Applied pesticide toxicity shifts toward plants and invertebrates, even in GM crops

Mapping pesticide-induced metabolic alterations in human gut bacteria

Pesticides can modulate gut microbiota composition, but their specific effects on it remain largely elusive. In our study, we show that pesticides inhibit or promote the growth of various gut microbial species and can be accumulated to prolong their presence in the host. Pesticide exposure also induces significant alterations in gut bacterial metabolism, as reflected by changes in hundreds of metabolites. We generate a pesticide-gut microbiota-metabolite network that not only reveals pesticide-sensitive gut bacteria species but also reports specific metabolic changes in 306 pesticide-gut microbiota pairs. Using an in vivo mouse model, we further demonstrate the interactions of a representative pesticide-gut microbiota pair and verify the inflammation-inducing effects of pesticide exposure on the host, mediated by microbially dysregulated lipid metabolism. Taken together, our findings generate a comprehensive atlas of pesticide-gut microbiota-metabolite interactions atlas and shed light on the molecular mechanisms by which pesticides affect host health via gut microbiota-modulated metabolism.

Honeybee toxicity of pesticides used in United States maize and soybean production, 1998-2020

Pesticides are widely used around the world and have demonstrated benefits to crop production. However, pesticides have also been associated with negative impacts to nontarget organisms, including pollinators. Here, we combined pesticide usage and toxicity data to create a toxicity index, which shows that pesticide hazard to honeybees (Apis mellifera) has changed substantially in U.S. maize (Zea mays) and soybean (Glycine max) production between 1998 and 2020. To reduce potential risks to honeybees and increase the eco-efficiency of crop production, efforts should be made to refine management strategies for pests that contribute most to the honeybee toxicity index. In maize, Coleoptera and Lepidoptera pests drive pesticide usage most responsible for hazard to honeybees, although the relative hazard from targeting those pests has decreased over time. In soybean, hemipteran pests were the largest relative contributor to insecticide honeybee hazard. Specific pests that contributed to honeybee toxicity hazard included corn rootworm species (Diabrotica spp.), silk-eating insects, and cutworms in maize, and stink bugs (family Pentatomidae) and aphid species (Family Aphididae) in soybean. We combined crop yield data with the toxicity index to quantify the eco-efficiency, a measure of crop yield per unit of toxicity hazard. While crop yield for both maize and soybean increased steadily throughout the study period, eco-efficiency decreased in both crops between 2012 and 2020, suggesting increases in crop yield have failed to keep pace with increases in insecticide hazard to honeybees.

Contribution of Nilaparvata lugens Nicotinic Acetylcholine Receptor Subunits Toward Triflumezopyrim and Neonicotinoid Susceptibility

Nicotinic acetylcholine receptors (nAChRs) are the molecular targets of some important insecticides including triflumezopyrim and neonicotinoids. However, our understanding of insect nAChR pharmacology and the specific nAChR subunits targeted by these insecticides remains limited. Here, we cloned 11 nAChR subunit genes, comprising Nlα1 to Nlα8, Nlα10, Nlβ1 and Nlβ3, from Nilaparvata lugens, a highly damaging insect pest of rice crops worldwide. Analysis of the expression of these genes in different tissues of N. lugens by qPCR analysis identified the brain as the primary site of expression. Knock down of the expression of Nlα1, Nlα2, Nlα8 and Nlβ1 using RNAi reduced N. lugens sensitivity to triflumezopyrim, suggesting these genes encode potential target subunits for triflumezopyrim. Knock out of Nlα2 and Nlα8 nAChR subunits by CRISPR/Cas9 genome editing showed that their deletion significantly reduced the toxicity of triflumezopyrim toward N. lugens. Furthermore, the deletion of Nlα2 also increased N. lugens resistance to imidacloprid and dinotefuran. However, numerous attempts revealed that the Nlβ1 knockout was nonviable. In vitro expression of receptors composed of Drosophila homologous subunits showed that this all-insect nAChR was inhibited by nanomolar concentrations of triflumezopyrim. The present findings identify specific nAChR subunits that are important both as targets for monitoring resistance-associated mutations and as subjects for molecular studies aimed at developing novel insecticides targeting these essential ion channels.

Plant volatiles-loaded core-shell micro-nano fibers to achieve efficient and sustained bisexual attraction to pests

BACKGROUND

Chemical pesticides face significant challenges regarding their efficacy and environmental impact. Plant-based food attractants have emerged as a promising green alternative for pest control. However, their field application is limited by the short duration of effectiveness, necessitating improved carrier systems for sustained release. Electrospinning is a promising technology in this field, with core-shell fibers offering superior performance in efficient loading and sustained release compared to uniaxial fibers, highlighting their potential for further development.

RESULTS

In this study, core-shell micro-nano fiber mats were prepared via coaxial electrospinning using multiple environmentally friendly polymers. These mats were firstly and successfully loaded with food attractants bisexually attractive to Loxostege sticticalis adults, including 1-octen-3-ol, trans-2-hexenal, linalool, and anethole, enabling sustained release and effective trapping. The components in the core-shell spinning solution were chemically compatible, and after spinning, the poly(3-hydroxybutyrate-co-4-hydroxybutyrate)/polycaprolactone (PHB/PCL) in the shell layer and polyethylene oxide (PEO) in the core layer formed core-shell fibers with clear boundaries. The mats achieved an average encapsulation efficiency of 78% for active ingredients, with a sustained release profile that delivered over 60% of the attractants within 80 days while mitigating early burst release. Electroantennogram and behavioral studies revealed that the mats retained electrophysiological activity for at least 90 days, effectively attracting male and female adult insects even after 75 days. Field trials demonstrated that the mats significantly outperformed commercial slow-release carriers, attracting a higher number of L. sticticalis adults. Additionally, the mats exhibited strong stress resistance, biodegradability, and environmental compatibility, effectively protecting active molecules while minimizing ecological impact.

CONCLUSIONS

The developed fiber mats provide a highly efficient, eco-friendly carrier for plant-based food attractants, offering prolonged efficacy and improved insect trapping performance. This study highlights their potential for sustainable agriculture and pest management, paving the way for greener alternatives to chemical pesticides.

Pesticides in France: ten years of combined exposure to active substances in land, air and surface water

Spatial and temporal fine-scale data of exposure to pesticide in the environment are of great need to environmental and health research. The omnipresence of pesticides in the environment is attested to by numerous analyses, but the availability of data remains inadequate, preventing temporal analyses on large spatial scales such as the national level, where agricultural policies are implemented or adopted. We have compiled data on the purchase of more than a hundred active substances with measurements of pollution of these substances in the air and surface water to propose a map of exposure to the most dangerous active substances between 2013 and 2022 in metropolitan France. We provide a technical validation of the exposure index using a dataset constructed from infield surveys. The combined exposure index is designed to be updated annually, and we anticipate that this dataset will provide first-rate information for conservation and health research.

Strategy for the Selection of Tank-Mix Adjuvants to Improve the Wettability of Unmanned Aerial Vehicle-Sprayed Liquids on Citrus Leaf Surfaces

The past decade has witnessed a growth spurt in aerial pesticide application by plant protection unmanned aerial vehicles (UAVs). However, compared to the traditional ground application, their operation characteristics of low capacity and high concentration put forward rather higher requirements for the wettability of pesticide solutions on the target crop surface, which was a critical link to the pesticide efficiency. Tank mix of adjuvants is a common measure to modify the spray liquid wettability during foliar pesticide application. Yet, given the wide variety of spray adjuvants available, how to select suitable ones based on crop leaf surface characteristics during pesticide application of plant-protection UAVs still lacks attention, especially for tree crops like citrus. Herein, the surface free energy of citrus leaf, the surface tension of tested liquids, and their contact angles on citrus leaf were determined, and the quantitative relationship between the contact angle and the surface tension and its components, as well as the citrus leaf surface free energy and its components, was analyzed. The surface free energy of the adaxial and abaxial surface of citrus leaf was as low as 30.31 mJ m-2 and 27.50 mJ m-2, respectively, showing that citrus leaves are relatively difficult to wet. However, addition with 1% (v/v) of the three tested spray adjuvants to the liquid significantly reduced the surface tension, especially the polar component, thereby substantially decreasing its contact angles on the citrus leaf surface. There was a significant positive correlation between the droplet contact angle on citrus leaf surfaces and liquid surface tension and its polar component, with total surface tension as the main variable and the polar component as the covariant. Our findings proposed a strategy for screening tank-mix adjuvants to improve spray liquid wettability on tree crop leaves during pesticide application by plant-protection UAVs.

