Biodegradation Kinetics Of Organochlorine Pesticides In Nanhu Lake In Changchun City

The purpose of this study was to investigate the dynamic characteristics of organochlorinepesticides in lake water, surface sediments, and biological membrane. Experiment were built tosimulate the degradation kinetics of sterilized samples and the original samples and analysis therelationship between main index and degradation rate.The kinetics of biological degradation of organochlorine pesticides HCHs in Nanhu Lakeconsistent with a first-order kinetic equation. The degradation rate constant range from0.0469to0.0672, where kγ-HCH>kδ-HCH>kα-HCH>kβ-HCH. MMS solution in biological degradation experimentseffectively maintain the microbial activity and promote the organic chlorine pesticidebiodegradation. In the orthogonal test factors on degradation of organochlorine pesticide effectsizes were: pH value, initial concentration, adding carbon source. The optimal conditions for thedegradation experiment were pH value is7, the initial concentration of4μg/L, while the additionof glucose and sodium bicarbonate as carbon source.In the study of the dynamic characteristics of γ-HCH and p,p’-DDT in surface sediments,comparied the fitting results of irst-order kinetic and the nonlinear dynamics model. The resultindicated that the nonlinear dynamics model was adopted to fit the experimental data in the study,the range of correlation coefficient of nonlinear model was0.901~0.989. The model simulatedresults of original samples showed higher fitness and accuracy than those of sterilized samples.Biological degradation rate were44.42%for γ-HCH and17.23%for p,p’-DDT in the experiment.Indicators including dissolved oxygen, redox potential and total organic carbon influencedegradation rate through affecting the activity of microorganism.The nonlinear dynamics model was adopted to fit the experimental data in the study of thedynamic characteristics of γ-HCH and p,p’-DDT in biological membrane. The range of correlationcoefficient of nonlinear model was from0.982to0.993. The biological degradation rate of γ-HCHand p,p’-DDT change with time presents a kind of fast-slow-fast ascendant trend. Biologicaldegradation rate were24.30%for γ-HCH and10.99%for p,p’-DDT in the experiment. Waterdissolved oxygen content present first decreasing and then increasing trend.