3,3′,4,4′,5-五氯联苯(PCB126)在食用罗非鱼不同组织中的蓄积、净化、迁移规律的动力学研究

Kinetic study of bioaccumulation, depuration, and transfer for 3,3′,4,4′5-pentachlorobiphenyl (PCB126) in different tissues of tilapia Oreochromis nilotica

为明确二英及其类似物通过饲料在食用鱼体内的蓄积、净化、迁移规律,了解模型在预测可食部和饲料中污染水平及计算动力学参数方面的准确性,本研究测定了饲料暴露的二英样多氯联苯(3,3′,4,4′,5-五氯联苯,PCB126)在养殖食用罗非鱼的肝脏、肌肉、肾脏、血液中的含量,利用非线性模型拟合了各组织的污染水平和清除速率常数等PCB126的蓄积、净化动力学参数.结果表明,该模型对肌肉中PCB126的污染水平有很好的预测效果(R^2=0.95),对各组织中污染物半衰期的预测也与实际接近.本研究用逸度表征污染物在各组织中的迁移趋势,结果表明肝脏可快速蓄积、清除PCB126,并在高浓度污染物刺激下生长以提高蓄积能力;肌肉中污染物的迁移不受暴露时长的影响,清除期污染物由其它组织迁移入肌肉,引起肌肉中污染物含量峰值的延后.

To understand accumulation, depuration, and transfer of dioxin-like compounds from feed to fish, the levels of 3,3′,4,4′5-pentachlorobiphenyl(PCB126) in liver, muscle, kidney and blood of oreochromis nilotica, exposured to the diet with contaminant were determined. Kinetic parameters were calculated by using a pharmacokinetic model to study application of the model in predicting concentrations for contaminants. Results showed that the predicted values of contents for PCB126 in muscle and the half life of PCB126 in tissues were in good agreement with the measured values. Fugacity was applied to indicate transfer of PCB126 in tissues. Results suggested that liver was an important organ for accumulation and transfer of PCB126 which stimulated the growth of liver to elevate capacity of bioaccumulation. The transfer of PCB126 in muscle was unaffected by exposure time, and the peak PCB126 concentration was delayed generating from the import of PCB126 from other tissues to muscle during depuration.