Enantioselective disruption of circadian rhythm behavior in goldfish (Carassius auratus) induced by chiral fungicide triadimefon at environmentally-relevant concentration

The pollution of triadimefon (TDF) fungicides significantly hinders the "One Health" frame achievement. However, the enantioselective effects of chiral TDF on the circadian rhythm of fish remained unclear. Herein, TDF enantiomers (R(-)-TDF and S(+)-TDF) and racemic Rac-TDF were selected to investigate their enantioselective effects and mechanisms on circadian rhythm of goldfish (Carassius auratus) at an environmentally-relevant concentration (100 µg L⁻¹). S(+)-TDF reduced the diurnal-nocturnal differences in schooling behavior more strongly than R(-)-TDF, proving the enantioselectively weakened circadian rhythm of goldfish by TDF. S(+)-TDF more preferentially bioaccumulated in goldfish than R(-)-TDF, mainly contributed to the enantioselectively disrupted circadian rhythm. On one hand, TDF enantiomers in brains differentially inhibited neuronal activity, leading to cholinergic system dysfunction. On the other hand, TDF enantiomers in intestines differentially disrupted intestinal barriers, thus potentially dysregulating the "brain-gut" axis. Importantly, the commercial probiotics alleviated the behavioral disorder, indirectly confirming that the dysbiosis of intestinal bacteria contributed to the TDF-induced circadian rhythm disruption. These findings provide novel insights into the enantioselective disruption of fish circadian rhythm behaviors by chiral fungicides at enantiomer levels, and offer novel strategies for early assessing the ecological risks of chiral agrochemicals in aquatic ecosystems.

Neglected impacts of plant protection products on invertebrate aquatic biodiversity: a focus on eco-evolutionary processes

The application of plant protection products (PPPs) may have delayed and long-term non-intentional impacts on aquatic invertebrates inhabiting agricultural landscapes. Such effects may induce population responses based on developmental and transgenerational plasticity, selection of genetic resistance, as well as increased extirpation risks associated with random genetic drift. While the current knowledge on such effects of PPPs is still scarce in non-target aquatic invertebrate species, evidences are accumulating that support the need for consideration of evolutionary components of the population response to PPPs in standard procedures of risk assessment. This mini-review, as part of a contribution to the collective scientific assessment on PPP impacts on biodiversity and ecosystem services performed in the period 2020-2022, presents a brief survey of the current results published on the subject, mainly in freshwater crustaceans, and proposes some research avenues and strategies that we feel relevant to fill this gap.

Effects of plant protection products on ecosystem functions provided by terrestrial invertebrates

Plant protection products (PPP) are extensively used to protect plants against harmful organisms, but they also have unintended effects on non-target organisms, especially terrestrial invertebrates. The impact of PPP on ecosystem functions provided by these non-target invertebrates remains, however, unclear. The objectives of this article were to review PPP impacts on the ecosystem functions provided by pollinators, predators and parasitoids, and soil organisms, and to identify the factors that aggravate or mitigate PPP effects. The literature highlights that PPP alter several ecosystem functions: provision and maintenance of biodiversity, pollination, biotic interactions and habitat completeness in terrestrial ecosystems, and organic matter and soil structure dynamics. However, there are still a few studies dealing with ecosystem functions, with sometimes contradictory results, and consequences on agricultural provisioning services remain unclear. The model organisms used to assess PPP ecotoxicological effects are still limited, and should be expanded to better cover the wide functional diversity of terrestrial invertebrates. Data are lacking on PPP sublethal, transgenerational, and "cocktail" effects, and on their multitrophic consequences. In empirical assessments, studies on PPP unintended effects should consider agricultural-pedoclimatic contexts because they influence the responses of non-target organisms and associated ecosystem functions to PPP. Modeling might be a promising way to account for the complex interactions among PPP mixtures, biodiversity, and ecosystem functioning.

The Benefit of Evolution of Pesticide Tolerance Is Overruled under Combined Stressor Exposure due to Synergistic Stressor Interactions

Despite pleas to consider both evolutionary and multistressor climate change perspectives to improve ecological risk assessment, the much needed combination of both perspectives is largely missing. This is especially important when evaluating the costs of the evolution of genetic tolerance to pollutants as these costs may become visible only under combined exposure to the pollutant and warming due to energetic constraints. We investigated the costs of chlorpyrifos tolerance in Daphnia magna when sequentially exposed to 4-day pesticide treatments and 4-day heat spike treatments. Exposure to chlorpyrifos reduced the fitness of chlorpyrifos-sensitive clones (reduced survival, mass, and reproductive performance), while it had positive (hormetic) effects on clones selected for chlorpyrifos tolerance. We did not find any costs of chlorpyrifos tolerance in the absence of the stressors and only a weak sublethal cost when only exposed to the heat spike. Notably, when sequentially exposed to the pesticide and the heat spike, the benefit of the evolution of chlorpyrifos tolerance was nullified as the chlorpyrifos-tolerant clones experienced (stronger) synergistic interactions between both stressors and stronger thermal costs when preceded by exposure to the pesticide. This highlights the importance of multistressor studies to correctly assess the costs of genetic pesticide tolerance and the potential of evolution of pesticide tolerance to rescue nontarget populations.

Diffuse soil pollution from agriculture: Impacts and remediation

Agricultural activities are essential for sustaining the global population, yet they exert considerable pressure on the environment. A major challenge we face today is agricultural pollution, much of which is diffuse in nature, lacking a clear point of origin for chemical discharge. Modern agricultural practices, which often depend on substantial applications of fertilizers, pesticides, and irrigation water, are key contributors to this form of pollution. These activities lead to downstream contamination through mechanisms such as surface runoff, leaching, soil erosion, wind dispersal, and sedimentation. The environmental and human health consequences of diffuse pollution are profound and cannot be ignored. Accurate assessment of the risks posed by agricultural pollutants is crucial for ensuring the production of safe, high-quality food while safeguarding the environment. This requires systematic monitoring and evaluation of agricultural practices, including soil testing and nutrient management. Furthermore, the development and implementation of best management practices (BMPs) are critical in reducing the levels of agricultural pollution. Such measures are essential for mitigating the negative impacts on ecosystems and public health. Therefore, the adoption of preventive strategies aimed at minimizing pollution and its associated risks is highly recommended to ensure long-term environmental sustainability and human well-being.

Glyphosate exposure and GM seed rollout unequally reduced perinatal health

The advent of herbicide-tolerant genetically modified (GM) crops spurred rapid and widespread use of the herbicide glyphosate throughout US agriculture. In the two decades following GM-seeds' introduction, the volume of glyphosate applied in the United States increased by more than 750%. Despite this breadth and scale, science and policy remain unresolved regarding the effects of glyphosate on human health. We identify the causal effect of glyphosate exposure on perinatal health by combining 1) county-level variation in glyphosate use driven by 2) the timing of the GM technology and 3) differential geographic suitability for GM crops. Our results suggest the introduction of GM seeds and glyphosate significantly reduced average birthweight and gestational length. While we find effects throughout the birthweight distribution, low expected-weight births experienced the largest reductions: Glyphosate's birthweight effect for births in the lowest decile is 12 times larger than that in the highest decile. Together, these estimates suggest that glyphosate exposure caused previously undocumented and unequal health costs for rural US communities over the last 20 years.

