Biofilms can be used as a biomonitoring tool to determine metal bioavailability in streams affected by mining and other anthropogenic activities. Surface water and biofilm were sampled over two years from rivers located in the vicinity of a mine located in a Nordic ecosystem (Nunavik, Quebec). Biofilm metal content (Cd, Cu, and Ni) as well as a variety of physicochemical properties were determined to examine relationships between metal accumulation and water quality. Among the three metals of interest, copper and nickel had the highest levels of accumulation and cadmium had the lowest. When considering the exposure levels, nickel was the most abundant metal in our sampling sites. Both exposure and accumulation levels were consistent over time. Biofilm metal content was highly correlated to the ambient free metal ion concentration for sites of circumneutral pHs for all three metals. When the surface water pH was below 6, biofilm metal content was much lower than at other sites with similar aqueous metal concentrations of exposure. This apparent protective effect of decreasing pH can be explained by proton competition with dissolved metals for uptake binding sites at the surface of the organisms within the biofilm as described by the Biotic Ligand Model principles. The relationships obtained for Cd and Cu were overlapping those observed in previous publications, indicating strong similarities in metal accumulation processes in biofilms over very large geographical areas. Although more data are needed for Ni, our results show that biofilms represent a promising metal biomonitoring tool.

中文翻译：

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质子竞争和自由离子活动推动北欧生态系统中河流生物膜中镉，铜和镍的积累

生物膜可以用作生物监测工具，以确定受采矿和其他人为活动影响的河流中金属的生物利用度。两年来，从位于北欧生态系统（魁北克努纳维克）矿山附近的河流中抽取了地表水和生物膜。确定了生物膜中的金属含量（Cd，Cu和Ni）以及各种物理化学性质，以检查金属积累与水质之间的关系。在感兴趣的三种金属中，铜和镍的累积量最高，而镉的最低。考虑到暴露水平，镍是我们采样点中含量最高的金属。随着时间的推移，暴露水平和积累水平均保持一致。对于所有三种金属而言，生物膜中的金属含量与周围pH值的周围环境中的游离金属离子浓度高度相关。当地表水的pH值低于6时，生物膜中的金属含量远低于其他暴露于相似的含水金属浓度的位置。如Biotic Ligand Model原理所述，质子与溶解的金属竞争吸收生物膜内生物表面上结合位点的现象，可以解释这种降低pH值的明显保护作用。Cd和Cu的关系与先前出版物中观察到的关系重叠，表明在非常大的地理区域内生物膜中金属积累过程的强烈相似之处。尽管Ni需要更多的数据，但我们的结果表明生物膜代表了一种有前途的金属生物监测工具。