Evaluating national ecological risk of agricultural pesticides from 2004 to 2017 in China

Comprehensive monitoring and prioritizing for contaminants of emerging concern in the Upper Yangtze River, China: An integrated approach

Contaminants of emerging concern (CECs) in aquatic environments can adversely impact ecosystems and human health even at low concentrations. This study assessed the risk of 162 CECs, including neonicotinoid pesticides, triazine pesticides, carbamate pesticides, psychoactive substances, organophosphate esters, antidepressants, per- and polyfluoroalkyl substances, and antibiotics in 10 drinking water sources and two tributaries (Jialing and Wujiang Rivers) of the Upper Yangtze River in Chongqing, China. Target screening detected 156 CECs at 0.01-2218.2 ng/L, while suspect screening via LC-QTOF-MS identified 64 CECs, with 13 pesticides, 29 pharmaceuticals and personal care products, and 2 industrial chemicals reported for the first time in the Yangtze River Basin. Risk quotient-based ecological risk assessment revealed that 48 CECs posed medium to high risks (RQ > 0.1) to aquatic life, with antibiotics (n = 20) as the main contributors. Non-carcinogenic risks were below negligible levels, but carcinogenic risks from neonicotinoids, triazines, antidepressants, and antibiotics were concerning. A multi-criteria prioritization approach integrating occurrence, physico-chemical properties, and toxicological data ranked 26 CECs as high priority. This study underscores the importance of comprehensive CEC screening in rivers and provides insights for future monitoring and management strategies.

Assessing environmental and human health risks: Insight from the enantioselective metabolism and degradation of fenpropidin

Fenpropidin (FPD), a widely employed chiral fungicide, is frequently detected in diverse environments. In an in vitro rat liver microsomes cultivation (RLMs), the metabolism exhibited the order of R-FPD > S-FPD, with respective half-lives of 10.42 ± 0.11 and 12.06 ± 0.15 min, aligning with kinetic analysis results. CYP3A2 has been demonstrated to be the most significant oxidative enzyme through CYP450 enzyme inhibition experiments. Molecular dynamics simulations unveiled the enantioselective metabolic mechanism, demonstrating that R-FPD forms hydrogen bonds with the CYP3A2 protein, resulting in a higher binding affinity (-6.58 kcal mol-1) than S-FPD. Seven new metabolites were identified by Liquid chromatography time-of-flight high-resolution mass spectrometry, which were mainly generated through oxidation, reduction, hydroxylation, and N-dealkylation reactions. The toxicity of the major metabolites predicted by the TEST procedure was found to be stronger than the predicted toxicity of FPD. Moreover, the enantioselective fate of FPD was studied by examining its degradation in three soils with varying physical and chemical properties under aerobic, anaerobic, and sterile conditions. Enantioselective degradation of FPD occurred in soils without enantiomeric transformation, displaying a preference for R-FPD degradation. R-FPD is a low-risk stereoisomer both in the environment and in mammals. The research presented a systematic and comprehensive method for analyzing the metabolic and degradation system of FPD enantiomers. This approach aids in understanding the behavior of FPD in the environment and provides valuable insights into their potential risks to human health.

Analysis of nationwide soil pesticide pollution: Insights from China

China is a typical agricultural country that heavily relies on pesticides. Some pesticides can remain in the soil after application and thus pose a significant threat to human health. In order to characterize the status and hazards of nationwide soil contamination, this study extracted concentration data from published literature and analyzed them by a scoring approach, standard comparison and health risk assessment. For the soil pollution score, northern regions got the highest values, such as Henan (0.63), Liaoning (0.55), Heilongjiang (0.54) and Jilin (0.53), which implies high soil pesticide residues in these provinces. In contrast, Qinghai (-0.77), Guizhou (-0.64) and Tibet (-0.63) had lower scores. China's soil pesticide standards cover only 16 pesticides, and these pesticide concentrations were all below the corresponding standards. Direct exposure to soil pesticides in this study generally posed a negligible risk to children. Furthermore, pesticide dissipation and usage intensity in each province were analyzed as they were possible influences on pollution. The result showed that soil in the northern regions could accumulate more pesticides than those in the southern regions, and this geographic pattern was basically consistent with the distribution of soil pollution. However, the relationship between agricultural activities and soil pollution was less well characterized. It is recommended to establish a long-term monitoring database for pesticides and include more pesticides in regulatory frameworks. Additionally, efforts to accelerate pesticide degradation and shift the planting structure to reduce pesticide usage can help alleviate the pressure on soil from pesticides. This study can serve as a critical reference for policymakers and stakeholders in the field of agriculture.