Solar-Light-Mediated Phototransformation of Herbicide Tribenuron-Methyl Initiated by Its Coexisting Nitrate Ion in Sunlit Agricultural Drainages

Understanding the environmental fate of chemical herbicides is crucial to sustainable agriculture. Due to their joint-use with nitrogen fertilizers, their residues often coexist with NO3- in agricultural drainages. In this study, tribenuron-methyl was used as a model to evaluate the role of NO3- in the phototransformation of chemical herbicides, which was characterized by a two-stage process. Initially, a slow hydrolysis occurs (kobs = 2.573 × 10-4 min-1), producing two hydrolysis products: methyl-2-(aminosulfonyl)-benzoate (MSB) and 2-methyl-4-methylamino-6-methoxy-1, 3, 5-triazine (MMT), which can be significantly accelerated by solar irradiation (kobs = 2.152 × 10-2 min-1). Subsequently, MSB undergoes a rapid NO3--initiated photodegradation process (kobs = 2.251 × 10-2 min-1). MMT was identified as the refractory unit and undergoes a slow NO3--initiated photodegradation process (kobs = 4.494 × 10-4 min-1). The underlying mechanisms were elucidated through electron paramagnetic resonance spectroscopy and reactive species quenching experiments. This study fills a knowledge gap on the interaction between NO3- and chemical herbicides, highlighting the pivotal role of NO3- in the phototransformation of chemical herbicides.

Degradation Kinetics and Mechanism of β-Cypermethrin and 3-Phenoxybenzoic Acid by Lysinibacillus pakistanensis VF-2 in Soil Remediation

Pyrethroid pesticide residues have detrimental effects on soil ecology and crop growth during insecticidal operations in agriculture. In this study, a novel strain Lysinibacillus pakistanensis VF-2 was isolated from long-term pesticide-treated cropland and had a maximum degradation efficiency of 81.66% for synthetic pyrethroid β-cypermethrin (β-CY) under optimized conditions. The analysis of intermediate products revealed that the degradation pathway of β-CY mainly involves ester bond hydrolysis, diphenyl ether decomposition, and phthalate ester degradation. Whole-genome sequencing and RT-qPCR analysis revealed the involvement of carboxylesterases, dioxygenases, and aromatic compound degrading enzymes in the degradation of β-CY. In the soil bioaugmentation experiment, the strain VF-2 can synergistically interact with indigenous microorganisms, significantly enhancing the degradation efficiency of β-CY and its metabolite 3-phenoxybenzoic acid (3-PBA) from 17.08% and 7.62% to 73.46% and 62.29%, respectively. This study suggests that strain VF-2 is a promising candidate for in situ coremediation of pyrethroid and intermediate metabolite residues in soil.

Potential Regional Pollination Services of Spodoptera litura (Lepidoptera: Noctuidae) Migrants as Evidenced by the Identification of Attached Pollen

Many species of noctuid moths exhibit long-distance migratory behavior and have an important pollination service function in terrestrial ecosystems. Spodoptera litura (Fabricius) is a globally distributed insect; however, its role in pollination remains underexplored. In this study, the feeding preferences and inter regional pollination of S. litura adults were explored. We conducted pollen analysis on 1253 S. litura migrants captured from 2018 to 2021 on Beihuangcheng Island in the Bohai Strait of China, which is located in the East Asian insect migration path. The results show that an average of 51.1% of S. litura migrants carry plant pollen each year, and the carrying rate shows fluctuations based on sex, year, and season. By combining morphological identification and DNA barcoding, pollen species were identified from 40 species of plants, representing 21 families and 26 genera, mainly from angiosperms of Dicotyledoneae, with Asteraceae, Apocynaceae, and Amaranthaceae being the dominant taxa. The geographical distribution range of Chrysanthemum zawadskii and Adenophora trachelioides and a migration trajectory simulation analysis indicate that S. litura predominantly migrate from Liaoning Province in Northeast China to North China over the Bohai Sea in autumn. These findings indicate the potential pollination activities of S. litura in North China and Northeast China, enriching our understanding of the interaction between S. litura and the plants it pollinates.

Deciphering the biodegradation of thiamethoxam by Phanerochaete chrysosporium with natural siderite: Synergistic mechanisms, transcriptomics characterization, and molecular simulation

Fungi play vital roles in the fate of organic pollutants, particularly when interacting with minerals in aquatic and soil environments. Mechanisms by which fungi may mitigate pollutions in fungus-mineral interactions are still unclear. Inspired by biogeochemical cycling, we constructed a range of co-culture systems to investigate synergistic effects of the white-rot fungus Phanerochaete chrysosporium and the iron-bearing mineral siderite on thiamethoxam (THX) transformation, a common neonicotinoid pesticide. Co-culturing with siderite significantly enhanced THX transformation during the initial 10 days with a dose effect, achieving 86 % removal within 25 days. Fungi could affect siderite's dissolution, transformation, and precipitation through their biological activities. These interactions triggered physiological adaptation and resilience in fungi. Siderite could enhance the activity of fungal ligninolytic enzymes and cytochrome P450, facilitating biotransformation. Genes expression related to growth, energy metabolism, and oxidative stress response upregulated, enhancing fungal resilience to THX. The primary THX degradation pathways included nitro-reduction, C-N cleavage, and de-chlorination. Molecular dynamics simulations provided insights into catalytic mechanisms of enzyme-THX interactions. Together, siderite could act as natural enhancers that endowed fungi to resist physical and chemical stresses in environments, providing insights into contaminants attenuation, fungal biomineralization, and the coevolution of the Earth's lithosphere and biosphere.

Pesticide impacts on insect pollinators: Current knowledge and future research challenges

With the need to intensify agriculture to meet growing food demand, there has been significant rise in pesticide use to protect crops, but at different rates in different world regions. In 2016, the Intergovernmental Science-Policy Platform on Biodiversity and Ecosystem Services (IPBES) global assessment on pollinators, pollination and food production identified pesticides as one of the major drivers of pollinator decline. This assessment highlighted that studies on the effects of pesticides on pollinating insects have been limited to only a few species, primarily from developed countries. Given the worldwide variation in the scale of intensive agricultural practices, pesticide application intensities are likely to vary regionally and consequently the associated risks for insect pollinators. We provide the first long-term, global analysis of inter-regional trends in the use of different classes of pesticide between 1995 and 2020 (FAOSTAT) and a review of literature since the IPBES pollination assessment (2016). All three pesticide classes use rates varied greatly with some countries seeing increased use by 3000 to 4000 % between 1995 and 2020, while for most countries, growth roughly doubled. We present forecast models to predict regional trends of different pesticides up to 2030. Use of all three pesticide classes is to increase in Africa and South America. Herbicide use is to increase in North America and Central Asia. Fungicide use is to increase across all Asian regions. In each of the respective regions, we also examined the number of studies since 2016 in relation to pesticide use trends over the past twenty-five years. Additionally, we present a comprehensive update on the status of knowledge on pesticide impacts on different pollinating insects from literature published during 2016-2022. Finally, we outline several research challenges and knowledge gaps with respect to pesticides and highlight some regional and international conservation efforts and initiatives that address pesticide reduction and/or elimination.

Unexpected soundscape response to insecticide application in oak forests

Rachel Carson's warning of a silent spring directed attention to unwanted side effects of pesticide application. Though her work led to policies restricting insecticide use, various insecticides currently in use affect nontarget organisms and may contribute to population declines. The insecticide tebufenozide is used to control defoliating Lepidoptera in oak forests harboring rich insect faunas. Over 3 years, we tested the effect of its aerial application on bird populations with autonomous sound recorders in a large, replicated, full factorial field experiment during a spongy moth (Lymantria dispar) outbreak. The soundscape analysis combined automated aggregation of recordings into sound indices with species identification by experts. After pesticide application in the year of the outbreak, acoustic complexity in early summer was significantly reduced. The soundscape analysis showed that the reduction was not related to birds, but instead to the large reduction in caterpillar feeding and frass dropping. Effects on the vocal activity of birds were smaller than originally expected from a related study demonstrating tebufenozide's negative effect on bird breeding success. The legacy of the pesticide treatment, in terms of soundscape variation, was not present in the second year when the outbreak had ended. Our results showed a dimension of insecticide-induced acoustic variation not immediately accessible to the human ear. It also illustrated how a multifaceted soundscape analysis can be used as a generic approach to quantify the impact of anthropogenic stressors in novel ways by providing an example of remote and continuous sound monitoring not possible in conventional field surveys.

