Decrease of Pirimiphos-Methyl and Deltamethrin Residues in Stored Rice with Post-Harvest Treatment

Abstract

A modified quick, easy, cheap, effective, rugged (QuEChERS) method with multi-walled carbon nanotubes (MWCNTs) as reversed-dispersive solid phase extraction (r-DSPE) material was applied to the analysis of pirimiphos-methyl and deltamethrin residues in stored rice. Two dustable powder (DP) formulations (2% pirimiphos-methyl and deltamethrin DP; 5% pirimiphos-methyl DP) were applied in simulated storehouse trials in the lab. The residues and dissipation of the two pesticides in stored rice were investigated. Slow dissipation of both pesticides was observed in stored rice. The half-lives of pirimiphos-methyl were 23.9–28.9 days, and those of deltamethrin were 23.9–24.8 days. Residues of pirimiphos-methyl from application rates of 4.5–6.75 a.i. mg/kg (active ingredient milligram per kilogram) and 10–15 a.i. mg/kg were 1.6–3.8 mg/kg and 3.0–4.5 mg/kg at 60 days Pre-harvest Interval (PHI). Residues of deltamethrin from an application rate of 0.5–0.75 a.i. mg/kg were 0.13–0.14 mg/kg at 60 days PHI. Both pesticides residues were below the Maximum Residue Limits (MRLs) established by the Codex Alimentarius Commission (CAC). Therefore, at the recommended dosages they are safe for use on stored rice.

Persistence of deltamethrin and diazinon in environment of dairy farm

“…The residue of sprayed deltamethrin disappeared within 21 st day after application. The current findings agreed quite well, with those recorded by Kan and Meijer (2007) and Yu C et al, (2014). The current findings disagreed quite well, with those recorded by Akhtar et al, (1992) who found that the levels of deltamethrin were 0.0095, 0.011, 0.0065, 0.0135, 0.002 and 0.01 mg/kg in milk samples collected in the 4 th , 10 th , 11 th ,18 th , 25 th and 28 th day respectively, from treated cows subcutaneously with 2ppm deltamethrin (2000µg/kg).…”

“…The current findings agreed quite well, with those recorded by Haug and Hoffman (1990). On the other hand, Yu C et al, (2014) reported that the half-life of deltamethrin were 23-24 days on stored feeds in clean, dry and cooled area which not exposed to environmental factors. It is clear from the table that diazinon was not detected in feed samples collected at 14 th day after application.…”

“…However, deltamethrin rapid degradable pesticides, it may contaminate large number of collected samples that may be attributed to application without any precaution and without following the instructions and dose on the bottle during application. Moreover, both diazinon and deltamethrin were persisted in milk for longer time than in water and feed, this may be attributed to store in lipid inside dairy cows and excreted in milk according to fat %, milk yield and times of milking/day (Yu et al, 2014). From all of these, several precautions should be taken during pesticides application to minimize reaching of residues to animal body and milk which may contribute to public health hazards especially for children.…”

The Role of Grafting in Improving the Productivity of Cucumber Under Saline Stress Conditions

“…The environment in the storehouse and the moisture content in stored grains will affect degradation of organophosphate and pyrethroid pesticide residues on grains (Afridi et al, 2001). Pirimiphos-methyl is widely used in the major grain producing countries to protect against insect attacks, and this organophosphate insecticide has long persistence (Fleuret-lessard et al, 2007;Yu et al, 2014). The organophosphate chlorpyrifos-methyl is also commonly used as grain protectant since the 1960s (Samson et al, 1989;Daglish, 1993;Arthur, 1996).…”

“…Withholding interval is the time lasting between when a chemical is last used and when the food can be harvested or an animal can be slaughtered. Maximum residue limits (MRLs) of primiphosmethyl in rice have been set by the European Union (5 mg/kg), USA (8 mg/kg) and codex alimentarius commission (CAC, 7 mg/kg) (Yu et al, 2014).…”