Removal, transformation and ecological risk assessment of pesticide in rural wastewater by field-scale horizontal flow constructed wetlands of treated effluent

Constructed wetlands (CWs) are widely used in sewage treatment in rural areas, but there are only a few studies on field-scale CWs in treating wastewater-borne pesticides. In this study, the treatment and metabolic transformation of 29 pesticides in rural domestic sewage by 10 field-scale horizontal flow CWs (HF-CWs), each with a treatment scale of 36‒5000 m3/d and operated for 2‒10 years, in Guangzhou, Southern China was investigated. The risk of pesticides in treated effluent and main factors influencing such risk were evaluated. Results demonstrated that HF-CWs could remove pesticides in sewage and reduce their ecological risk in effluent, but the degree varied among types of pesticides. Herbicides had the highest mean removal rate (67.35 %) followed by insecticides (60.13 %), and the least was fungicides (53.22 %). In terms of single pesticide compounds, the mean removal rate of butachlor was the highest (73.32 %), then acetochlor (69.41 %), atrazine (68.28 %), metolachlor (58.40 %), and oxadixyl (53.28 %). The overall removal rates of targeted pesticides in each HF-CWs ranged from 11 %‒57 %, excluding two HF-CWs showing increases in pesticides in treated effluent. Residues of malathion, phorate, and endosulfan in effluent had high-risks (RQ > 5). The pesticide concentration in effluent was mainly affected by that in influent (P = 0.042), and source control was the key to reducing risk. The main metabolic pathways of pesticide in HF-CWs were oxidation, with hydroxyl group to carbonyl group or to form sulfones, the second pathways by hydrolysis, aerobic condition was conducive to the transformation of pesticides. Sulfones were generally more toxic than the metabolites produced by hydrolytic pathways. The present study provides a reference on pesticides for the purification performance improvement, long-term maintenance, and practical sustainable application of field-scale HF-CWs.

Predictionof Environmental FateandToxicityofInsecticidesUsing Multi-Target QSAR Approach

Ecotoxicological risk assessments form the foundation of regulatory decisions for industrial chemicals used in various sectors. In this study, a multi-target-QSAR model established by a backpropagation neural network trained with the Levenberg-Marquardt (LM) algorithm was used to construct a statistically robust and easily interpretable Mt-QSAR model with high external predictability for the simultaneous prediction of the environmental fate in form of octanol-water partition coefficient (LogP), (BCF) and acute oral toxicity in mammals and birds (LD50rat ) and (LD50bird ) for a wide range of chemical structural classes of insecticides. Principal component analysis was performed on descriptors selected by the SW-MLR method, and the selected PCs were used for constructing the SW-MLR-PCA-ANN model. The developed well-trained model (RMSE=0.83, MPE=0.004, CCC=0.82, IIC=0.78, R2 =0.69) was statistically robust as indicated by the external validation parameters (RMSE=0.93, MPE=0.008, CCC=0.77, IIC=0.68, R2 =0.61). The AD of the developed Mt-QSAR model was also defined to identify the most reliable predictions. Finally, the missing values in the dataset for the aforementioned targets were predicted using the constructed Mt-QSAR model. The proposed approach can be used for simultaneous prediction of the environmental fate of new insecticides, especially ones that haven't been tested yet.

Assessing the ecological risk of croplands in loess drylands by combining environmental disturbance with ecosystem vulnerability

Agroecosystems suffer various ecological risks due to the intensive production of crops. However, comprehensive assessments of cropland ecological risks remain limited. This study developed an assessment method for cropland ecological risks by combining environmental disturbance with ecosystem vulnerability. Environmental disturbance reflects stresses caused by risk sources in an environment, while ecosystem vulnerability is the susceptibility of an ecosystem to adverse disturbances and its capacity to cope and adapt. The proposed method is conducive to understanding the complex exposure-response relationship between croplands and environmental stresses. Cropland ecological risk was evaluated by conducting a case study on a loess dryland region in Shaanxi. The hot spots and driving factors of risk were explored using spatial autocorrelation and quantile regression methods, respectively. Results show that overall cropland ecological risk is at medium low level. Risk hot spots are concentrated in the north of the loess dryland. Ecosystem vulnerability exerts greater effect on the distribution of hot spots than environmental disturbance in the study area. Road density (RDD), river density, and soil organic matter exert the most important effects on cropland ecological risk. Moreover, the same driving factor exhibits various effects on cropland ecological risk in different risk level areas. RDD, slope, precipitation, elevation, fertilizer application rate, gross domestic product, and distance to town center have greater effects on risk in regions with high cropland ecological risk than in regions with low cropland ecological risk. The findings of this study must be considered in formulating targeted policies for controlling cropland ecological risk in loess drylands to realize sustainable crop production.

Cytochrome P450 CYP90D5 Enhances Degradation of the Herbicides Isoproturon and Acetochlor in Rice Plants and Grains

The rice cytochrome P450 gene has been comprehensively studied in the present study. This gene encodes CYP90D5 in promoting the degradation of isoproturon (IPU) and acetochlor (ACT) in rice tissues and grains. It has here been found that CYP90D5 improved the resistance of the plant to IPU and ACT, which was reflected in the improvement of the growth of the overexpression (OE) lines. CYP90D5 also reduced the levels of IPU and ACT accumulation in rice, and the CRISPR-Cas9 (Cas9) lines displayed the opposite effects. This function of CYP90D5 for pesticide degradation was also confirmed by the transformation of CYP90D5 in Pichia pastoris. Compared with the control yeast, it grew better and could degrade more pesticides. In addition, the relative contents of the IPU and ACT derivatives increased in the OE rice, while they decreased in the Cas9 rice. This suggested that CYP90D5 plays a pivotal role in the pesticide detoxification and degradation.