Mapping Pesticide-Induced Metabolic Alterations in Human Gut Bacteria

Pesticides can modulate gut microbiota (GM) composition, but their specific effects on GM remain largely elusive. Our study demonstrated that pesticides inhibit or promote growth in various GM species, even at low concentrations, and can accumulate in GM to prolong their presence in the host. Meanwhile, the pesticide induced changes in GM composition are associated with significant alterations in gut bacterial metabolism that reflected by the changes of hundreds of metabolites. We generated a pesticide-GM-metabolites (PMM) network that not only reveals pesticide-sensitive gut bacteria species but also report specific metabolic changes in 306 pesticide-GM pairs (PGPs). Using an in vivo mice model, we further demonstrated a PGP's interactions and verified the inflammation-inducing effects of pesticides on the host through dysregulated lipid metabolism of microbes. Taken together, our findings generate a PMM interactions atlas, and shed light on the molecular level of how pesticides impact host health by modulating GM metabolism.

Integrating Anthropogenic-Pesticide Interactions Into a Soil Health-Microbial Index for Sustainable Agriculture at Global Scale

Soil microbiota in intensive agriculture are threatened by pesticides, economic activities, and land-use changes. However, the interactions among these anthropogenic factors remain underexplored. By analyzing 2356 soil metagenomes from around the world, we developed a comprehensive soil health-microbial index that integrates microbial diversity, nutrient cycling potential, metabolic potential, primary productivity, and health risks to assess how the soil microbiota respond to anthropogenic factors. Our results indicated that the health-microbial index was the lowest with severe pesticide contamination. Pesticides, in combination with other anthropogenic and climatic factors, exacerbate the decline in this index. Machine learning predictions suggest that the health-microbial index in approximately 26% of global farmland could decline between 2015 and 2040, even under sustainable development scenarios. Even with strategies to reduce pesticide usage, we cannot completely halt the decline in the health-microbial index. Our findings highlight that sustaining soil microbial health on a global scale requires addressing not only pesticide management but also broader anthropogenic impacts.

Field and Laboratory Evidence That Chlorpyrifos Exposure Reduced the Population Density of a Freshwater Snail by Increasing Juvenile Mortality

Pesticides have been frequently detected in global freshwater ecosystems, but attempts to document changes in population dynamics of organisms upon exposure to pesticides, establish a causal relationship between exposure and population effects, and identify the key toxic events within individuals under natural field conditions remain rare. Here, we used a field survey, a reciprocal cross-transplant experiment, and a laboratory toxicity experiment to build a compelling case that exposure to the insecticide chlorpyrifos was responsible for differences in snail (Bellamya aeruginosa) densities in eastern (ELL) and western basins of Liangzi Lake in China. Our field survey and reciprocal cross-transplant experiment revealed significant differences in snail densities, juvenile percentage, survival, and relative telomere length (RTL) in the two basins. The insecticide chlorpyrifos detected in snail tissues was negatively correlated with snail densities, the percentage of juvenile snails, and RTL and had an extremely high risk quotient in ELL. In the laboratory experiment, tissue concentrations of chlorpyrifos detected in ELL were associated with reduced RTL and increased juvenile mortality in B. aeruginosa. These results support the hypothesis that chlorpyrifos exposure in ELL reduced the density of snails by reducing juvenile survival and, consequently, recruitment to the adult population.

Temporal and spatial trends of imidacloprid-related hazards in France

Neonicotinoids are the top-selling insecticides worldwide. Because of their method of use, mainly to coat seeds, neonicotinoids have been found to widely contaminate the environment. Their high toxicity has been shown to be a major concern in terms of impact on biodiversity, and the use of these insecticides has been associated with population declines of species in different countries. Despite the widespread recognition of the risk of neonicotinoids to biodiversity, their temporal and spatial use remains poorly known in many countries. Yet this information is essential to address the potential impacts of these pesticides on biodiversity and to inform measures to establish protected areas or biodiversity restoration. The present study relied a large publicly available dataset to characterise the temporal and spatial use in France of imidacloprid, the most widely used neonicotinoid worldwide, as well as analysed water contamination surveys between 2005 and 2022 to assess the contamination of the environment. The results show that imidacloprid was the main neonicotinoid used in France over the study period. This use was spatially structured, with higher use in northern and western France, particularly related to cereal and beet crops area. The water contamination survey indicated that imidacloprid has widely contaminated the environment and consequently increased the risk to biodiversity, especially in counties crossed by the Loire, Seine and Vilaine rivers. This risk increased between 2005 and 2018 due to the higher use of imidacloprid and decreased sharply after 2018 due to its ban, although it was reauthorized by derogation for sugar beet in 2021. This study is the first assessment of imidacloprid pressure on biodiversity in France and shows the spatial and temporal correlation between agricultural practices and the freshwater contamination level. These results will help to identify priority areas for mitigation and restoration measures.

The economic impacts of ecosystem disruptions: Costs from substituting biological pest control

Biodiversity loss is accelerating, yet we know little about how these ecosystem disruptions affect human well-being. Ecologists have documented both the importance of bats as natural predators of insects as well as their population declines after the emergence of a wildlife disease, resulting in a potential decline in biological pest control. In this work, I study how species interactions can extend beyond an ecosystem and affect agriculture and human health. I find that farmers compensated for bat decline by increasing their insecticide use by 31.1%. The compensatory increase in insecticide use by farmers adversely affected health-human infant mortality increased by 7.9% in the counties that experienced bat die-offs. These findings provide empirical validation to previous theoretical predictions about how ecosystem disruptions can have meaningful social costs.

Plant Root Secretion Alleviates Carbamate-Induced Molecular Alterations of Dissolved Organic Matter

Studying the interaction between pesticide contamination in the plant system and the dissolved organic matter (DOM) composition is important to understand the impact of pesticides and plants on the ecological function of DOM. The present study investigated the effects of DOM on the bioaccumulation and biotransformation of carbamates in plants, carbamate exposure on DOM composition, and plant root secretion on the interaction between DOM and carbamates. The concentrations of carbamates and their metabolites in living cabbage plants were continuously tracked through an in vivo analytical method. The presence of DOM was found to reduce the highest bioconcentrations and shorten the time it took to reach the highest bioaccumulated amounts of isoprocarb and carbofuran in plants, while it showed no significant effect on the uptake behavior of carbaryl. DOM profiling results indicated that carbamate exposure substantially decreased the number and molecular diversity of DOM. Notably, plant root secretion alleviated carbamate-induced DOM molecular alterations by inducing a higher turnover rate of DOM compared to that in the uncontaminated group, highlighting the role of plants in mitigating the effects of exogenous pesticide exposure on DOM composition and maintaining DOM molecular homeostasis.

Dynamic changes of fatty acids and (R)-dichlorprop toxicity in Arabidopsis thaliana: correlation, mechanism, and implications

Plant fatty acids (FAs) are critical components of lipids and play an important role in coping with pollution-induced stress. However, the relationship between the fluctuating changes of FAs and the toxic effects of pollutants is not clear. Here, we analyzed and identified 19 FAs, namely 14 medium and long chain fatty acids (MLCFAs) and 5 very long chain fatty acids (VLCFAs). First, a positive correlation between plant biomass and LCFA content was observed. Changes in unsaturation were inversely related to cell membrane permeability, which serves as an indicator of the toxic effects. In particular, the use of herbicides led to a reduction in total FA content, but caused a significant increase in free fatty acids (FFAs), which facilitate oxidative stress. In addition, supplementation with exogenous FAs, particularly linoleic and alpha-linolenic acids, effectively alleviated the toxic inhibition. (R)-dichlorprop causes abnormal FA metabolism that can be reversed by ferrostatin-1, a ferroptosis inhibitor. Under (R)-dichlorprop exposure, the balance of FA unsaturation in plants is disrupted by inhibition of FA desaturase activity, ultimately leading to ferroptosis and disruption of cell membrane integrity. This study aims to enhance the understanding of the ecotoxic effects of herbicides by examining changes in FAs. The findings will provide a scientific basis for controlling environmental risks associated with hazardous substances.

