the behavioral changes of zebrafish larvae exposed to the Cu(OH)2 nanopesticide and assessed its potential to induce neurotoxicity. Metabolomic and transcriptomic profiling was also conducted to uncover the molecular mechanisms related to potential neurotoxicity. The Cu(OH)2 nanopesticide at 100 μg/L induced zebrafish hypoactivity, dark avoidance, and response to the light stimulus, suggestive of neurotoxic effects. Altered neurotransmitter-related pathways (serotoninergic, dopaminergic, glutamatergic, GABAergic) and reduction of serotonin (5-HT), dopamine (DA), glutamate (GLU), γ-aminobutyric acid (GABA), and several of their precursors and metabolites were noted following metabolomic and transcriptomic analyses. Differentially expressed genes (DEGs) were associated with the synthesis, transport, receptor binding, and metabolism of 5-HT, DA, GLU, and GABA. Transcripts (or protein levels) related to neurotransmitter receptors for 5-HT, DA, GLU, and GABA and enzymes for the synthesis of GLU and GABA were downregulated. Effects on both the glutamatergic and GABAergic pathways in zebrafish were specific to the nanopesticide and differed from those in fish exposed to copper ions. Taken together, the Cu(OH)2 nanopesticide induced developmental neurotoxicity in zebrafish by inhibiting several neurotransmitter-related pathways. This study presented a model for Cu(OH)2 nanopesticide-induced neurotoxicity in developing zebrafish that can inform ecological risk assessments.

Microbiome predators in changing soils

Microbiome predators shape the soil microbiome and thereby soil functions. However, this knowledge has been obtained from small-scale observations in fundamental rather than applied settings and has focused on a few species under ambient conditions. Therefore, there are several unaddressed questions on soil microbiome predators: (1) What is the role of microbiome predators in soil functioning? (2) How does global change affect microbiome predators and their functions? (3) How can microbiome predators be applied in agriculture? We show that there is sufficient evidence for the vital role of microbiome predators in soils and stress that global changes impact their functions, something that urgently needs to be addressed to better understand soil functioning as a whole. We are convinced that there is a potential for the application of microbiome predators in agricultural settings, as they may help to sustainably increase plant growth. Therefore, we plea for more applied research on microbiome predators.

Deciphering the degradation characteristics of the fungicides imazalil and penflufen and their effects on soil bacterial community composition, assembly, and functional profiles

The adsorption-desorption and degradation characteristics of two widely applied fungicides, imazalil and penflufen, and the responses of soil bacterial diversity, structure, function, and interaction after long-term exposure were systemically studied in eight different soils. The adsorption ability of imazalil in soil was significantly higher than that of penflufen. Both imazalil and penflufen degraded slowly in most soils following the order: imazalil > penflufen, with soil pH, silt, and clay content being the potential major influencing factors. Both imazalil and penflufen obviously inhibited the soil microbial functional diversity, altered the soil bacterial community and decreased its diversity. Although exposure to low and high concentrations of imazalil and penflufen strengthened the interactions among the soil bacterial communities, the functional diversity of the co-occurrence network tended to be simple at high concentrations, especially in penflufen treatment. Both imazalil and penflufen markedly disturbed soil nitrogen cycling, especially penflufen seriously inhibited most nitrogen cycling processes, such as nitrogen fixation and nitrification. Meanwhile, sixteen and ten potential degradative bacteria of imazalil and penflufen, respectively, were found in soils, including Kaistobacter and Lysobacter. Collectively, the long-term application of imazalil and penflufen could cause residual accumulation in soils and subsequently result in serious negative effects on soil ecology.

Pseudomonas stutzeri improves the tolerance of Lemna minor to Cu(OH)2 nanopesticide by regulating the uptake of copper, antioxidant defense mechanisms, and the expression of metacaspase-1, chlorophyllase, and stress-responsive genes

This study investigated the effect of Pseudomonas stutzeri inoculation on Lemna minor treated with Cu(OH)2 nanopesticide (NP). The results showed that P. stutzeri inoculation increased the relative growth rate (RGR) in NP-treated plants. Although chlorophyll and carotenoid contents decreased significantly in NP-treated plants, P. stutzeri inoculation led to an increase in chlorophyll and carotenoid contents in NP-treated plants. Copper (Cu) content increased with increasing NP concentration, but it decreased significantly in the presence of P. stutzeri. NP treatment caused increased H2O2 and TBARS levels, as well as proline levels. However, P. stutzeri inoculation led to decreased H2O2 and TBARS levels and increased SOD, POX, GST, GR, GPX, and DHAR activities. The expression of genes encoding SOD, GST, metacaspase-1, and chlorophyllase was upregulated by NP treatment alone. Additionally, when plants were inoculated with P. stutzeri, the expression of these genes was further enhanced. In conclusion, P. stutzeri inoculation had a positive effect on the growth and antioxidant system of L. minor treated with NP as it enhanced RGR, increased chlorophyll and carotenoid contents, and decreased Cu content and oxidative stress. These findings suggested that P. stutzeri has the potential to promote aquatic plant growth and counteract the negative impacts of NP on these plants.

