Dissipation and risk assessment of fluopyram and trifloxystrobin on onion by GC-MS/MS.

The dissipation and risk assessment studies on fluopyram, trifloxystrobin and their metabolites were carried out on onion under field conditions after two treatments of fluopyram 250 g/L + trifloxystrobin 250 g/L SC @ 150 and 300 g a.i. ha-1. The onion bulb samples were collected at 0, 3, 7, 14, and 21 days after second spray to study the pattern of dissipation using QuEChERS methodology for processing and analysis on GC-MS/MS. The total initial residues of fluopyram (fluopyram + fluopyram benzamide) in immature onion bulb were 2.14 and 4.93 mg kg-1, at single and double dose, respectively. The residues of 0.02 and 0.06 mg kg-1 persisted in the mature onion bulb collected at the harvest (30 days after treatment). The total initial residues of trifloxystrobin (trifloxystrobin + CGA 321113) in immature onion bulb were 0.65 and 1.97 mg kg-1, at single and double dose, respectively, which reached < LOQ and 0.06 mg kg-1 at the respective doses at the harvest time. Dissipation of fluopyram followed second-order kinetics with DT50 values of 1.83 and 1.74 days, whereas trifloxystrobin followed first-order kinetics with DT50 values of 4.73 and 4.78 days, at single and double dose respectively. Risk assessment in terms of hazard quotient was done to estimate the risk that can occur due to application of this combination pesticide. It was observed that even the spray at the double recommended dose could not have dietary risks on the consumers.

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 96 g a.i. ha(-1). The residues reached below determination limit (BDL) of 0.01 mg kg(-1) in 7, 10, 10, 15 and 15 days for 24, 36, 48, 72 and 96 g.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 2.27 days, respectively, at 24, 36, 48, 72 and 96 g a.i. ha(-1). Theoretical maximum residue contributions (TMRC) values reached below the maximum permissible limit (MPI) for 3, 5 and 7 days in treatments at 24, 36 and 48 g.a.i. ha(-1), respectively, whereas in case of higher dose treatments i.e. 72 and 96 g a.i. ha(-1), the residues of flubendiamide reached below MPI after 10 days 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 1000 g a.i. ha(-1), the average initial deposits were found to be 3.61 and 6.26 mg kg(-1), respectively. These residues dissipated below the limit of quantification (LOQ) of 0.05 mg kg(-1) in 10 and 15 days at the recommended and double the recommended dosages, respectively. The calculated values of half-life were 2.31 and 2.14 days at recommended and double the recommended dosages, respectively. Theoretical maximum residue contribution (TMRC) values were found to be 28.8 and 41.6 µg person(-1) day(-1) at 500 and 1000 g 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 7 days is suggested for consumption of capsicum sprayed with triazophos at the recommended dosages.

Dissipation pattern and risk assessment of flubendiamide on chili at different agro-climatic conditions in India.

Dissipation pattern and risk assessment of flubendiamide and its metabolite (desiodo flubendiamide) on chili were studied at four different agro-climatic locations of India at the standard and double dose at 60 and 120 g a.i. ha(-1) at 10 days interval. Quantification of residues was done on a high-performance liquid chromatograph (HPLC) with a photo diode array detector. The limit of quantification (LOQ) of this method was found to be 0.01 mg kg(-1) while limit of detection (LOD) being 0.003 mg kg(-1). Residues of flubendiamide were found to be below the determination limit in 15 days at both the dosages in all locations. Half-life of flubendiamide when applied at 60 and 120 g a.i. ha(-1) ranged from 0.85 to 1.80 and from 0.95 to 2.79 days, respectively. On the basis of data generated under the All India Network Project on Pesticide Residues, a preharvest interval (PHI) of 1 day has been recommended and the flubendiamide 480 SC has been registered for use on chili in India by the Central Insecticide Board and Registration Committee, Ministry of Agriculture, Government of India. The maximum residue limit (MRL) of flubendiamide on chili has been fixed by the Food Safety Standard Authority of India, Ministry of Health and Family Welfare, Government of India, as 0.02 µg g(-1) after its risk assessment.

Persistence and risk assessment of cypermethrin residues on chilli (Capsicum annuum L.).

The study was conducted to observe the persistence pattern and risk assessment of cypermethrin in chilli fruits following three applications of cypermethrin (Super fighter 25 EC) at 50 and 100 g a.i. ha(-1) at 10-day interval. Residues of cypermethrin in chilli were estimated by gas liquid chromatography (GLC) and were confirmed by gas chromatography-mass spectrometry (GC-MS). The average initial deposits of cypermethrin in chilli fruits were found to be 1.46 and 3.11 mg kg(-1), at recommended and double the recommended dosages, respectively, following third application of the insecticide. Half-life periods for cypermethrin were found to be 4.43 and 4.70 days at recommended and double the recommended dosages, respectively. Residues of cypermethrin declined below its limit of quantification (LOQ) of 0.05 mg kg(-1) after 25 days at both the application dosages. Theoretical maximum residue contribution (TMRC) values were calculated from the residue data generated and were found to be below maximum permissible intake (MPI) even on 0 day. Therefore, according to our risk assessment studies, a waiting period of 1 day is suggested for consumption of chilli sprayed with cypermethrin at the recommended dosages.

