Dissipation of flubendiamide residues in/on cabbage (Brassica oleracea L.)

Residues of fubendiamide and its metabolite desiodo flubendiamide were estimated in cabbage and soil using high-performance liquid chromatography with UV–vis detector. The initial deposits of flubendiamide residues on cabbage were found to be 0.16 and 0.31 μg g^?1 following two applications of flubendiamide 20 WG at 12.5 (standard dose) and 25 (double dose) g a.i. ha^?1 respectively at 10-days interval. The half-life values (t _1/2) of flubendiamide on cabbage ranged from 3.4 to 3.6 days. When flubendiamide applied at both the standard and double dose, no detectable residues were found in cabbage and soil at harvest. Thus, a waiting period of 1.63 days was suggested for the safe consumption of flubendiamide-treated cabbage. These data could provide guidance for the proper and safe use of this pesticide on cabbage crops in India.     

Residues and dissipation of trifloxystrobin and its metabolite in tomatoes and soil

A simple residue analytical method using the quick, easy, cheap, effective, rugged, and safe (QuEChERS) procedure for the determination of trifloxystrobin and its metabolite trifloxystrobin acid (CGA321113) in tomato and soil was developed using high-performance liquid chromatography-tandem mass spectrometry (HPLC-MS/MS). The limits of detection were 0.0005 mg/kg for trifloxystrobin and 0.001 mg/kg for trifloxystrobin acid, respectively. The average recoveries in tomato and soil ranged from 73–99 % for trifloxystrobin and 75–109 % for trifloxystrobin acid, with relative standard deviations below 15 %. The method was then used to study the dissipation and residues in tomato and soil. The dissipation half-lives of trifloxystrobin in tomato were 2.9 days (Beijing) and 5.4 days (Shandong), while in soil were 1.9 days (Beijing) and 3.0 days (Shandong), respectively. The final results showed that the major residue compound was trifloxystrobin in tomato whereas it was its metabolite, trifloxystrobin acid, in soil. The final residues of total trifloxystrobin (including trifloxystrobin acid) were below the EU maximum residue limit of 0.5 mg kg^?1 in tomato 3 days after the treatment.     

Persistence of metaflumizone on cabbage (Brassica oleracea Linne) and soil, and its risk assessment

Metaflumizone is a novel sodium channel blocker insecticide of semicarbazone class. It provides good to excellent control of most of the economically important lepidopterous pests and certain pests in the orders Coleoptera, Hemiptera, Hymenoptera, Diptera, Isoptera, and Siphonaptera. Although metaflumizone has been marketed globally for several years and got registered in India in the year 2009, specifically for the control of DBM on cabbage, to our knowledge, no food safety aspects of metaflumizone residue on cabbage have ever been reported in the literature in India or elsewhere. The present study was undertaken to evaluate the persistence of metaflumizone on cabbage and soil, vis-a-vis its risk assessment, following two spray applications of metaflumizone 220 SC (Verismo®), each at recommended and double dose of 200 and 400 g?a.i.?ha^?1 respectively. Initial residue deposits of metaflumizone on cabbage were 0.46 and 0.51 mg?kg^?1 at recommended and 0.76 and 0.85 mg?kg^?1 at double the recommended dose following the first spray and second spray application. The residues persisted beyond 5 days from both the treatments and dissipated with the half-life ranging from 1.7–2.1 days. Initial deposits of metaflumizone on soil ranged from 0.23–0.37 mg?kg^?1 and degraded with a half life ranging from 4.0–4.8 days. No degradation product of metaflumizone was detected in cabbage and soil at any point of time. Soil samples collected from the treated field after 7 days were free from any residue of metaflumizone or its metabolites. A pre-harvest waiting period of 3 days after application was suggested based on calculation of theoretical maximum daily intake.     

