Pesticides In Rice Research Articles

Reduced graphene oxide decorated NiCo2(OH)6 nanoflowers for vortexed assisted dispersive µ-solid-phase extraction of organophosphorus pesticides in baby food cereal, rice and wheat flour

Food safety is an important issue to protect humane health and improve the life quality. Hence, analysis of the possible contaminants in food samples is essential. A rapid and efficient vortexed-assisted dispersive µ-solid-phase extraction coupled with gas chromatography-mass spectrometry was proposed for simultaneous separation/preconcentration and determination of five commonly used organophosphorus pesticides. Reduced graphene oxide decorated NiCo2(OH)6 nanoflowers as a novel nanostructure was synthetized and introduced for separation of the target pesticides from the wheat flour, rice flour, and baby food cereal samples. The characterization of the nanoflowers was accomplished by SEM-EDX, XRD, and FT-IR techniques. The main factors including pH, the amount of nanoflower, the volume of sample solution, salt concentration (ionic strength), desorption conditions (i.e. desorption solvent type and volume, and desorption time) on the pesticides extraction efficiencies were inquired using matrixed match method. Applying the optimum conditions, the linearity of 0.100–500.000 µg kg−1, LODs and LOQs in the range of 0.03–0.04 µg kg−1 and 0.1 µg kg−1 for the studied food samples were obtained. The repeatability (intra–day precision (n = 5)) of ≤ 2.0 % and reproducibility (inter–day precision, days = 5, n = 3) of ≤3.1 % and were appraise at three concentration levels (10, 50 and 100 μg kg−1 of each analyte). High relative recoveries of 90.0–99.3 % ascertained high potential of the presented method for complex matrix analysis.

Exposure to pesticides used in rice farming (bentazone, chlorantraniliprole and tebuconazole) affects biochemical biomarkers and hepatic histopathological parameters of hammertoad tadpoles (Boana faber)

Pesticides used in rice cultivation can cause negative health effects to non-target organisms representative of natural biodiversity. In this context, the present study aimed to investigate the occurrence of pesticides in surface waters from a river that flows in the middle of a rice farming-dominated area. We were also interested in evaluate biochemical and histological effects caused by exposure (16 d) to the lower and higher concentrations of the main found herbicide (bentazone, BTZ), insecticide (chlorantraniliprole, CTP) and fungicide (tebuconazole, TBZ), isolated or mixed, in Boana faber tadpoles. No significant differences were observed in the development of the animals. Tadpoles exposed to the herbicide BTZ showed higher hepatic levels of malondialdehyde (MDA). In animals exposed to CTP, MDA levels were lower than controls. Animals exposed to the fungicide TBZ showed higher hepatic activity of glutathione S-transferase and carboxylesterase (CbE), as well as higher levels of carbonyl proteins and MDA. Animals exposed to Mix showed higher activity in CbE and glucose-6-phosphate dehydrogenase activity in the liver, as well as higher levels of MDA. In the brain and muscle of tadpoles exposed to Mix, acetylcholinesterase activity was higher. Histological changes were also observed in pesticide-exposed animals, such as increased occurrence of melanomacrophages, inflammatory infiltrates and congestion. Our data evidences the contamination of natural aquatic environments by rice pesticides, and the adverse effects of main ones in B. faber tadpoles, which suggests the contribution of pesticides derived from rice cultivation to the degradation of local biodiversity health.

Simultaneous determination of four pesticides residues in rice by modified QuEChERS coupled with GC-MS/MS

A QuEChERS pretreatment technique integrated with GC-MS/MS method was founded to determine pesticides residues in rice (Triazophos, Dichlorvos, Chlorpyrifos and Malathion). By comparing and analyzing the eventual recoveries of these analytes, the type of extraction solvents, the amount of salting out agents, water content, and the selection of adsorbents in the QuEChERS method were ameliorated. Finally, the recovery experiment was conducted using acetonitrile as the extraction solvent, 10 mg PSA, 150 mg anhydrous MgSO4, and 50 mg C18 as purification conditions of QuEChERS method. Under the ameliorative conditions, there was a good linear relationship between the peak areas of these pesticides in rice (r2>0.99). At three spiking levels (20, 40 and 200 μg/kg), the recoveries of four pesticides were 75.6–104.0 % with RSD of 1.5–10.2 %, the LOD of 3.4–5.4 μg/kg and the LOQ of 20 μg/kg. This method is easy to operate, highly sensitive, and accurate, greatly improving work efficiency, and providing reference for future exploration in the field of pesticide residues.

