Fate of imidacloprid and acetamiprid residues during black tea manufacture and transfer into tea infusion

Abstract

The objective of this paper is to investigate the loss/stability of neonicotinoids (imidacloprid and acetamiprid) residues during the manufacture of black tea and to study the transfer of these pesticides from made tea to its infusion. For orthodox black tea, the manufacturing process involves leaf harvesting (plucking two leaves and a bud), withering, rolling, fermentation (oxidation), and drying. Initial withering and final drying resulted in the loss of pesticide residues, but no significant reduction in residue levels resulted from the rolling and fermentation steps. The drying process resulted in a residue transfer of 64-70% and 69-74% of the initial level, whereas the brewing process resulted in a residue transfer of 37-39% and 45-49% of imidacloprid and acetamiprid, respectively, from dried tea into the infusion. The decrease in acetamiprid levels during drying was also significant (8-13%), whereas the total loss during the manufacturing process ranged from 26 to 31%. Further, brewing for longer periods (an extended brewing time) resulted in higher transfer (up to 44% for imidacloprid and 53% for acetamiprid) of pesticides to tea infusion. Further, the extent of pesticide leaching depends on its water solubility, partition coefficient, and the brewing time.

Degradation Dynamics of the Insecticide: Clothianidin (Dantop 50 % WDG) in a Tea Field Ecosystem

“…The clothianidin residues in soil were detected only at 0 day in all the cases except from Hantapara tea estate where residues were detected on the 1st day for double dose. The result almost consistent with that of the dissipation pattern of imidacloprid and acetamiprid -neonicotinoid insecticides on tea was applied at a almost similar rate which went below detectable limit after 5th day of application (Gupta and Shanker 2009) …”

The mechanism of damage by trace amounts of acetamiprid to the midgut of the silkworm, Bombyx mori

“…As a promising insecticide, acetamiprid is used for controlling Hemiptera (especially aphids), Thysanoptera, Lepidoptera, and so on . However, acetamiprid is inevitably released into the environment due to its extensive use, and its residues can be detected in a variety of plants . Therefore, long term and intensive use of pesticides may contaminate agricultural land and water, adversely affecting nontarget organisms …”

“…3 However, acetamiprid is inevitably released into the environment due to its extensive use, and its residues can be detected in a variety of plants. [4][5][6] Therefore, long term and intensive use of pesticides may contaminate agricultural land and water, adversely affecting nontarget organisms. [7][8][9] The silkworm, Bombyx mori, is an important economic insect that belongs to the order of Lepidoptera.…”

Dissipation behavior of octachlorodipropyl ether residues during tea planting and brewing process

“…Tea leaves were dehydrated during processing, causing a concentration factor of three to four fold (Gupta and Shanker 2009; Lavelli and Scarafoni 2012). In the present study, the moisture content of each of the fresh tea shoots and prepared tea samples was determined, and the dissipation rates in green tea processing were calculated with the OCDPE residue in the dry matter of prepared tea and tea shoots.…”