Response of microbial communities in the phyllosphere ecosystem of tobacco exposed to the broad-spectrum copper hydroxide

Copper hydroxide is a broad-spectrum copper fungicide, which is often used to control crop fungal and bacterial diseases. In addition to controlling targeted pathogens, copper hydroxide may also affect other non-targeted microorganisms in the phyllosphere ecosystem. At four time points (before spraying, and 5, 10 and 15 days after fungicide application), the response of diseased and healthy tobacco phyllosphere microorganisms to copper hydroxide stress was studied by using Illumina high-throughput sequencing technology, and Biolog tools. The results showed that the microbiome communities of the healthy group were more affected than the disease group, and the fungal community was more sensitive than the bacterial community. The most common genera in the disease group were Alternaria, Boeremia, Cladosporium, Pantoea, Ralstonia, Pseudomonas, and Sphingomonas; while in the healthy group, these were Alternaria, Cladosporium, Symmetrospora, Ralstonia, and Pantoea. After spraying, the alpha diversity of the fungal community decreased at 5 days for both healthy and diseased groups, and then showed an increasing trend, with a significant increase at 15 days for the healthy group. The alpha diversity of bacterial community in healthy and diseased groups increased at 15 days, and the healthy group had a significant difference. The relative abundance of Alternaria and Cladosporium decreased while that of Boeremia, Stagonosporopsis, Symmetrospora, Epicoccum and Phoma increased in the fungal communities of healthy and diseased leaves. The relative abundance of Pantoea decreased first and then increased, while that of Ralstonia, Pseudomonas and Sphingomonas increased first and then decreased in the bacterial communities of healthy and diseased leaves. While copper hydroxide reduced the relative abundance of pathogenic fungi Alternaria and Cladosporium, it also resulted in the decrease of beneficial bacteria such as Actinomycetes and Pantoea, and the increase of potential pathogens such as Boeremia and Stagonosporopsis. After treatment with copper hydroxide, the metabolic capacity of the diseased group improved, while that of the healthy group was significantly suppressed, with a gradual recovery of metabolic activity as the application time extended. The results revealed changes in microbial community composition and metabolic function of healthy and diseased tobacco under copper hydroxide stress, providing a theoretical basis for future studies on microecological protection of phyllosphere.

Biotic and Abiotic Interactions in Freshwater Mesocosms Determine Fate and Toxicity of CuO Nanoparticles

Transformation, dissolution, and sorption of copper oxide nanoparticles (CuO-NP) play an important role in freshwater ecosystems. We present the first mesocosm experiment on the fate of CuO-NP and the dynamics of the zooplankton community over a period of 12 months. Increasingly low (0.08-0.28 mg Cu L-1) and high (0.99-2.99 mg Cu L-1) concentrations of CuO-NP and CuSO4 (0.10-0.34 mg Cu L-1) were tested in a multiple dosing scenario. At the high applied concentration (CuO-NP_H) CuO-NP aggregated and sank onto the sediment layer, where we recovered 63% of Cu applied. For the low concentration (CuO-NP_L) only 41% of applied copper could be recovered in the sediment. In the water column, the percentage of initially applied Cu recovered was on average 3-fold higher for CuO-NP_L than for CuO-NP_H. Zooplankton abundance was substantially compromised in the treatments CuSO4 (p < 0.001) and CuO-NP_L (p < 0.001). Community analysis indicated that Cladocera were most affected (bk = -0.49), followed by Nematocera (bk = -0.32). The abundance of Cladocera over time and of Dixidae in summer was significantly reduced in the treatment CuO-NP_L (p < 0.001; p < 0.05) compared to the Control. Our results indicate a higher potential for negative impacts on the freshwater community when lower concentrations of CuO-NP (<0.1 mg Cu L-1) enter the ecosystem.

