Namba Hiroki, Iwasaki Yuichi, Morita Kentaro, Ogino Tagiru, Mano Hiroyuki, Shinohara Naohide, Yasutaka Tetsuo, Matsuda Hiroyuki, Kamo Masashi
Graduate School of Environment and Information Sciences, Yokohama National University, Yokohama, Kanagawa, Japan.
Nippon Koei, Tokyo, Japan.
PeerJ. 2021 Jan 27;9:e10808. doi: 10.7717/peerj.10808. eCollection 2021.
Researchers have long assessed the ecological impacts of metals in running waters, but few such studies investigated multiple biological groups. Our goals in this study were to assess the ecological impacts of metal contamination on macroinvertebrates and fishes in a northern Japanese river receiving treated mine discharge and to evaluate whether there was any difference between the metrics based on macroinvertebrates and those based on fishes in assessing these impacts. Macroinvertebrate communities and fish populations were little affected at the downstream contaminated sites where concentrations of Cu, Zn, Pb, and Cd were 0.1-1.5 times higher than water-quality criteria established by the U.S. Environmental Protection Agency. We detected a significant reduction in a few macroinvertebrate metrics such as mayfly abundance and the abundance of heptageniid mayflies at the two most upstream contaminated sites with metal concentrations 0.8-3.7 times higher than the water-quality criteria. There were, however, no remarkable effects on the abundance or condition factor of the four dominant fishes, including masu salmon (). These results suggest that the richness and abundance of macroinvertebrates are more sensitive to metal contamination than abundance and condition factor of fishes in the studied river. Because the sensitivity to metal contamination can depend on the biological metrics used, and fish-based metrics in this study were limited, it would be valuable to accumulate empirical evidence for ecological indicators sensitive to metal contamination within and among biological groups to help in choosing which groups to survey for general environmental impact assessments in metal-contaminated rivers.
长期以来，研究人员一直在评估河流水体中金属的生态影响，但很少有此类研究调查多个生物类群。我们这项研究的目的是评估金属污染对日本北部一条接收矿山处理后废水排放的河流中的大型无脊椎动物和鱼类的生态影响，并评估在评估这些影响时，基于大型无脊椎动物的指标和基于鱼类的指标之间是否存在差异。在美国环境保护局制定的水质标准基础上，铜、锌、铅和镉的浓度在下游受污染地点高出0.1 - 1.5倍，而大型无脊椎动物群落和鱼类种群受影响较小。在最上游的两个受污染地点，金属浓度比水质标准高出0.8 - 3.7倍，我们检测到一些大型无脊椎动物指标显著下降，如蜉蝣数量和七鳃蜉蝣数量。然而，对包括马苏大麻哈鱼在内的四种主要鱼类的数量或状况因子没有显著影响。这些结果表明，在所研究的河流中，大型无脊椎动物的丰富度和数量对金属污染比鱼类的数量和状况因子更敏感。由于对金属污染的敏感性可能取决于所使用的生物指标，并且本研究中基于鱼类的指标有限，积累生物类群内部和之间对金属污染敏感的生态指标的经验证据，对于帮助选择在金属污染河流中进行一般环境影响评估时调查哪些生物类群将具有重要价值。