Sensitivity and antioxidant response of forest species seedlings to the atrazine under simulated conditions of subsurface water contamination

Atrazine is an herbicide with a high soil leaching capacity, contaminating subsurface water sources. Once the water table is contaminated, riparian species can be exposed to atrazine. In this way, understanding the impacts of this exposure must be evaluated for planning strategies that minimize the effects of this herbicide on native forest species. We aimed to evaluate forest species' sensitivity and antioxidant response to exposure to subsurface waters contaminated with atrazine, as well the dissipation this herbicide. The experiment was conducted in a greenhouse in a completely randomized design, with three replications and one plant per experimental unit. The treatments were arranged in a 2 × 10 factorial. The first factor corresponded to the presence or absence (control) of the atrazine in the subsurface water. The second factor comprised 10 forest species: Amburana cearensis, Anadenanthera macrocarpa, Bauhinia cheilantha, Enterolobium contortisiliquum, Hymenaea courbaril, Libidibia ferrea, Mimosa caesalpiniifolia, Mimosa tenuiflora, Myracrodruon urundeuva, and Tabebuia aurea. The forest species studied showed different sensitivity levels to atrazine in subsurface water. A. cearensis and B. cheilantha species do not have efficient antioxidant systems to prevent severe oxidative damage. The species A. macrocarpa, E. contortisiliquum, L. ferrea, and M. caesalpiniifolia are moderately affected by atrazine. H. courbaril, M. urundeuva, and T. aurea showed greater tolerance to atrazine due to the action of the antioxidant system of these species, avoiding membrane degradation events linked to the production of reactive oxygen species (ROS). Among the forest species, H. courbaril has the most significant remedial potential due to its greater tolerance and reduced atrazine concentrations in the soil.

Acute toxicity effects of pesticides on beneficial organisms - Dispelling myths for a more sustainable use of chemicals in agricultural environments

Agricultural practitioners, researchers and policymakers are increasingly advocating for integrated pest management (IPM) to reduce pesticide use while preserving crop productivity and profitability. Using selective pesticides, putatively designed to act on pests while minimising impacts on off-target organisms, is one such option - yet evidence of whether these chemicals control pests without adversely affecting natural enemies and other beneficial species (henceforth beneficials) remains scarce. At present, the selection of pesticides compatible with IPM often considers a single (or a limited number of) widely distributed beneficial species, without considering undesired effects on co-occurring beneficials. In this study, we conducted standardised laboratory bioassays to assess the acute toxicity effects of 20 chemicals on 15 beneficial species at multiple exposure timepoints, with the specific aims to: (1) identify common and diverging patterns in acute toxicity responses of tested beneficials; (2) determine if the effect of pesticides on beetles, wasps and mites is consistent across species within these groups; and (3) assess the impact of mortality assessment timepoints on International Organisation for Biological Control (IOBC) toxicity classifications. Our work demonstrates that in most cases, chemical toxicities cannot be generalised across a range of beneficial insects and mites providing biological control, a finding that was found even when comparing impacts among closely related species of beetles, wasps and mites. Additionally, we show that toxicity impacts increase with exposure length, pointing to limitations of IOBC protocols. This work challenges the notion that chemical toxicities can be adequately tested on a limited number of 'representative' species; instead, it highlights the need for careful consideration and testing on a range of regionally and seasonally relevant beneficial species.

Transfer and bioaccumulation of pesticides in terrestrial arthropods and food webs: State of knowledge and perspectives for research

Arthropods represent an entry point for pesticide transfers in terrestrial food webs, and pesticide accumulation in upper chain organisms, such as predators can have cascading consequences on ecosystems. However, the mechanisms driving pesticide transfer and bioaccumulation in food webs remain poorly understood. Here we review the literature on pesticide transfers mediated by terrestrial arthropods in food webs. The transfer of pesticides and their potential for bioaccumulation and biomagnification are related to the chemical properties and toxicokinetic of the substances, the resistance and detoxification abilities of the contaminated organisms, as well as by their effects on organisms' life history traits. We further identify four critical areas in which knowledge gain would improve future predictions of pesticides impacts on terrestrial food webs. First, efforts should be made regarding the effects of co-formulants and pesticides mixtures that are currently understudied. Second, progress in the sensitivity of analytical methods would allow the detection of low concentrations of pesticides in small individual arthropods. Quantifying pesticides in arthropods preys, their predators, and arthropods or vertebrates at higher trophic level would bring crucial insights into the bioaccumulation and biomagnification potential of pesticides in real-world terrestrial food webs. Finally, quantifying the influence of the trophic structure and complexity of communities on the transfer of pesticides could address several important sources of variability in bioaccumulation and biomagnification across species and food webs. This narrative review will inspire future studies aiming to quantify pesticide transfers in terrestrial food webs to better capture their ecological consequences in natural and cultivated landscapes.

Regulatory potential of secondary metabolite DIMBOA and baicalein to imazethapyr-induced toxicity in wheat seedlings

Controlling and mitigating the toxicity of herbicides to non-target plants is of significant importance in reducing ecological risks. The development of green and natural herbicide control technologies has become an urgent necessity. In this paper, how 2,4-dihydroxy-7-methoxy-2H-1,4-benzoxazine-3(4H)-one (DIMBOA) and baicalein alleviated oxidative stress induced by imazethapyr (IM) in wheat seedlings was investigated. We found that DIMBOA and baicalein enhanced the antioxidant enzyme activities in wheat seedlings exposed to IM and reduced the excessive reactive oxygen species due to IM stress by 21.3% and 23.5%, respectively. DIMBOA and baicalein also restored the iron content reduced by IM and effectively mitigated Fe2+ overload by alleviating the response of heme oxygenase 1 to IM stress. The antioxidant and iron homeostatic maintenance properties of DIMBOA and baicalein enhanced the defenses of wheat seedlings against IM stress. Our results highlight the potential implication of secondary metabolites as natural products to modulate herbicide toxicity to non-target plants.

Making the Complicated Simple: A Minimizing Carrier Strategy on Innovative Nanopesticides

The flourishing progress in nanotechnology offers boundless opportunities for agriculture, particularly in the realm of nanopesticides research and development. However, concerns have been raised regarding the human and environmental safety issues stemming from the unrestrained use of non-therapeutic nanomaterials in nanopesticides. It is also important to consider whether the current development strategy of nanopesticides based on nanocarriers can strike a balance between investment and return, and if the complex material composition genuinely improves the efficiency, safety, and circularity of nanopesticides. Herein, we introduced the concept of nanopesticides with minimizing carriers (NMC) prepared through prodrug design and molecular self-assembly emerging as practical tools to address the current limitations, and compared it with nanopesticides employing non-therapeutic nanomaterials as carriers (NNC). We further summarized the current development strategy of NMC and examined potential challenges in its preparation, performance, and production. Overall, we asserted that the development of NMC systems can serve as the innovative driving force catalyzing a green and efficient revolution in nanopesticides, offering a way out of the current predicament.

Biodiversity-production feedback effects lead to intensification traps in agricultural landscapes

Intensive agriculture with high reliance on pesticides and fertilizers constitutes a major strategy for 'feeding the world'. However, such conventional intensification is linked to diminishing returns and can result in 'intensification traps'-production declines triggered by the negative feedback of biodiversity loss at high input levels. Here we developed a novel framework that accounts for biodiversity feedback on crop yields to evaluate the risk and magnitude of intensification traps. Simulations grounded in systematic literature reviews showed that intensification traps emerge in most landscape types, but to a lesser extent in major cereal production systems. Furthermore, small reductions in maximal production (5-10%) could be frequently transmitted into substantial biodiversity gains, resulting in small-loss large-gain trade-offs prevailing across landscape types. However, sensitivity analyses revealed a strong context dependence of trap emergence, inducing substantial uncertainty in the identification of optimal management at the field scale. Hence, we recommend the development of case-specific safety margins for intensification preventing double losses in biodiversity and food security associated with intensification traps.

Survival of a microbial inoculant in soil after recurrent inoculations

Microbial inoculants are attracting growing interest in agriculture, but their efficacy remains unreliable in relation to their poor survival, partly due to the competition with the soil resident community. We hypothesised that recurrent inoculation could gradually alleviate this competition and improve the survival of the inoculant while increasing its impact on the resident bacterial community. We tested the effectiveness of such strategy with four inoculation sequences of Pseudomonas fluorescens strain B177 in soil microcosms with increasing number and frequency of inoculation, compared to a non-inoculated control. Each sequence was carried out at two inoculation densities (106 and 108 cfu.g soil-1). The four-inoculation sequence induced a higher abundance of P. fluorescens, 2 weeks after the last inoculation. No impact of inoculation sequences was observed on the resident community diversity and composition. Differential abundance analysis identified only 28 out of 576 dominants OTUs affected by the high-density inoculum, whatever the inoculation sequence. Recurrent inoculations induced a strong accumulation of nitrate, not explained by the abundance of nitrifying or nitrate-reducing microorganisms. In summary, inoculant density rather than inoculation pattern matters for inoculation effect on the resident bacterial communities, while recurrent inoculation allowed to slightly enhance the survival of the inoculant and strongly increased soil nitrate content.