Dissipation behavior and risk assessment of acephate in brinjal using GLC with FPD.

A study was conducted to observe the persistence, dissipation behavior, and risk assessment of acephate on brinjal fruit. Brinjal crop was sprayed with acephate 75 SP at 560 and 1120 g a.i. ha(-1) at fruiting stage followed by another application at 10-day interval. After sampling, the samples were extracted and cleaned up using quick, easy, cheap, effective, rugged, and safe (QuEChERS) technique, and the residues of acephate were analyzed with gas chromatography using flame photometric detector (FPD). The average initial deposits of acephate on brinjal fruits were found to be 2.54 and 4.07 mg kg(-1) following application of insecticide at 560 and 1120 g a.i. ha(-1), respectively. Residues of acephate reached below determination level of 0.10 mg kg(-1) after 7 days at recommended dosages and after 10 days at double the recommended dosages. The half-life of acephate was found to be 1.55 and 1.52 days, respectively, at 560 and 1120 g a.i. ha(-1). For risk assessment studies, theoretical maximum residue contributions (TMRC) were calculated and compared with maximum permissible intake (MPI). It was observed that TMRC values reached below MPI in 0-day samples at both recommended and double the recommended dosages. Therefore, it was concluded that if waiting period of 1 day is observed, there will be much reduced risk to consumers and the insecticide could be safely used for the protection of brinjal crop from insect pests.

Risk assessment of mixture formulation of spirotetramat and imidacloprid in chilli fruits.

Persistence and risk assessment of spirotetramat and imidacloprid in chilli fruits were studied following three applications of a mixture formulation of spirotetramat (12%) and imidacloprid (12%) at 1000 and 2000 mL ha(-1). Residues of spirotetramat and imidacloprid in chilli were estimated by high-performance liquid chromatograph (HPLC). Residues of spirotetramat and imidacloprid dissipated to more than 65% after 3 days at both the dosages. Residues of spirotetramat on chilli fruits were found to be below its limit of quantification (LOQ) of 0.03 mg kg(-1) after 5 and 7 days for recommended and double the recommended dosages, respectively. Similarly, imidacloprid residues were found to be below its LOQ of 0.01 mg kg(-1) at 7 and 10 days, respectively. Half-life periods for spirotetramat were found to be 1.91 and 1.30 days, whereas, for imidacloprid, these values were observed to be 1.41 and 1.65 days at recommended and double the recommended dosages, respectively. Red chilli samples collected after 20 days of the last application did not show the presence of spirotetramat and imidacloprid at their respective determination limit. As the theoretical maximum residue contributions on chilli fruits are found to be less than the maximum permissible intake values on initial deposits, a waiting period of 1 day may follow to reduce risk before consumption at the recommended dose.

Persistence and risk assessment of spiromesifen on tomato in India: a multilocational study.

Supervised field trials were conducted at four different agro-climatic locations of India to evaluate the dissipation pattern and risk assessment of spiromesifen on tomato. Spiromesifen 240 SC was sprayed on tomato at 150 and 300 g a.i. ha(-1). Samples of tomato fruits were drawn at 0, 1, 3, 5, 7, 10 and 15 days after treatment and soil at 15 days after treatment. Quantification of residues was done on gas chromatograph-mass spectrophotometer in selective ion monitoring mode in the mass range of 271-274 (m/z). The limit of quantification of the method was found to be 0.05 mg kg(-1), while the limit of determination was 0.015 mg kg(-1). Residues were found below the LOQ of 0.05 mg kg(-1) in 10 days at both the doses of application at all the locations. Spiromesifen dissipated with a half-life of 0.93-1.38 days at the recommended rate of application and 1.04-1.34 days at the double the rate of application. Residues of spiromesifen in soil were detectable level (<0.05 mg kg(-1)) after 15 days of treatment. A preharvest interval (PHI) of 1 day has been recommended on tomato on the basis of data generated under All India Network Project on Pesticide Residues. Spiromesifen 240 SC has been registered for its use on tomato by Central Insecticide Board and Registration Committee, Ministry of Agriculture, Government of India. The maximum residue limit (MRL) of spiromesifen on tomato has been fixed by Food Safety Standard Authority of India, Ministry of Health and Family Welfare, Government of India as 0.3 µg/g after its risk assessment.

Degradation pattern and risk assessment of chlorantraniliprole on berseem (Trifolium alexandrinum L.) using high performance liquid chromatography.

