Imidacloprid (IMI) is one of the most applied neonicotinoid insecticides worldwide. The occurrence of its degradates such as desnitro-imidacloprid (DN-IMI), imidacloprid-urea (IMI-urea), and ...desnitro-imidacloprid-olefin (DN-IMI-olefin) in environment water and their fate during drinking water treatment were seldom documented. In this study, IMI and its degradates were determined in source water (the Yangtze River and its largest tributary, the Hanshui River), treated water, and tap water (n = 20, 20, and 169, respectively) in different seasons of 2019 in Wuhan, central China. Their occurrence, removal efficiency, and seasonal variations were evaluated. Advanced water treatment with ozone combined with activated carbon might remove target analytes efficiently but conventional water treatment cannot. IMI and its degradates were 100% detectable in the conventionally treated water samples in July. IMI and DN-IMI decreased while IMI-urea, DN-IMI-olefin, imidacloprid-olefin (IMI-olefin), and 5-hydroxy-imidacloprid (5-OH-IMI) increased during conventional drinking water treatment. IMI and its degradates were found in the tap water samples treated conventionally (range: 1.17–32.0 ng/L for IMI; 0.57–7.00 ng/L for DN-IMI; 0.58–4.50 ng/L for IMI-urea; 0.04–0.65 ng/L for DN-IMI-olefin; < method detection limit MDL–0.80 ng/L for IMI-olefin; < MDL–0.35 ng/L for 5-OH-IMI). The concentrations of DN-IMI and IMI-urea observed in this study were higher than those observed in North America. Sodium sulfite did not increase the levels of DN-IMI and IMI-urea in tap water samples in the present study. This is the first study to demonstrate the occurrence of DN-IMI and IMI-urea in water in China and the occurrence of DN-IMI-olefin, IMI-olefin, and 5-OH-IMI in water.
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•IMI and its degradates were 100% detectable in conventionally treated water in July.•IMI and DN-IMI decreased while 4 degradates increased during conventional treatment.•Degradates DN-IMI, IMI-urea, and DN-IMI-olefin were detectable in all the tap water•DN-IMI and IMI-urea in this study were higher than those in North America•In tap water, the highest concentrations of IMI occurred in July and the lowest in April
An investigation of the metabolism and transfer of imidacloprid (IMI) in banana plants and soil was performed using high-resolution mass spectrometry. Results indicated the presence of eight IMI ...metabolites in soil and leaves that resulted from hydroxylation of the imidazolidine ring, the reduction and loss of nitro groups, and oxidative cleavage of methylene bridges. Six metabolites, including 4/5-hydroxy IMI (4/5-hydroxy), IMI olefin (olefin), and 6-chloronicotinic acid (6-CNA), were detected in the fruits following leaf treatment, while only three were detected after soil treatment. Quantitative analysis showed that the total amount of imidacloprid and its metabolites transferred from leaves to fruits was higher than that transferred from soil to fruits. Therefore, leaf transfer was considered the main means by which IMI and its metabolites transferred to banana fruits. We found that adjuvants tank-mixed with IMI could reduce the total concentration of pesticide transfer from leaves to fruits, especially reducing the amount of metabolites transformed from the reduction and loss of nitro groups and oxidative cleavage of methylene bridges, thus reducing the pesticide residue in fruits and achieving the purpose of reducing the safety risk.
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•Metabolism of imidacloprid (IMI) was investigated in banana plants and soil. Eight metabolites were formed resulting from hydroxylation of the imidazolidine ring, the reduction and loss of nitro groups, and oxidative cleavage of methylene bridges•Both species and amount of metabolites of IMI transferred from leaves were higher than soil, indicating the main source of IMI pollution was leaves.•New tank-mix adjuvants with IMI reduced the IMI and metabolites residue in fruit at harvest period.
