Theoretical Maximum Residue Research Articles

Dissipation and dietary risk evaluation of cyantraniliprole, diafenthiuron and its metabolites in tomato

Supervised field trial was conducted to study the residue decline of cyantraniliprole and diafenthiuron with its metabolites in tomato fruits. Two foliar applications of combined formulation (Cyantraniliprole 7.3 % w/w + Diafenthiuron 36.4 % w/w SC) were applied at 360 (X dose) and 720 g a.i. ha−1 (2X dose). The tomato fruit samples were collected at 0, 1, 3, 5, 7, 10 and 15 days after second spray to study the residual behaviour. Extraction and cleanup of the samples was done following QuEChERS methodology and the residues were quantified on Liquid Chromatography Mass Spectrometry (LCMS/MS). The mean initial residues of cyantranliprole in tomato fruits were 0.17 and 0.31 mg kg−1, at X and 2X doses, respectively. The residues reached below limit of quantification (LOQ) after five and seven days of treatment at X and 2X doses, respectively. The total initial residues of diafenthiuron (diafenthiuron + CGA 177960 + CGA 227352 + CGA 140408) in tomato fruits were 0.33 and 0.75 mg kg−1, which reached below LOQ on seventh and tenth day at X and 2X doses, respectively. Dissipation of cyantraniliprole followed first-order kinetics with half-life values of 1.31 and 1.84 days, while total diafenthiuron residues followed first-order kinetics with half-life values of 1.25 and 2.27 days, at X and 2X doses, respectively. Risk assessment was done by comparing Maximum Permissible Intake (MPI) with Theoretical Maximum Residue Contribution (TMRC) and results showed that TMRC is less than MPI.

Residues determination, risk assessment, and dissipation behavior of myclobutanil formulation on apple.

This study aimed to investigate the dissipation pattern, risk assessment, and waiting period of myclobutanil on apple fruit (Malus domestica Borkh.) under temperate conditions in Kashmir, India. The study involved the application of myclobutanil 10 WP at a single recommended dosage (125 g a.i.ha-1) and double dosage (250 g a.i.ha-1) on Red Velox apple trees, 2 months before harvest. GC equipped with an electron capture detector was used to analyze myclobutanil residues in fruit samples. The study revealed that myclobutanil, at both recommended and double recommended doses, dissipated rapidly and became nondetectable after 55 and 60 days, respectively. The waiting period for myclobutanil application was determined to be 12.41 days for the single dose and 25.58 days for the double dose, respectively. These waiting periods were based on the maximum residue limit of 0.6 ppm as prescribed by the Codex Alimentarius Commission, Food Safety and Standards Authority of India, and European Commission. The study concludes that myclobutanil 10 WP is safe for consumers at both recommended and double recommended doses when applied 2 months before harvest. Risk assessment, considering the average daily apple consumption in India and theoretical maximum residue contributions (TMRCs), indicates negligible health hazards even at double the recommended dosage. The calculated TMRC values at Day 0 were significantly below the maximum permissible intake. For average and maximum myclobutanil residues at single and double doses, the TMRC values were found to be 0.0069 and 0.0070 mg day-1 person-1 and 0.0105 and 0.0106 mg day-1 person-1, respectively. These results indicate that myclobutanil, when used according to recommended dosages and waiting periods, poses minimal health risks to consumers. The study emphasizes the importance of prudent fungicide use to minimize fungicide residues on fruits, thereby ensuring their safety for consumption.

Assessment of flusilazole residues on apples: Detection, quantification and health risk implications.