Strong Opponent of Walnut Anthracnose-Bacillus velezensis and Its Transcriptome Analysis

Walnut is a significant economic tree species worldwide. Walnut anthracnose, caused by the pathogen Colletotrichum gloeosporioides, greatly reduces walnut production and economic benefits. Our study showed that Bacillus velezensis effectively halted the growth of C. gloeosporioides, inducing noticeable abnormalities such as hyphal breakage and distortion, thereby curtailing the pathogen's virulence. A 50-100 times dilution of B. velezensis fermentation broth, applied every two to three days, served as an efficient protective layer for walnut leaves and fruits against C. gloeosporioides infection. Transcriptomic analysis of B. velezensis unveiled its dynamic response against C. gloeosporioides. On the second day, B. velezensis upregulated a significant number of differentially expressed genes related to the synthesis of metabolic products, amino acid biosynthesis, and motility. On the fourth day, continuous synthesis of metabolic products and amino acids, along with differential expression of spore-related genes, was observed. By the sixth day, the focus shifted towards environmental adaptation and carbon source utilization. Throughout the process, B. velezensis likely employed strategies such as the release of metabolic products, increased chemotaxis, and nutrient competition to exert its antagonistic effect on C. gloeosporioides. Fluorescence quantitative results showed that 15 primer pairs were up-regulated and 15 were down-regulated, with a 100% similarity rate to transcriptome sequencing results, confirming their authenticity. These findings provided a foundation for the widespread application of B. velezensis as a biocontrol agent in agriculture and forestry.

Fabrication and application of hydrangea-like magnetic titanium dioxide (Fe3O4-TiO2) particles: Development of magnetic "one-step" pretreatment method for multi-pesticide residues analysis in fish

Magnetic titanium dioxide (Fe₃O₄-TiO₂) was prepared and utilized as the cleanup adsorbent and separation medium to modify the QuEChERS method, affording a facile, robust, and rapid magnetic "one-step" pretreatment method for the determination of multi-pesticide residues in fish. The pretreatment key parameters, such as the dosages of the purification adsorbents (Fe₃O₄-TiO₂ and PSA), the dehydrating and salting out reagents, were systematically optimized by the orthogonal test method. Under the optimal conditions, satisfactory results of method evaluation were obtained. Good linearity of 127 target analytes was obtained from 1 to 250 μg L^-1. The recoveries of 127 analytes at five spiked levels of 10, 25, 50, 125, and 250 μg kg^-1 ranged from 71.0% to 129% with RSDs less than 15.0%. The method LOQs (MLOQs) of 127 analytes were 10 μg kg^-1, meeting the requirement for multi-pesticide residues analysis in fish. Additionally, this magnetic "one-step" method was used for the analysis of multi-pesticide residues in real fish samples collected from Zhejiang Province, China. In summary, this method can work as a viable tool for multi-pesticide residues monitoring in fish.

The dual impacts of specialized agricultural services on pesticide application intensity: Evidence from China

BACKGROUND

Specialized agricultural services are a new trend in agricultural production around the world, especially in developing countries. However, the growing impacts of specialized agricultural services on pesticide application intensity are unclear. In regions facing pesticide overuse, do specialized agricultural services exacerbate or mitigate the problem?

RESULTS

Based on province-level panel data from China from 2004 to 2018, this study examines the impact of specialized agricultural services on pesticide application intensity, considering both direct and indirect (i.e. spatial spillover) effects. The dual impacts of specialized agricultural services on pesticide application intensity in China are identified. First, specialized agricultural services directly increase pesticide application intensity, likely due to increased cultivation and specialized management of land that was previously abandoned or marginally managed. Second, there is a negative indirect or spatial spillover effect of specialized agricultural services on pesticide application intensity, likely due to technology and efficiency diffusion enabled by the cross-regional provision of specialized agricultural services. The net impact of specialized agricultural services on pesticide application intensity is negative.

CONCLUSION

Crop protection services are regarded as the core force to promote the reduction of pesticide application intensity. Steps should be taken to promote the research and development, demonstration, and promotion of new technologies and equipment for crop protection services, particularly the development of crop protection by drones. © 2022 Society of Chemical Industry.

