东洞庭湖网箱养殖鲤鱼生长期内重金属的富集特征

于2012年2—7月对东洞庭湖网箱养殖鲤鱼(Cyprinus carpio)按生长期进行样品采集,采用原子吸收分光光度法测定水样和饲料以及鲤鱼鳃、肝脏和肌肉中的重金属含量. 结果表明:鲤鱼生长环境中的水质属于GB 3838—2002《地表水环境质量标准》中Ⅰ类水平,但饲料中重金属质量分数相对较高,成为鲤鱼富集重金属的主要来源. 在鲤鱼生长期内,鱼体内的w(Pb)和w(Cu)均随着鲤鱼的生长而增加. 鲤鱼鳃中Pb未检出,w(Cu)为0.143～0.703mg/kg；肝脏中w(Pb)和w(Cu)分别为0.006～0.181和0.625～6.177mg/kg；肌肉中w(Pb)和w(Cu)分别为nd～0.034和nd～0.161mg/kg. w(Zn)和w(Cd)均随着鲤鱼的生长先增加后下降,在1～4月龄的鲤鱼体内w(Zn)在鳃、肝脏和肌肉中分别从40.121、21.302和2.032mg/kg增至258.964、146.155和18.011mg/kg,w(Cd)则分别从0.015、0.031和0.003mg/kg增至0.078、0.151和0.021mg/kg；4月龄后,w(Zn)在鳃、肝脏和肌肉中逐渐降至173.182、104.219和5.490mg/kg,w(Cd)也降至0.037、0.111和0.018mg/kg. 在鲤鱼生长过程中,肝脏是Pb、Cd和Cu的主要富集部位,鳃是Zn的主要富集部位,肌肉是重金属富集的最弱部位,并且这3个部位间重金属富集的相关性较强. 

Enrichment of Heavy Metals in Growth Period of Cage Cultured Carp (Cyprinus carpio) from the East Dongting Lake

Samples of cage cultured carp (Cyprinus carpio) in different growth periods were collected in the East Dongting area from February to July 2012. The w(Pb), w(Zn), w(Cd), w(Cu) were measured by the atomic absorption spectrophotometry in water samples, fodders and the gills, livers and muscles of carp. The results showed that the water quality belonged to level Ⅰ according to the “Environmental Quality Standards for Surface Water” (GB 3838-2002). The mass fraction of heavy metals in the fodder was relatively higher, which made the fodder become the main possible source of heavy metals pollution in carp. The w(Pb) and w(Cu) increased with the fish growth. In the gills, Pb were not detected (nd) while the w(Cu) were 0.143-0.703mg/kg. In the livers, w(Pb) and w(Cu) ranged in 0.006-0.181mg/kg and in 0.625-6.177mg/kg respectively. In the muscles, w(Pb) and w(Cu) were nd-0.034mg/kg, nd-0.161mg/kg respectively. During the growth of the carp, the w(Zn) and w(Cd) increased firstly and decreased later. During the first to the 4th month, the w(Zn) in gills, livers and muscles increased from 40.121,1.302,2.032mg/kg to 258.964,6.155,8.011mg/kg respectively. Similarly, the w(Cd) increased from 0.015,0.031,0.003mg/kg to 0.078,0.151,0.021mg/kg respectively in gills, livers and muscles. After four months, the w(Zn) in gills, livers and muscles declined gradually to 173.182,4.219,5.490mg/kg respectively while the w(Cd) declined to 0.037,0.111,0.018mg/kg at the same time. During the whole growth process of the fish, the liver was the main enrichment site for Pb, Cd and Cu while the gills were the main enrichment site for Zn. The mass fraction of heavy metals in muscles was the lowest among all tissues. All these three parts strongly correlated.