Apple, a major fruit of temperate Himalayas, is sprayed with chemical pesticides around 12 times during the cropping season. Various systemic and contact fungicides are applied for the management of major diseases. In order to manage disease, flusilazole 40 EC is frequently used. However, excessive chemical application has been found to be detrimental for consumer safety. Keeping in view consumer safety, risk assessment, the half-life and waiting period for flusilazole 40 EC were evaluated on the Red Velox variety of apple. The QuEChERS (quick, easy, cheap, effective, rugged and safe) method and high-performance liquid chromatography were adapted for sample processing and analysis, respectively. The recovery percentages of flusilazole at three fortification levels (0.04, 0.09 and 0.50 mg kg-1 ) were 98.85, 99.83 and 98.98%, respectively. Flusilazole at the recommended dose (80 g a.i.ha-1 ) left an initial deposit of 0.733 mg kg-1 , which dissipated by 93.45% in 60 days and was non-detectable beyond this period. Meanwhile flusilazole at double the recommended dose (160 g a.i.ha-1 ) left an initial deposit of 0.913 mg kg-1 , which dissipated by 93.43% in 70 days and was non-detectable beyond this period. Based on the maximum residue limit of 0.3mg kg-1 as prescribed by the Codex Alimentarius Commission, a waiting period of 28.74 and 46.03 days was recorded for single and double doses, respectively. Moreover, in order to assess the consumer risk, theoretical maximum residue contributions (TMRCs) were derived using flusilazole residues (average and maximum) recorded at various time intervals and compared with the maximum permissible intake, which was found to be 0.42 mg per person per day. Based on the average per capita daily consumption of 6.76 g apple in India, the TMRC values were computed. Although the values of TMRC decreased below maximum permissible intake at the first day after application, indicating minimal consumer health risks, fruits sprayed with a double dose of flusilazole carried the risk even up to the tenth day after flusilazole application. The results of the present study will be valuable for safe and timely use of flusilazole on apple.

Behavior of trifloxystrobin and propineb as combi-product in tomato (Solanum lycopersicum) and their risk assessment for human health.

Fungicides have their own unique characteristics and modes of action; a combination formulation of trifloxystrobin and propineb was applied to tomatoes for their dissipation kinetics and to ensure consumer safety. The combi-product was applied at a 10-day interval with standard (61.25 + 1072.75 g a.i. ha-1 ) and double (122.5 + 2145.50 g a.i. ha-1 ) doses. The efficient analytical method was established using the QuEChERS approach followed by liquid chromatography-mass spectrometry. The maximum residue levels of 0.15 and 0.35 mg kg-1 of trifloxystrobin were detected in tomato fruits immediately after application at standard and double doses, respectively. The corresponding levels of propineb as carbon disulfide were 0.47 and 0.90 mg kg-1 , respectively. Considering trifloxystrobin (0.7 mg kg-1 ) codex MRL and propineb as dithiocarbamate (3.0 mg kg-1 ) EU-MRL in tomato, a PHI of 1 day can be proposed. The anticipated residue contributions of both fungicides were far less than the acceptable daily intake. The targeted hazard quotient and hazard index were also less than one for both fungicides. Furthermore, the theoretical maximum residue contribution was less than its maximum permissible intake, which indicates that the consumption of tomatoes containing the measured value of each fungicide residue could not pose any health risks.

Dissipation kinetics, risk assessment, and waiting period of spiromesifen on chili fruits using gas chromatography-electron capture detector.

A supervised field trial was designed in Rajasthan Agricultural Research Institute, Durgapura, Jaipur, Rajasthan, to assess the dissipation and persistence of spiromesifen in chili fruits. Spiromesifen (22.9% suspension concentrate) was sprayed two times at an interval of 10 days at the recommended dose (96 g. a.i. ha-1 ) and double the recommended dose (192 g. a.i. ha-1 ) with four replications. Sampling was done according to the planned interval of days after the second spray. Extraction and cleanup were performed using the modified QuEChERS (quick, easy, cheap, effective, rugged, and safe) method and the spiromesifen residue was analyzed by GC-electron capture detector and confirmation performed using GC-MS. The average initial deposit of spiromesifen was 1.207 mg kg-1 and 1.948 mg kg-1 at the recommended and double the recommended dose, respectively. The half-life values of spiromesifen ranged between 2.7 and 3.2 days at the recommended and double the recommended dose. The safe waiting period was calculated for the respective doses and it was concluded that an average of 7 days is safe for picking. The FSSAI (Food Safety and Standards Authority of India) have set the maximum residue limit of 0.1 mg kg-1 for spiromesifen in green chili. The theoretical maximum residue contribution value of spiromesifen was lower than the maximum permissible intake at both the applications on the 0th day. Hence, there will be no adverse effects on human health after consumption of green chilies.

