| Determination method of deltamethrin residues in water and degradation regulation of deltamethrin in different conditions were researched. Results showed it’s a simple method that after extracted by petrol ether and dehydrated, deltamethrin was determined by GC-ECD with the recoveries of80-110%and the detection limit of0.1ug/L. The method is sensitive and suitable for the determination of deltamethrin in water. When the concentration was llng/mL, lOng/mL and50ng/mL, deltamethrin had degraded44.2%～72.4%in continuous aeration water after24h while the degradation ratio was7.5%～26.2%in static condition. High concentration of deltamethrin degraded faster than low concentration and the same as the water which feed crabs.Following the fishery drug testing method of changing water, the acute toxicity effects of dicis (containing25gram deltamethrin per liter) were studied with three different kinds of river crabs when the water temperature was in the range of20-23℃. The results indicated that the48hLC50for adult, juvenile and button crabs were2.19μg/L,1.01μg/L/L,0.67μg/L respectively;96hLC50values were0.65μg/L,0.42μg/L,0.31μg/L respectively The safe Concentration was0.46μg/L,0.19μg/L,0.15μg/L respectively。Gas chromatography with electron capture detection method was developed for the determination of7pyrethroids residues in aquatic products. Pyrethroids was extracted with cyclohexane and ethyl acetate (1:1,V/V) and remove lipids with petroleum ether. Cleanup was performed on a LC-Florisil column. The working curves for the pyrethroids were linear (r>0.992) in the range of1to100μg·L-1. When spiked with5,10and20μg/kg of pyrethroids, the average recoveries were70.0%～114.8%and the intra-day RSD(n=5) were1.2%～9.8%and the inter-day RSD(n=3) were3.8%～11.2%. The detection limit as estimated by2times signal to noise method for bifenthrin, fenpropathrin, lambda-cyhalothrin, permethrin was1μg/kg and for permethrin, fenvalerate, deltamethrin was2μg/kg respectively. |
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