Simultaneous monitoring and dietary risk assessment of 386 pesticides in market samples of black tea.

Black tea samples (390) collected from local markets situated in different locations of India were monitored for the residues of 386 pesticides using QuEChERS (Quick, Easy, Cheap, Effective, Rugged, and Safe) based extraction and analysis by gas and liquid chromatography tandem mass spectrometry (GC-MS/MS and LC-MS/MS). Residues of seventeen pesticides were detected, of which propargite, cypermethrin, and novaluron showed the highest % positive detections. A comparison of the concentrations of the detected pesticide residues with the available national and international maximum residue limits (MRLs) showed that seven samples exceeded the Indian MRLs while no sample was found to exceed the CODEX MRLs. The risk due to the detected pesticide levels evaluated in terms of hazard quotient (HQ) and hazard index (HI) was found to be very low (<1), suggesting that the pesticide residues in the tea were safe for consumption by Indian adults and children.

Persistence evaluation of fluopyram + tebuconazole residues on mango and pomegranate and their risk assessment.

The persistence of combination formulation of fluopyram 200 + tebuconazole 200-400 SC was evaluated across different agro-climates in India for the management of fungal diseases in two commercially important fruit crops, mango and pomegranate. The residues were extracted using quick easy cheap effective rugged and safe (QuEChERS) method and quantification was done on liquid chromatography-tandem mass spectrometry (LC-MS/MS). The fungicide degradation followed 1st-order kinetics and the half-lives were 2.9-6.4 days for mango, and 3.5-7.4 days for pomegranate for both the fungicides. On the basis of Organisation for Economic Co-operation and Development (OECD) maximum residue limit (MRL) calculation, 1.0 mg kg-1 MRL was obtained for fluopyram while for tebuconazole, it was 0.5 mg kg-1 on mango, at the pre-harvest interval (PHI) of 5 days. For pomegranate, the respective MRLs were 1.0 mg kg-1 and 0.7 mg kg-1 at PHI of 7 days. The dietary risk assessment study indicated that % acceptable daily intake (% ADI) and % acute reference dose (% ARfD) were much lower than 100; thus, the application of fluopyram and tebuconazole on mango and pomegranate is unlikely to present public health concern.

Long-term monitoring of 155 multi-class pesticide residues in Indian vegetables and their risk assessment for consumer safety.

A systematic long-term study was conducted to monitor the pesticide residues in commercially important vegetables that are produced, consumed, and exported from India. Residues of 155 commonly used pesticides were determined in 966 samples of cabbage, green chilli, and okra grown in North and North-Western part of India. The residues were extracted using modified Quick, Easy, Cheap, Effective, Rugged, and Safe (QuEChERS) method and quantified by gas chromatography-mass spectrometry and liquid chromatography tandem-mass spectrometry. Acetamiprid, cypermethrin, imidacloprid, metalaxyl, and profenofos were the most frequently detected pesticides. No pesticide was detected in 94.4% cabbage, 34.5% green chilli, and 61% okra samples. The chronic risk assessment due to the dietary exposure of the pesticides was evaluated for Indian adult and child. The results suggested that the detected residue levels in vegetables were within safe limits and their consumption will not pose any dietary risk to the consumers.

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 (t1/2) 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.

Dissipation kinetics and consumer risk assessment of novaluron + lambda-cyhalothrin co-formulation in cabbage.

Cabbage, one of the most popular vegetables in the world is infested by several insect-pests and diseases. Novaluron, a chitin synthesis inhibitor and lambda-cyhalothrin, a synthetic pyrethroid group insecticide are used to manage insect-pests on cabbage. The dissipation kinetics and risk assessment of combination formulation (novaluron 9.45% + lambda-cyhalothrin 1.9%) with different modes of action has not yet been investigated in cabbage. Multi-location supervised field trials were therefore, conducted in different agro-climatic regions of India for safety evaluation of the combination product. The co-formulation at the recommended (novaluron 750 g a.i. ha-1 + lambda-cyhalothrin 750 g a.i. ha-1) and double the recommended (novaluron 1500 g a.i. ha-1 + lambda-cyhalothrin 1500 g a.i. ha-1) dose was sprayed on the cabbage crop. The samples were extracted and cleaned up using a modified QuEChERS method, and the residues analyzed by GC-ECD and GC-MS. The half-life (t1/2) varied between 1.77 and 2.51 and 2.00-3.38 days for novaluron and 1.36-2.24 and 1.69-3.82 days for lambda-cyhalothrin in cabbage at respective doses. The Food Safety and Standards Authority of India (FSSAI) has set the MRL of 0.7 mg kg-1 for novaluron at PHI of 5 days, and no MRL is set for lambda-cyhalothrin in cabbage. On the basis of OECD MRL calculator, the MRLs of 0.6 and 1.5 mg kg-1 for novaluron and lambda-cyhalothrin, respectively were calculated at the respective doses at PHI of 3 days. Hazard quotient (HQ) <1, theoretical maximum daily intake (TMDI) < acceptable daily intake (ADI) and < maximum permissible intake (MPI), percent acute hazard index (% aHI) <1, and percent chronic hazard index (% cHI) <1 for both novaluron and lambda-cyhalothrin suggested that the combination formulation is safe and will not pose any dietary risk to the consumers. The study will be helpful to conduct risk assessment of other pesticides/combination pesticides on food crops on which their MRLs have not yet been fixed.

Persistence, dissipation, and risk assessment of a combination formulation of trifloxystrobin and tebuconazole fungicides in/on tomato.

Multi-locational supervised field trials were conducted in different agro-climatic regions in India to study dissipation of trifloxystrobin and tebuconazole in tomato after spraying a combination formulation (trifloxystrobin 25% + tebuconazole 50%, 75WG) at recommended doses: (i) single (trifloxystrobin 87.5 g a.i. ha-1 + tebuconazole 175 g a.i. ha-1) and (ii) double (trifloxystrobin 175 g a.i. ha-1 + tebuconazole 350 g a.i. ha-1). Fruit samples were extracted with ethyl acetate using a modified QuEChERS method. The residues (parent fungicides + metabolite) were analyzed and confirmed by GC-ECD and GC-MS, respectively. The half-life (t1/2) of trifloxystrobin and tebuconazole in tomato varied from 1.08 to 1.72 and 1.13 -to 1.64 days at single; and 1.27 to 2.13 and 1.24 to 1.96 days at double dose, respectively. Since maximum residue limit (MRL) at pre-harvest interval (PHI) of 5 days is impractical, as tomato is usually harvested and consumed almost everyday after the last spray, the risk assessment was performed at minimum PHI of 1 day. Accordingly, on the basis of supervised field trial data and using OECD MRL calculator, MRL of 0.5 and 1.5 mg kg-1 at single dose were proposed for trifloxystrobin and tebuconazole in/on tomato, respectively.