Residual Behavior of Tebuconazole and Trifloxystrobin in Okra Fruits and Soil

ABSTRACT A field trial was conducted to study the dissipation of trifloxystrobin and tebuconazole on okra following application of Nativo (tebuconazole 50% + trifloxystrobin 25% WG) at 350 and 700 g ha−1. The estimation of trifloxystrobin and CGA 321113 residues was carried on gas–liquid chromatograph equipped with electron capture detector and that of tebuconazole on gas chromatograph–mass spectrometry. Average initial deposits of tebuconazole in okra were found to be 0.75 and 1.45 mg kg−1, whereas trifloxystrobin was found to be 0.28 and 0.61 mg kg−1 following the application of Nativo at 350 and 700 g ha−1, respectively. Residues of tebuconazole dissipated below limit of quantification of 0.05 mg kg−1 after 7 and 10 days and of trifloxystrobin after 5 days of last application at recommended and double of the recommended dosages, respectively. For risk assessment studies, theoretical maximum residue contributions (TMRC) were calculated and compared with maximum permissible intake (MPI). It was observed that TMRC values were below MPI in zero day samples at both recommended and double of the recommended dosages. Therefore, the waiting period of 1 day should be observed for safe consumption of okra treated with tebuconazole and trifloxystrobin.

National probabilistic risk assessment of newly registered pesticides in agricultural products to propose maximum residue limit (MRL).

Following the EPA recommended method, a chronic diet risk assessment for pesticides was recently performed for adults and children in the Iranian population. The National Theoretical Maximum Daily Intake (NTMDI) for 32 pesticides was computed using the theoretical maximum residue limits (MRLs) of food consumption regulations and data from the comprehensive database of the Iranian Research Institute of Plant Protection (IRIPP). The risk was assessed by comparing TMDI with the acceptable daily intakes (ADI) evaluated by FAO. From 32 investigated pesticides, 10 pesticides had TMDI > 65% of the ADI. Some of these ADI-exceeding compounds (spirodiclofen, abamectin, trifloxystrobin, spiromesifen, fipronil, difenoconazole, tetraconazole) were found in citrus, cucumber, grapes, tomato, and potato as the foods that have played the most roles in the consumption of these pesticides. Furthermore, a probabilistic risk assessment was performed to estimate the contingency of extravagance of the ADI. In the current research, only cyazofamid in potato for children consumers exceeded the 1 of the HQ. However, carcinogenic risk (CR) due to spirodiclofen in citrus fruit and difenoconazole in tomato was higher than the 1E-6 value; therefore, consumers were at considerable carcinogenic risk in these commodities. This scrutiny is essential for improving the activities' risk assessment, regulation, and surveillance.

Determination of Tetraniliprole and its Metabolite Residues in Tomato

Dissipation of tetraniliprole and its metabolite, chinazolinon in tomato was studied. Immature fruit samples were collected at specific intervals with three applications. Modified QuEChERS method was used and satisfactory recovery of 78.28 to 104.77 % was obtained. Good linearity (0.05 to 1.00 μg g-1) with coefficient of determination (R2) > 0.99 was recorded. The initial deposit at 60 (x) and 120 g a.i. ha-1 (2x) was 0.42 and 0.65 μg g-1 and reached the below limit of quantification on 5th and 7th days after spraying. The half-life period was 1.3 and 1.6 days and the safe waiting period was 4.5 and 5.8 days at x and 2x doses, respectively. The harvest time (20th day) samples, mature fruit and soil were at BLQ in both the doses. The metabolite, chinazolinon was not detected in any of the sample analyzed. Theoretical maximum residue contribution (TMRC) was less than maximum permissible intake even on the day of spraying.