Safety evaluation of flubendiamide and its metabolites on cabbage and persistence in soil in different agroclimatic zones of India

Supervised field trials following good agricultural practices were conducted at the research farms of four agricultural universities located at four different agroclimatic zones of India to evaluate the persistence and dissipation of flubendiamide and its metabolite, des-iodo flubendiamide, on cabbage. Two spray applications of flubendiamide 480 SC of standard and double dose at the rate of 24 and 48 g a.i. ha^?1 were given to the crop at a 15-day interval, and the residues of flubendiamide 2 h after spray were found in the range of 0.107–0.33 and 0.20–0.49 mg kg^?1 at respective doses. Residue of des-iodo flubendiamide was not detected in any cabbage sample during study period. No residues were found in the soil samples collected from all treated fields after 15 days of application. On the basis of data generated under All India Network Project on Pesticide Residues, a preharvest interval (PHI) of 10 days has been recommended, and the flubendiamide 480 SC has been registered for its use on cabbage by Central Insecticide Board and Registration Committee, Ministry of Agriculture, Government of India. The maximum residue limit (MRL) of flubendiamide on cabbage has been fixed by the Ministry of Health and Family Welfare, Government of India, under Food Safety Standard Authority of India as 0.05 μg/g after its risk assessment.     

Determination and study on dissipation and residue determination of cyhalofop-butyl and its metabolite using HPLC-MS/MS in a rice ecosystem

Cyhalofop-butyl is an aryloxyphenoxypropionate postemergence herbicide with good control of barnyard grass in rice paddies. In this study, method for the determination of cyhalofop-butyl and its metabolite was developed with high-performance liquid chromatography tandem mass spectrometry. Dissipation and residue levels of cyhalofop-butyl and its metabolite in rice ecosystems were also investigated. Recoveries and relative standard deviations of cyhalofop-butyl and cyhalofop acid in six matrices at three spiking levels ranged from 76.1 to 107.5 % and 1.1 to 8.2 %, respectively. The limit of quantitation (LOQ) of cyhalofop-butyl and cyhalofop acid was 0.01 mg/kg in paddy water, paddy soil, rice plant, rice straw, rice hulls, and husked rice. For field experiments, the results showed that cyhalofop-butyl degraded to cyhalofop acid quickly, and the half-lives of cyhalofop acid in paddy water, paddy soil, and rice plant were 1.01–1.53, 0.88–0.97, and 2.09–2.42 days, respectively. Ultimate residues of cyhalofop-butyl and its metabolite in the rice samples were not detectable or below 0.01 mg/kg at harvest.     

Dissipation and residues of bispyribac-sodium in rice and environment

The dissipation and residues of bispyribac-sodium in rice cropping system were studied. Bispyribac-sodium residues were extracted by a simple analytical method based on QuEChERs and detected by LC-MS/MS. The limit of detection for bispyribac-sodium of this method was 0.375?×?10^?3 ng. The limit of quantification (LOQ) was 5.0 μg/kg for rice plant samples, 2.0 μg/kg for rice hull, 0.2 μg/kg for water, and 0.1 μg/kg for soil and husked rice samples. The average recoveries of bispyribac-sodium ranged from 74.7 to 108 %, with relative standard deviations less than 13 %. The half-lives of bispyribac-sodium in rice plant, water, and soil were in the range of 1.4–5.6 days. More than 90 % of bispyribac-sodium residue dissipated within 5 days. The final residues of bispyribac-sodium in rice were all below LOQ at harvest time.     

Comparative assessment of pesticide residues in grain, soil, and water from IPM and non-IPM trials of basmati rice

The integrated pest management (IPM) modules of pesticide schedule on Basmati rice were validated at field experiments conducted in Northern India for consecutive 3 years (2005–2008). The pesticide residues were found below the detectable limit (<0.01–0.001 mg/kg) in soil and irrigation water samples of Kaithal region. In Dehra Dun region of Uttrakhand, the residues of carbendazim in rice grains and soil were detected below <0.01 mg/kg level. In second year experiments (2006–2007), only four non-IPM soil samples indicated the presence of chlorpyrifos and endosulfan in the range of ND <0.001 to 0.07 mg/kg, out of 45 samples analyzed. Carbendazim applied as seed treatment at Dehradun and Kaithal field trials was found below detectable limit in both IPM and non-IPM rice grains (<0.01 mg/kg) and irrigation water (0.01 μl/ml). Chlorpyrifos was detected in five water samples from Kaithal and one from Pant Nagar in the range of 0.003–0.006 μl/L, α- and β-isomer of endosulfan in the range of 0.005–0.03, and 0.005–0.02 μl/ml, respectively, in one sample from Pant Nagar and two from Kaithal, out of a total of 22 samples. In the region of Uttrakhand and Uttar Pradesh during 2007–2008, four non-IPM samples of soil indicated trace levels of endosulfan, out of 16 samples analyzed. The residues were detected below detection limit for carbendazim (<0.01 mg/kg) in soil samples of Dehradun IPM fields and for endosulfan and carbendazim (0.001–0.01 μl/L) in water samples each from IPM and non-IPM fields of Uttar Pradesh. The results of 3-year trials of IPM module indicated basmati rice as safe and economical with pesticide residue-free rice grains.     

