Degradation of Pesticides - Pesticides: Evaluation of Environmental Pollution - page 54

3.2.5 Pyrethroid Pesticides

Pyrethroid pesticides undergo hydrolysis on the ester linkage and produce a num-
ber of metabolites. Hydroxylation of alcohol moiety at 2′, 4′, 5′, or 6′ position also occurs.
Fenvalerate underwent hydration of the cyano group on soil with a trace formation of
decarboxylated derivative. Flucythrinate and fluvalinate similarly underwent hydration of
the cyano group and cleavage of the ester. Permethrin undergoes ester cleavage and forms
3-phenoxybenzyl alcohol and the dichlorovinyl chrysanthemic acid.

3.2.6 Miscellaneous

Imidacloprid undergoes a more rapid hydrolysis in alkaline medium than in acidic
medium (Liu et al. 2006).

O O

NH N NH

N

NH CH 2

CH 2 N CH 2

N N

Cl N

Cl N NO 2 Cl N NO

N NO 2

O

NH

CH 2 N

N NH

CH 2

N

Cl

NH

N

Cl NH

COOH

NH

CH 2 N

N

N Cl

Cl O

It was also reported that chemical hydrolysis is slower than photodegradation.
Phenyl propionate on hydrolysis forms 2-phenyl ethanol and propionic acid (Hu and
Coats 2008).

O

H 2
C

H 3 C

C
H 2

O

C
H 2

H 2 O

OH

H 2
C

H 2
C

[O]

HO HO

C
H 2

C
H 2

+CH 3 COOH