The role of OsBZR4 as a brassinosteroid-signaling component in mediating atrazine and isoproturon degradation in rice

Development of a biotechnological system for rapid degradation of pesticides is important to mitigate the environmental, food security, and health risks that they pose. Degradation of atrazine (ATZ) and isoproturon (IPU) in rice crops promoted by the brassinosteroid (BR) signaling component BRASSINAZOLE RESISTANT4 (OsBZR4) is explored. OsBZR4 is localized in the plasma membrane and nucleus, and is strongly induced by ATZ and IPU exposure. Transgenic rice OsBZR4-overexpression (OE) significantly enhances resistance to ATZ and IPU toxicity, improving growth, and reducing ATZ and IPU accumulation (particularly in grains) in rice crops. Genetic destruction of OsBZR4 (CRISPR/Cas9) increases rice sensitivity and leads to increased accumulation of ATZ and IPU. OE plants promote phase I, II, and III metabolic reactions, and expression of corresponding pesticide degradation genes under ATZ and IPU stress. UPLC-Q-TOF-MS/MS analysis reveals increased relative contents of ATZ and IPU metabolites and conjugates in OE plants, suggesting an increased OsBZR4 expression and consequent detoxification of ATZ and IPU in rice and the environment. The role of OsBZR4 in pesticide degradation is revealed, and its potential application in enhancing plant resistance to pesticides, and facilitating the breakdown of pesticides in rice and the environment, is discussed.

Steps Taken to Mitigate the Threats of Maximum Residue Limits (MRL) of Pesticides in Rice and Protecting Guyana Rice Exports Markets: Present and Future Prospects

Governments of many countries are setting Maximum Residue Levels (MRLs) for food and feed being imported. To safeguard the threat of MRLs to rice exported from Guyana, the GRDB embarked on several research projects with the view to reduce MRLs and manage ‘Paddy bug’ (Oebalus poecilus (Dallas)). Studies included viz. identification of biological control agents; screening advance germplasm for tolerance; evaluation of bio-pesticides and synthetic molecules with higher MRLs; pesticide residue studies-growth stages, cut-off points and MRLs between paddy vs. cargo rice. Results from the bioagent survey found relatively low populations of predators such as damsel fly, lady bird beetle, spider, and dragon fly in Regions #2, #3, #4, #5, and #6. Also, there were isolated cases of parasitoids, viz. Telenomus podisi and Beskia aelops at very low levels. Results from the tolerance screening revealed that entry FG-18-222 recorded the highest percentage of damage and high incidence of paddy bugs (PB), while significantly (p < 0.05) lowest damage was recorded in FG-15-35 (2.13%), G17-109 (3.93%), followed by G-14-10 (4.10%) in 2022. These entries appeared to be the least preferred to PB due to the high presence and relatively low percentage of grain damage. However, all 12 entries were found to be susceptible to paddy bug lighting and feeding. Likewise, Bio-insecticide Boom (MRLs 3.0 mg/kg) was evaluated against PB and 162 ml/ac. was the most effective rate. In a separate experiment, Malathion (MRLs of 8.0 mg/kg) at 12–18 ml/ac. was most effective in controlling PB population compared to untreated control. There were no significant differences between these two treatments and the Pronto (Imidacloprid) check. The results from the pesticide residue analysis viz. Imidacloprid and Thiamethoxam, showed that systemic A.I. can only be applied once in a rice growing season for PB control no later than 67 DAS. Additionally, results comparing detected MRLs between paddy grains versus shelled rice grains revealed >84.41% reduction in the detected MRLs for these systemic A.I. Further research work is recommended in this MS to be undertaken to better understand the PB and mitigate the threat of MRLs with the view of developing an IPM approach to manage PB at the same time protect Guyana rice export markets.

