Adapting an enzymatic toxicity test to allow comparative evaluation of natural freshwater biofilms' tolerance to metals
Adapting an enzymatic toxicity test to allow comparative evaluation of natural freshwater biofilms' tolerance to metals
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DOI：
10.1007/s10646-010-0517-9
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发表时间：
2010-10-01
期刊：
影响因子：
2.7
通讯作者：
Tusseau-Vuillemin, Marie-Helene
中科院分区：
文献类型：
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作者：
Fechner, Lise C.;Gourlay-France, Catherine;Tusseau-Vuillemin, Marie-Helene
为研究城市金属对天然淡水围生植物群落的影响，开发了一种简单、低成本、无放射性的短期毒性试验。以现场采集的天然淡水生物膜的β-葡萄糖苷酶活性为终点。金属(Cd、铜、镍、铅和锌)在暴露1小时后成功地抑制了细菌的酶活性，从而能够计算EC(50)。生物膜样品的EC(50)值随生物膜悬浮液的总悬浮固体浓度(TSS)而变化，表明EC(50)值(以添加金属的总浓度表示)不能代表毒性试验期间生物可利用金属的浓度。对于铜、镉、镍、锌和铅，EC(50)值随TSS浓度线性增加，从而定义了归一化EC(50)：EC(50)值除以相应的TSS浓度。归一化EC(50)被证明是一种稳健、可靠的方法来评估生物膜对Cd、铜、镍、锌和铅的耐受性。得到的归一化EC(50)，以kg(金属)/g(TSS)表示，在0.2到7.6之间变化，Cd在1到8之间，镍在1.8到92.3之间，锌在1.8到76.6之间，铅在25到189之间。
A simple, low-cost and non-radioactive short-term toxicity test was developed to study the effects of urban metals on natural freshwater periphytic communities. beta-glucosidase activity of natural freshwater biofilms collected in situ was chosen as an endpoint. Metals (Cd, Cu, Ni, Pb, and Zn) successfully inhibited bacterial enzymatic activity after a 1-h exposure enabling the calculation of EC(50). The EC(50) value of a biofilm sample varied with the Total Suspended Solids concentration (TSS) of the biofilm suspension, showing that EC(50) values (expressed as total added metal concentrations) are not representative of the bioavailable metal concentration during the toxicity test. For Cu, Cd, Ni, Zn and Pb, the EC(50) values increased linearly with the TSS concentration leading us to define a normalized EC(50): the value of the EC(50) divided by the corresponding TSS concentration. Normalized EC(50) proved to be a robust, reliable way to assess metal tolerance of a biofilm for Cd, Cu, Ni, Zn and Pb. Normalized EC(50) obtained, expressed as kg(metal)/g(TSS), varied between 0.2 to 7.6 for Cu, 1 to 8 for Cd, 1.8 to 92.3 for Ni, 1.8 to 76.6 for Zn and 25 to 189 for Pb.