Negative effects of abamectin on soil microbial communities in the short term

With the widespread use of abamectin in agriculture, there is increasing urgency to assess the effects of abamectin on soil microorganisms. Here, we treated plant-soil microcosms with abamectin at concentrations of 0.1 and 1.0 mg/kg and quantified the impacts of abamectin on bulk and rhizosphere soil microbial communities by shotgun metagenomics after 7 and 21 days of exposure. Although abamectin was reported to be easily degradable, it altered the composition of the soil microbial communities, disrupted microbial interactions, and decreased community complexity and stability after 7 days of exposure. After treatment with abamectin at a concentration of 1.0 mg/kg, some opportunistic human diseases, and soil-borne pathogens like Ralstonia were enriched in the soil. However, most ecological functions in soil, particularly the metabolic capacities of microorganisms, recovered within 21 days after abamectin treatment. The horizontal and vertical gene transfer under abamectin treatments increased the levels of antibiotic resistance genes dissemination. Overall, our findings demonstrated the negative effects of abamectin on soil ecosystems in the short-term and highlight a possible long-term risk to public and soil ecosystem health associated with antibiotic resistance genes dissemination.

The spatial-temporal chemical footprint of pesticides in China from 1999 to 2018

The massive use of pesticides brings considerable environmental and human health impacts. This study conducted an overall assessment of the ecological impact of the extensive pesticide use in China from 1999 to 2018 through the Chemical Footprint (ChF) calculation. The results demonstrated that the primary ecological impacts caused by pesticides occurred in the most central and eastern regions in China, e.g., provinces of Shandong, Henan, Hubei, Anhui, and Jiangsu. The northeastern, some southern and central provinces, e.g., Heilongjiang, Jilin, Liaoning, Yunnan, Guangxi, Guangdong, Ningxia, and Shaanxi, got moderate impacts, whereas the northwest regions, e.g., Qinghai, Xinjiang, and Tibet, had much lighter impacts relatively. The agricultural soil in inland areas and surface sea waters in coastal provinces bore the major impacts of the pesticide pollution in China, shared above 80% of the ChF across all environmental compartments. Chlorpyrifos, pymetrozine, fenpropathrin, pyridaben, atrazine, etc., were the pesticides that had the greatest impacts on the ecosystem, which contributed over 95% of the total ChF of pesticides used in China, although the use amount of these pesticides accounted for less than 10% of the total use amount of all pesticides annually. The study also indicated that the overall ChF of pesticide use in China has been declining since 2010, which was corresponding with the control actions of highly hazardous pesticides, especially the elimination of high toxic organophosphorus insecticides during the past decade.

Magnetic polymer particles as a highly efficient and facile cleanup adsorbent for multi-pesticide residues analysis in aquatic products

A novel and efficient sample pretreatment procedure using magnetic particles was exploited for the determination of multi-pesticide residues in aquatic products. The magnetic adsorbent was prepared using divinyl benzene and N-vinyl pyrrolidone as functional monomers modified on the Fe₃O₄ @SiO₂. The obtained magnetic adsorbent, octadecylsilane sorbents, and graphitized carbon black were employed as effective adsorbents to remove matrix interferences in aquatic products, and their dosages were optimized. Satisfactory levels of accuracy and precision were procured under optimum conditions. The method limits of quantification ranged from 0.1 to 2.0 μg/kg. The analytical accuracy of the developed method for the analysis of multi-pesticide residues in freshwater and seafood products was validated. It was found to be suitable for the analysis of multi-pesticide residues in different types of aquatic products. Additionally, the method was successfully applied for the analysis of pesticide residues in fish samples obtained from aquaculture plants located in Zhejiang Province, China. The detected concentrations of pesticides ranged from 0.14 to 0.95 μg/kg. In general, this method shows promising application prospects for the rapid determination of multi-pesticide residues in aquatic products.

Diffuse phthalate acid esters losses induced from large amount of agricultural plastic film residues caused low risks for water quality in China during 1991-2017

Extensive application of agricultural plastic films has resulted in abundant film residues in farmlands. Phthalate acid esters (PAEs) are vital additives of the agricultural plastic film and are easily emitted into soils. However, spatio-temporal variations of diffuse PAEs loss to water bodies have not been explored in China. This study used an integrated estimation framework and high-resolution activity data to conduct a comprehensive inventory of diffuse PAEs loss associated with plastic films of six main crop types in China for 1991-2017. We found that the diffuse PAEs loss induced from agricultural plastic films increased 10.57-46.30 kg over the same time. Di-butyl phthalate (DBP) and bis(2-ethylhexyl) phthalate (DEHP) accounted for ~75% of the national total loss. High PAEs loss regions are mainly located in Eastern China, the Middle-Lower Yangtze Plain, and eastern Yunnan and Sichuan provinces. We proved that PAEs emission, agricultural film residues, surface runoff, precipitation, and soil organic carbon explained 19.64%, 17.50%, 15.45%, 12.88%, and 9.83% of the total variation, respectively. The potential ecological risks to the various aquatic species were assessed to be low. Overall, our results are valuable for addressing severe agricultural plastic film residues and associated pollutant emissions and losses in China.

