Fate of bifenthrin and Λ -cyhalothrin in water

The distribution of synthetic pyrethroids in the surface waters was assessed by measuring the concentration in water samples. For this purpose water was collected from the nearby canal of agricultural field CCS HAU, Hisar. Water samples (200 mL) were treated with bifenthrin and λ-cyhalothrin at levels of 0.5mgL-1 and 1.0 mgL-1 separately. Liquid-liquid partitioning was used for the extraction of the pyrethroid from the water. Analysis of the pyrethroids extracts was done with gas chromatography equipped with electron capture detector. In case of bifenthrin residues persisted up to 90 days with half-life 10.38-12.04 while in λ-cyhalothrin the residues reached below detectable level (0.001 mg L-1) within 60 days after treatment with half-life 7.16-7.52 days.