Pesticides in Ethiopian surface waters: A meta-analytic based ecological risk assessment

In most developing countries, including Ethiopia, a conspicuous gap exists in understanding risk of pesticides and establishing robust regulatory frameworks for their effective management. In this context, we present a detailed assessment of pesticide risks within Ethiopian aquatic ecosystems in at least 18 distinct surface water bodies, including 46 unique sample locations. Measured environmental concentrations (MECs; n = 388) of current-use pesticides (n = 52), sourced from existing field studies, were compared against their respective regulatory threshold levels (RTLs). The results indicated a scarcity of pesticide exposure data across the majority of Ethiopian water bodies situated within agricultural watersheds. Importantly, surface water pesticide concentrations ranged from 0.0001 to 142.66 μg/L, with a median concentration of 0.415 μg/L. The available dataset revealed that 142 out of 356 MECs (approximately 40 %) of the identified pesticides entail significant acute risks to aquatic ecosystems, with the highest RTL exceedances up to a factor of 8695. Among the pesticide use groups, insecticides exhibited the highest exceedance rate, while this was rarer for fungicides and herbicides. Furthermore, a species-specific insecticide risk assessment indicated aquatic invertebrates (54.4 %) and fishes (38.4 %) are more exposed to pesticide risks, attributable to pyrethroids and organophosphates. In conclusion, our findings demonstrate that the presently registered pesticides in Ethiopia carry elevated risks towards aquatic environments under real-world settings. This challenges the notion that pesticides approved through Ethiopian pesticide regulatory risk assessment entail minimal environmental hazards. Consequently, we advocate for the adoption of more refined risk assessment strategies, a post-registration reevaluation process, and, if deemed necessary, the imposition of bans or restrictions on highly toxic pesticides.

Ultrasensitive and visual detection of genetically modified crops using two primers-induced cascade exponential amplification assay

The increased global cultivation area of genetically modified (GM) crops has caused severe controversies over potential health and environmental risks worldwide. There is an urgent need to verify even trace amount of a particular GM material in products. Herein, a two primers-induced cascade exponential amplification reaction combined with cationic conjugated polymers (CCPs)-based visual detection method is developed for rapid and ultrasensitive detection of GM crops. This method only uses two primers to specifically recognize the four regions of the target gene, which is easier for primer design and probably more suitable for the detection of shorter targets. By integrating the two exponential amplification reactions, as low as 5 pg genomic DNA from GM maize can be accurately detected, which is more sensitive than the single amplification-based methods. Taking advantage of the efficient fluorescence resonance energy transfer (FRET) between CCPs and the commercial fluorescent dye SYBR Green I (SG), our method can differentiate as low as 0.01 % GM maize from a large amount of non-GM maize, which is the most accurate method so far. By changing the two primers according to target gene, our method can be modified to the detection of any other GM materials, indicating that our method is promising to be applied in other GM materials-related testing and screening system.

Comparative deterministic and probabilistic approaches for assessing the aquatic ecological risk of pesticides in a mixed land use basin: A case study in Uruguay

Environmental concentrations of 25 pesticides in superficial water were employed to conduct an ecological risk assessment (ERA) in a mixed land-use basin utilized as a drinking water source. A deterministic risk assessment (RQ) was utilized to evaluate the chronic risk to aquatic biota, while a probabilistic risk assessment (PRA) approach was applied to assess the acute and chronic risk in the most sensitive species and at the community level. A high risk was identified for insecticides (pyrethroids, organophosphates and organochlorines). RQs ranged from 4.0e-4 (2,4-D) to 105.3 (ethion) considering median concentrations and from 8.0e-4 (2,4-D) to 230 (p,p'-DDT) considering extreme concentrations. Temporal variation in ΣRQs showed the highest risk during spring and summer months, which is related to the crop calendar and land use in the Laguna del Cisne basin. For PRA, the probability of exceeding the hazardous concentration HC5 (5th percentile) was higher for the most sensitive species in chronic exposure, especially for cypermethrin (38.9 %), permethrin (25.6 %), and chlorpyrifos (16.6 %). In the case of acute exposures, the probability of surpassing HC5 was higher for the entire freshwater biota, with the highest values observed for bifenthrin (28.3 %), cypermethrin (25.5 %), permethrin (11.75 %), and ethion (11.1 %). The advantages and disadvantages of PRA for assessing pesticide ecological risk were compared with the conventional deterministic RQs approach, highlighting that PRA offers improvements over the deterministic risk assessment, especially for organophosphate pesticides. Additionally, PRA provides a more comprehensive evaluation of risk for both short and long-term exposure, has the potential to incorporate others available toxicity data (e.g., LD50, Daily Intake), and utilizes different hazardous concentrations, such as HC5, HC10, and HC50. Our findings emphasize the urgent need to establish a national regulatory framework to evaluate and mitigate pesticide risks in aquatic ecosystems, especially in drinking water source like Laguna del Cisne.

A spatially explicit model of landscape pesticide exposure to bees: Development, exploration, and evaluation

Pesticides represent one of the greatest threats to bees and other beneficial insects in agricultural landscapes. Potential exposure is generated through compound- and crop-specific patterns of pesticide use over space and time and unique degradation behavior among compounds. Realized exposure develops through bees foraging from their nests across the spatiotemporal mosaic of floral resources and associated pesticides throughout the landscape. Despite the recognized importance of a landscape-wide approach to assessing exposure, we lack a sufficiently-evaluated predictive framework to inform mitigation decisions and environmental risk assessment for bees. We address this gap by developing a bee pesticide exposure model that incorporates spatiotemporal pesticide use patterns, estimated rates of pesticide degradation, floral resource dynamics across habitats, and bee foraging movements. We parameterized the model with pesticide use data from a public database containing crop-field- and date-specific records of uses throughout our study region over an entire year. We evaluate the model performance in predicting bee pesticide exposure using a dataset of pesticide residues in pollens gathered by bumble bees (Bombus vosnesenskii) returning to colonies across 14 spatially independent landscapes in Northern California. We applied alternative model formulations of pesticide accumulation and degradation, floral resource seasonality, and bee foraging behavior to evaluate different levels of detail for predicting observed pesticide exposure. Our best model explained 73 % of observed variation in pesticide exposure of bumble bee colonies, with generally positive correlations for the dominant compounds. Timing and location of pesticide use were integral, but more detailed parameterizations of pesticide degradation, floral resources, and bee foraging improved the predictions little if at all. Our results suggest that this approach to predict bees' pesticide exposure has value in extending from the local field scale to the landscape in environmental risk assessment and for exploring mitigation options to support bees in agricultural landscapes.

A synthesis of anthropogenic stress effects on emergence-mediated aquatic-terrestrial linkages and riparian food webs

Anthropogenic stress alters the linkage between aquatic and terrestrial ecosystems in various ways. Here, we review the contemporary literature on how alterations in aquatic systems through environmental pollution, invasive species and hydromorphological changes carry-over to terrestrial ecosystems and the food webs therein. We consider both the aquatic insect emergence and flooding as pathways through which stressors can propagate from the aquatic to the terrestrial system. We specifically synthesize and contextualize results on the roles of pollutants in the emergence pathway and their top-down consequences. Our review revealed that the emergence and flooding pathway are only considered in isolation and that the overall effects of invasive species or pollutants on food webs at the water-land interface require further attention. While very few recent studies looked at invasive species, a larger number of studies focused on metal transfer compared to pesticides, pharmaceuticals or PCBs, and multiple stress studies up to now left aquatic-terrestrial linkages unconsidered. Recent research on pollutants and emergence used aquatic-terrestrial mesocosms to elucidate the effects of aquatic stressors such as the mosquito control agent Bti, metals or pesticides to understand the effects on riparian spiders. Quality parameters, such as the structural and functional composition of emergent insect communities, the fatty acid profiles, yet also the composition of pollutants transferred to land prove to be important for the effects on riparian spiders. Process-based models including quality of emergence are useful to predict the resulting top-down directed food web effects in the terrestrial recipient ecosystem. In conclusion, we present and recommend a combination of empirical and modelling approaches in order to understand the complexity of aquatic-terrestrial stressor propagation and its spatial and temporal variation.