The persistence pattern of chlorantraniliprole on berseem leaves and its risk assessment for the safety of cattle were studied. QuEChERS method was used for the extraction and cleanup of samples and the residues of chlorantraniliprole were estimated using high performance liquid chromatography (HPLC) and confirmed by Liquid Chromatograph-Mass Spectrometer (LCMS-MS). The dissipation studies on berseem were carried out by application of chlorantraniliprole at five different dosages i.e. 11.6, 17.1, 23.1, 34.7 and 46.2 g a.i. ha(-1). Average initial deposits of chlorantraniliprole were found to be 0.47, 0.61, 0.78, 1.15 and 1.31 mg kg(-1), respectively. The residues reached below determination limit (BDL) of 0.01 mg kg(-1) in 5, 7, 7, 10 and 10 days for 11.6, 17.1, 23.1, 34.7 and 46.2 g a.i. ha(-1) dosages, respectively. Half-life (t1/2) of chlorantraniliprole on berseem was observed to be 0.93, 1.14, 1.06, 1.00 and 1.33 days, respectively, at 11.6, 17.1, 23.1, 34.7 and 46.2 g a.i. ha(-1). It was found that the theoretical maximum residue contributions (TMRC) values reached below maximum permissible intake (MPI) on 0 day in berseem samples treated with chlorantraniliprole. These studies, therefore suggest that the use of chlorantraniliprole formulation at different dosages does not seem to pose any hazards to the consumers and a waiting period of one day is suggested to reduce the risk before consumption of berseem leaves. These data could provide guidance for the proper and safe use of this pesticide on berseem in India.

Persistence and risk assessment of emamectin benzoate residues on okra fruits and soil.

Emamectin benzoate, a synthetic derivative of abamectin, is found effective against fruit borer and jassid in okra crops. The present studies were carried out to study the dissipation pattern of emamectin benzoate on okra and to suggest a suitable waiting period for the safety of consumers. Following three applications of emamectin benzoate (Proclaim 5 SG) at 68.1 and 136.2 g a.i. ha-1, the average initial deposits of emamectin benzoate were observed to be 0.22 and 0.42mg kg-1, respectively. These residues dissipated below the limit of quantification (LOQ) of 0.05 mg kg-1 after 5 days at both the dosages. Soil samples collected after 15 days did not reveal the presence of emamectin benzoate at LOQ of 0.05 mg kg-1. Acceptable daily intake (ADI) of emamectin benzoate is 0.0005 mg kg-1 body weight day-1, which means an adult of 55 kg weight can safely tolerate an intake of 27.50 microg emamectin benzoate. Assuming an average consumption of 80 g okra fruit and multiplying it by average and maximum residues observed on 0 day at recommended dosage, the intake of emamectin benzoate comes out to be about 20 Itg and these values are quite safe in comparison to its ADI. These studies, therefore, suggest that the use of emamectin benzoate at the minimum effective dosages do not seem to pose any hazards to the consumers if a waiting period of 1 day is observed.

Risk assessment of ß-cyfluthrin and imidacloprid in chickpea pods and leaves.

Dissipation of ß-cyfluthrin and imidacloprid in chickpea pods and leaves was measured following three applications of Solomon 300 OD (ß-cyfluthrin 9 percent +imidacloprid 21 percent) at 200 and 400mLha(-1). Residues of ß-cyfluthrin on chickpea pods and leaves were found to be below its limit of quantification (LOQ) of 0.01mgkg(-1) after 7 days at both the dosages. Similarly, imidacloprid residues were found to be below its LOQ of 0.01mgkg(-1) at 10 days. Half-life periods on chickpea pods and leaves for ß-cyfluthrin were found to be 1.06 and 0.58 days, whereas for imidacloprid these values were observed to be 2.07 and 1.75 days at recommended dose. As the theoretical maximum residue contributions on chickpea pods and leaves are found to be less than the maximum permissible intake values even on 0 day, therefore consumer health risks are minimal at both the dosages on chickpea.

Persistence of fipronil and its risk assessment on cabbage, Brassica oleracea var. capitata L.

Persistence of fipronil in cabbage was studied following three applications of Jump 80 WG at 75 and 150 g a.i. ha(-1) at 7 day interval. The average initial deposits of total fipronil (fipronil and its metabolites) were 1.226 and 2.704 mg kg(-1) on the heads following 3rd application of fipronil at single and double the dosages, respectively. Desulfinyl was found to be the main metabolite followed by sulfone and sulfide. Metabolite amide was not detected in cabbage samples. Half-life periods for fipronil were found to be 3.43 and 3.21 day at single and double the application rates, respectively. Risk assessment of fipronil to the consumers was calculated on the basis of per capita 80 g consumption of cabbage and comparing it to its ADI for an adult of 55 kg which was found to be less than its ADI on 10th day at both the dosages.