•Seven NNIs and metabolites were frequently detected in drinking water•High levels of NNIs and IMIeq were found in surface water derived tap water•NNI levels and patterns varied in different regions ...and according to water sources•NNIs in 16 drinking water samples exceeded the guideline recommended by the EU•Drinking water ingestion is a significant exposure pathway of NNIs in China
Neonicotinoid insecticides (NNIs) are the most extensively used insecticides worldwide, threatening ecosystem and human health. However, nationwide studies of NNIs and their metabolites in drinking water are limited. In order to characterize the contamination status of NNIs in drinking water throughout China, we collected 884 drinking water samples including 789 tap water and 95 groundwater samples from 32 provinces (covering seven regions of mainland China: south, central, east, north, northeast, northwest, and southwest) and Hong Kong. Ten NNIs and six of their main metabolites were determined in the water samples. The relative potency factor method was used to assess the cumulative concentrations of NNIs and their metabolites (imidacloprid-equivalent total NNIs, IMIeq) based on the chronic reference doses (cRfDs) of the NNIs or the toxic effects of the mataboilites. The IMIeq varied among the studied regions, with a median concentration of 24.5 ng/L and a maximum concentration of 8,622 ng/L. The predominant NNIs in drinking water were acetamiprid (ACE) and imidacloprid (IMI). Compared with tap water derived from groundwater, much higher concentrations of IMIeq and NNIs were found in tap water derived from surface water. Different concentrations and patterns of NNIs in drinking water were observed in different regions, provinces, and capital cities, mainly due to regional and provincial differences in crop types and volumes of pesticide usage. The concentrations of NNIs in the drinking water of provincial capitals and small/medium cities were higher than the concentrations in rural areas. The estimated daily intake (EDI) of IMIeq was at least two orders of magnitude lower than the cRfD of IMI, while the NNIs in 16 drinking water samples exceeded the acceptable value (100 ng/L) recommended by the European Union. This study provided a nationwide profile of the occurrence of NNIs and their metabolites in the drinking water of China and the associated potential cumulative human health risks, taking into account of the toxicity differences between NNIs and their metabolites.
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•A novel porous Ag@Cu-BTCIPA composite was synthesized by modifying Cu-BTC with isopropyl alcohol and silver.•Imidacloprid was adsorbed onto Cu-BTC, Cu-BTCIPA and ...Ag@Cu-BTCIPA.•Maximum adsorption attained by Ag@Cu-BTCIPA at pH 7 was 83.6%.•Kinetic studies for adsorption and release were performed.
Imidacloprid, which is harmful for humans as well as many other aquatic invertebrate species, is extensively present in water worldwide. Hydrophobic Cu-BTCIPA and a novel composite, Ag@Cu-BTCIPA, was synthesized for adsorption of imidacloprid from water. The synthesis of the composite and the increase in surface area and pore volume were confirmed by FTIR, XRD, SEM, and BET analysis. A comparative study of the adsorption efficiencies of the synthesized composites was performed. The maximum adsorption efficiency achieved was 83.6 % at pH 7 by the Ag@Cu-BTCIPA composite. Kinetic and isotherm analyses suggested multilayer chemisorption involving p-p conjugation and pore-filling mechanisms. Intra-particle diffusion was the rate limiting step. Release studies of imidacloprid from water showed that the percentage release amount was 90.2 % at 70 min. Kinetic analysis of the release process suggested release through chemisorption, with swelling-controlled release from the dosage form, corresponding to the super case II transport mechanism.
