| The characteristics of organochlorine pesticides are low water solubility, hightoxicity and environmental durability. They could damage to the ecosystem and humanhealth, and even cause the global pollution. Thus, further research is necessary.In the middle of Jiangan plain, soil and shallow layer sediment near the Qianjiangcity were chosen as an example. By making use of batch experiments, we studiedadsorption kinetics, isothermal adsorption/desorption characteristics and influencingfactors of organochlorine pesticides in different soil/sediment.First of all, adsorption dynamics of HCHs and DDTs in one soil sample wereanalyzed which determined24h as the oscillation time of adsorption experiments. Thenwe discussed isothermal adsorption/desorption characteristics of HCHs and DDTs indifferent soil/sediment, simulating adsorption/desorption by meanings of linear fittingmodel and Freundlich model, and calculated desorption hysteresis coefficients. Resultsshowed that the amount of adsorption/desorption of organochlorine pesticides increasedwith the increasing of the concentration of pesticides, and the adsorption quantity ofDDTs is obviously higher than that of HCHs. The linear equation fit better withisothermal adsorption/desorption process. The last research was about how endogenousand exogenous soluble organic matter and clay minerals affected HCHs and DDTsadsorption process. After removal of soluble organic matter, adsorption quantity of HCHsin soil sample and1-1and1-8decreased, while adsorption quantity of DDTs in soilsample1-8and3-7increased in the increasing with the DOM dissolution. AdditionalDOM made adsorption quantity of HCHs increase, which a downward trend instead ofafter reaching a certain amount. Adsorption quantity of DDTs with exogenous DOM keptthe decreasing trend. By removing the organic carbon of soil samples1-8,1-1,3-7,3-5,3-4, adsorption capacity of HCHs and DDTs in soil/sediment increased with the increasing of clay mineral contents. |
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