3,3',4,4',5-五氯联苯通过饲料在罗非鱼体内的转移富集净化规律及膳食暴露评估

The Distribution,Bioaccumulation,Depuration and dietary exposure estimation of 3,3',4,4'5-pentachlorobiphenyl in tilapia Oreochromis nilotica through fish feed

鱼类是人体摄入二噁英样多氯联苯的重要途径,饲料又是鱼类摄入该类污染物的主要途径.本实验采用对鱼类毒性当量贡献最大的3,3',4,4',5-五氯联苯(PCB126),在饲料中添加接近欧盟饲料限量标准的化合物,考察了在50 d富集期和随后34 d净化期内PCB126在罗非鱼各组织中的转移富集净化规律,并做出膳食暴露评估.结果表明,PCB126易在鱼体内蓄积,富集期第1 d肝脏、肌肉、肾脏和血液中的PCB126水平上升了8倍多,随后肝脏和血液中污染物的富集呈现快速上升与平稳蓄积交替的现象,肌肉和肾脏中污染物水平峰值的出现晚于肝脏、血液.在净化期,除肉外其余组织中PCB126水平均出现显著下降,肉中PCB126净化缓慢.鱼肉的最高毒性当量为1.08 pg TEQ·kg-1鲜重(188.1 pg TEQ·kg^(-1)脂肪),本研究中我国居民的每日最高暴露量为2.82 pg TEQ·kg^(-1)体重,接近WHO推荐的每日耐受摄入量(TDI),其健康风险有待进一步评估.

Fish is the main source for human to intake dioxin-like Polychlorinated Biphenyls（ dlPCBs）,and feed contributes significantly to the concentration of dl-PCBs in fish. Besides,3,3＇,4,4＇,5-pentachlorobiphenyl（ PCB126） contributed most to the total toxic equivalencies（ TEQs） of PCBs in fish. In this study,tilapias were fed with PCB126-containing feed（ the level of PCB126 in feed stuffs was close to the limit of European Union） for 50 days followed by 34 days of clean feed.The regularity of bioaccumulation,depuration and dietary exposure estimation of PCB126 in fish tissues were investigated. The results showed that PCB126 accumulated easily in fish,and the levelof PCB126 in liver,muscle,kidney and blood were increased by more than 8 times on the first day,then the rapid and smooth increase of PCB126 in liver and blood appeared. The peak level of PCB126 in muscle and kidney appeared later than in liver and blood. During depuration period,the levels of PCB126 in tissues except muscle decreased significantly,and PCB126 content in muscle decreased slowly. The highest TEQ of PCB126 in muscle was 1. 08 pg TEQ·kg-1 fresh weight（ 188.1 pg TEQ·kg-1 lipid）,and the daily maximum exposure of residents in our country was2.82 pg TEQ·kg-1 body weight in this study,which is close to the Tolerable Daily Intake（ TDI）recommended by WHO. The health risk ought to be further evaluated.