Human exposure to neonicotinoids and the associated health risks: A review

Neonicotinoids (NEOs) are a class of broad-spectrum insecticides dominant in the global market. They were distributed extensively in the environment and occurred frequently in humans. Potential health effects of NEOs, such as neurological toxicity and diabetes to non-targeted mammals, have raised concerns. This review summarizes analytical methods of NEOs in human samples, their internal exposure levels and composition profiles in urine, blood, hair, breast milk, saliva and tooth samples with global comparisons, and daily NEOs exposure dose and relative health risks.Urinary NEOs levels in Asian populations were substantially higher than those in the U.S. and Europe, which may be due to different dietary patterns and insecticide applications across regions. N-desmethyl acetamiprid, 5-hydroxy-imidacloprid and olefin-imidacloprid were dominant among detected NEOs. NEO metabolites exhibited higher detection frequencies and levels than their parent compounds in humans, while investigations on NEO metabolites remain much limited. Current exposure assessments mainly focused on short-term urine analysis, while biomaterials for long-term monitoring, such as hair, nail and other alternatives, should also be considered. Large-scale epidemiological studies are critically needed to elucidate potential health outcomes associated with NEOs exposure.

Expression of CYP76C6 Facilitates Isoproturon Metabolism and Detoxification in Rice

Agricultural chemical residues in farmland and crops is one of the serious public issues that constantly threatens crop production, food security, and human health. Understanding their decay mechanism in crops for accelerating their degradative metabolism is important. In this study, a rice uncharacterized cytochrome P450 gene encoding CYP76C6 was functionally identified in rice exposed to isoproturon (IPU). To verify the role of CYP76C6 in rice resistance to IPU toxicity, CYP76C6 overexpression (OEs) and knockout mutant rice by CRISPR/Cas9 were generated through genetic transformation and gene-editing technologies. Assessment of growth and physiological responses revealed that the growth of OE lines was improved, the IPU-induced cellular damage was attenuated, and IPU accumulation was significantly repressed, whereas the Cas9 lines displayed a contrasting phenotype compared to the wild-type. Both relative contents of IPU metabolites and conjugates in OE lines were reduced and those in Cas9 line were increased, suggesting that CYP76C6 plays a critical role in IPU degradation. Our study unveils a new regulator, together with its mechanism for IPU decay in rice crops, which will be used in reality to reduce environmental risks in food safety and human health.

The role of crop insurance in reducing pesticide use: Evidence from rice farmers in China

Pesticides play a significant role in increasing agricultural yields. However, the overuse of chemical pesticides on crops is a major challenge faced by China, which damages human health, threatens food security, and increases production costs. This paper provides empirical evidence on the relationship between crop insurance and pesticide use. Based on micro-survey data collected from 3410 households, we estimate a control function (CF) approach and find that farmers who purchase crop insurance use 33.30% lower pesticides than those who do not. A series of robustness tests confirm these findings. The results of the moderating effect analysis suggest that rice cultivation training, experience, schooling years, and agricultural laborers can negatively moderate the effect of crop insurance on pesticide use. Furthermore, we also find that the treatment effect of crop insurance is stronger for farmers who are most inclined to purchase crop insurance.

Ecological risk assessment for difenoconazole in aquatic ecosystems using a web-based interspecies correlation estimation (ICE)-species sensitivity distribution (SSD) model

Difenoconazole is a typical triazole fungicide that can inhibit demethylation during ergosterol synthesis. Due to its wide use, difenoconazole is frequently detected in surface water, paddy water, agricultural water, and other aquatic environments. Presently, an assessment of the ecological risk posed by difenoconazole in aquatic ecosystems is lacking. Here, a web-based interspecies correlation estimation (ICE)-species sensitivity distribution (SSD) model was first applied to assess the ecological risk of difenoconazole in aquatic environments. Meanwhile, maximum acceptable concentration (MAC), maximum risk-free concentration (MRFC), and risk quotient (RQ) values were used to evaluate the potential risk of difenoconazole to aquatic organisms. Our results showed that an aquatic MAC value of 0.31 μg/L was acceptable for difenoconazole in aquatic environments. Further, the detected concentration of difenoconazole was lower than the MRFC value of 0.09 μg/L indicating no risk to aquatic organisms. Assessment data suggested that difenoconazole exhibited potential risks to eight studied aquatic ecosystems (including surface water, paddy water, and agricultural water) in different countries (RQ > 1), indicating that difenoconazole overuse could cause adverse effects to aquatic organisms in these aquatic ecosystems. Thus, restricted use and rational use of difenoconazole are recommended.