Lanthanum Silicate Nanomaterials Enhance Sheath Blight Resistance in Rice: Mechanisms of Action and Soil Health Evaluation

In the current study, foliar spray with lanthanum (La) based nanomaterials (La10Si6O27 nanorods, La10Si6O27 nanoparticle, La(OH)3 nanorods, and La2O3 nanoparticle) suppressed the occurrence of sheath blight (Rhizoctonia solani) in rice. The beneficial effects were morphology-, composition-, and concentration-dependent. Foliar application of La10Si6O27 nanorods (100 mg/L) yielded the greatest disease suppression, significantly decreasing the disease severity by 62.4% compared with infected controls; this level of control was 2.7-fold greater than the commercially available pesticide (Thifluzamide). The order of efficacy was as follows: La10Si6O27 nanorods > La10Si6O27 nanoparticle > La(OH)3 nanorods > La2O3 nanoparticle. Mechanistically, (1) La10Si6O27 nanorods had greater bioavailability, slower dissolution, and simultaneous Si nutrient benefits; (2) transcriptomic and metabolomic analyses revealed that La10Si6O27 nanorods simultaneously strengthened rice systemic acquired resistance, physical barrier formation, and antioxidative systems. Additionally, La10Si6O27 nanorods improved rice yield by 35.4% and promoted the nutritional quality of the seeds as compared with the Thifluzamide treatment. A two-year La10Si6O27 nanorod exposure had no effect on soil health based on the evaluated chemical, physical, and biological soil properties. These findings demonstrate that La based nanomaterials can serve as an effective and sustainable strategy to safeguard crops and highlight the importance of nanomaterial composition and morphology in terms of optimizing benefit.

Nanotechnology-based pesticides: Environmental fate and ecotoxicity

The imminent increase in global food demand inevitably leads to an increase in agricultural practices, with an emphasis on pesticide applications. Nanotechnology-based pesticides, or nanopesticides, have gained importance as they are more efficient and, in some cases, less toxic than their conventional counterparts. However, concerns about these novel products have arisen as evidence about their (eco)safety is controversial. This review aims to: (1) introduce the currently applied nanotechnology-based pesticides and their mechanisms of toxic action; (2) describe their fate when released into the environment, with an emphasis on aquatic environments; (3) summarize available research on ecotoxicological studies in freshwater non-target organisms through a bibliometric analysis; and (4) identify gaps in knowledge from an ecotoxicological perspective. Our results show that the environmental fate of nanopesticides is poorly studied and depends on both intrinsic and external factors. There is also a need for comparative research into their ecotoxicity between conventional pesticide formulations and their nano-based counterparts. Among the few available studies, most considered fish species as test organisms, compared to algae and invertebrates. Overall, these new materials generate toxic effects on non-target organisms and threaten the integrity of the environment. Therefore, deepening the understanding of their ecotoxicity is crucial.

Environmental effect of agriculture-related manufactured nano-objects on soil microbial communities

Agriculture-related manufactured nano-objects (MNOs) can revolutionize the crop production and help to achieve sustainable development goals. MNOs with diverse physico-chemical properties and ability to encapsulate and deliver active ingredients in controlled, targeted and stimuli responsive manner can enhance the efficiency while minimizing collateral damage to non-target organisms and environment. Application of MNOs in the form of nanopesticides and nanofertilizers is known to affect soil microbial communities both positively and negatively, but detailed studies with varying dose, type and environmental conditions are scarce. Therefore, it is imperative to understand the complex mechanisms and factors which shape the MNOs-microbial interactions through integrating state of the art technologies including omics (transcriptomics, metabolomics, and proteomics), artificial intelligence, and statistical frameworks. Lastly, we propose the idea of MNOs-mediated manipulation of soil microbiome to modify the soil microbial communities for improved microbial services. These microbial services, if harnessed appropriately, can revolutionize modern agriculture and help in achieving sustainable development goals.

Engineered microbes as effective tools for the remediation of polyaromatic aromatic hydrocarbons and heavy metals

