循环水养殖欧洲鲈鱼(Dicentrarchus labrax)重金属污染状况与富集分布特征

Contamination and Accumulation of Heavy Metals in Dicentrarchus labrax Cultured in Recirculating Aquatic Systems

中文关键词: 循环水养殖  欧洲鲈鱼  重金属  污染  组织分布  富集规律

英文关键词: Recirculating aquatic systems (RAS)  Dicentrarchus labrax  Heavy metals  Contamination  Distribution  Enrichment

中文摘要:

      为了解并评估天津市某循环水养殖企业的养殖产品重金属安全性和分布规律，本研究采用电感耦合等离子体发射光谱法(ICP法)和原子荧光法(AFS法)，对该封闭循环水养殖系统中欧洲鲈鱼(Dicentrarchus labrax)幼鱼、养殖中期和成鱼3个阶段的鱼体肌肉、肝脏和鳃中8种重金属(As、Cd、Cr、Cu、Ni、Pb、Zn和Hg)含量进行测定。结果显示，从生长阶段来看，随养殖过程推进，各重金属在欧洲鲈鱼体内分布特征不同，肌肉中As含量随时间增加而增加，最大值为1.93 mg/kg，Cu和Hg则相反，最大值分别为0.354和0.021 mg/kg；肝脏中As、Cd和Cu含量均随时间增加，最大值分别为1.47、1.09和143.00 mg/kg；鳃中As含量随时间增加而增加，最大值为0.321 mg/kg，Cr、Cu、Zn和Hg含量呈先降后升的趋势，最大值分别为0.356、45.8、19.2和0.0137 mg/kg。从组织分布特征来看，As含量为肌肉>肝脏>鳃，Cd、Cu和Zn含量均为肝脏>鳃>肌肉，Hg含量为肌肉>鳃>肝脏，Cr含量为鳃>肝脏>肌肉。可食部分，即肌肉中各重金属含量均符合食品安全国家标准(GB 2762-2012)，参考鱼体重金属残留污染程度分级，该系统中的欧洲鲈鱼均属于未污染。水体样本，除养殖中期进水中Pb和Cd超标，其余重金属含量均符合我国渔业水质标准(GB 11607-89)。表明该养殖系统中重金属污染在安全范围内。

英文摘要:

      Aquaculture provides human beings with steady sources of high-quality proteins and has been an ever-growing industry thanks to the recirculating aquatic system (RAS). RAS allows aquaculture to be less dependent on natural resources. However, RAS is prone to the accumulation of hazardous substances such as flocculation, non-ionic ammonia and heavy metals, so the safety of produces raised in RAS needs to be carefully evaluated. In this study, we analyzed the safety and the distribution of eight heavy metals in Dicentrarchus labrax cultured in a closed RAS in Tianjin. The contents of arsenic, cadmium, chromium, copper, nickel, lead and zinc were measured with Inductively Coupled Plasma (ICP), and the level of mercury was measured with Atomic Fluorescence (AFS) during the three growth stages including juvenile, mid-term and adult. It was found that the distribution of heavy metals varied at different growth stages. In the muscle, the content of arsenic increased over time with the maximum value of 1.93 mg/kg. The contents of copper and mercury changed in an opposite pattern and the maximum values were 0.354 mg/kg and 0.021 mg/kg respectively. In the liver, the contents of arsenic, cadmium and copper increased over time with the maximum value of 1.47 mg/kg, 1.09 mg/kg and 143.00 mg/kg respectively. In the gill, the content of arsenic increased over time with the maximum value of 0.321 mg/kg. The contents of chromium, copper, arsenic and mercury first rose and then dropped, and the maximum values were 0.356 mg/kg, 45.8 mg/kg, 19.2 mg/kg and 0.0137 mg/kg respectively. The distribution of arsenic in different tissues followed the order of muscle>liver>gill; the distribution of cadmium, copper and zinc followed the order of liver>gill>muscle; mercury followed the order of muscle>liver>gill; and chromium followed the order of gill>liver>muscle. In general, the contents of all elements in the muscle complied with the national food safety standard (GB 2762-2012). All the samples were unpolluted according to the grading of heavy metal residues in fishes. Contents of all heavy metal elements were under the limits of the water quality standard for fisheries (GB 11607-89) except for Pb and Cd. In conclusion, the heavy metal contents in the tested RAS were in a safe range.