三峡水库蓄水初期鱼体汞含量及其水生食物链累积特征

Abstract

PDF HTML阅读 XML下载 导出引用 引用提醒 三峡水库蓄水初期鱼体汞含量及其水生食物链累积特征 DOI: 10.5846/stxb201211091568 作者: 作者单位: 中国水利水电科学研究院水环境所,中国水利水电科学研究院水环境所,中国水利水电科学研究院水环境所,中国水利水电科学研究院水环境所,中国水利水电科学研究院水环境所 作者简介: 通讯作者: 中图分类号: 基金项目: 国家自然科学基金资助项目(51179205);国家水体污染控制与治理科技专项三峡水库水环境演化与安全问题诊断研究课题(2009ZX07104-001) Mercury contents in fish and its biomagnification in the food web in Three Gorges Reservoir after 175m impoundment Author: Affiliation: Department of Water Environment,China Institute of Water Resources and Hydropower Research,Department of Water Environment,China Institute of Water Resources and Hydropower Research,Department of Water Environment,China Institute of Water Resources and Hydropower Research,Department of Water Environment,China Institute of Water Resources and Hydropower Research,Department of Water Environment,China Institute of Water Resources and Hydropower Research Fund Project: 摘要 | 图/表 | 访问统计 | 参考文献 | 相似文献 | 引证文献 | 资源附件 | 文章评论 摘要:于2011-2012年在三峡库区干流水域及7条典型支流采集了11种鱼类样品,以稳定同位素(δ13C和δ15N)营养等级分析为基础,研究了三峡水库蓄水后的鱼类汞含量水平及其食物链累积特征。结果表明,库区鱼类(以鲤为例)平均总汞含量为57.1 μg/kg,与蓄水前鱼体总汞水平相当,但在库区不同水域鱼体总汞含量差异显著:干流入库水域(洛碛断面)鱼体总汞含量平均值为88.0μg/kg,显著高于水库腹区水域(巫山断面)的平均值43.1μg/kg。稳定同位素分析表明,库区支流鱼体的δ13C范围为-22.08‰--28.92‰,大于干流鱼体的δ13C范围(-23.11‰--26.87‰),表明支流鱼类的食物来源具有更明显的湖沼型特征。同时,支流鱼类食物链上汞的累积放大效率显著高于干流水域。水文水动力差异可能是库区内汞累积等生态过程存在空间差异的重要原因。 Abstract:Three Gorges Reservoir (TGR) is a giant canyon-shaped reservoir located in the lower section of the upper reaches of the Yangtze River. After impoundment, hydrological signatures, chemical factors and species composition, had been greatly changed in TGR. The new environmental conditions could increase methylmercury (MeHg) production, and induce substantial increase of mercury concentration in the predator fish through food chain biomagnification. Concern about human consumption of fish contaminated with MeHg had been raised even before the construction of TGR. This study tried to investigate the total mercury concentrations in fish and biomagnification characters of mercury along food chains in TGR after 175m impoundment. The stable isotope analysis could be a useful method of checking and evaluating the trophic conditions of aquatic ecology. We collected eleven fish species from three main stem sections and seven typical tributaries of TGR from 2011 to 2012. Carp (Cyprinus carpio) was selected as a typical species to investigate the spatial distribution of mercury level in fish from TGR. Total mercury concentrations and stable isotope ratios (δ13C and δ15N) of all fish samples were determined. Result showed that mercury concentrations in fishes from TGR had not obviously increased after impoundment. The carp mercury concentrations in TGR were comparable to values reported for other areas of Yangtze River Basin. But spatial difference was found among different sections of main stem. Due to the enhanced sediment deposition along reservoir, there was a decreasing trend of mercury concentration in fish from upper stream to lower stream within TGR. Mercury concentrations in the fishes from Luoqi in up area of reservoir (88.0μg/kg, average) was significantly higher than those from Wushan in middle area of reservoir (43.1μg/kg, average) and tributaries (57.1μg/kg, average). The mercury concentrations in fish from tributaries were comparable to those from main stem, and there were no significant difference among most tributaries. Based on the carbon and nitrogen stable isotope ratios and total mercury contents in eleven species fish, the biomagnification power of mercury in two sections and one tributary were evaluated. While log-transformed mercury contents were consistently correlated with δ15N values for the fish food web in all sampling sites, the slope of the relationship with δ15N (biomagnification power value) was significant higher in Shennong River than that in Wanzhou and Wushan section. This indicated that biomagnification power of mercury is greater in tributary than in main stem of TGR. Carbon and nitrogen stable isotope analysis also indicate a difference in food source of fishes between tributary and main stem. In tributary (Shennong River), the values of fish samples were-22.08‰--28.92‰ for δ13C and 8.26‰-13.15‰ for δ15N; In main stem, the values of fish samples were-23.11‰--26.87‰ for δ13C and 8.95‰-16.98‰ for δ15N. This indicate fishes in tributary rely more on pelagic primary production while those in main stem tend to take allochthonous materials carried by runoff. In conclusion, the body type of tributary and main stem after impoundment could be different, and this may be an important reason of different mercury bioaccumulation between tributary and main stem within TGR. 参考文献 相似文献 引证文献