A comparative study on pesticide residue profiles in locally grown rice from conventional and sustainable agricultural methods

Amid escalating concerns about pesticide residues in agricultural product, this study conducts a meticulous comparative analysis of pesticide residue profiles in locally grown rice, aiming to contribute essential insights for informed decision-making in agriculture. The overarching problem addressed involves identifying pesticides in rice from conventional and sustainable farming and understanding their potential environmental and health implications on food safety. Utilizing HPLC/MS-MS, the research discerns a notable absence of over 500 pesticide types in rice cultivated according to good agricultural practices (GAP). Conversely, rice from fields deviating from GAP guidelines reveals the presence of 7 pesticide active ingredients, with 2 exceeding globally established residue limits by twice the recommended amount. Notably, bifenthrin and tebuconazole, uncommonly used in the last one years, are identified. This study underscores the urgency of adhering to sustainable agricultural practices for the safety and quality of rice, offering critical insights for future research. It not only contributes to current knowledge but also emphasizes the global necessity of safe agricultural practices to safeguard our food supply.

Effects of Clothianidin Pesticide Application on the Strength of Honey Bee Colonies and Stress-Related Genes in the Vicinity of Rice Fields in the Republic of Korea

The honey bee, a crucial organism that provides ecological and economic value to humans, is currently facing threats from various environmental factors including pesticides. Numerous studies have been conducted to demonstrate the risks associated with neonicotinoid pesticides, but research on their occurrence in actual field conditions has not been identified. Therefore, in this study, we observed changes in honey bee (Apis mellifera) colonies located near rice cultivation areas as they progressed beyond the rice pesticide application period. Furthermore, we collected honey bees exposed to the clothianidin and analyzed their stress-related gene expression. The results showed that the foraging behavior of honey bee colonies located near rice cultivation areas did not exhibit significant differences between the treatment sites (Cheongyang and Gimje) and the control site (Wanju) during the experimental period. However, it was observed that the expression levels of stress-related genes in honey bees collected from the treatment group were significantly higher than those in the control. Most of the stress-related genes were associated with detoxification processes in response to pesticides. As a result, pesticide treatment in proximity to rice cultivation areas did not cause direct damage to honey bees but had an indirect impact, suggesting the potential for ongoing chronic damage.

Occurrence of Pesticides in Polished Rice Samples From Tanjung Karang and Sekinchan and the Health Risk among Consumers

Introduction: One of the key staple foods in many different countries, including Malaysia, is rice (Oryzae sativa L.). Pesticides are used to reduce weed growth and safeguard crops from insect attacks in order to boost paddy output. Objective: This research quantifies the concentration of pymetrozine, chlorantraniliprole, and difenoconazole, along with any potential health risks to consumers. Methods: Samples of polished rice from three rice milling factories in Tanjung Karang and Sekinchan were extracted using the QuEChERS (Quick Easy Cheap Effective Rugged Safe) technique. The amount of pesticide residue in polished rice was then measured using ultra-high performance liquid chromatography-tandem mass spectrometry (UHPLC-MS/MS). A health risk assessment was conducted utilizing the Hazard Quotient (HQ) and Lifetime Cancer Risk (LCR) to estimate the non-carcinogenic and carcinogenic health risks. Results: The mean concentration of pesticides in polished rice ranged from less than the detection limit (difenoconazole) to 1.122 µg/kg (pymetrozine). No rice samples above the Maximum Residue Limit (MRL) specified in the Food Act 1983 as implemented by Malaysia’s Food Regulations 1985. Pymetrozine, chlorantraniliprole, and difenoconazole in rice had respective MRLs of 50 µg/kg, 2000 µg/kg, and 100 µg/kg. For all age groups, no significant non-carcinogenic health risk was associated with consuming polished rice from the study area, where the HQ and Hazard Index (HI) were less than one. When LCR values were less than 10-6, carcinogenic health risks of consuming polished rice from the study area were at a clearly acceptable risk level. Conclusion: As no sample exceeded the MRL, the findings indicated that all rice samples collected from Tanjung Karang and Sekinchan were safe for consumption.

Evaluation of supercritical fluid chromatography coupled to tandem mass spectrometry for the analysis of pesticide residues in grain.