Dissipation and risk assessment of Solomon (300 OD), a combination product of beta-cyfluthrin and imidacloprid in lemon and onion samples

ABSTRACT Supervised field trials were conducted to study dissipation of combination product of beta-cyfluthrin and imidacloprid (Solomon) in various samples of lemon and onion. The pesticides were extracted and analysed using QuEChERS (with some modifications) based methods after validation of the method. Linearity, accuracy and precision data showed that the results were in the acceptable range as per SANTE 2019. The results of dissipation revealed that the initial accumulation of beta-cyfluthrin was 0.6 and 1.1 mg kg−1 in lemon and 0.24 and 0.97 mg kg−1 in onion samples at standard and double dose respectively. The residues of imidacloprid were 2.61 and 4 mg kg−1 in lemon and 0.36 and 0.53 in onion at two doses. The residues of beta-cyfluthrin followed first order dissipation in both the crops at standard dose and showed biphasic dissipation in double dose in both lemon and onion samples. Imidacloprid followed first-order dissipation in lemon in both the doses. Half-life of beta-cyfluthrin ranged from 3.6 to 23.2 days in lemon samples and that of imidacloprid was 15.1 and 21.5 days in two different doses. In onion the half-life ranged from 2.1 to 4.0 for beta-cyfluthrin and 2.8 to 5.2 days for imidacloprid in different doses. Theoretical maximum residue concentration (TMRC) was always less than maximum permissible intake (MPI) in all the samples suggesting that the use of combination product is safe.

Safety Evaluation of Lambda-cyhalothrin and Quinalphos in Mango (Mangifera indica L.)

Persistence of lambda-cyhalothrin and quinalphos in mango (cv. Dashehari) following their foliar application is reported. Lambda-cyhalothrin and quinalphos dissipated from 2.01 and 3.45 mg kg–1 and 1.52 and 2.78 mg kg–1 at 0 d to 0.07 and 0.11 mg kg–1 and 0.15 and 0.26 mg kg–1 at 15 and 22 d of their application at single and double doses, respectively. No residue of these insecticides was detected in mature fruit and its pulp at the time of harvest. The rate of dissipation followed first-order exponential kinetics with half-lives of 3 d for lambda-cyhalothrin and 7 d for quinalphos. Based on their MRL values of 0.5 and 0.02 mg kg–1, pre harvest intervals of 5.0 and 7.5 d for lambda-cyhalothrin and 42 and 48 d for quinalphos were suggested at the two respective rates of application. The theoretical maximum residue contribution (TMRC) values for both the insecticides were found below the maximum permissible intake (MPI) values on fruit. The residues of both the insecticides are harmless to consumers if sprayed at single dose and following the suggested PHI before consumption.

Dinotefuran Residues and their Dissipation in Chilli Pepper (Capsicum annuum L.) and Soil and their Risk Assessment

The results of a study conducted to assess the degradation pattern and risk assessment of dinotefuran in chilli pepper and soil using LC-ESI-MS/MS are reported. A modified “QuEChERS” method for the extraction and clean up giving acceptable recovery value for all the three matrices was used. Residues in fresh chilli peppers reached below the limit of quantitation, (LOQ 0.01 mg kg-1) on 15th and 21st d of application of dinotefuran at 27.5 and 55 g a.i. ha−1 respectively whereas in dried chilli peppers, these reached below 0.01 mg kg−1 on the 21st and 25th d. The residues got magnified by 2.69 to 3.00 times during sun drying of fresh chilli peppers, necessitating detailed study on its dynamics during different processing steps. Half-live of dinotefuran at the standard and double doses were 2.1 and 2.4 d for fresh chilli peppers, and 2.3 and 2.6 d respectively in the dried chilli peppers. The corresponding calculated waiting periods were 1.34 and 3.45 d for fresh chilli peppers. The residue in soil reached below the LOQ on the 10th d, registering a half-life of 1.86 and 1.43 d at the standard and the double doses respectively. The risk assessment showed that the the theoretical maximum residue contribution (TMRC) in fresh chilli peppers on 0 d were 3.024 and 5.739 μg person−1 d−1 at the standard and the double doses respectively. The residues present in the food were considered safe since the TMRC value was lower than the maximum permissible intake (MPI). Therefore, the dinotefuran applied at the standard and the double doses in chilli pepper did not pose any risk to humans, even on the day of its application. It can be incorporated as one of the insecticides in integrated management of pest complex in chilli under the humid climatic conditions.