Dissipation and residue of metalaxyl and cymoxanil in pepper and soil

A simple and accurate method of determining metalaxyl and cymoxanil in pepper and soil was developed by ultra-performance liquid chromatography–photodiode array detection. The limits of detection were 0.015 mg/kg for metalaxyl and 0.003 mg/kg for cymoxanil. The limits of quantification were 0.05 mg/kg for metalaxyl in pepper and soil as well as 0.01 mg/kg for cymoxanil in pepper and soil. Recoveries of pepper and soil were investigated at three spiking levels and ranged within 77.52 to 102.05 % for metalaxyl and 87.15 to 103.21 % for cymoxanil, with relative standard deviations below 9.30 %. For field experiments, the half-lives of metalaxyl were 3.2 to 3.9 days in pepper and 4.4 to 9.5 days in soil at the three experimental locations in China. At harvest, pepper samples were found to contain metalaxyl and cymoxanil well below the maximum residue limit MRLs of the European Union (EU) following the recommended dosage and the interval of 21 days after last application.     

Dissipation kinetics and residues of triazolopyrimidine herbicides flumetsulam and florasulam in corn ecosystem

The dynamic and residues of florasulam and flumetsulam in corn field ecosystem were investigated using quick, easy, cheap, effective, rugged, and safe (QuEChERS) procedure with high-performance liquid chromatography-tandem mass spectrometry (HPLC-MS/MS). The limits of quantification (LOQs) of the proposed method ranged from 0.005 to 0.01 mg/kg. Mean recoveries and relative standard deviations (RSDs) of the two compounds in all samples at three spiking levels ranged 94–110 % and 2.0–9.2 %, respectively. Florasulam and flumetsulam degradation followed first-order kinetics with half-lives 1.7–2.9 and 3.3–8.7 days in soil and 1.3–1.8 and 0.9–1.7 days in plant, respectively. The residues in all the samples were found to be less than the LOQs at preharvest intervals of 53 and 78 days. The results suggest that the combined use of florasulam and flumetsulam on corn is considered to be safe under the recommended conditions and can be utilized for establishing the maximum residue limit (MRL) of florasulam in corn in China.     

Dissipation and residue of triforine in strawberry and soil

Two independent field trials were performed in Guangdong and Hubei, China in 2011 to investigate the dissipation and residue levels of triforine in strawberry and soil. A fast and simple method using gas chromatography with electron capture detector was developed and validated to determine triforine levels in strawberry and soil. The average recovery of triforine in strawberry ranged from 87.46 to 104.32 % with a relative standard deviation (RSD) of 0.72 to 4.54 %; that in soil ranged from 83.82 to 103.01 % with an RSD of 3.89 to 4.36 %. The limit of quantification of the proposed method was 0.01 mg/kg for both strawberry and soil. The results suggest that the triforine dissipation curves followed the first-order kinetic. The half-lives of triforine in strawberry from Guangdong and Hubei were 3.58 and 4.42 days, respectively; those in soil were 3.53 and 4.10 days, respectively. The terminal residues of triforine in strawberry ranged from 0.032 to 0.264 mg/kg at preharvest intervals of 0.5, 1, and 3 days. These values are lower than the maximum residue limit of 1 mg/kg in strawberry set by the Codex Alimentarius Commission.     

