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.

Behavior of trifloxystrobin and propineb as combination 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 [combination product (combi product)] 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 quick, easy, cheap, effective, rugged, and safe (QuEChERS) approach followed by LC-MS. 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 maximum residue limit and propineb as dithiocarbamate (3.0 mg kg-1 ) European Commission maximum residue limit in tomato, a pre-harvest interval 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 1 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.

Validation, residue analysis, and risk assessment of fipronil and flonicamid in cotton (Gossypium sp.) samples and soil.

Cotton crop is highly susceptible to attack by sucking pests. Being an important oilseed and feed crop, it is essential to monitor the pesticides and ensure health protection at consumer level. Therefore, a method was validated to estimate fipronil and flonicamid in various cotton samples and risk assessment was performed. Contamination of oil in the extracts from the various oil seeds and cake samples is a major problem as this oil contaminates the column and interferes with the detection of pesticides. The present manuscript for the first time describes successful analysis of the pesticides from various cotton samples including cotton oil, seed, and cake. Quick, easy, cheap, effective, rugged, and safe (QuEChERS)-based methods were validated for estimation of fipronil and flonicamid in cotton samples and in soil by LC-MS/MS. Recoveries were within the acceptable range of 70-120% with relative standard deviation ≤ 20% and HorRat values < 0.3-1.3. R2 was > 0.99. Matrix effects of 150 and 13.5% were observed for fipronil and flonicamid, respectively, in cotton leaves. Limits of quantitation (LOQs) were in the range of 0.0004 to 0.004 mg kg-1 for fipronil and flonicamid. Cotton samples collected from a field study at different locations were analyzed. Half-life ranged from 2.2 to 5.8 for fipronil and 4.6 to 7.0 days for flonicamid. A pre-harvest interval of 33 days is suggested. The risk assessment studies at maximum residue level values showed HQ < 1 at pre-harvest interval (PHI). The methods being short and easy can be extended to estimate more types of pesticides in different oilseeds. Following a PHI of 33 days, fipronil and flonicamid can be used on cotton at standard dose. As the levels of fipronil and flonicamid were below determination limit in all the soils, the environmental risk is negligible.

Correction to: Behaviour and risk assessment of fluopyram and its metabolite in cucumber (Cucumis sativus) fruit and in soil.

Unfortunately, the original publication of this paper contains a mistake. The correct name of the 3rd Author is Sunny H. Patel. The original article has been corrected.

Behaviour and risk assessment of fluopyram and its metabolite in cucumber (Cucumis sativus) fruit and in soil.

A field experiment was conducted to estimate residue persistence of fluopyram and its metabolite benzamide in cucumber fruits and soil and their risk assessment in humans and soil environment. Fluopyram (Kafka, 400 SC) was applied as soil drench twice at the interval of 15 days at the rate of 250 (standard dose) and 500 (double dose) g a.i. ha-1 (active ingredient per hectare). Cucumber fruits were collected at 0 (1 h), 1, 3, 5, 7, 10, 15, 20, 30, 40 and 50 days after second application. Soil samples were collected on 15th day after second application. Drench application resulted in detection of residues on the third day in standard dose at the levels of 0.056 mg kg-1 in cucumber fruit. The residue level increased until 20 days reaching 0.092 mg kg-1 followed by decrease to 0.068 mg kg-1 on 30th day after application. In double dose, the residues started accumulating from 0 day with initial levels of 0.093 mg kg-1 and persisted until 30th day. The levels varied between 0.123 and 0.184 mg kg-1 until 15th day of application followed by decrease to 0.127 mg kg-1 by 30th day. The residues reached below determination level (< 0.05 mg kg-1) on 40th day in both the doses after second application. The residue of metabolite benzamide was below determination level (< 0.05 mg kg-1) at both the doses. Hazard quotient (HQ) for residues levels at 15th and 30th day was less than one (HQ < 1). Hence, a pre-harvest interval of 15 days is suggested. Present data can be used to establish maximum residue limit (MRL) in India. The residue of fluopyram in soil on 15th day and the data on soil adsorption coefficient of fluopyram from literature suggests moderate mobility of fluopyram in soil. However, residues of metabolite of benzamide were not detected in soil. Further studies on translocation of fluopyram in soil over the time can be conducted for better understanding of environmental risk. To our knowledge, this is the first report on residue levels of fluopyram in any crop when applied as soil drench.

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 + 150 g a.i. ha-1 at an interval of 10 days on onion using Knapsack sprayer. First spray was made at bulb setting stage. Spring onion samples were drawn at 0 (1 h), 1, 3, 5, 7, 10, 15, and 20 days and matured onion bulb at harvest (52 days) after the last spray. Soil samples were also drawn at harvest. Foliar application of the combination product resulted in 1.14 and 2.86 mg kg-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 0.58 mg kg-1 on 20th day of application with half-lives of 8.8 and 9.1 days at standard and double dose, respectively. For tebuconazole, the corresponding residues observed after 1 h (0 day) of application were 0.92 and 2.29 mg kg-1. The levels declined gradually to 0.12 and 0.33 mg kg-1 on 20th days with half-life of 6.7 to 7.7 days at standard and double dose, respectively. Here, we are proposing a pre-harvest interval of 7 day for fluopyram and tebuconazole in spring onion when applied at 75 + 75 g 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 7 days. The data can be used in establishing MRLs (maximum residue limits) for spring onion after considering multilocation trials.