A supercritical fluid chromatography-tandem mass spectrometry (SFC-MS/MS) technique was developed for the rapid and simultaneous detection of nine pesticides (carbendazim, isoprocarb, paclobutrazol, isoprothiolane, flusilazole, quinalphos, piperonylbutoxide, propargite, and bioresmethrin) in rice, wheat, and maize. The cereal samples were extracted with a solution of 0.5% acetic acid in acetonitrile and purified using quick, easy, cheap, effective, rugged, and safe method. The samples were characterized using multi-reaction monitoring and quantified with the external standard method. Excellent linearities (R2 >0.9991) and limits of quantification (0.4-40.0μg/kg) were established for all nine pesticides. Satisfactory pesticide recovery rates (62.2%-107.4%) were obtained at three standard concentrations (50, 100, and 200μg/kg), with relative standard deviations in the range of 2.1%-14.3%. The results confirmed that the proposed method was suitable for the routine detection of these pesticides in grain samples. Compared with high-performance liquid chromatography-MS/MS, the overall test run time and the amount of solvent required were reduced by 66% and 90%, respectively, when SFC-MS/MS was applied. Therefore, the use of SFC-MS/MS permits a shorter run time and affords greater analytical efficiency, such that it is both economical and environmentally sustainable.

Monitoring of paddy rice pesticides in river water by passive sampling method: Validation of application to the Kokai River in Tochigi Prefecture

Monitoring of paddy rice pesticides in river water by passive sampling method: Validation of application to the Kokai River in Tochigi Prefecture

Efficient determination of pesticides in rice by QuEChERS and UV spectroscopy in combination with chemometrics

AbstractBackground and ObjectivesTargeting the problems, like various residual pesticides, the high interference of sample matrix and the slow detection speed, this work studied the rapid screening method of multipesticide residues in rice by taking bensulfuron‐methyl, propanil and cypermethrin as examples.FindingsRice matrix solution was obtained by using the improved QuEChERS method, matrix standard solution, and solvent standard solution were prepared to obtain the linear range and matrix effect of each pesticide. QuEChERS method could rapidly pretreat samples, and the matrix effect was soft, with matrix effect values lower than 16%. Mixed solutions of the three pesticides in four combinations were prepared within the linear range. The type of pesticides in rice was determined by support vector machine (SVM), and the pesticide concentration was predicted by partial least square regression (PLSR). SVM provided a supervised identification method for pesticide residues, making the recognition accuracy higher than 90%. The error of PLSR in predicting pesticide concentration was lower than 5.36%.ConclusionsUV spectroscopy had fast test speed, so the combination of QuEChERS and UV spectroscopy could improve the efficiency of analysis. SVM combined with PLSR could preliminarily determine the type of pesticides in rice sample, and then accurately predict the concentration of pesticides.Significance and NoveltyThe QuEChERS sample pretreatment technology and UV spectroscopy in combination with chemometrics was expected to be a new technology for rapid detection of pesticide residues in samples.

Effect of rice milling, washing, and cooking on reducing pesticide residues

The effects of milling, washing, and cooking on etofenprox, flubendiamide, and tebufenozide levels in brown and polished rice were investigated by HPLC using a UV detector. The reduction rates of etofenprox, flubendiamide, and tebufenozide after milling were 68.74–93.16%, 64.49–90.25%, and 69.74–92.58%, respectively, 11.64–41.44%, 31.36–65.37%, and 31.61–73.79%, respectively, after washing brown rice, and 30.85–82.08%, 52.13–83.05%, and 43.04–83.89%, respectively, after washing polished rice. The residue levels of the three pesticides in brown rice decreased after electric and pressure cooking by 56.49 and 54.41%, 75.80 and 73.42%, and 70.01 and 71.27%, respectively, and the corresponding levels in polished rice decreased after electric and pressure cooking by 85.58 and 85.82%, 86.70 and 87.06%, and 89.89 and 89.68%, respectively. In conclusion, various processing methods decrease the residual levels of etofenprox, flubendiamide, and tebufenozide in rice.