Residual status and risk assessment of forbidden and restricted pesticides of organophosphorus in Loincerae Japonicae Flos

This paper reports the residual status of forbidden and restricted pesticides of organophosphorus in Loincerae Japonicae Flos to provide reference for the risk control and the formulation of maximum residue limits of the flower. A method for the determination of residues of 23 forbidden and restricted pesticides of organophosphorus was established, and 64 collected samples were tested. Then a risk assessment based on the maximum residue limit was carried out. Results showed that the detection rate of samples was 58%. 6 of 23 pesticides were detected and the ratio was chlorpyrifos 41%, omethoate 23%, triazophos 11%, isofenphos-methyl 6.3%, methamidophos 1.6%, isocarbophos 1.6%, respectively. And the median of pesticide residues in the positive samples was chlorpyrifos 0.037 mg·kg⁻¹, omethoate 0.043 mg·kg⁻¹, triazophos 0.030 mg·kg⁻¹, isofenphos-methyl 0.18 mg·kg⁻¹, methamidophos 0.041 mg·kg⁻¹, isocarbophos 0.041 mg·kg⁻¹, respectively. In the samples with pesticide residues, the residue amount of methamidophos and isocarbophos was lower than the theoretical maximum residue limit, and the residue amount of chlorpyrifos, isofenphos-methyl, triazophos were higher than it individually, while, all the residue amount of omethoate was higher than it. According to the assessment result of theoretical maximum residue limit, it is suggested that relevant departments should accelerate the formulation of the maximum residue limit standard, and strengthen the supervision of the use of forbidden and restricted pesticides of organophosphorus in Loincerae Japonicae Flos.

Dissipation kinetics and risk assessment of chlorfenapyr on tomato and cabbage.

A field experiment was conducted over two seasons to evaluate the dissipation kinetics and assess the risks of chlorfenapyr in tomato and cabbage following foliar application of chlorfenapyr 10% SC at 100 and 200ga.i.ha-1. Samples of tomato, cabbage, and soil were analyzed and quantified by gas chromatography-electron capture detector (GC-ECD). The limit of detection (LOD) and limit of quantification (LOQ) of chlorfenapyr were found to be 0.01 and 0.03mgkg-1, respectively, in tomato, cabbage, and soil. The dissipation of chlorfenapyr followed first-order kinetics. The compound showed less persistence in both the vegetables and soil as the calculated half-life values of chlorfenapyr ranged between 4.54 and 7.74days considering two different doses and seasons. The residue was below detection limit in all the untreated plant and soil samples. The pre-harvest interval (PHI) of chlorfenapyr in both the vegetables was determined to be 9-14days regardless of dose or season. The theoretical maximum residue contribution (TMRC) of chlorfenapyr was calculated for tomato and cabbage and was found to be lower than the maximum permissible intake (MPI) of the compound. Therefore, the application of chlorfenapyr at the recommended dose in tomato and cabbage for crop protection seems to be safe from both environmental contamination and consumer safety standpoints.

Dissipation kinetics and safety evaluation of tebuconazole and trifloxystrobin in tea under tropical field conditions

ABSTRACTDissipation kinetics of tebuconazole, trifloxystrobin and its acid metabolite residues were studied in tea under tropical field conditions using GC-MS (SIM). The average recoveries ranged from 80.7% to 105.8%, with a RSD of <9.3%. Dissipation rate for both doses applied followed first-order kinetics, with half-lives in green leaves in the range of 2.8–3.3 and 2.9–3.3 days; ranges in processed tea were 2.7–3.6 days for trifloxystrobin and 3.0–3.1 days for tebuconazole. The trifloxystrobin residues were not transferred into the tea infusion during the infusion process; tebuconazole did transfer, in the range of 14.3–18.9%. As the theoretical maximum residue contributions on tea from initial deposits were found to be less than the maximum permissible intake values, at the recommended application dose a withdrawal period of 23 days before consumption should be applied to reduce risk.

Dissipation of Flonicamid in Honeysuckle and Its Transfer during Brewing Process.