Heavy metals (HMs) and polycyclic aromatic hydrocarbons (PAHs) have become a major concern to human health and the environment due to rapid industrialization and urbanization. Traditional treatment measures for removing toxic substances from the environment have largely failed, and thus development and advancement in newer remediation techniques are of utmost importance. Rising environmental pollution with HMs and PAHs prompted the research on microbes and the development of genetically engineered microbes (GEMs) for reducing pollution via the bioremediation process. The enzymes produced from a variety of microbes can effectively treat a range of pollutants, but evolutionary trends revealed that various emerging pollutants are resistant to microbial or enzymatic degradation. Naturally, existing microbes can be engineered using various techniques including, gene engineering, directed evolution, protein engineering, media engineering, strain engineering, cell wall modifications, rationale hybrid design, and encapsulation or immobilization process. The immobilization of microbes and enzymes using a variety of nanomaterials, membranes, and supports with high specificity toward the emerging pollutants is also an effective strategy to capture and treat the pollutants. The current review focuses on successful bioremediation techniques and approaches that make use of GEMs or engineered enzymes. Such engineered microbes are more potent than natural strains and have greater degradative capacities, as well as rapid adaptation to various pollutants as substrates or co-metabolizers. The future for the implementation of genetic engineering to produce such organisms for the benefit of the environment andpublic health is indeed long and valuable.

Pesticide soil microbial toxicity: setting the scene for a new pesticide risk assessment for soil microorganisms (IUPAC Technical Report)

Pesticides constitute an integral part of modern agriculture. However, there are still concerns about their effects on non-target organisms. To address this the European Commission has imposed a stringent regulatory scheme for new pesticide compounds. Assessment of the aquatic toxicity of pesticides is based on a range of advanced tests. This does not apply to terrestrial ecosystems, where the toxicity of pesticides on soil microorganisms, is based on an outdated and crude test (N mineralization). This regulatory gap is reinforced by the recent methodological and standardization advances in soil microbial ecology. The inclusion of such standardized tools in a revised risk assessment scheme will enable the accurate estimation of the toxicity of pesticides on soil microorganisms and on associated ecosystem services. In this review we (i) summarize recent work in the assessment of the soil microbial toxicity of pesticides and point to ammonia-oxidizing microorganisms (AOM) and arbuscular mycorrhizal fungi (AMF) as most relevant bioindicator groups (ii) identify limitations in the experimental approaches used and propose mitigation solutions, (iii) identify scientific gaps and (iv) propose a new risk assessment procedure to assess the effects of pesticides on soil microorganisms.

Interactions between soil protists and pollutants: An unsolved puzzle

Soil protists are essential but often overlooked in soils, although they play crucial functional roles in the terrestrial ecosystem. While soil protists have drawn increased attention to their functional role in soils, their interaction with soil pollutants remains unresolved. This review provides a first overview of the current understanding of interactions between soil protists and major pollutants (heavy metals, organic pollutants, nanoparticles, and soil pathogens). We summarize how soil pollutants affect protists and vice versa, showing that we are just beginning to understand their complex interactions. In addition, we identify five research gaps, including hidden diversity, adaptive mechanisms, species interactions, soil bioindicators and environmental applications, and we hope that our review will help promote and build research guidelines for the future. In conclusion, a better understanding of soil pollutant-protist interactions will significantly increase our knowledge of the pollution ecology in the soil and how soil organisms respond and adapt to environmental pollution, which will contribute to the bioremediation and environmental applications of protists in soil.

Complex Bilateral Interactions Determine the Fate of Polystyrene Micro- and Nanoplastics and Soil Protists: Implications from a Soil Amoeba

Nano- and microplastics have become a serious global concern, threatening our living environments. Previous studies have shown that many organisms, including bacteria, animals, and plants, can be affected by microplastics. However, little is known about one ecologically important group of soil organisms, the protists. In this study, we investigated how polystyrene micro- and nanoplastics interacted with a soil amoeba Dictyostelium discoideum. The results showed that environmental concentrations of nano- and microplastics could negatively affect the soil amoeba's fitness and development. D. discoideum ingested both nano- and microplastics through phagocytosis but packed and excreted them during slug migration, which also promoted their biodegradation. Fourier transform infrared spectroscopy analyses revealed the formation of new oxygen-containing functional groups and the sign of possible oxidation of polystyrene. Also, nano- and microplastic exposure disrupted the nutrient and energy metabolisms of D. discoideum and affected the expression of key genes (e.g., cf45-1, dcsA, aprA, dymB, and gefB) related to morphogenesis and phagocytosis. In conclusion, our results show that nano- and microplastics have complex bilateral interactions with the soil amoeba, affecting each other's fate in the soil environment. This study provides new insights into how soil protists interact with nano- and microplastics in the soil ecosystem.