Mobility of spiromesifen in packed soil columns under laboratory conditions

On percolating water equivalent to 1,156 mm of rainfall, spiromesifen formulation did not leach out of 25-cm long columns, and 62.7 % of this was recovered in 5–10-cm soil depth. In columns treated with the analytical grade, 52.40 % of the recovered spiromesifen was confined to 0–5-cm soil depth, with 0.04 % in leachate fraction, suggesting high adsorption in soil. Results revealed that percolating 400 mL of water, residues of enol metabolite of spiromesifen was detected up to 20–25-cm soil layer, with 23.50 % residues of spiromesifen in this layer and 1.73 % in the leachate fraction indicating that metabolite is more mobile as compared to the parent compound. Results suggested a significant reduction in leaching losses of enol metabolite in amended soil columns with 5 % nano clay, farmyard manure (FYM), and vermicompost. No enol spiromesifen was recovered in the leachate in columns amended with nano clay, vermicompost, and FYM; however, 85.30, 70.5, and 65.40 %, respectively, was recovered from 0–5 cm-soil depth of column after percolating water equivalent to 1,156 mm of rainfall. Spiromesifen formulation is less mobile in sandy loam soil than analytical grade spiromesifen. The metabolite, enol spiromesifen, is relatively more mobile than the parent compound and may leach into groundwater. The study suggested that amendments were very effective in reducing the downward mobility of enol metabolite in soil column. Further, it resulted in greater retention of enol metabolite in the amendment application zone.     

Dissipation and residue of azoxystrobin in banana under field condition

A method was developed for determining azoxystrobin in banana and cultivation soil using gas chromatography. The dissipation and residue of azoxystrobin in banana fields at GAP conditions were investigated. The average recoveries ranged from 80.3 to 96.0 % with relative standard deviations of 2.9 to 7.2 % at three different spiking levels for each matrix. The results indicated that the half-life of azoxystrobin in bananas and soil ranged from 7.5 to 13.5 days in Guangdong and from 8.7 to 12.7 days in Fujian. The dissipation rates of azoxystrobin in banana and soil were almost the same. Terminal residues in banana and banana flesh (0.01 mg/kg) were all below the maximum residue limit (2 mg/kg by Codex Alimentarius Commission and China). The results demonstrated that the safety of using azoxystrobin at the recommended agriculture dosage to protect bananas from diseases.     

Dissipation and residue of 2,4-<Emphasis Type="SmallCaps">d</Emphasis> in citrus under field condition

The dissipation, residues, and risks of 2,4-dicholrophenoxyacetic acid (2,4-d) in citrus under field condition were investigated based on a simple ultra-performance LC (UPLC)-MS/MS method. The results indicated that the residue level of 2,4-d in citrus did not degrade gradually with sampling time under field condition. At pre-harvest intervals (PHI) of 20–40 days, 2,4-d residues were 0.021–0.269 mg/kg in citrus flesh, 0.028–0.337 mg/kg in whole citrus, and 0.028–0.376 mg/kg in citrus peel, all bellow the China maximum residue limit in citrus (1 mg/kg). Risks of 2,4-d were assessed by calculation of risk quotient, and the results revealed no significant health risks after consumption of citrus.     

Residue and intake risk assessment of prothioconazole and its metabolite prothioconazole-desthio in wheat field

In the environment, plants and animals in vivo, pesticides can be degraded or metabolized to form transformation products (TPs) or metabolites, which are even more toxic than parent pesticides. Hence, it was necessary to evaluate residue and risk of pesticides and their TPs (or metabolites). Here, a rapid, simple, and reliable method using QuEChERS and LC-MS/MS had been developed for simultaneous analysis of prothioconazole and its toxic metabolite, prothioconazole-desthio, in soil, wheat plant, straw, and grain. The average recoveries of prothioconazole and prothioconazole-desthio in four matrices ranged from 86 to 108% with relative standard deviations (RSDs) of 0.53–11.87% at three spiking levels. The method was successfully applied to investigate the dissipation and terminal residues of the two compounds in wheat field. It was shown that prothioconazole was rapidly degraded to prothioconazole-desthio, with half-lives below 5.82 days. Prothioconazole-desthio was slowly dissipated in soil and plant. The terminal residues of prothioconazole in wheat grain with a pre-harvest interval (PHI) of 21 or 28 days were below the maximum residue limits (MRLs) (0.1 mg/kg, Codex Alimentarius Commission (CAC)). We also evaluated the intake risk of prothioconazole-desthio residues in wheat grain in China. For long-term intake assessment, the hazard quotients (HQ) ranged from 1.30 to 5.95%. For short-term intake assessment, the acute hazard indexes (aHI) ranged from 1.94 to 18.2%. It indicated that the intake risk of prothioconazole-desthio in wheat consumption was acceptable. Thus, the prothioconazole application on wheat with the scientific practices would not pose public health risk.     