Pesticide residues in rice planted in South and Southwest China

ABSTRACT In 2019 and 2020, 70 paddy and 70 brown rice samples were collected from South China and Southwest China, wherein the residues of 15 target pesticides were investigated. A gas chromatography-mass spectrometry (GC-MS) method was established for the simultaneous detection of 15 pesticides, which achieved good linear relationship with limits of detection (LODs) of 0.10–4.00 μg kg−1. The average recoveries and relative standard deviations (RSD) were satisfied for the pesticide residues detection. Analysis results showed that the detection rates of 15 typical pesticides in paddy and brown rice were 0%-12.9% and 0%-1.4%, respectively. None of the 15 pesticides exceed their maximum residue limit (MRL) stipulated by China. The pesticide with the highest detection rate and concentration was chlorpyrifos. This study can provide data support for the control of pesticide residues in rice and the realisation of the improving the efficiency of pesticide and fertiliser while reducing their application.

Simultaneous Analysis of Mycotoxins, Potentially Toxic Elements, and Pesticides in Rice: A Health Risk Assessment Study.

Rice is a widely consumed food worldwide; however, it can be a source of pollutants, such as potentially toxic elements (PTEs), mycotoxins, and pesticides. Sixty rice samples imported from Pakistan (PAK), India (IND), and Thailand (THAI), as well as domestic Iranian (IRN) rice, were collected from Bushehr, Iran, and investigated for the contamination of PTEs, including arsenic (As), lead (Pb), cadmium (Cd), and nickel (Ni); pesticides, including chlorpyrifos, trichlorfon, diazinon, fenitrothion, and chlorothalonil; mycotoxins, such as aflatoxin B1 (AFB1), zearalenone (ZEN), ochratoxin A (OTA), and deoxynivalenol (DON); and molds. Estimated daily intake (EDI) and hazard quotient (HQ) of pollutants and hazard index (HI) and incremental lifetime cancer risk (ILCR) of rice types for the Iranian adult population were calculated. The content of PTEs in Iranian rice was not higher than Iran's national standard limits. In contrast, other types of rice (imported) had at least one PTE above the permissible level. OTA content was below the detection limit, and all other mycotoxins were within the allowable range in all rice types. Thai rice was the only group without pesticides. The HI order of rice types was as follows: HIPAK = 2.1 > HIIND = 1.86 > HIIRN = 1.01 > HITHAI = 0.98. As was the biggest contributor to the HI of Iranian and Thai rice, and diazinon in the HI of Pakistani and Indian rice. The calculation of ILCR confirmed that the concentrations of Ni and Pb in Pakistani and Ni and As in Indian, Thai, and Iranian rice were not acceptable in terms of lifetime carcinogenic health risks.

Identification and in vitro Evaluation of Environmental Stress Resilient Plant Growth Promoting Rhizobacterial Consortia for Rice (Oryza sativa L.)

The present study screened bacteria isolated from rice rhizosphere for various beneficial traits related to three categories of plant growth promotion, abiotic stress tolerance, and compatibility with multiple agrichemicals to identify a microbial consortium that performs better than individual isolates in improving rice growth under normal and stressful environmental conditions. Among thirty-two isolates screened, 29, 9, 20 isolates were able to solublilize insoluble minerals of nutrients like phosphorous, potassium and zinc respectively. About 29, 31, 23, 17 isolates were found to possess the traits of IAA, ammonia, siderophore and HCN production respectively. Abiotic stress related traits of salinity, drought and high temperature tolerance were displayed by 8, 2 and 10 isolates respectively when examined for their growth in NaCl (4%, 6% 8%), in PEG (64 g/l equivalent to -0.73Mpa) and at 45℃ temperature. Agrichemical tolerant isolates were identified by screening for compatibility with fertilizers and commonly used rice pesticides. Based on the scores assigned during screening tests, 9 best isolates, three from each category, were selected for development of consortia. Our aim in this initial study was to identify three consortia (C-1, 2 and 3) consisting of three compatible bacteria, and to evaluate their effect on rice seed germination and seedling growth under normal in vitro conditions. C1 enhanced the growth of rice when compared with individual strains, C2 and C3 with highest vigour index I, II values of 1616 ± 18 and 5.47 ± 0.68 respectively. The 16S rRNA sequence analysis identified the bacterial isolates in C1 as Achromobacter sp, Stenotrophomonas sp and Pseudomonas stutzeri. Therefore, this study has identified a unique consortium that can be used for rice growth promotion while simultaneously demonstrating the advantage of bacterial consortia over single isolate inoculants under non stressed conditions.