Spatial-temporal evolution of agricultural ecological risks in China in recent 40 years

Excessive use of agricultural chemicals and unreasonable utilization of agricultural wastes have led to severe agricultural non-point source pollution (ANPSP) problems in China. Based on the agricultural pollution loads and pollution control strength, the ecological risk index (ERI) was constructed and was used to explore the spatial-temporal pattern of agricultural ecological risks in China during 1978-2017. The findings indicated that Chinese agricultural ERI was gradually increased from 0.031 to 0.348 in 1978-2017, which has the same phased change characteristics as the succession of agricultural policies. At present, the ecological risk grade of ANPSP was present in the stair-step distribution characteristics of "high in the east and south and low in the west and north" as a whole. Southern China, as the main producing area of aquatic products, had the higher ecological risks. Northeastern China, the Huang-Huai-Hai Area, and the middle and lower reaches of the Yangtze River, as the grain-producing bases, had moderate ecological risks, but Southwestern China and Northwestern China with the poor agricultural production conditions had the lower ecological risks. It evidently showed that the ecological risk problems faced by the high-quality development of Chinese agricultural industrialization are increasingly severe.

Long-term exposure to cyprodinil causes abnormal zebrafish aggressive and antipredator behavior through the hypothalamic-pituitary-interrenal axis

Cyprodinil, one of the main pyrimidinamine fungicides, has been used to control fungal diseases in plants and vegetables worldwide. Previous studies have investigated the influences of cyprodinil on the developmental and reproductive toxicity of fish. However, it remains unknown whether it affects fish behaviors and the underlying mechanisms. In our current study, zebrafish, an ideal model animal for behavioral studies, were exposed to cyprodinil from fertilization to 240 days postfertilization at 0.1 μg/L (environmentally relevant concentration) and 1, 10 μg/L. Firstly, we observed that aggressive behavior of zebrafish was significantly enhanced after exposure to 0.1-10 μg/L cyprodinil and antipredator behavior was decreased after exposure. Cyprodinil exposure altered the adrenocorticotropic hormone and cortisol levels, which regulate cortisol homeostasis and were significantly reduced in all exposure groups (0.1-10 μg/L). In addition, most of the key genes in the hypothalamic-pituitary-interrenal gland axis, such as corticotropin-releasing hormone and melanocortin 2 receptor, were downregulated significantly in all exposure groups, which was consistent with the hormone levels. In addition, in the hypothalamus, the number of apoptotic cells increased in a dose-dependent manner in the cyprodinil exposure groups. Moreover, these changes were potentially responsible for the increased aggression of zebrafish during the mirror-like aggressive test and for the reduced antipredator behavior during the predator avoidance test. Overall, the data provided herein further our understanding of cyprodinil toxicity and can be used to assess the ecological effects of cyprodinil on the induction of abnormal behaviors at the environmental level.

Inhibition of the Nrf2/p38MAPK pathway involved in deltamethrin-induced apoptosis and fibrosis in quail kidney

Deltamethrin (DLM) is a broad-spectrum and effective pyrethroid insecticide. However, DLM has good residual activity on most surfaces and many insects, so it poses a threat to the environment and health of animals and human. Exposure to DLM can cause kidney injury, but the mechanism is not well understood. Therefore, we investigated the possible mechanism of quail kidney injury induced by chronic exposure to different doses of DLM for 12 weeks. The results showed that chronic exposure to DLM induced apoptosis and fibrosis of quail kidney through the promotion of oxidative stress by down-regulating nuclear factor erythroid 2 related factor 2 (Nrf2), up-regulating the phosphorylation of p38 mitogen-activated protein kinases (p38MAPK). Furthermore, DLM-induced kidney apoptosis in quails as evidenced by increased expression of B-cell lymphoma gene 2-associated X while decreased expression of B-cell lymphoma-extra large. Simultaneously, DLM-induced kidney fibrosis in quails as evidenced by increased expression of fibrosis maker proteins. Overall, the results demonstrate that chronic DLM exposure induces kidney apoptosis and fibrosis via inhibition of the Nrf2/p38MAPK pathway. This study provides a new understanding for the mechanism of DLM-induced quail kidney injury and also provides a theoretical basis for treatment of the DLM poisoning.

Dynamics and risk assessment of pesticides in cucumber through field experiments and model simulation

Pesticides are often applied multiple times during cucumber cultivation in China. In order to obtain the residue concentrations and subsequently human health risk assessment after pesticide multiple applications, plenty of field trials have been conducted, consuming a lot of labor force and funds. The application of kinetic models can address this problem to some extent by predicting the residue values of pesticides in cucumber. In this study, a dynamic model (dynamiCROP) was applied in combination with field experiments to investigate the distribution, translocation, and dissipation after the one-time application of seven pesticides in a cucumber-soil environment. Moreover, the residue concentrations after the second and third applications of the seven pesticides were estimated through a "simple superposition method", i.e., superimposing the output results of dynamiCROP after each single pesticide application. The estimated residue concentrations show good agreement with that measured through field experiments with R² = 0.865 and relative root mean squared error (RRMSE) = 13.2%. Meanwhile, the short- and long-term risks of each pesticide were assessed according to the concentrations estimated by the "simple superposition method" with the dynamiCROP model. It shows that the seven pesticides, applied multiple times during cucumber cultivation, pose a very low dietary risk to human health through cucumber intake. Our study presents a cost- and time-efficient way to investigate the dissipation of pesticides in the cucumber-soil environment, predicate the residue concentrations of pesticides after multiple applications and assess the dietary risk of pesticides to human health through cucumber intake.