Dissipation behavior and risk assessment of butralin in soybean and soil under field conditions

Dissipation behavior, final residue, and risk assessment of butralin in soybean, green soybean, plant, and soil were investigated. Butralin residues were extracted with acetonitrile and then soybean samples were detected with gas chromatography-mass spectrometer (GC-MS) and soil samples were determined with GC with nitrogen phosphorous detector (GC-NPD). The limit of quantification (LOQ) of the method was 0.01 mg/kg for soybean, green soybean, plant, and soil. Average recoveries ranged from 90.4 ~ 98.2% for green soybean, 86.2 ~ 86.6% for soybean, 86.0 ~ 98.8% for plant, and 85.0 ~ 106.8% for soil. The relative standard deviations (RSDs) were 2.0 ~ 7.2% for green soybean, 2.0 ~ 3.0% for soybean, 3.1 ~ 8.1% for plant, and 1.8 ~ 6.6% for soil. Half-lives of butralin in soil samples varied in the range of 11–22 days. At harvest time, final residues of butralin in soybean and green soybean were lower than LOQ. Risk assessment demonstrated that, at recommended dosage and frequency, butralin would not induce significant harm on humans. The study could be used as a quantitative basis for application of butralin on soybean.     

Ecological vulnerability: seasonal and spatial assessment of trace metals in soils and plants in the vicinity of a scrap metal recycling factory in Southwestern Nigeria

The concentrations of selected heavy metals in the soil and vegetation in the immediate vicinity of a metal scrap recycling factory were determined in the dry and wet seasons using the Atomic Absorption Spectrophotometer. The results showed that the soil pH in all the sites indicated slight acidity (from 5.07 to 6.13), high soil organic matter content (from 2.08 to 5.60 %), and a well-drained soil of sandy loam textural composition. Soil heavy metal content in the dry season were 0.84–3.12 mg/kg for Pb, 0.26–0.46 mg/kg for Cd, 9.19–24.70 mg/kg for Zn, and 1.46–1.97 mg/kg for Cu. These values were higher than those in the wet season which ranged from 0.62–0.69 mg/kg for Pb, 0.67–0.78 mg/kg for Cd, 0.84–1.00 mg/kg for Zn, and 1.26–1.45 mg/kg for Cu. Except for cadmium in the dry season, the highest concentrations occurred in the northern side of the factory for all the elements in both seasons. An increase in the concentrations of the elements up to 350 m in most directions was also observed. There was no specific pattern in the level of the metals in the leaves of the plant used for the study. However, slightly elevated values were observed in the wet season (Pb 0.53 mg/kg, Cd 0.59 mg/kg, Cu 0.88 mg/kg) compared with the dry season values (Pb 0.50 mg/kg, Cd 0.57 mg/kg, Cu 0.83 mg/kg). This study showed that the elevated concentrations of these metals might be associated with the activities from the recycling plant, providing the basis for heavy metal pollution monitoring and control of this locality that is primarily used for agricultural purposes.     