Cumulative Risk Assessment of Dietary Exposure to Pesticide Residues in Brown Rice (Oryza sativa L.) from the Three Main Rice-Growing Regions in China during 2016–2020

The residual levels of 25 monitored pesticides in 6,229 brown rice samples obtained from the 17 provinces of the three main rice-growing regions in China during 2016–2020 were analyzed, and the cumulative risks of chronic and acute exposure to pesticides for the Chinese population were assessed. The QuEChERS extraction coupled with liquid chromatography-mass spectrometry for simultaneous determination of 25 pesticide residues in brown rice was developed and validated with good accuracy and precision (recoveries of 70%–120% and RSD ≤20%). The overall detection rate and over the maximum residue limit (MRL) rate of pesticides in brown rice decreased from 39.15% and 3.59% in 2016 to 34.11% and 1.53% in 2020, respectively. The Yangtze River basin had a higher detection rate and over MRL rate (43.14% and 2.88%, respectively) compared with the Southeast Coastal region (37.28% and 2.77%) and the Northeast Plain (11.28% and 0.17%). Isoprothiolane (13.57%) and carbendazim (8.32%) were the most frequently detected in rice samples. Pesticide residues exceeding the MRLs were found most often in triazophos (0.75%) and isocarbophos (0.51%). The risk ranking of pesticide residues based on the ranking matrix showed that carbofuran, methamidophos, and isocarbophos had the highest residual risk scores of 25.09, 25.01, and 25.00, respectively. 17.7% of rice samples contained two or more pesticide residues. The cumulative risk assessments based on the relative potency factor (RPF) approach revealed that the cumulative risks of chronic and acute dietary exposure to organophosphorus, neonicotinoid insecticides, and triazole fungicides from rice ranged from 7.43 × 10−4 to 3.36 × 10−2, which were not considered of health concern. The study provides national-scale information on the contamination levels and health risks of pesticide residues in rice, which can help develop continuous monitoring programs for pesticide residue contamination in rice in China.

Human health risk assessment of pesticides used for rice cultivation in an agricultural pockets of Eastern India

AbstractFood consumption is one of the principal reasons of human exposures to pesticides. The research analyses the relation between pesticide contaminations and their possible adverse health impacts. Rice grain and soil samples were collected from seven blocks of Bargarh district, Odisha. Gas Chromatography‐Mass Spectrometry (GC/MS) was used for the analysis and characterization of various pesticides present in rice grain as well as in soil samples. The identified pesticide residues in rice grain samples were found to be in the sequence of ∑DDT > chlorpyrifos > chlorothalonil > vinclozolin > chlorthal‐dimethyl > endosulfan‐1 > lindane. Detected pesticide concentrations were found to exceed the Maximum Residue Limits (MRLs) set by the Codex Alimentarius International Food Standards with DDT having the highest concentration of 29.27 mg/kg (which is 292 times the MRLs) and lindane with the least concentration of 4.35 mg/kg (which is 435 times the MRLs). Estimated average daily intake (EADI) was found to be higher for DDT and lower for lindane. The Health Risk Index (HRI) for DDT was higher and lower for chlorothalonil in all the samples. Results of one‐way ANOVA reflected no significant differences in variance between the concentrations of pesticides in rice grain samples. Result showed that the residual levels of ∑DDT in soil ranged between 7.8 and 29.3 mg/kg which was the maximum concentration among all the pesticides. Lindane and chlorthal‐dimethyl showed the least concentration ranging between 1.2–4.2 and 1.6–4.1 mg/kg, respectively. DDT had the highest bioconcentration factor (BCF) ranging between 1 and 4. Lindane and endosulfan‐1 had the lowest BCF ranging between 1 and 2. BCF value of other pesticides were found between the range of 1 and 4. Bioconcentration factors of pesticides in rice and soil samples indicated that pesticides in soil could get accumulated in rice. It was observed that the health risk associated with the consumption of rice could be because of its contamination by the pesticides in the study area or of the biomagnification of pesticides from the soil. It is necessary to spreading the awareness regarding safer use, storage and disposal of pesticides should be given utmost importance at the moment as an attempt to reduce or eliminate the environmental contaminations caused by them. National authorities should enforce proper rules and regulations in order to monitor and control the vigorous use of chemical loaded pesticides in agriculture and various other fields. It would be even better to substitute the chemical pesticides with the organic component‐based Bio‐pesticides as a safer option for the mankind and its environment.

