大沙河水库微囊藻水华期间重金属在食物链中的传递特征

Characteristic of Metals Trophic Transfer in Food Web in Microcystis spp Bloom Period from Dasa River Reservoir

为了解大沙河水库微囊藻水华期间重金属在食物链中的传递特征,于2016年5月对出现肉眼可观的轻度微囊藻水华的大沙河水库的进行微囊藻,浮游动物,鱼类采集,通过测定其重金属(Fe、Cr、Cd、Pb、Ni、Cu、Zn、Mn、Co),并结合水体中相关水质参数,探讨大沙河水库微囊藻水华期间重金属在食物链中的传递和富集特征。结果表明:微囊藻Fe、Mu、Zn、Cu含量较高,平均值分别为616.78 mg/kg,24.88 mg/kg,72.19 mg/kg,24.88 mg/kg,32.44 mg/kg,重金属的富集系数最低值为7.1×10~2,其主要根源是由于水库环境中,富营养化水平水间接影响微囊藻对Fe、Mu、Zn、Cu的富集。蓝藻对Cd、Cr、Pb毒性元素的富集含量超过国家食品安全标准,它们的富集系数为平均值6.52×105,且表明低浓度毒性金属元素对生物体的危害风险高于有益元素;大沙河水库蓝藻水华期间,重金属在食物链中的传递特征浮游生物>鱼类,其主要原因是,本研究所采集得到的鱼类都是未成熟鱼体,个体小,在蓝藻水华期间,并未大量摄食蓝藻及浮游动物为食,从而导致其体内重金属含量较低。

Microcystis spp., zooplankton and fish were collected at Microcystis spp bloom period from Dasa River Reservoir in May, 2016 in order that characteristic of metals trophic transfer in food web can be understood. Metals （Fe, Cr, Cd, Pb, Ni, Cu, Zn, Mn, Co ） in zooplankton water quality parameters were determined. Our study showed there is high concentrations of metals （Fe, Cu, Zn, Mn） in Microcystis spp., with average mean 616.78 mg/kg,24.88mg/kg, 72.19mg/kg, 24.88mg/kg and 32.44mg/kg respectively. The lower of coefficient metals bioaccumulation was7.1 ×10^2, it main may reason was Fe, Cu, Zn, Mn of Microcystis spp was impacted by water eutrophic in reservoir environment. A high level ofCd, Cr, Pb in Microcystis spp. was found, its coefficient with average mean 6.52 ×10^5. the result showed a low concentration of metals in water means a higher bioaccumulation factor BAF and a higher ecological risk more than essential metals. Characteristic of metals transfer in food web was order zooplankton〉 fish. main may reason collected sample fish were small individual and immaturity, and a lots of Microcystis spp and zooplankton were not ingested by fish so that lower concentration metals was found in fish tissue.