Assessment of Iprovalicarb, a systemic fungicide in/on cabbage (Brassica oleracea var. capitata)

Analysis, residue behaviour and risk assessment of combination product of iprovalicarb + copper oxychloride in representative fruiting vegetables, cucurbit and in soil using LC-MS/MS and ICP-MS

Combination product of two herbicides, i.e. iprovalicarb and copper oxychloride, is a new formulation. There is paucity of data on the dissipation pattern and risk assessment of this combination product in crops. To understand the dissipation behaviour/kinetics of this product, a supervised field trial was undertaken on cucumber and tomato. Method validation for a QuEChERS-based method for analysis of these pesticides from cucumber and tomato matrices reveals that all the parameters were within the acceptance range in accordance with SANTE. The limit of quantitation (LOQ) for iprovalicarb in cucumber and tomato fruits, and in soil matrices when analysed on LC-MS/MS was established at 0.01 mg kg-1. Similarly, the LOQ for copper oxychloride (as copper) on ICP-MS was established at 0.5 mg kg-1 in cucumber and tomato fruits and 5.0 mg kg-1 in soil. Dissipation of iprovalicarb was slower in tomato fruits as compared to cucumber fruits. The initial accumulation of the residues of iprovalicarb was 0.073 and 0.243 mg kg-1 in cucumber and 0.214 and 0.432 mg kg-1 in tomato fruits at standard and double dose, respectively. Similarly, copper oxychloride residues were 3.51 and 6.45 mg kg-1 in cucumber and 1.26 and 2.56 mg kg-1 in tomato fruits at standard and double dose, respectively. The residues were below LOQ in cucumber fruits, tomato fruits and soil at the time of harvest. The residues of copper oxychloride persisted till harvest time in cucumber fruits and in soil. A preharvest interval (PHI) of 3 day is recommended on safer side for the combination product of iprovalicarb + copper oxychloride. Theoretical maximum daily intake (TMDI) is less than maximum permissible intake (MPI) for iprovalicarb and copper oxychloride at both the doses from 0 day and onward. The results from the present study can be of immense importance for establishing label claims, maximum residue limits (MRLs) and risk assessment by national and international regulatory agencies.

Dissipation kinetics and risk assessment of iprovalicarb + propineb fungicide in tomato under different agroclimates

Multi-location supervised field trials in India were conducted with a combination pesticide formulation (iprovalicarb 5.5% + propineb 61.25%, 66.75% WP) in tomato to study dissipation behavior at single (iprovalicarb 137.5 g a.i. ha^-1 + propineb 1531.25 g a.i. ha^-1) and double (iprovalicarb 275 g a.i. ha^-1 + propineb 3062.5 g a.i. ha^-1) dose. The samples were processed using a modified QuEChERS method for iprovalicarb and acid hydrolysis followed by carbon disulfide estimation for propineb and confirmation of their respective residues by LC-MS/MS and GC-MS. Both the fungicides in tomato fruits obey first-order kinetics irrespective of location and doses. Half-life (t_1/2) values at all the four locations ranged from 1.08 to 4.67 days for iprovalicarb and 3.36 to 11.41 days for propineb in tomato. The Food Safety and Standards Authority of India (FSSAI) has set MRL of 1 mg kg^-1 for propineb, but no MRL is yet fixed for iprovalicarb. Using OECD MRL calculator, the calculated MRL for iprovalicarb and propineb was found to be 2 and 4 mg kg^-1, respectively. The hazard quotient (HQ) < 1, theoretical maximum daily intake (TMDI) < acceptable daily intake (ADI), TMDI < maximum permissible intake (MPI), percent acute hazard index (% aHI) ≤ 1, and percent chronic hazard index (% cHI) < 1 for both the fungicides indicated that the combination formulation will not pose any dietary risk and thus considered safe for human health.

Analytical method validation, dissipation and safety evaluation of combination fungicides fenamidone + mancozeb and iprovalicarb + propineb in/on tomato

Dissipation behavior and degradation kinetics of fenamidone + mancozeb (Sectin 60 WG) and iprovalicarb + propineb (Melody Duo 66.75 WP) in tomato were studied at recommended dose (RD) and double dose (DD) of application. The analysis of the field samples were carried out by employing liquid chromatography tandem mass spectrometry (LC-MS/MS) for fenamidone and iprovalicarb residues and gas chromatography mass spectrometry for mancozeb and propineb residues after thorough validation of the extraction methods. The dissipation of residues best followed 1st + 1st order for all the test fungicides. The half-life period for fenamidone, mancozeb, iprovalicarb and propineb were 2, 2, 1.5 and 2 days for RD and 3, 2.5, 2 and 3 days for DD, respectively. The pre-harvest intervals were not applicable for iprovalicarb, fenamidone and mancozeb (at RD) as the residues at 0 day were below maximum residue limit set by European Union, and it was 1 day for DD of iprovalicarb, 3.5 days for DD of fenamidone, 3 days for DD of mancozeb, 3 and 7 days for propineb at RD and DD, respectively. A PHI of 4 and 7 days are proposed for fenamidone + Mancozeb and iprovalicarb + propineb, respectively. Dietary exposure calculated for all the pesticides were safe on all the sampling days except for propineb residues for which it was safe after first day of the double dose application. The study will be useful for promoting effective residue management and safe use of these chemicals for controlling fungal diseases in tomato crop.

Dissipation of six fungicides in greenhouse-grown tomatoes with processing and health risk

Greenhouse studies were conducted to evaluate the dissipation rate kinetics and estimate the behavior of selected pesticides after washing, peeling, simmering, and canning of tomato expressed as processing factor (PF). Two varieties (Marissa and Harzfeuer) were treated by six fungicides: azoxystrobin, boscalid, chlorothalonil, cyprodinil, fludioxonil, and pyraclostrobin at single and double dose and risk assessment defined as hazard quotient was performed. The QuEChERS method was used for sample preparation followed by liquid chromatography coupled with tandem mass spectrometry (LC-MS/MS). The dissipation of fungicides approximately fitted to a first-order kinetic model, with half-life values ranging from 2.49 and 2.67 days (cyprodinil) to 5.00 and 5.32 days (chlorothalonil) for Marissa and Harzfeuer variety, respectively. Results from processing studies showed that treatments have significant effects on the removal of the studied fungicides for both varieties. The PFs were generally less than 1 (between 0.01 and 0.90) and did not depend on variety. The dietary exposure assessed based on initial deposits of application at single and double dose on tomatoes and concentration after each process with PF correction showed no concern to consumer health. Our results would be a useful tool for monitoring of fungicides in tomatoes and provide more understanding of residue behavior and risk posed by these fungicides.