A sensitive silver nanoflower-based SERS sensor coupled novel chemometric models for simultaneous detection of chlorpyrifos and carbendazim in food

In this study, a simultaneous detection platform utilizing SERS coupled chemometric models was developed to sensitively detect chlorpyrifos and carbendazim pesticides in rice in a single step for the first time. Initially, silver nanoflowers (AgNFs) were synthesized and used as the SERS substrate to acquire the spectra of pesticides. AgNFs have multiple chinks on their surface that can generate strong electromagnetic enhancement for SERS signal of chlorpyrifos and carbendazim. To obtain effective variables from the dataset, a novel wavelength selection method called interval combination population analysis (ICPA) was used. The ICPA-partially least square (ICPA-PLS) method showed a significant linear relationship over the concentration range of 0.01–1000 μg/mL for both pesticides when compared to other established chemometric methods. This model, yielded correlation coefficients in the calibration of 0.9802 and 0.9995, with an RPD of 3.74 and 7.8 for chlorpyrifos and carbendazim, respectively. A limit of detection of 0.01 μg/mL was determined using PCA analysis. Finally, the method was compared to HPLC, and the results revealed no significant differences (t < t0.05 (3),P>0.05) between two methods, implying that the proposed method could be used for food safety monitoring.

OsBR6ox, a member in the brassinosteroid synthetic pathway facilitates degradation of pesticides in rice through a specific DNA demethylation mechanism

This manuscript described a comprehensive study on a pesticide degradation factor OsBR6ox that promoted the degradation of pesticides atrazine (ATZ) and acetochlor (ACT) in rice tissues and grains through an epigenetic mechanism. OsBR6ox was transcriptionally induced under ATZ and ACT stress. Genetic disruption of OsBR6ox increased rice sensitivity and led to more accumulation of ATZ and ACT, whereas transgenic rice overexpressing OsBR6ox lines (OEs) showed opposite effects with improved growth and lower ATZ and ACT accumulation in various tissues, including grains. OsBR6ox-mediated detoxification of ATZ and ACT was associated with the increased abundance of brassinolide (one of the brassinosteroids, BRs), a plant growth regulator for stress responses. Some Phase I-II reaction protein genes for pesticide detoxification such as genes encoding laccase, O-methyltransferase and glycosyltransferases were transcriptionally upregulated in OE lines under ATZ and ACT stress. HPLC-Q-TOF-MS/MS analysis revealed an enhanced ATZ/ATC metabolism in OE plants, which removed 1.21–1.49 fold ATZ and 1.31–1.44 fold ACT from the growth medium but accumulated only 83.1–87.1 % (shoot) and 71.7–84.1 % (root) of ATZ and 69.4–83.4 % of ACT of the wild-type. Importantly, an ATZ-responsive demethylated region in the upstream of OsBR6ox was detected. Such an epigenetic modification marker was responsible for the increased OsBR6ox expression and consequent detoxification of ATZ/ACT in rice and environment. Overall, this work uncovered a new model showing that plants utilize two mechanisms to co-regulate the detoxification and metabolism of pesticides in rice and provided a new approach for building up cleaner crops and eliminating residual pesticides in environments.

Part-Time Farming, Diseases and Pest Control Delay and Its External Influence on Pesticide Use in China’s Rice Production

The highly intensive use of pesticide is a big threat to environmental sustainability in China. This study explains the increase of rice pesticide use in China’s rapid urbanization process from the perspective of changes in the delay of pest control. Based on multi-stage random sampling, 20 villages of five counties in central Jiangsu were selected, and the production data of 430 paddy fields were surveyed. Logit model results show that living outside village of agricultural labors will increase the probability of delay in control of diseases and pest, while the increase of farm size and the development of outsourcing services and public monitoring and forecasting services will help reduce the probability of delay. The OLS model results show that the delay in rice diseases and pest control has negative externalities. The delays of other farmers in the village will significantly increase the frequency of pesticide use. These results highlight important policy implications for the development of large-scale farming to substitute part-time farming and the development of diseases and pest control services.