Persistence of bifenthrin in okra (Abelmoschus esculentus L.) and its leaching behaviour in soil
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Date
2012
Authors
Journal Title
Journal ISSN
Volume Title
Publisher
CCSHAU
Abstract
A field experiment was carried to study the persistence behaviour in okra and soil underneath
and effect of processing on the reduction of residues of bifenthrin in okra fruits . A laboratoy
experiment was performed for assessing the leaching potential of bifenthrin at two doses in soil (sandy
loam, clay loam and sandy ) and leachate fractions. Bifenthrin (Commercial formulation) @ 25 and 50
g a.i ha
-1
was sprayed in the Vegetable Research Farm of Chaudhary Charan Singh (CCS) Haryana
Agricultural University (HAU), Hisar on okra crop (variety Varsha Uphar ) at fruiting stage. Samples of
okra and soil were collected periodically on 0 (1h), 1, 3, 7, 10, 15, 30 day s after applications and at
harvest. In leaching experiment, bifenthrin was applied as 25µg (single dose) and 50 µg (double dose)
in different soils packed inplexi glass columns. Residues were estimated by gas chromatograph
equipped with capillary column and electron capture detector (ECD). Per cent recoveries at the
for tification levels of 0.10 and 0.25 mg kg
-1
in okra fruits and soil were more than 80 per cent depicting
validity of methods used for present studies. Limit of quantification for bifenthrin was 0.005 µg ml
-1
in
okra and soil both. The residues of bifenthr in did not persist for more than 15 days after treatment.
Dissipation followed the first order kinetics showing half -life value of 1.58-2.18 day s for single and
double dose, respectively . The per cent reduction of bifenthrin residues by washing was 22.91 -36.71
and 21.50-40.00 at single and double dose, respectively . Washing followed by boiling was found more
effective in reducing the residues from 64.58-68.42 pe r cent. Bifenthrin persisted in soil upto 7 day s in
single dose and 15 day s for double dose with quite low residues. A leaching experiment was carried out
under laboratory conditions . The residues of bifenthrin were retained in three different soils from 85 to
99 per cent in 0-10 cm soil core showing their immobility in soil. As residues of bifenthrin were not
detected in any of the leachate fractions of any soil and doses, hence considered safe for ground water .
Description
Keywords
Persistence, Bifenthrin, Dissipat ion, Half - life period, Processing, Okra, Soil, Leaching