Department of Ecology and Environmental Science, Umeå University, SE-90187 Umeå, Sweden.
Department of Ecology and Environmental Science, Umeå University, SE-90187 Umeå, Sweden.
Sci Total Environ. 2020 Sep 10;734:139406. doi: 10.1016/j.scitotenv.2020.139406. Epub 2020 May 19.
Metal contamination of freshwater ecosystems is a great threat to aquatic insect communities. In the past, focus has been on the toxic effects on the insect larvae, despite emerging evidence showing that negative effects can occur during metamorphosis to adults. There is therefore a risk that traditional studies on insect larvae would underestimate effect from metals. In this study, we investigated the effect of lead (Pb) and zinc (Zn) on aquatic insect abundance, including metamorphosis and adult emergence at 9 lakes, near an abandoned Pb/Zn mine, with different Pb and Zn concentrations in sediment and water. Further, differences in response to metal contamination among taxa, and potential community composition changes, were also investigated. Total insect abundance was not affected by metal contamination, but Zn had a negative effect on metamorphosis and proportionally less adults emerged compared to larval abundance when the bioavailable Zn concentration in water increased. The opposite pattern was found for bioavailable Pb (negative effect on larvae but not on adult emergence). All studied insect groups had similar response to metal contamination, and no change in community structure towards dominance of more tolerant taxa was observed. Our study shows that it is important to include metamorphosis when metal toxicity is evaluated in aquatic insects, and that metals can have opposite and contradicting effects. Thus, although combined cocktail effects of metal mixtures are important to assess, effects of individual metals can be underestimated.
金属污染对淡水生态系统中的水生昆虫群落是一个巨大的威胁。过去，人们的研究重点主要集中在金属对昆虫幼虫的毒性影响上，尽管有新的证据表明，在向成虫变态的过程中也可能产生负面影响。因此，传统的昆虫幼虫研究可能低估了金属的影响。在这项研究中，我们调查了铅（Pb）和锌（Zn）对水生昆虫丰度的影响，包括在 9 个湖泊中的变态和成虫出现的情况，这些湖泊靠近一个废弃的 Pb/Zn 矿，其沉积物和水中的 Pb 和 Zn 浓度不同。此外，我们还研究了不同类群对金属污染的反应差异，以及潜在的群落组成变化。金属污染并没有影响总昆虫丰度，但随着水中可利用 Zn 浓度的增加，Zn 对变态有负面影响，与幼虫丰度相比，成虫出现的比例减少。而对于可利用的 Pb，则出现相反的模式（对幼虫有负面影响，但对成虫出现没有影响）。所有研究的昆虫类群对金属污染的反应相似，没有观察到群落结构向更耐受类群占优势的方向变化。我们的研究表明，在评估金属对水生昆虫的毒性时，将变态包括在内非常重要，而且金属可能会产生相反和矛盾的影响。因此，尽管评估金属混合物的综合鸡尾酒效应很重要，但对个别金属的影响可能会被低估。