Effects of Zinc Thiazole and Oxytetracycline on the Microbial Metabolism, Antibiotic Resistance, and Virulence Factor Genes of Soil, Earthworm Gut, and Phyllosphere

Pesticides and antibiotics are believed to increase the incidence of antibiotic resistance genes (ARGs) and virulence factor genes (VFGs), constituting a serious threat to global health. However, the impact of this combined pollution on the microbiome and that of the related ARGs and VFGs on soil-plant-animal systems remain unknown. In this study, a 60-day microcosm experiment was conducted to reveal the effects of zinc thiazole (ZT) and oxytetracycline (OTC) on microbial communities, antibiotic resistomes, and virulence factors in soil, earthworm gut, and phyllosphere samples using metagenomics. ZT exposure perturbed microbial communities and nutrient metabolism and increased the abundance of ARGs and VFGs in the gut. Combined exposure changed the profiles of ARGs and VFGs by decreasing microbial diversity in the phyllosphere. Host-tracking analysis identified some genera, such as Citrobacter and Aeromonas, as frequent hosts of ARGs and VFGs in the gut. Notably, some co-occurrence patterns of ARGs and MGEs were observed on the metagenome-assembled contigs. More importantly, ZT markedly increased the abundance of potentially drug-resistant pathogens Acinetobacter soli and Acinetobacter junii in the phyllosphere. Overall, this study expands our current understanding of the spread of ARGs and VFGs in soil-plant-animal systems under pollutant-induced stress and the associated health risks.

Significant improvement in freshwater invertebrate biodiversity in all types of English rivers over the past 30 years

There remains a persistent concern that freshwater biodiversity is in decline and being threatened by pollution. As the UK, and particularly England, is a densely populated nation with rivers of modest dilution capacity, this location is very suitable to examine how freshwater biodiversity has responded to human pressures over the past 30 years. A long-term dataset of 223,325 freshwater macroinvertebrate records from 1989 to 2018 for England was retrieved and examined. A sub-set of approximately 200 sites per English Region (1515 sites in total with 62,514 samples), with the longest and most consistent records were matched with predicted wastewater exposure, upstream land cover and terrain characteristics (latitude, altitude, slope gradient and flow discharge). To understand changes in macroinvertebrate diversity and sensitivity with respect to these parameters, the biotic indices of (i) overall family richness, (ii) Ephemeroptera, Plecoptera, Trichoptera (EPT) family richness, and (iii) the Biological Monitoring Working Party (BMWP) scores of NTAXA (number of scoring taxa) and (iv) ASPT (average score per taxon) were selected. A review of how close the BMWP scores come to those expected at minimally impacted reference sites was included. For all latitudes, altitudes, channel slope, river size, wastewater exposure levels, and differing proportions of upstream woodland, seminatural, arable and urban land cover, all diversity or sensitivity indices examined improved over this period, although this improvement has slowed in some cases post 2003. Mean overall family richness has increased from 15 to 25 family groups, a 66 % improvement. The improvement in mean EPT family richness (3 to 10 families, >300 % improvement), which are considered to be particularly sensitive to pollution, implies macroinvertebrate diversity has benefited from a national improvement in critical components of water quality.

Quantitative Metabolism and Urinary Elimination Kinetics of Seven Neonicotinoids and Neonicotinoid-Like Compounds in Humans

Reverse dosimetry, i.e., calculating the dose of hazardous substances that has been taken up by humans based on measured analyte concentrations in spot urine samples, is critical for risk assessment and requires metabolic and kinetic data. We quantitatively studied the metabolism of seven major neonicotinoid and neonicotinoid-like compounds (NNIs) after single oral doses in male volunteers and determined key kinetic parameters and urinary elimination for NNIs together with their metabolites. Complete and consecutive urine samples were collected over 48 h. All samples were analyzed by tandem mass spectrometry, following liquid or gas chromatographic separation. Single- and group-specific NNI metabolites were quantified, i.e., hydroxylated and N-dealkylated NNIs and NNI-associated carboxylic acids and their glycine derivatives. Large, substance-dependent variations of key toxicokinetic parameters were observed. Mean times of concentration maxima (tmax) in urine varied between 2.0 (imidacloprid) and 25.8 h (N-desmethyl-clothianidin), whereas mean urinary elimination half-times (t1/2) were between 2.5 (acetamiprid) and 49.5 h (sulfoxaflor). Mean 48 h excretion fractions (Fue's) were between 0.03% (2-chloro-1,3-thiazole-5-carboxylic acid glycine) and 84% (clothianidin). In contrast, the interindividual differences of Fue's between the volunteers for each of the NNIs and their metabolites remained low (below a factor of 2 between the maximum and minimum derived Fue with the exception of 6-chloronicotinic acid in the acetamiprid dose study). The obtained quantitative data enabled choosing appropriate biomarkers for exposure assessment and, at the same time, for risk assessment by reverse dosimetry at current environmental exposures, i.e., comparing the calculated doses that have been taken up to currently available acceptable daily intakes of NNIs.

Phytotoxicity alleviation of imazethapyr to non-target plant wheat: active regulation between auxin and DIMBOA

Effectively controlling target organisms while reducing the adverse effects of pesticides on non-target organisms is a crucial scientific inquiry and challenge in pesticide ecotoxicology research. Here, we studied the alleviation of herbicide (R)-imazethapyr [(R)-IM] to non-target plant wheat by active regulation between auxin and secondary metabolite 2,4-dihydroxy-7-methoxy-2H-1,4-benzoxazine-3(4H)-one (DIMBOA). We found (R)-IM reduced 32.4% auxin content in wheat leaves and induced 40.7% DIMBOA accumulation compared to the control group, which effortlessly disrupted the balance between wheat growth and defense. Transcriptomic results indicated that restoration of the auxin level in plants promoted the up-regulation of growth-related genes and the accumulation of DIMBOA up-regulated the expression of defense-related genes. Auxin and DIMBOA alleviated herbicide stress primarily through effects in the two directions of wheat growth and defense, respectively. Additionally, as a common precursor of auxin and DIMBOA, indole adopted a combined growth and defense strategy in response to (R)-IM toxicity, i.e., restoring growth development and enhancing the defense system. Future regulation of auxin and DIMBOA levels in plants may be possible through appropriate methods, thus regulating the plant growth-defense balance under herbicide stress. Our insight into the interference mechanism of herbicides to the plant growth-defense system will facilitate the design of improved strategies for herbicide detoxification.

The role of miRNA-26a-5p and target gene socs1a in flutolanil induced hepatotoxicity of zebrafish at environmental relevant levels

Flutolanil has been detected worldwide in aquatic environment and fish, which has become an undeniable stressor on ecosystem and human health. Flutolanil has been reported to be toxic to aquatic organisms. However, the pathophysiological and molecular mechanism behind the detrimental effects remains obscure. Here we reported hepatotoxicity induced by flutolanil in HepG2 cells and zebrafish, as revealed by toxicokinetic, HE staining, miRNAs-mRNAs sequencing, molecular dynamic simulations and dual luciferase reporter assays. Collectively, our results indicated that flutolanil could be absorbed by and accumulated in the liver of zebrafish, causing hepatic vacuolar degeneration, steatosis and nuclear condensation and abnormal liver function, where its exposure at environmental levels disrupted the expressions of miRNA-26a-5p and its target gene socs1a by mediating JAK-STAT signaling pathway, which was partially responsible for hepatotoxicity, correlated with oxidative stress, cell apoptosis, inflammation, cell cycle disorder and mitochondrial dysfunction. These findings suggest that miRNA-26a-5p/socs1a can serve as potential biomarkers of hepatotoxicity in zebrafish following exposure to flutolanil. This uncovered route will provide a new tool for the risk assessment of flutolanil and a guide to proper use of flutolanil and environmental remedy, and open up a new horizon for liver disease assessment.

