Degradation Of Trichlorfon Enantiomers In Mariculture Environment

Trichlorfon is a keed of organophosphorus pesticide which usded in kill the fish parasites, prevent and treat fish from lice. The using of trichlorfon always polluting the envrionment of seawater, and trichlorfon residing in seafood,residing in sediment of mariculture pond. So, researching the degradation of trichlorfon in the evrionment of brooding seawater could provide some date for security risk assessment of seafood.In this study, the degradation behaviour of trichlorfon enantiomers in mariculture pond water, sediment and aquatic product under different conditions were investigated. The main contents include:The solid-phase extraction methods for trichlorfon enantiomers in mariculture pond water, sediment and aquatic product were established by optimized extraction solvents, extraction volume, p H and other parameters.1. The HPLC detection methods for trichlorfon enantiomers in mariculture pond water, sediment and aquatic product were established. The mobile phase for detection trichlorfon enantiomers in mariculture pond water was n-hexane-isopropanol-ethanol(90:8.5:1.5, v/v/v) at a flow rate of 1.0 m L/min, method detection limit and the quantitative limit of R-(–)-TF and S-(+)-TF was 0.012mg/L, 0.040 mg/L and 0.015 mg/L, 0.050 mg/L, respectively. Intra-and inter-day was 2.94%~7.10% and 5.22%~10.81%. The mobile phase for detection trichlorfon enantiomers in sediment was n-hexane-isopropanol(90:10, v/v) at a flow rate of 1.0 m L/min, method detection limit and the quantitative limit of R-(–)-TF and S-(+)-TF was 0.031μg/g, 0.090μg/g and 0.040μg/g, 0.097 μg/g, respectively, and of DDVP, the method detection limit and the quantitative limit was 0.013μg/g and 0.039μg/g. Recovery rate of TF and DDVP was 87.15% ~ 91.76% and 87.03% ~ 91.85, Intra-day precisionof TF and DDVP was 4.13% ~ 8.97% and 1.22% ~ 3.17%, Inter-day precision of TF and DDVP was 4.36% ~ 9.10% and 2.11% ~ 3.87%, respectively. The mobile phase for detection trichlorfon enantiomers in aquatic product was n-hexane-isopropanol(91:9, v/v) at a flow rate of 0.8 m L/min, method detection limit and the quantitative limit of R-(–)-TF and S-(+)-TF was 0.016μg/g, 0.09041μg/g and 0.018μg/g, 0.047 μg/g, respectively, and of DDVP, the method detection limit and the quantitative limit was 0.009μg/g and 0.027μg/g. Recovery rate of TF and DDVP was 89.70% ~ 99.96% and 90.87% ~ 97.85%, and the recovery rate of IS was 95%. Intra-day precision of TF and DDVP was 4.13% ~ 8.97% and 1.22% ~ 3.17%, Inter-day precision of TF and DDVP was 4.30% ~ 9.91% and 2.10% ~ 3.69%, respectively.2. The degradation behavior of trichlorfon enantiomers under natural, sterile and dark conditions with two concentration levels(0.5mg/L and 10mg/L) at 4oC and 20 oC was investigated. Results showed that ESnatural >ESdark>ESsterile≈ESsterie, dark and we inferred that the reason of stereoselectivity of trichlorfon derradation was microorganism. The microorganism in mariculture pond water absorbed energy from light and utilized trichlorfon as carbon source and p Hosp Horus source to create matter they required. It was the microorganism activity that resulted in the stereoselectivity of trichlorfon derradation.The effect on the degradation of trichlorfon enantiomers by microbe in sediment samples was investigated. The results that ESunsterile >ESsterile suggested the stereoselective degradation of trichlorfon enantiomers should be attributed to microbe. Otherwise, the results that kunsterile>ksterile,t1/2unsterile> t1/2sterile suggested that microbe could accelerate the degradation of trichlorfon enantiomers.The residual trichlorfon in aquatic product might degrade and the highly toxic degradation product was emerged. The effect on the degradation rate of trichlorfon enantiomers by different storage temperature(-18 oC 、4 oC 、18 oC 、25oC) and different amount of microorganism was investigated. We found that trichlorfon enantiomers degraded more quickly under the higher storage temperature and larger amount of microorganism conditions. The EF value was 0.57 at 25 oC and it suggested that the increase in amount of microorganism resulted in the prior degradation of R-(–)-TF and the stereoselectivity of trichlorfon derradation.