摘要:
为揭示浑河重金属污染的潜在生态风险,分析测定了浑河野生鲫鱼体内重金属的残留水平以及肝和鳃组织中金属硫蛋白基因表达。对鱼体各组织中Cr、Cd、Pb、Cu和Zn含量的分析结果显示,各组织重金属含量的排序为肠 > 肝 > 鳃 > 肌肉,且Zn含量最高(17.49~176.01 mg·kg-1,以湿体质量计算),Cd含量最低(N.D.~0.57 mg·kg-1,以湿体质量计算)。均值综合污染指数评价结果显示,浑河野生鲫鱼受到重金属的轻微污染,且从上游至下游呈现逐渐升高的趋势,其中,Cr、Pb和Zn对均值综合污染指数贡献较大。利用实时定量PCR方法分析鲫鱼肝组织金属硫蛋白基因表达发现,中、下游鲫鱼肝组织的金属硫蛋白基因表达水平较上游有所升高,且与肌肉组织综合污染指数具有较好相关性(R2=0.71),这表明金属硫蛋白基因可作为监测环境重金属污染的敏感标志物。
Abstract:
To study the potential ecological risk of heavy metal contamination in Hun River, the contents of heavy metals in different tissues of wild crucian carps from Hun River were analyzed, and the metallothionein mRNA expressions in gill and hepatic tissues were also investigated. Results showed that the accumulation amounts of Cr, Cd, Pb, Cu and Zn in tissues followed the order of intestine > liver > gill > muscle. Zn content was the highest, ranging from 17.49 to 176.01 mg·kg-1(wet weight), and Cd content was the lowest, ranging from non-detectable level to 0.57 mg·kg-1(wet weight). The average pollution index assessment results showed that the wild crucian carps in Hun River were slightly contaminated by heavy metals. Furthermore, the pollution level in wild crucian carps increased from upstream to downstream. Among the studied heavy metals, the contents of Cr, Pb and Zn mostly contributed to the pollution index. The metallothionein mRNA expression levels in livers of crucian carps detected with real-time quantitative polymerase chain reaction were found to increase from upstream to downstream. A positive relationship was observed between the metallothionein mRNA expression levels in livers and the average pollution index in muscles (R2=0.71), indicating that the metallothionein gene can be used as a promising biomarker for monitoring the heavy metal contamination.
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