Wei Li-li, Zhou Qiong, Xie Cong-xin, Wang Jun, Li Jun
Huan Jing Ke Xue. 2016 Jan 15;37(1):325-34.
Three Gorges Reservoir (TGR) reached the maximum water level (175 m) of impoundment in Oct. 2010. In order to reveal the potential influence of the greatest water-level impoundment on the heavy metal pollution in the typical waters of TGR, the content level of trace metals ( Hg, Cd and Pb) in biota and potential biomagnification along the aquatic food chain were investigated in the main stem of TGR from July 2011 to August 2012, as well as the relationship between the trace metal concentrations of aquatic consumers (fish and aquatic invertebrate) and biological factors. Our study showed that no individual data of the three trace metals in biota exceeded the edible safety criteria of aquatic products in China and FAO. In contrast with those before the impoundment of TGR, Hg showed a little higher, while Cd and Pb exhibited a little lower level after the impoundment. Trace metals in TGR exhibited relatively lower concentrations compared with those in reservoirs in other countries. Significant correlations were found between the Cd concentration and body size (body length and body weight) of Cyprinus carpio, as well as the Hg concentration and body size (body length and body weight) of Erythroculter ilishaeformis. As for feeding habits, there was statistically significant difference between trace metal concentrations in herbivorous, planktonic, omnivorous and carnivorous fish. However, no significant difference was found between the metal concentrations in fish with different habitats (pelagic, mesopelagic and benthic). Even so, the overall trend was that fish living in benthic layer had higher heavy metal concentrations than those in pelagic and mesopelagic zones. The regression slopes of log-Hg concentration versus delta(15)N, served as an indicator of trophic magnification factor (TMF). Significant correlations (P < 0.05) were observed for Hg in the food web of TGR. TMF of Hg in TGR indicated lower level (0.046-0.066) in contrast with those in the reservoirs of United States and Canada, and this was explained by the relatively lower organic carbon in the soil and sediment of TGR.
三峡水库（TGR）于2010年10月达到了175米的最高蓄水水位。为揭示最大水位蓄水对三峡水库典型水域重金属污染的潜在影响，于2011年7月至2012年8月对三峡水库干流生物群中痕量金属（汞、镉和铅）的含量水平及沿水生食物链的潜在生物放大作用进行了调查，同时还研究了水生消费者（鱼类和水生无脊椎动物）的痕量金属浓度与生物因子之间的关系。我们的研究表明，生物群中这三种痕量金属的单个数据均未超过中国和粮农组织的水产品食用安全标准。与三峡水库蓄水前相比，汞含量略高，而镉和铅含量在蓄水后略低。与其他国家的水库相比，三峡水库中的痕量金属浓度相对较低。发现鲤鱼的镉浓度与体型（体长和体重）之间以及翘嘴红鲌的汞浓度与体型（体长和体重）之间存在显著相关性。至于食性，草食性、浮游性、杂食性和肉食性鱼类的痕量金属浓度在统计学上存在显著差异。然而，不同栖息地（中上层、中层和底层）鱼类的金属浓度之间未发现显著差异。即便如此，总体趋势是生活在底层的鱼类重金属浓度高于中上层和中层水域的鱼类。以对数汞浓度与δ(15)N的回归斜率作为营养放大因子（TMF）的指标。在三峡水库的食物网中观察到汞存在显著相关性（P < 0.05）。与美国和加拿大的水库相比，三峡水库中汞的TMF表明其水平较低（0.046 - 0.066），这是由三峡水库土壤和沉积物中相对较低的有机碳所解释的。