The dissipation of flonicamid in Honeysuckle and transfer pattern from Honeysuckle to its tea infusion were investigated. Flonicamid was applied on Honeysuckle crop at two dosages, 60 g of active gradient per hectare (g a.i. hm-2) and 180 g a.i. hm-2 (recommended and triple the recommended) in Fenqiu, Henan Province in 2015 and 2016. Gas Chromatography-Electron Capture Detector (GC-ECD) detection methods were developed for the analysis of flonicamid residues in honeysuckles and its infusion. The recoveries in both honeysuckles and its infusion ranged from 81.5 to 101.7% with relative standard deviations (RSDs) of 3.2-9.1%. The dissipations of flonicamid in Honeysuckle were found to follow the first order kinetics with half-life ranging between 2.8 and 3.2 d. After recommended dose pesticide application, contents of flonicamid residues were lower than theoretical maximum residue limit (tMRL). Flonicamid residues can easily transfer from Honeysuckle to its tea infusion and transfer rates of flonicamid decrease with the brewing temperature reduction or the brewing times increase. These results are helpful to establish maximum residue limit and develop guidance on the appropriate and secure use of flonicamid in Honeysuckle.

Residue decline and risk assessment of fluopyram + tebuconazole (400SC) in/on onion (Allium cepa).

A method was validated for estimating fluopyram and tebuconazole in onion on LC-MS/MS using dispersive QuEChERS. Three sprays of a combination fungicide fluopyram+tebuconazole (Luna experience, 400 SC) were applied @ 75+75 and 150+150g a.i. ha-1 at an interval of 10days on onion using Knapsack sprayer. First spray was made at bulb setting stage. Spring onion samples were drawn at 0 (1h), 1, 3, 5, 7, 10, 15, and 20days and matured onion bulb at harvest (52days) after the last spray. Soil samples were also drawn at harvest. Foliar application of the combination product resulted in 1.14 and 2.86mgkg-1 fluopyram residues on spring onion at standard and double dose, respectively, one hour after the last application. The levels of fluopyram residues gradually declined and recorded 0.25 and 0.58mgkg-1 on 20th day of application with half-lives of 8.8 and 9.1days at standard and double dose, respectively. For tebuconazole, the corresponding residues observed after 1h (0day) of application were 0.92 and 2.29mgkg-1. The levels declined gradually to 0.12 and 0.33mgkg-1 on 20th days with half-life of 6.7 to 7.7days at standard and double dose, respectively. Here, we are proposing a pre-harvest interval of 7day for fluopyram and tebuconazole in spring onion when applied at 75+75g a.i. ha-1 (400 SC). Risk assessment was done by calculating hazard quotient and by comparing theoretical maximum residue intake (TMRI) with maximum permissible intake (MPI). In all the cases, results of the study showed that HQ (Hazard Quotient) ≤1 and TMDI<MPI. Hence, the use of this combination product can be recommended with pre harvest interval of 7days. The data can be used in establishing MRLs (maximum residue limits) for spring onion after considering multilocation trials.

Dissipation kinetics and risk assessment of thiamethoxam and dimethoate in mango.

Thiamethoxam and dimethoate are two insecticides used to control hoppers and inflorescence midges in mango. Thiamethoxam (0.008 and 0.016%) and dimethoate (0.06 and 0.12%) were sprayed on Dashehari mango trees during the pre-mature stage of fruit (first week of May) to study their dissipation kinetics and risk assessment in mango fruit. Thiamethoxam dissipated in fruit from 1.93 and 3.71 mg kg(-1) after 2 h of spraying to 0.08 and 0.13 mg kg(-1) after 20 days of spraying at single and double doses, respectively. Its residue did not persist beyond 20 days in fruit. Dimethoate dissipated in fruit from 2.81 and 5.34 mg kg(-1) after 2 h of application to 0.12 and 0.19 mg kg(-1) after 10 days of application at single and double doses, respectively. No residue was detected in fruit beyond 10 days after its application. Both ready-to-harvest mature mango fruit and pulp (after 40 days of spraying) were free from any residues of these insecticides at both the concentration levels. The rate of dissipation of these insecticides followed first-order kinetics in fruit with residual half-lives of 4.0 to 4.5 days for thiamethoxam and 2 days for dimethoate. Based on their MRL values of 0.5 and 2.0 mg kg(-1) in mango, pre-harvest intervals of 7 and 11 days, and 6 and 7 days were suggested for thiamethoxam and dimethoate, respectively, after spraying at single and double doses. The theoretical maximum residue contribution (TMRC) values for both the insecticides, calculated for residues corresponding to each sampling date, were found to be below the maximum permissible intake (MPI) values on mango fruit (except for dimethoate double dose up to 3 days); hence, both thiamethoxam and dimethoate could be considered non-hazardous to consumers at the above doses and time intervals.