Nano-enabled pesticides for sustainable agriculture and global food security

Achieving sustainable agricultural productivity and global food security are two of the biggest challenges of the new millennium. Addressing these challenges requires innovative technologies that can uplift global food production, while minimizing collateral environmental damage and preserving the resilience of agroecosystems against a rapidly changing climate. Nanomaterials with the ability to encapsulate and deliver pesticidal active ingredients (AIs) in a responsive (for example, controlled, targeted and synchronized) manner offer new opportunities to increase pesticidal efficacy and efficiency when compared with conventional pesticides. Here, we provide a comprehensive analysis of the key properties of nanopesticides in controlling agricultural pests for crop enhancement compared with their non-nanoscale analogues. Our analysis shows that when compared with non-nanoscale pesticides, the overall efficacy of nanopesticides against target organisms is 31.5% higher, including an 18.9% increased efficacy in field trials. Notably, the toxicity of nanopesticides toward non-target organisms is 43.1% lower, highlighting a decrease in collateral damage to the environment. The premature loss of AIs prior to reaching target organisms is reduced by 41.4%, paired with a 22.1% lower leaching potential of AIs in soils. Nanopesticides also render other benefits, including enhanced foliar adhesion, improved crop yield and quality, and a responsive nanoscale delivery platform of AIs to mitigate various pressing biotic and abiotic stresses (for example, heat, drought and salinity). Nonetheless, the uncertainties associated with the adverse effects of some nanopesticides are not well-understood, requiring further investigations. Overall, our findings show that nanopesticides are potentially more efficient, sustainable and resilient with lower adverse environmental impacts than their conventional analogues. These benefits, if harnessed appropriately, can promote higher crop yields and thus contribute towards sustainable agriculture and global food security.

Impact of hexachlorocyclohexane addition on the composition and potential functions of the bacterial community in red and purple paddy soil

Soil studies have reported the effect of Hexachlorocyclohexane (HCH) on soil microbial communities. However, how soil microbial communities and function shift after HCH addition into the red and purple soil remains unclear. Here, we analyzed the HCH residue fate, and the functional composition and structure of microbial communities to HCH in the two soils. Under the 100 g/ha and 1000 g/ha treatment, the dissipation rate of HCH was 0.0386 and 0.0273 in the purple soil, 0.0145 and 0.0195 in the red soil. The enrichment of HCH degrading genes leads to a higher HCH dissipation rate in the purple soil. PCoA results demonstrated that HCH addition has a different effect on the community diversity in the two soils, and Proteobacteria and Acidobacteria were the major phyla in the two soils. The soil microbiome average variation degree values of red soil were higher than purple soil, which indicated that the soil microbiome in the purple soil was more stable than in the red soil under HCH addition. PICRUSt2 results indicated that functional genes involved in the carbon, nitrogen biogeochemical cycles and HCH degradation were more tolerant to HCH addition in the purple soil. This study provides new insights into understanding of the effect of HCH addition on soil microbial communities and function in the red and purple paddy soil.

Terrestrial organisms react differently to nano and non-nano Cu(OH)2 forms

The application of nanomaterials in agriculture is deemed as a promising strategy to increase the sector's sustainability. Nanopesticides are expected to improve solutions for pest/disease management, while reducing adverse effects to ecosystems, in accordance with the European Green Deal strategy. Hitherto, nanopesticide research has mostly focused on assessing effects to target species or crops, and less attention has been devoted to non-target soil species. In this study, we explored whether three copper hydroxide-based forms (nano and non-nano) show different toxicity and accumulation patterns in two terrestrial invertebrates, the isopod Porcellionides pruinosus and the mealworm larvae Tenebrio molitor. Toxicity and bioaccumulation experiments were performed and time-course toxicity and toxicokinetics analyzed and modelled. We found important differences in copper sensitivity and accumulation: T. molitor was more resistant and able to eliminate copper compared to P. pruinosus. The nanopesticide mostly elicited lower effects for both species. Slower toxicokinetics by the nanopesticide and lower bioaccumulative potential to P. pruinosus must be partially responsible for the differences in toxicity. Although no toxicokinetics differences were found in T. molitor between Cu forms, distinct negative effects on growth must reflect different energetic costs for copper regulation. Even though effects on toxicity and bioaccumulation are species-specific, copper hydroxide-based nanopesticides may cause less adverse effects to soil organisms than conventional products, being a good solution for reducing the environmental impact. CAPSULE: Copper hydroxide-based nanopesticide was less toxic and bioaccumulative to soil organisms than conventional copper hydroxide products, being a good solution for reducing the environmental impact.

Thin interfacial film spontaneously produces hydrogen peroxide: mechanism and application for perfluorooctanoic acid degradation

We have unambiguously demonstrated spontaneous formation of hydrogen peroxide (H2O2) in thin film formats by evaporating almost all the water and its effective for perfluorooctanoic acid (PFOA) degradation without catalysts.

