Thiacloprid

Fate in :
Thiacloprid shows low acute toxicity to birds, moderate toxicity to fish and slight toxicity to earthworms. Freshwater algae and duckweed are not sensitive to thiacloprid or its major metabolites. Bees are not sensitive to thiacloprid in acute oral, contact and semi-field tests. The effect on beneficials is variable, depending on the species.

Fate in soil:
In the laboratory, the DT₅₀for thiacloprid in soil photolysis studies is 74 days.
Thiacloprid degrades rapidly in soil; the aerobic soil metabolism DT₅₀ is 0.4 to 2.6 days and the DT₉₀ is 11.7 – 29 days (laboratory study on four soils). The two major metabolites (an amide and a sulphonic acid) were shown to degrade with DT₅₀ values of 32-142 and 16-79 days, respectively.
Degradation in anaerobic soil (laboratory study) is much slower; the DT₅₀ for thiacloprid is greater than one year (64-74% parent remaining after 360 days with 89% of the residual parent located in the sediment).
K_oc values in six soils were 261-870 ml/g indicating medium to low mobility in soil. The K_oc of the amide metabolite is 166-438 ml/g (medium mobility) while the sulfonic acid metabolite is classed as very highly mobile with a K_oc of 11.9-28.2 ml/g. Field lysimeter studies in sandy loam with a grass cover were conducted over a period of three years. No parent thiacloprid or amide metabolite was detected in the leachates. The sulfonic acid metabolite was detected in the leachates in year two. After three years, no radiolabelled residues were observed below a depth of 40 cm.
In field dissipation studies, the DT₅₀ and DT₉₀ values for thiacloprid applied at 288 g ai/ha to bare soil were 3.4-27 and 31-91 days, respectively. No residues were detected in the 20-30 cm soil layer.

Fate in aquatic systems:
Thiacloprid is stable to hydrolysis at pH 5-9. The aqueous photolysis DT₅₀is 324 days.