滇池几种鱼体汞含量与δ^(13)C、δ^(15)N特征

Mercury Concentrations and Characterization of δ^(13)C and δ^(15)N in Some Fish Species from Lake Dianchi

鱼体是人体摄入甲基汞的重要暴露途径。对滇池几种重要鱼类的总汞、甲基汞和13 C、15 N进行了测定,结果发现:滇池中鱼体总汞和甲基汞含量范围(平均值)分别为5.6~287ng/g(74±59ng/g)和2.7~400ng/g(73±67ng/g)。总汞和甲基汞含量存现显著的相关关系,(R2=0.65,p<0.001),且甲基汞占总汞的平均比例大于80%,表明鱼体中的汞主要以甲基汞的形态存在。滇池几种鱼类的δ13 C平均值为-20.5±4.2‰,范围为-29.0‰^-15.1‰,δ15 N平均值为17.1±4.3‰,范围为5.9‰~25.8‰。同位素比值与鱼体汞含量之间没有显著的相关性,可能是由于滇池中采集的黄颡鱼和白鱼与其他鱼类不属于同一种食物源,因此对13 C和15 N的分馏不同。另外,采集的鱼类大小和年龄不均一,也可能是造成13 C和15 N异常分馏的原因之一。

Fish digestion is one of the dominant pathways of mercury exposure for human beings.Total Hg and methyl Hg concentrations as well as the isotopes of 13 C and 15 N were determined in some fish species collected from a large,shallow,eutrophic lake,Dianchi.The results showed that the average total Hg and methyl Hg are within the ranges of 5.6-287ng/g（74±59ng/g）and 2.7-400ng/g（73±67ng/g）,respectively.The correlation coefficient（R2）between total Hg and methyl Hg is0.65（p〈0.001）,and over 80%of Hg in fish is presented as methyl Hg on average,indicating that the dominant form of Hg in fish from Lake Dianchi is methyl Hg.No significant relationship between Hg concentration and the ratio ofδ13 C toδ15 N was observed,possibly due to different food sources of Erythroculter ilishaeformis Bleeker and Pelteobagrus fulvidraco.In addition,inhomogeneity of mass and age of the collected fish species may be a potential reason.