Dilemma and solution of land scarcity, agro-production, and environmental risk for typical grain-producing areas in rapid urbanizing process in China

How to satisfy food production sustainably in the rapid urbanizing process is a vital problem for major grain-producing areas. Taking two national grain-producing regions in China, Shandong and Dongting Lake Region as examples, this study uses step-by-step prediction and a double-objective linear programming model to analyze the dilemma of land scarcity, food demand, and environmental load. It is found that food demand by 2030 will induce partial regional cropland deficiency and heterogeneous agro-environmental risk among cities. The double-objective linear programming model finds possible solutions in different scenarios: on the premise of keeping the current cropland area unchanged, the upper threshold of crop yield by 2030 will be 2539.06 × 10⁴ t in Dongting and 7175.13 × 104 t in Shandong, respectively. On the condition of guaranteeing food self-sufficiency and minimizing the environmental load, the lower threshold of arable land area should be 99.47 × 10⁴ ha in Dongting and 436.85 × 10⁴ ha in Shandong. Pollutant reduction will be realized by reallocation of agro-production task and optimized practices. The food carbon impact can be reduced by up to 1.27 kg CO₂ eq/kg. This study contributes to feasible pathways towards adequate agro-production, lessened land scarcity, and minimal environmental risk for rapid urbanizing cities in a sustainable way.

Advanced Material Against Human (Including Covid-19) and Plant Viruses: Nanoparticles As a Feasible Strategy

The SARS-CoV-2 virus outbreak revealed that these nano-pathogens have the ability to rapidly change lives. Undoubtedly, SARS-CoV-2 as well as other viruses can cause important global impacts, affecting public health, as well as, socioeconomic development. But viruses are not only a public health concern, they are also a problem in agriculture. The current treatments are often ineffective, are prone to develop resistance, or cause considerable adverse side effects. The use of nanotechnology has played an important role to combat viral diseases. In this review three main aspects are in focus: first, the potential use of nanoparticles as carriers for drug delivery. Second, its use for treatments of some human viral diseases, and third, its application as antivirals in plants. With these three themes, the aim is to give to readers an overview of the progress in this promising area of biotechnology during the 2017-2020 period, and to provide a glance at how tangible is the effectiveness of nanotechnology against viruses. Future prospects are also discussed. It is hoped that this review can be a contribution to general knowledge for both specialized and non-specialized readers, allowing a better knowledge of this interesting topic.

Recessive Transition Mechanism of Arable Land Use Based on the Perspective of Coupling Coordination of Input–Output: A Case Study of 31 Provinces in China

In the rapid process of urbanization in China, arable land resources are faced with dual challenges in terms of quantity and quality. Starting with the change in the coupling coordination relationship between the input and output on arable land, this study applies an evaluation model of the degree of coupling coordination between the input and output (D_CCIO) on arable land and deeply analyzes the recessive transition mechanism and internal differences in arable land use modes in 31 provinces on mainland China. The results show that the total amount and the amount per unit area of the input and output on arable land in China have presented different spatio-temporal trends, along with the mismatched movement of the spatial barycenter. Although the D_CCIO on arable land increases slowly as a whole, 31 provinces show different recessive transition mechanisms of arable land use, which is hidden in the internal changes in the input–output structure. The results of this study highlight the different recessive transition patterns of arable land use in different provinces of China, which points to the outlook for higher technical input, optimized planting structure, and the coordination of human-land relationships.

Larvicidal activity of substituted chalcones against Aedes aegypti (Diptera: Culicidae) and non-target organisms

BACKGROUND

The expansion of Aedes aegypti (Diptera: Culicidae) population has increased the number of cases of arboviruses, in part due to the inefficiency and toxicity of the chemical control methods available to control this vector. We synthesized 19 chalcone derivatives and examined their activity against Ae. aegypti larvae in order to select larvicidal compounds that are non-toxic to other organisms.

RESULTS

Seven chalcone derivatives (3a, 3e, 3f, 6a, 6c, 6d, and 6f) had lethal concentrations of substituted chalcones capable of killing 50% (LC₅₀ ) values lower than 100 mg mL^-1 at 24 h post-treatment, which is the dose that the World Health Organization recommends for the selection of promising larvicides. The type of substituent added to (E)-1,3-diphenylprop-2-en-1-one (3a) markedly affected the larvicidal activity. Addition of chlorine, bromine and methoxy groups to the aromatic rings reduced the larvicidal activity, while replacement of the B-ring (phenyl) by a furan ring significantly increased the larvicidal activity. The furan-chalcone (E)-3-(4-bromophenyl)-1-(furan-2-yl)prop-2-en-1-one (6c) killed Ae. aegypti larvae (LC₅₀ = 6.66 mg mL^-1 ; LC₉₀ = 9.97 mg mL^-1 ) more effectively than the non-substituted chalcone (3a) (LC₅₀ = 14.43 mg mL^-1 ; LC₉₀ = 20.96 mg mL^-1 ), and was not toxic to the insect Galleria mellonella, to the protozoan Tetrahymena pyriformis, and to the algae Chorella vulgaris.

