海洋养殖鱼类体内汞污染及其在不同器官中的生物富集特征

以浙江省宁波市象山港和舟山市六横岛海洋渔业养殖区典型养殖鱼体为研究对象,选取三种人工海洋网箱养殖鱼类(黑鲷、鲈鱼和红鮋),通过测定其不同组织和器官中总汞和甲基汞的含量,探讨了不同形态汞在海洋养殖鱼体不同组织和器官中的分布及富集特征。结果显示:象山港和六横岛渔业养殖区鱼体肌肉组织中总汞平均含量分别为106、43.4 ng·g~(-1),甲基汞含量分别为81.0、33.6 ng·g~(-1);鱼体不同器官组织的功能不同导致其对汞的富集程度也不同,各器官组织总汞和甲基汞含量分布规律基本表现为肌肉肝脏其他器官。肌肉组织中总汞和甲基汞在两地均表现为黑鲷显著高于鲈鱼和红鮋,主要是由于黑鲷以杂鱼为主要食物,而鲈鱼和红鮋以颗粒鱼粮为主要食物,杂鱼汞含量显著高于颗粒鱼粮;但是鱼鳃、鱼鳞等组织中的汞在不同鱼种之间无显著差异,说明这些组织中的汞主要来源于水体。象山港和六横岛两地鱼体肌肉组织中甲基汞的生物富集系数高于总汞的生物富集系数,说明甲基汞更易在鱼体中富集。

Mercury contamination and bioaccumulation in different tissues of marine aquaculture fish

Three kinds of aquacultured fish, including black seabream(Acanthopagrus schlegelii), red snapper(Lutjanus campechanus), and perch(Perca fluviatilis) were collected from Xiang-shan(XS) Bay and Liu-heng(LH) Island, Zhejiang Province, in an attempt to investigate the distribution patterns and bioaccumulation levels in different tissues and organs of fish in terms of total mercury(THg) and methylmercury(MeHg). The results showed that the mean values of THg concentration in fish muscle samples from XS and LH were 106 and 43.4 ng·g^-1, respectively, whereas the average MeHg concentrations in fish muscle were 81.0 and 33.6 ng·g^-1, respectively. THg and MeHg showed a decreasing order in different tissues as follows:muscle >liver> other organs. The THg and MeHg concentrations in the muscles of black seabream were higher than those in red snapper and perch because black seabream was fed with trash fish whereas red snapper and perch were fed with commercial feed pellets. It was found that THg and MeHg concentrations in the trash fish were significantly higher than in the feed pellets. However, there were no significant differences for THg and MeHg concentrations in the gills and scales among the three kinds of fish, indicating that Hg in gills and scales was mainly from the water. The bioaccumulation factor of MeHg in fish muscle was higher than that of THg for both sites, which implies that it was much easier for MeHg to bioaccumulate in fish muscle than for THg.