Aquatic Mesocosm Strategies for the Environmental Fate and Risk Assessment of Engineered Nanomaterials

In the past decade, mesocosms have emerged as a useful tool for the environmental study of engineered nanomaterials (ENMs) as they can mimic the relevant exposure scenario of contamination. Herein, we analyzed the scientific outcomes of aquatic mesocosm experiments, with regard to their designs, the ENMs tested, and the end points investigated. Several mesocosm designs were consistently applied in the past decade to virtually mimic various contamination scenarios with regard to ecosystem setting as well as ENMs class, dose, and dosing. Statistical analyses were carried out with the literature data to identify the main parameters driving ENM distribution in the mesocosms and the potential risk posed to benthic and planktonic communities as well as global ecosystem responses. These analyses showed that at the end of the exposure, mesocosm size (water volume), experiment duration, and location indoor/outdoor had major roles in defining the ENMs/metal partitioning. Moreover, a higher exposure of the benthic communities is often observed but did not necessarily translate to a higher risk due to the lower hazard posed by transformed ENMs in the sediments (e.g., aggregated, sulfidized). However, planktonic organisms were generally exposed to lower concentrations of potentially more reactive and toxic ENM species. Hence, mesocosms can be complementary tools to existing standard operational procedures for regulatory purposes and environmental fate and risk assessment of ENMs. To date, the research was markedly unbalanced toward the investigation of metal-based ENMs compared to metalloid- and carbon-based ENMs but also nanoenabled products. Future studies are expected to fill this gap, with special regard to high production volume and potentially hazardous ENMs. Finally, to take full advantage of mesocosms, future studies must be carefully planned to incorporate interdisciplinary approaches and ensure that the large data sets produced are fully exploited.

A Literature Review of Wetland Treatment Systems Used to Treat Runoff Mixtures Containing Antibiotics and Pesticides from Urban and Agricultural Landscapes

Wetland treatment systems are used extensively across the world to mitigate surface runoff. While wetland treatment for nitrogen mitigation has been comprehensively reviewed, the implications of common-use pesticides and antibiotics on nitrogen reduction remain relatively unreviewed. Therefore, this review seeks to comprehensively assess the removal of commonly used pesticides and antibiotics and their implications for nitrogen removal in wetland treatment systems receiving non-point source runoff from urban and agricultural landscapes. A total of 181 primary studies were identified spanning 37 countries. Most of the reviewed publications studied pesticides (n = 153) entering wetlands systems, while antibiotics (n = 29) had fewer publications. Even fewer publications reviewed the impact of influent mixtures on nitrogen removal processes in wetlands (n = 16). Removal efficiencies for antibiotics (35–100%), pesticides (−619–100%), and nitrate-nitrogen (−113–100%) varied widely across the studies, with pesticides and antibiotics impacting microbial communities, the presence and type of vegetation, timing, and hydrology in wetland ecosystems. However, implications for the nitrogen cycle were dependent on the specific emerging contaminant present. A significant knowledge gap remains in how wetland treatment systems are used to treat non-point source mixtures that contain nutrients, pesticides, and antibiotics, resulting in an unknown regarding nitrogen removal efficiency as runoff contaminant mixtures evolve.

Fate and toxicity of engineered nanomaterials in the environment: A meta-analysis

The global environment annually receives thousands of tons of engineered nanomaterials (ENMs, particles less than 100 nm diameter). These particles have high active surface area, unique chemical properties, and can enter cells. Humanity uses many ENMs for their biological reactivity (e.g. microbicides), but their environmental effects are complex. We cataloged 2102 experimental results on whole organisms for 22 particle classes (mainly on Ag, Zn, Ti, and Cu) to assess biological responses, effective and lethal concentrations, and bioaccumulation of ENMs. Most responses were negative and varied significantly by particle type, functional group of organism, and type of response. Smaller particles tended to be more toxic. Aquatic organisms responded more negatively than did terrestrial organisms. Animals generally were most sensitive and plants least. Silver ENMs generally had the strongest negative effects. Effective and lethal concentrations generally exceeded modeled environmentally relevant concentrations and organisms usually did not accumulate or biomagnify to concentrations above those in their environment. However, most experiments lasted less than a week and were not field studies. Research to date is probably insufficient to understand chronic effects and long-term biomagnification. Numerous unique and untested ENMs continue to enter environments at accelerating rates, and our analysis indicates potential for negative effects. Our data suggest substantial research is still required to understand the ultimate influence of ENMs as they continue to accumulate in the environment. Around 40% of the papers with experimental data for ENMs failed with respect to reporting means, sample sizes, or experimental error, or they did not have proper experimental design (e.g. lack of true controls). We need more high-quality experiments that are more realistic (field or mesocosm), longer duration, contain a wider range of organisms, and account for complex food web structure.