Dissipation dynamic and residue distribution of flusilazole in mandarin

In this paper, dissipation dynamic and terminal residue of flusilazole in mandarin and soil, as well as residue distribution of flusilazole in mandarin, were studied at three sites in China. Mandarin peel, mandarin pulp, whole mandarin, and soil samples were extracted by acetonitrile, cleaned up with dispersive solid-phase extraction, then analyzed by gas chromatography–mass spectrometry. The dissipation half-lives of flusilazole in mandarin and soil at all three experiment sites were 6.3–8.4 days and 5.5–13.4 days, respectively, with the exception of the soil dissipation at the Hunan site, which showed an increase–decrease process. Flusilazole residue levels in whole mandarin were all below 0.1 mg/kg on 14 days after the last application. Terminal residue study showed that flusilazole was mostly distributed in mandarin peel, which indicates minimal risk for eating mandarin pulp. These results could provide guidance for the proper and safe use of flusilazole on citrus fruits, and further our understanding of pesticide distribution in citrus fruits.     

Occurrence of phthalic acid esters in Gomti River Sediment, India

Cadmium and lead are important environmental pollutants with high toxicity to animals and human. Soils, though have considerable metal immobilizing capability, can contaminate food chain via plants grown upon them when their built-up occurs to a large extent. Present experiment was carried out with the objective of quantifying the limits of Pb and Cd loading in soil for the purpose of preventing food chain contamination beyond background concentration levels. Two separate sets of pot experiment were carried out for these two heavy metals with graded levels of application doses of Pb at 0.4–150 mg/kg and Cd at 0.02–20 mg/kg to an acidic light textured alluvial soil. Spinach crop was grown for 50 days on these treated soils after a stabilization period of 2 months. Upper limit of background concentration levels (C _ul) of these metals were calculated through statistical approach from the heavy metals concentration values in leaves of spinach crop grown in farmers’ fields. Lead and Cd concentration limits in soil were calculated by dividing C _ul with uptake response slope obtained from the pot experiment. Cumulative loading limits (concentration limits in soil minus contents in uncontaminated soil) for the experimental soil were estimated to be 170 kg Pb/ha and 0.8 kg Cd/ha. Based on certain assumptions on application rate and computed cumulative loading limit values, maximum permissible Pb and Cd concentration values in municipal solid waste (MSW) compost were proposed as 170 mg Pb/kg and 0.8 mg Cd/kg, respectively. In view of these limiting values, about 56% and 47% of the MSW compost samples from different cities are found to contain Pb and Cd in the safe range.     

Dissipation and residues determination of propamocarb in ginseng and soil by high-performance liquid chromatography coupled with tandem mass spectrometry

Two-year field trials were performed at two experimental sites to investigate dissipation and terminal residues of propamocarb in ginseng root, stem, leaf, and soil by high-performance liquid chromatography coupled with tandem mass spectrometry (HPLC-MS/MS). Mean recoveries ranged from 80.5 to 95.6 % with relative standard deviations (RSDs) of 5.5–9.1 % at fortified levels of 0.01, 0.02, 0.05 and 0.20 mg kg^?1. The half-lives of propamocarb were 5.00–11.36 days in root, 5.07–11.46 days in stem, 6.83–11.31 days in leaf and 6.44–8.43 days in soil. The terminal residues of propamocarb were below the maximum residue limits (MRLs) of EU (0.20 mg kg^?1) and South Korea (0.50 mg kg^?1 in fresh ginseng and 1.0 mg kg^?1 in dried ginseng) over 28 days after last spraying at recommended dosage. The results provide a quantitative basis for establishing the MRL and give a suggestion of safe and reasonable use of propamocarb in ginseng.     

Metabolic degradation of imidacloprid in paddy field soil

The metabolic degradation and persistence of imidacloprid in paddy field soil were investigated following two applications of imidacloprid at 20 and 80 g a.i. ha^?1 at an interval of 10 days. The soil samples were collected at various time intervals. The limit of quantification for the analysis of imidacloprid and its metabolites was obtained at the concentration of 0.01 mg kg^?1. The initial deposits of total imidacloprid were found to be 0.44 and 1.61 mg kg^?1 following second applications. These residues could not be detected after 60 and 90 days following second applications of imidacloprid at lower and higher dosages, respectively. In soil, urea metabolite was found to be the maximum, followed by olefine, nitrosimine, 6-chloronicotinic acid, 5-hydroxy and nitroguanidine. The half-life values (t _1/2) of imidacloprid were worked out to be 12.04 and 11.14 days, respectively, when applied at lower and higher doses, respectively.