Effect of copper on the degradation of pesticides cypermethrin and cyhalothrin
LIU Ting-feng , SUN Cheng , TA Na , HONG Jun , YANG Shao-gui , CHEN Chuan-xiang
DOI:
Received December 13, 2006,Revised March 27, 2007, Accepted , Available online
Volume 19,2007,Pages 1235-1238
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The influence of coexisting copper (Cu) ion on the degradation of pesticides pyrethroid cypermethrin and cyhalothrin in soil and
photodegradation in water system were studied. Serial concentrations of the pesticides with the addition of copper ion were spiked in
the soil and incubated for a regular period of time, the analysis of the extracts from the soil was carried out using gas chromatography
(GC). The photodegradation of pyrethroids in water system was conducted under UV irradiation. The e ect of Cu2+ on the pesticides
degradation was measured with half life (t0:5) of degradation. It was found that a negative correlation between the degradation of the
pyrethroid pesticides in soil and Cu addition was observed. But Cu2+ could accelerate photodegradation of the pyrethroids in water. The
t0:5 for cyhalothrin extended from 6.7 to 6.8 d while for cypermethrin extended from 8.1 to 10.9 d with the presence of copper ion in
soil. As for photodegradation, t0:5 for cyhalothrin reduced from 173.3 to 115.5 min and for cypermethrin from 115.5 to 99.0 min. The
results suggested that copper influenced the degradation of the pesticides in soil by a ecting the activity of microorganisms. However,
it had catalyst tendency for photodegradation in water system. The di erence for the degradation e ciency of pyrethroid isomers in
soil was also observed. Copper could obviously accelerate the degradation of some special isomers.