CONCLUSIONS

The substitution pattern of chalcones influenced their larvicidal activity. In the set of compounds tested, (E)-3-(4-bromophenyl)-1-(furan-2-yl)prop-2-en-1-one (6c) was the most effective larvicide against Ae. aegypti, with no clear signs of toxicity to other animal models. Its mechanism of action and effectiveness under field conditions remain to be determined.

A Review on Prediction Models for Pesticide Use, Transmission, and Its Impacts

The lure of increased productivity and crop yield has caused the imprudent use of pesticides in great quantity that has unfavorably affected environmental health. Pesticides are chemicals intended for avoiding, eliminating, and mitigating any pests that affect the crop. Lack of awareness, improper management, and negligent disposal of pesticide containers have led to the permeation of pesticide residues into the food chain and other environmental pathways, leading to environmental degradation. Sufficient steps must be undertaken at various levels to monitor and ensure judicious use of pesticides. Development of prediction models for optimum use of pesticides, pesticide management, and their impact would be of great help in monitoring and controlling the ill effects of excessive use of pesticides. This paper aims to present an exhaustive review of the prediction models developed and modeling strategies used to optimize the use of pesticides.

Effectiveness of melatonin to restore fish brain activity in face of permethrin induced toxicity

Present study demonstrates permethrin induced oxidative damage in fish brain and explores effectiveness of melatonin to ameliorate brain function. Adult female Notopterus notopterus were exposed to nominal permethrin concentrations at 1/20th (0.34 μg/l) and 1/10th (0.68 μg/l) of LC₅₀ for 15 days. The measured permethrin concentrations using gas chromatography (GC-ECD) were 0.28 μg/l and 0.57 μg/l, respectively. Some fish were sacrificed to collect brain tissue after 15 days of exposure. Remaining fish from both groups were administered exogenous melatonin (50 μg/kg, 100 μg/kg body weight) for 7 days and brain tissues were collected. Brain enzymes, ntioxidant factors, HSP70, HSP90, nuclear factor-kappa binding (NFkB), melatonin receptor (MT1R) proteins were measured. Permethrin treatment significantly (P < 0.05) decreased the levels of glutathione and brain enzymes. Malondialdehyde (MDA), xanthine oxidase (XO), HSPs increased at each concentration of permethrin. However, superoxide dismutase, glutathione s-transferase levels increased at low permethrin concentration followed by sharp decrease at higher concentration. Expression of NFkB and MT1R increased significantly (P < 0.05). Melatonin administration reinstated activity of brain enzymes, reduced MDA, XO levels and modulated HSPs. Melatonin also increased expression of NFkB and MT1R. Exogenous melatonin improves oxidative status in permethrin stressed fish brain. Melatonin modulates expression of HSPs that enables brain to become stress tolerant and survive by initiating NFkB translocation. Melatonin could act through melatonin receptor protein to induce synthesis of antioxidant proteins. Therefore the study successfully evaluates the potential of melatonin application for better culture and management of fish against pesticide toxicity.

The effects of metaldehyde on non-target aquatic macroinvertebrates: Integrating field and laboratory-based evidence

The use of pesticides has historically helped improve agricultural productivity, although their continued use may have unforeseen effects upon the natural environment when not applied appropriately. Metaldehyde is a commercial pesticide widely used to reduce crop losses resulting from terrestrial mollusc damage. However, following precipitation and runoff it frequently enters waterbodies with largely unknown consequences for aquatic fauna. This study represents one of the first attempts to examine its potential effects on aquatic macroinvertebrate communities at sites known to have experienced elevated metaldehyde concentrations alongside unaffected control sites. In addition, a series of laboratory exposures specifically examined the effects of metaldehyde on the survivorship of non-target aquatic mollusc species. When the entire aquatic macroinvertebrate community and aquatic mollusc community were considered, limited differences were observed between metaldehyde affected and control sites based on field data. Laboratory exposures highlighted that for the molluscs examined, gastropods (Bithynia tentaculata, Planorbis planorbis, Radix balthica and Potamopyrgus antipodarum) had a greater tolerance to metaldehyde than bivalves (Sphaerium corneum and Corbicula fluminea). However, the concentrations required to reduce survivorship of all species were much greater than those ever recorded historically under field conditions. The results suggest that the differences in the community composition recorded between sites exposed to elevated metaldehyde concentrations and control sites were probably due to nutrient loading (N and P from agricultural fertilizers) rather than metaldehyde. However, these results do not negate wider concerns regarding metaldehyde use, particularly issues caused when ingested by vertebrate wildlife, livestock or children and pets in domestic settings.