|
KMID : 0903519800230020131
|
|
Journal of the Korean Society of Agricultural Chemistry and Biotechnology
1980 Volume.23 No. 2 p.131 ~ p.139
|
|
|
Degradation of the Herbicide , TOK(2,4 - dichloro - 4´ - nitro diphenyl ether) in Soil
|
|
|
|
|
Abstract
|
|
|
TOK(2, 4-Dichloro-4´-nitrodiphenyl ether) was applied to two Korean soils possessing different physico-chemical properties at a certain concentration and incubated for a certain time under flooded conditions. The metabolites and the soil microorganisms involved in the degradation of TOK are studied.
Chong Ju and Chung Ju soils treated with TOK at a concentration of 500 ppm and incubated for two, four, and six months at 30℃ yielded 4-chloro-4´-amino diphenyl ether, 2,4-dichloro-4´-amino diphenyl ether(amino-TOK), N-[4´-(4-chloro-phenoxy)] phenyl acetamide, and N[4´-(4-chloro-phenoxy)] phenyl formamide as the major metabolites. TOK underwent the reduction of nitrogroup to amino group, dechlorination, acetylation, and formylation. No cleavage at the ether linkage was recognized. TOK was more readily degraded in Chung Ju soil which is characterized by the higher pH (pH 6.43), clay loam in textural class, and the higher cation exchange capacity.
The toxicity of TOK as a possible environmental contaminant is expected to be considerably reduced as a result of the above degradation
Twelve strains of soil bacteria were isolated from the TOK-treated Chong Ju and Chung Ju soils.
As a result of the incubation of TOK in pure cultures of the isolates, T-1-1 strain isolated from Chong Ju soil had almost no degradability, whereas T-2-3 strain turned out to be the most potent.
The degradation of TOK by the isolates constituted mostly the reduction of the nitro group to amino group.
The citrate buffer extract of Chung Ju soil reduced TOK more readily to amino-TOK than that of Chong Ju soil.
|
|
|
KEYWORD
|
|
|
|
|
|
FullTexts / Linksout information
|
|
|
|
|
|
Listed journal information
|
|
|
|
|