洞庭湖不同营养级鱼组织中PCBs的分布特征

采用稳定同位素分析技术和气相色谱-高分辨质谱联用技术，测定了洞庭湖6种鱼组织的稳定氮同位素丰度值（δ¹⁵N值）和多氯联苯（PCBs）的含量，研究了鱼组织中PCBs分布特征及其与营养级的相关性.结果表明，∑PCBs₁₁₅的浓度范围为0.04~9.77ng/g湿重，在鲤鱼性腺组织中最高.毒性当量为：0.0003~2.39pg/g湿重，在鳡鱼脂肪组织中最高.洞庭湖鱼中PCBs的含量处于较低水平.PCB28，52，95，99，101，105，110，118，138，153，155和209在所有组织中检出.Co-PCBs，Ind-PCBs和PCB209具有组织分布特异性.不同计量方式下，鱼组织中PCBs与δ¹⁵N值具有相关性的同类物不同.

Characteristics of PCBs in different trophic level tissues of fish from Dongting Lake

The toxicity of polychlorinated biphenyls (PCBs) and their transformation have been intensively investigated in recent years. However, the potential mechanisms of biotransformation in a lake food web remain unclear. In current study, the distribution characteristics of PCBs and δ¹⁵N values in different tissues of six species of fishes, collected in Dongting Lake, were analysed with gas chromatography-high resolution mass spectrometer and stable isotope mass spectrometer, respectively. The correlation between PCBs and the trophic level were explored based on the concentrations and δ¹⁵N values. The concentration of ∑PCBs₁₁₅ranged from 0.04 to 9.77ng/g wet weight (ww), and the highest level was found in the gonad of Cyprinus carpio. The concentration of toxicity equivalent (TEQ) varied from 0.003 to 2.39pg/g, with highest level detected in the fat of Silurus asotus. And the PCB levels in fish collected from Dongting Lake were at low level comparing with previous study. PCB28, 52, 95, 99, 101, 105, 110, 118, 138, 153, 155 and 209 were found in all tissues. The coplanar PCBs (Co-PCBs), Ind-PCBs (Indicator PCBs) and PCB209 was in a tissue-specific manner. The significant positive correlation (P<0.05) between the PCB congeners and δ¹⁵N values varied depending on the calculation mode of PCB concentrations (such as, ng/g ww, ng/g dry weight and lipid- normalized).