STUDY ON PHOTO-DEGRADATION OF PYRETHROID IN JIULONG RIVER ESTUARY WATERS

This article study on photo-degradation of pyrethroid pesticides in estuary water by means of HPLC-DAD. Samples were degraded in a self-made photo-reactor, separated through integrating high performance liquid chromatography (HPLC) and tested with diode array detector (DAD). Photo-degradation reaction of fenvalerate was studied. The results show that the photo-degradation kinetics of fenvalerate in Jiulong River estuary water follows the first-order reaction. Degradation rate of fenvalerate was strongly influ- enced by pH, initial concentration of H2O2 and illumination time, whereas the effect of salinity on degradation rate of fenvalerate is not obvious in the natural water. Degradation rate of fenvalerate in this estuary water was 97% after 10 seconds under UV light, and the main degradation products are not stable in this degradation system, with their concentration first increasing and then decreasing, reach to maximum in 8 seconds, degradation rate is 71.6% in 10 seconds.