Genetically engineered microbial remediation of soils co-contaminated by heavy metals and polycyclic aromatic hydrocarbons: Advances and ecological risk assessment

Soils contaminated with heavy metals (HMs) and polycyclic aromatic hydrocarbons (PAHs) have been becoming a worldwide concerned environmental problem because of threatening public healthy via food chain exposure. Thus soils polluted by HMs and PAHs need to be remediated urgently. Physical and chemical remediation methods usually have some disadvantages, e.g., cost-expensiveness and incomplete removal, easily causing secondary pollution, which are hence not environmental-friendly. Conventional microbial approaches are mostly used to treat a single contaminant in soils and lack high efficiency and specificity for combined contaminants. Genetically engineered microorganisms (GEMs) have emerged as a desired requirement of higher bioremediation efficiency for soils polluted with HMs and PAHs and environmental sustainability, which can provide a more eco-friendly and cost-effective strategy in comparison with some conventional techniques. This review comments the recent advances about successful bioremediation techniques and approaches for soil contaminated with HMs and/or PAHs by GEMs, and discusses some challenges in the simultaneous removal of HMs and PAHs from soil by designing multi-functional genetic engineering microorganisms (MFGEMs), such as improvement of higher efficiency, strict environmental conditions, and possible ecological risks. Also, the modern biotechnological techniques and approaches in improving the ability of microbial enzymes to effectively degrade combined contaminants at a faster rate are introduced, such as reasonable gene editing, metabolic pathway modification, and protoplast fusion. Although MFGEMs are more potent than the native microbes and can quickly adapt to combined contaminants in soils, the ecological risk of MFGEMs needs to be evaluated under a regulatory, safety, or costs benefit-driving system in a way of stratified regulation. Nevertheless, the innovation of genetic engineering to produce MFGEMs should be inspired for the welfare of successful bioremediation for soils contaminated with HMs and PAHs but it must be supervised by the public, authorities, and laws.

Comprehensive Interrogation of Metabolic and Bioenergetic Responses of Early-Staged Zebrafish (Danio rerio) to a Commercial Copper Hydroxide Nanopesticide

The use of copper hydroxide nanopesticide can pose exposure risks to aquatic organisms. In this study, the toxicity of a copper hydroxide nanopesticide, compared to conventional copper sulfate at environmentally relevant doses, was evaluated using metabolomics and bioenergetic assays in embryonic zebrafish. At a copper concentration of 100 μg/L, the nanopesticide caused higher mortality and deformity compared to copper ions alone; despite higher copper accumulation, increased metallothionein and elevated ATP-binding cassette (ABC) transporter activity in zebrafish exposed to copper ions were observed. Both nanopesticide and copper ions reduced the abundance of metabolites of glycolysis and induced energetic stress in zebrafish. The nanopesticide also increased concentrations of several organic acids involved in the tricarboxylic acid (TCA) cycle and elevated the activity of isocitrate dehydrogenase and α-ketoglutarate dehydrogenase, suggesting enhanced TCA cycle activity. Nanopesticide exposure depleted both glutamate and glutamine parallel to the upregulation of the TCA cycle. In addition, zebrafish exposed to the nanopesticide appeared to shift metabolism toward amino acid catabolism and lipid accumulation based upon altered expression profiles of glutaminase, glutamate dehydrogenase, fatty acid synthase, and acetyl-CoA carboxylase. Lastly, the ability of the ions to increase oxidative phosphorylation to alleviate energetic stress was reduced in the case of the nanopesticide. We hypothesize that, unlike copper ions alone, the nanopesticide induces higher toxicity to zebrafish because of increased protein catabolism. This study provides a comprehensive understanding of the risks of copper hydroxide nanopesticide exposure in relation to metabolic activity and mitochondrial function.