Imidacloprid (IMI) is a contaminant widespread in surface water, causing serious intestinal damage in the common carp. Melatonin (MT), an endogenous indoleamine hormone, plays a crucial role in ...mitigating pesticide-induced toxicity. Our previous research has demonstrated that MT effectively reduces the production of intestinal microbial-derived signal peptidoglycan (PGN) induced by IMI, thereby alleviating intestinal tight junction injuries in the common carp. In this study, we performed a transcriptomic analysis to explore the effect of MT on the IMI exposure-induced gut damage of the common carp. The results elucidated that the ferroptosis, mitogen-activated protein kinases (MAPKs), and nucleotide oligomerization domain (NOD)-like signaling pathways were significantly associated with IMI exposure and MT treatment. Meanwhile, the exposure to IMI resulted in the formation of pyroptotic bodies and distinct morphological features of ferroptosis, both mitigated with the addition of MT. Immunofluorescence double staining demonstrated that MT abolished the elevated expression of NOD-like receptor thermal protein domain associated protein 3 (NLRP3) and Gasdermin D (GSDMD) induced by IMI, as well as reduced expression of ferritin heavy chains (FTH) and glutathione peroxidase 4 (GPX4) in gut tissues. Subsequently, we found that the exposure to IMI or PGN enhanced the expression of toll-like receptors (TLR) 2 (a direct recognition receptor of PGN) triggering the P38MAPK signaling pathway, thereby aggravating the process of pyroptosis and ferroptosis of cell models. The addition of MT or SB203580 (a P38MAPK inhibitor) significantly reduced pyroptotic cells, and also decreased iron accumulation. Consequently, these results indicate that MT alleviates IMI-induced pyroptosis and ferroptosis in the gut of the common carp through the PGN/TLR2/P38MAPK pathway.
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•MT can alleviate the gut damage caused by IMI in common carp.•IMI triggers pyroptosis and ferroptosis in the gut of common carp through PGN.•MT modulates the TLR2/P38 axis to alleviate IMI-induced pyroptosis and ferroptosis.
Imidacloprid (IMI) are widely used in modern tea industry for pest control, but IMI residues pose a great threat to human health. Herein, we propose a regeneration metal-semiconductor SERS substrate ...for IMI detection. We fabricated the SERS sensor through the in-situ growth of a nano-heterostructure incorporating a semiconductor (TiO2) and plasmonic metals (Au, Ag) on oxidized carbon cloth (OCC). Leveraging the high-density hot spots, the formed Ag/AuNPs-TiO2-OCC substrate exhibits higher enhancement factors (1.92 × 108) and uniformity (RSD = 7.68%). As for the detection of IMI on the substrate, the limit of detection was lowered to 4.1 × 10−6 μg/mL. With a hydrophobic structure, the Ag/AuNPs-TiO2-OCC possessed excellent self-cleaning performance addressing the limitation of single-use associated with traditional SERS substrates, as well as the degradation capability of the substrate under ultraviolet (UV) light. Accordingly, Ag/AuNPs-TiO2-OCC showcases outstanding SERS sensing and regenerating properties, making it poised for extensive application in the field of food safety assurance.
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•A heterogeneous SERS substrate of Ag/AuNPs-TiO2-OCC was developed.•The substrate was synthesized by simple photoreduction and hydrothermal routes.•Efficient SERS enhancement is achieved by the synergistic effect of EM and CT.•The reusability of substrates is obtained by the hydrophobicity and UV degradation.
Glutathione S-transferases (GSTs) are multifunctional enzymes, and insect GSTs play a pivotal role in the metabolism of insecticides. Grapholita molesta is a worldwide pest that causes substantial ...economic losses to the fruit industry. However, it remains unclear how imidacloprid, a commonly used insecticide in orchards, is metabolized by G. molesta. In the present study, the synergist diethyl maleate (DEM), which inhibits the GST activity, exhibited a 22-fold synergistic ratio against imidacloprid. Two new GST genes, GmGSTD2 (OR096251) and GmGSTD3 (OR096252), were identified and successfully cloned, showing the highest expression in the Malpighian tubes. Knockdown of GmGSTD2 and GmGSTD3 by RNA interference, increased the mortality of G. molesta from 28% to 47% following imidacloprid treatment. Both recombinant GmGSTD2 and GmGSTD3 proteins exhibited 1-chloro-2,4-dinitrobenzene (CDNB) activity and could be inhibited by imidacloprid in vitro, with maximum inhibition was 60% for GmGSTD2 and 80% for GmGSTD3. These results suggested that GSTs participate in the metabolism of imidacloprid with GmGSTD2 and GmGSTD3 playing key roles in this process.