Airborne Pesticides from Agricultural Practices: A Critical Review of Pathways, Influencing Factors, and Human Health Implications

This critical review examines the release of pesticides from agricultural practices into the air, with a focus on volatilization, and the factors influencing their dispersion. The review delves into the effects of airborne pesticides on human health and their contribution to anthropogenic air pollution. It highlights the necessity of interdisciplinary research encompassing science, technology, public policy, and agricultural practices to effectively mitigate the risks associated with pesticide volatilization and spray dispersion. The text acknowledges the need for more research to understand the fate and transport of airborne pesticides, develop innovative application technologies, improve predictive modeling and risk assessment, and adopt sustainable pest management strategies. Robust policies and regulations, supported by education, training, research, and development, are crucial to ensuring the safe and sustainable use of pesticides for human health and the environment. By providing valuable insights, this review aids researchers and practitioners in devising effective and sustainable solutions for safeguarding human health and the environment from the hazards of airborne pesticides.

Investigation of the Persistence, Toxicological Effects, and Ecological Issues of S-Triazine Herbicides and Their Biodegradation Using Emerging Technologies: A Review

S-triazines are a group of herbicides that are extensively applied to control broadleaf weeds and grasses in agricultural production. They are mainly taken up through plant roots and are transformed by xylem tissues throughout the plant system. They are highly persistent and have a long half-life in the environment. Due to imprudent use, their toxic residues have enormously increased in the last few years and are frequently detected in food commodities, which causes chronic diseases in humans and mammals. However, for the safety of the environment and the diversity of living organisms, the removal of s-triazine herbicides has received widespread attention. In this review, the degradation of s-triazine herbicides and their intermediates by indigenous microbial species, genes, enzymes, plants, and nanoparticles are systematically investigated. The hydrolytic degradation of substituents on the s-triazine ring is catalyzed by enzymes from the amidohydrolase superfamily and yields cyanuric acid as an intermediate. Cyanuric acid is further metabolized into ammonia and carbon dioxide. Microbial-free cells efficiently degrade s-triazine herbicides in laboratory as well as field trials. Additionally, the combinatorial approach of nanomaterials with indigenous microbes has vast potential and considered sustainable for removing toxic residues in the agroecosystem. Due to their smaller size and unique properties, they are equally distributed in sediments, soil, water bodies, and even small crevices. Finally, this paper highlights the implementation of bioinformatics and molecular tools, which provide a myriad of new methods to monitor the biodegradation of s-triazine herbicides and help to identify the diverse number of microbial communities that actively participate in the biodegradation process.

A multi-residue method for trace analysis of pesticides in soils with special emphasis on rigorous quality control

A multi-residue trace analytical method is presented to accurately quantify 146 currently used pesticides in (agricultural) soils with varying soil properties. Pesticides were extracted using an optimized quick, easy, cheap, effective, rugged, and safe (QuEChERS) approach and chemical analysis was carried out by liquid chromatography coupled to tandem mass spectrometry (triple quadrupole). Quantification was based on matrix-matched internal standards calibration, using 95 isotopically labeled analyte analogues. In contrast to the common approach of method validation using soils freshly spiked with analytes shortly before the extraction, our method is additionally validated via an in-house prepared partly aged soil, which contains all target pesticides and via agricultural field soils with native pesticide residues. The developed method is highly sensitive (median method limit of quantification: 0.2 ng/g), precise (e.g., median intra-day and inter-day method precision both ~ 4% based on field soils), and true ((i) quantified pesticide concentrations of the partly aged soil remained stable during 6 months, were close to the initially spiked nominal concentration of 10 ng/g, and thus can be used to review trueness in the future; (ii) median freshly spiked relative recovery: 103%; and (iii) participation in a ring trial: median z-scores close to one (good to satisfactory result)). Its application to selected Swiss (agricultural) soils revealed the presence of in total 77 different pesticides with sum concentrations up to 500 ng/g. The method is now in use for routine soil monitoring as part of the Swiss Action Plan for Risk Reduction and Sustainable Use of Plant Protection Products.

Mean species responses predict effects of environmental change on coexistence

Environmental change research is plagued by the curse of dimensionality: the number of communities at risk and the number of environmental drivers are both large. This raises the pressing question if a general understanding of ecological effects is achievable. Here, we show evidence that this is indeed possible. Using theoretical and simulation-based evidence for bi- and tritrophic communities, we show that environmental change effects on coexistence are proportional to mean species responses and depend on how trophic levels on average interact prior to environmental change. We then benchmark our findings using relevant cases of environmental change, showing that means of temperature optima and of species sensitivities to pollution predict concomitant effects on coexistence. Finally, we demonstrate how to apply our theory to the analysis of field data, finding support for effects of land use change on coexistence in natural invertebrate communities.

Insight into the Long-Lasting Control Efficacy of Neonicotinoid Imidacloprid against Wheat Aphids during the Entire Growth Period

Understanding the mechanism of long-lasting control efficacy of pesticides is important for developing sustainable high-efficacy pesticides, decreasing pesticide-use frequency and environmental input. This study investigates the long-term control mechanism of imidacloprid against wheat aphids under seed treatment. The concentrations of imidacloprid and its metabolites were 2.2-69.6 times lower than their individual LC50 after 238 days of treatment, and the control efficacy was still higher than 94.6%. The mixed bioactivity tests demonstrated that the insecticidal activity of the mixture of imidacloprid and its bioactive metabolites was approximately 1.5-189.7 times greater than that of a single compound against wheat aphids. The concentrations of imidacloprid, 5-hydroxy imidacloprid, and imidacloprid olefin in top flag leaves were 0.022, 0.084, and 0.034 mg/kg, respectively, during the aphid flourishing period, which were higher than the LC50 of the mixture (0.011 mg/kg), therefore providing long-lasting control efficacy. The study provides a first insight into the synergistic effects between a pesticide and its bioactive metabolites in ensuring long-term control performance.

Agricultural pesticide land budget and river discharge to oceans

Pesticides are ubiquitous environmental pollutants negatively affecting ecosystem and human health1,2. About 3 Tg of pesticides are used annually in agriculture to protect crops3. How much of these pesticides remain on land and reach the aquifer or the ocean is uncertain. Monitoring their environmental fate is challenging, and a detailed picture of their mobility in time and space is largely missing4. Here, we develop a process-based model accounting for the hydrology and biogeochemistry of the 92 most used agricultural pesticide active substances to assess their pathways through the principal catchments of the world and draw a near-present picture of the global land and river budgets, including discharge to oceans. Of the 0.94 Tg net annual pesticide input in 2015 used in this study, 82% is biologically degraded, 10% remains as residue in soil and 7.2% leaches below the root zone. Rivers receive 0.73 Gg of pesticides from their drainage at a rate of 10 to more than 100 kg yr-1 km-1. By contrast to their fate in soil, only 1.1% of pesticides entering rivers are degraded along streams, exceeding safety levels (concentrations >1 μg l-1) in more than 13,000 km of river length, with 0.71 Gg of pesticide active ingredients released to oceans every year. Herbicides represent the prevalent pesticide residue on both land (72%) and river outlets (62%).

Two-Compartmental Toxicokinetic Model Predicts Interspecies Sensitivity Variation of Imidacloprid to Aquatic Invertebrates

Interspecies sensitivity to the same chemical can be several orders of magnitude different. Quantifying toxicologically internal levels and toxicokinetic (TK) parameters is critical in elucidating the interspecies sensitivity. Herein, a two-compartmental TK model was constructed to characterize the uptake, distribution, and elimination kinetics toward interspecies sensitivity to an insecticide, imidacloprid. Imidacloprid exhibited the highest lethality to the insect Chironomus dilutus, followed by Lumbriculus variegatus, Hyalella azteca, and Daphnia magna. Interspecies sensitivity of imidacloprid to these invertebrates varied by ∼1000 folds based on water concentrations (LC50). Remarkably, the sensitivity variation decreased to ∼50 folds based on the internal residues (LR50), highlighting the critical role of TK in interspecies sensitivity. A one-compartmental TK model failed to simulate the bioaccumulation of imidacloprid in these invertebrates except for D. magna. Instead, a two-compartmental model successfully simulated the slow elimination of imidacloprid in the remaining three species by internally distinguishing the highly dynamic (C1) and toxicologically available (C2) fractions. We further showed that the species sensitivity of the invertebrates to imidacloprid was significantly related to C2, demonstrating that C2 was toxicologically available and responsible for the toxicity of imidacloprid. This mechanistic-based model bridged the internal distribution of organic contaminants in small invertebrates and the associated toxic potency.