Relaxation of putative plant defenses in a tropical agroecosystem

Evidence of the effects of agriculture on natural systems is widespread, but potential evolutionary responses in nontarget species are largely uncharacterized. To explore whether exposure to agrochemicals may influence selective pressures and phenotypic expression in nonagricultural plant populations, we characterized the expression of putative antiherbivore defense phenotypes in three nonagricultural species found upstream and downstream of irrigated rice fields in Guanacaste Province, Costa Rica. We found that plants downstream of chemically intensive agriculture showed shifts toward reduced expression of putative antiherbivore defenses relative to upstream counterparts. In two of three tested species, leaf extracts from downstream plants were more palatable to a generalist consumer, suggesting a possible reduction of chemical defenses. In one species with multiple modes of putative defenses, we observed parallel reductions of three metrics of putative biotic and physical defenses. These reductions were concurrent with reduced herbivore damage on downstream plants. Together, these results suggest that agriculture has the potential to alter intraspecific phenotypic expression, ecological interactions, and natural selection in nontarget plant populations.

Reduced bacterial network complexity in agricultural soils after application of the neonicotinoid insecticide thiamethoxam

Pesticides may alter soil microbial community structure or diversity, but their impact on microbial co-occurrence patterns remains unclear. Here, the effect of the widely used neonicotinoid insecticide thiamethoxam on the bacterial community in five arable soils was deciphered using the 16S rRNA gene amplicon sequencing technique. The degradation half-life of thiamethoxam in nonsterilized soils was significantly lower than that in sterilized soils, suggesting a considerable contribution from biodegradation. Soil bacterial community diversity diminished in high concentration thiamethoxam treatment and its impact varied with treatment concentration and soil type. Bacterial co-occurrence network complexity significantly decreased after exposure to thiamethoxam. Under thiamethoxam stress, the relative changes in bacterial co-occurrence networks were closely related (the majority of p-values < 0.05) to the soil physicochemical properties, yet the diversity and dominant phyla were slightly related (the majority of p-values > 0.05). Additionally, three bacterial genera, Sphingomonas, Streptomyces, and Catenulispora, were identified to be relevant to the degradation of thiamethoxam in soils. This finding deciphers the succession of the bacterial community under thiamethoxam stress across multiple soils, and emphasizes the potential role of physicochemical properties in regulating the ecotoxicological effect of pesticides on the soil microbiome.

Long-term effects of Cu(OH)2 nanopesticide exposure on soil microbial communities

Copper-based (nano)pesticides in agroecosystems may result in unintended consequences on non-target soil microbial communities, due to their antimicrobial broad spectrum. We studied the impact of a commercial Cu(OH)₂-nanopesticide, over 90 days, at single and season agricultural application doses, in the presence and absence of an edaphic organism (the isopod Porcellionides pruinosus), on microbial communities' function, structure and abundance. Results were compared to the effects of Cu(OH)₂-ionic. The nanopesticide application resulted in significant changes on both bacterial and fungal communities' structure, particularly at the season application. The exposed bacterial community presented a significantly lower richness, and higher diversity and evenness while the exposed fungal community presented lower diversity and richness. At the functional level, a significant increase on microbial ability of carbon utilization and a significant decrease on the β-glucosidase activity was observed for communities exposed to the nanopesticide. Regarding Cu forms, less pronounced effects were observed in soils spiked with Cu(OH)₂-ionic, which might result from lower Cu concentration in porewater. The presence of P. pruinosus did not induce significant changes in diversity indexes (fungal community) and community-level physiological profiling, suggesting an attenuation of the nanopesticide effect. This study revealed that Cu(OH)₂-nanopesticide, at doses applied in agriculture, impact the soil microbial community, possibly affecting its ecological role. On the other hand, invertebrates may attenuate this effect, highlighting the importance of jointly including different interacting communities in the risk assessment of nanopesticides in soils.

Cadmium Immobilization in the Rhizosphere and Plant Cellular Detoxification: Role of Plant-Growth-Promoting Rhizobacteria as a Sustainable Solution

Food is the major cadmium (Cd)-exposure pathway from agricultural soils to humans and other living entities and must be reduced in an effective way. A plant can select beneficial microbes, like plant-growth-promoting rhizobacteria (PGPR), depending upon the nature of root exudates in the rhizosphere, for its own benefits, such as plant growth promotion as well as protection from metal toxicity. This review intends to seek out information on the rhizo-immobilization of Cd in polluted soils using the PGPR along with plant nutrient fertilizers. This review suggests that the rhizo-immobilization of Cd by a combination of PGPR and nanohybrid-based plant nutrient fertilizers would be a potential and sustainable technology for phytoavailable Cd immobilization in the rhizosphere and plant cellular detoxification, by keeping the plant nutrition flow and green dynamics of plant nutrition and boosting the plant growth and development under Cd stress.