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•Glutathione S-transferases play an important role in the metabolism of imidacloprid.•GmGSTD2 and GmGSTD3 are highly expressed in the Malpighian tubes.•Knockdown of GmGSTD2 and GmGSTD3 increases the susceptibility of the Grapholita molesta to imidacloprid.•The activity of GmGSTD2 and GmGSTD3 proteins was inhibited by imidacloprid in vitro.
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•DN-IMI, IMI-olefin, and DM-ACE had high detection frequencies.•Fair-to-good inter-day reliability was found for DN-IMI, IMI-olefin, and DM-ACE.•DN-IMI and IMI-olefin were identified ...in human urine for the first time.•Higher urinary NNI concentrations were found in urban areas and in autumn.
While neonicotinoid insecticides (NNIs) have been widely used worldwide, limited studies have measured specific metabolites of imidacloprid (IMI, the most commonly used NNI) in human urine. To better understand human exposure to NNIs, 10 parent compounds, and 6 of their metabolites were analyzed in 408 urine samples collected from 129 healthy adults in Wuhan, Central China, during autumn and winter of 2018. These specimens included repeated urine samples taken in 3 d from 75 volunteers. The urinary concentrations of desnitro-imidacloprid (DN-IMI), imidacloprid-olefin (IMI-olefin), and desmethyl-acetamiprid (DM-ACE) were higher (4–40 times) than those of their parent compounds (IMI and acetamiprid, ACE). DN-IMI and IMI-olefin accounted for 92% of the urinary Σ3IMI (the sum of IMI and its specific metabolites measured). Positive correlations (r) were observed between DN-IMI and IMI (0.50), IMI-olefin and IMI (0.75), and DM-ACE and ACE (0.53). Good to excellent inter-day reliabilities (unadjusted intraclass correlation coefficients) were observed for IMI-olefin (0.61) and DM-ACE (0.81), while moderate inter-day reliability was observed for DN-IMI (0.43). The urinary NNI concentrations were significantly higher in autumn than in winter, and higher in urban areas than in rural areas, while no significant gender or age-related differences were observed. To our knowledge, this is the first report on DN-IMI and IMI-olefin in human urine.
Imidacloprid (IMI) is one of the top-notch insecticides that adversely affects the body organs including the liver. Malvidin (MAL) is a natural flavonoid which exhibits a wide range of ...pharmacological properties. This research was designed to evaluate the protective ability of MAL to counteract IMI instigated liver toxicity in rats. Thirty-two rats were divided into four groups including control, IMI (5mg/kg), IMI (5mg/kg) + MAL (10mg/kg) and MAL (10mg/kg) alone treated group. The recommended dosages were administrated through oral gavage for 4 weeks. It was revealed that IMI intoxication disrupted the PI3K/AKT and Nrf-2/Keap-1 pathway. Furthermore, the activities of catalase (CAT), glutathione peroxidase (GPx), superoxide dismutase (SOD), heme-oxygenase-1 (OH-1) and glutathione reductase (GSR) were reduced while upregulating reactive oxygen species (ROS) and malondialdehyde (MDA) levels after IMI treatment. Moreover, IMI poisoning increased the levels of ALT (Alanine aminotransferase), AST (Aspartate transaminase), and ALP (Alkaline phosphatase) while reducing the levels of total proteins and albumin in hepatic tissues of rats. Besides, IMI administration escalated the expressions of Bcl-2-associated protein x (Bax) and cysteine–aspartic acid protease-3 (Caspase-3) while downregulating the expressions of B-cell lymphoma 2 (Bcl-2). Similarly, IMI intoxication, increased the levels of Interleukin-6 (IL-6), Nuclear factor kappa-B (NF-κB), Interleukin-1β (IL-1β), tumor necrosis factor-α (TNF-α), and the activity of cyclooxygenase-2 (COX-2). Furthermore, IMI disrupted the normal architecture of hepatic tissues. However, MAL treatment remarkably protected the liver tissues via regulating abovementioned disruptions.
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