Estimation and risk assessment of flubendiamide on fodder berseem clover (Trifolium alexandrinum L.) by QuEChERS methodology and LC-MS/MS.

The residues of flubendiamide from berseem were extracted and cleaned up by the QuEChERS approach and analysed by liquid chromatography/mass spectrometry (LC-MS/MS). The dissipation studies on berseem were carried out by application of flubendiamide at five different dosages i.e. 24, 36, 48, 72 and 96g a.i. ha(-1). The residues reached below determination limit (BDL) of 0.01mgkg(-1) in 7, 10, 10, 15 and 15days for 24, 36, 48, 72 and 96g.a.i. ha(-1)dosages, respectively. Half-life (t1/2) of flubendiamide on berseem was observed to be 1.08, 1.88, 1.94, 2.26 and 2.27days, respectively, at 24, 36, 48, 72 and 96g a.i. ha(-1). Theoretical maximum residue contributions (TMRC) values reached below the maximum permissible limit (MPI) for 3, 5 and 7days in treatments at 24, 36 and 48g.a.i. ha(-1), respectively, whereas in case of higher dose treatments i.e. 72 and 96g a.i. ha(-1), the residues of flubendiamide reached below MPI after 10days of treatment. These data could provide guidance for the proper and safe use of this pesticide on berseem in India.

Dissipation pattern and risk assessment studies of triazophos residues on capsicum (Capsicum annuum L.) using GLC-FPD and GC-MS.

The present study was carried out to observe the dissipation pattern of triazophos on capsicum and risk assessment of its residues on human beings and to suggest a waiting period for the safety of consumers. Following two applications of triazophos (Truzo 40 EC) at 500 and 1000g a.i. ha(-1), the average initial deposits were found to be 3.61 and 6.26mgkg(-1), respectively. These residues dissipated below the limit of quantification (LOQ) of 0.05mgkg(-1) in 10 and 15days at the recommended and double the recommended dosages, respectively. The calculated values of half-life were 2.31 and 2.14days at recommended and double the recommended dosages, respectively. Theoretical maximum residue contribution (TMRC) values were found to be 28.8 and 41.6μg person(-1)day(-1) at 500 and 1000g a.i. ha(-1), respectively, and found to be below the maximum permissible intake on capsicum fruit on the 7th day. Therefore, a waiting period of 7days is suggested for consumption of capsicum sprayed with triazophos at the recommended dosages.

Degradation of chlorpyrifos residues in apple under temperate conditions of Kashmir Valley.

The present studies were carried out to observe the dissipation pattern of chlorpyrifos on apple in Kashmir Valley. Persistence of chlorpyrifos in apple was studied following two applications rates of chlorpyrifos (Dursban 20 EC) at 200g a.i. ha(-1) (single dose T 1) and 400g a.i. ha(-1) (double dose T 2). The average initial deposit of chlorpyrifos was found to be 1.61 and 1.98μgg(-1) for T 1 and T 2 application rates respectively on apple. The residues dissipated to 0.09 and 0.06μgg(-1) after 15- and 30-day post treatment with half-life periods of 3.34 and 5.47days in T 1 and T 2 application rates, respectively. The residues of chlorpyrifos dissipated to below limit of quantification (LOQ) of 0.04μgg(-1) after 30day at T 1 application rate. A waiting period of 6days must be observed for chlorpyrifos on apple at recommended application rate for the safety of consumers. Theoretical maximum residue contribution (TMRC) values were found to be far less than maximum permissible intake (MPI) at 0day in both the dosages suggesting chlorpyrifos on apple in Kashmir is unlikely to cause health risks.