Peixoto Sara, Santos Bárbara, Lopes Graça, Dias-Pereira Patrícia, Lopes Isabel
CESAM and Department of Biology, University of Aveiro, Aveiro, Portugal.
Department of Biological and Marine Sciences, University of Hull, Hull, UK.
Environ Sci Pollut Res Int. 2022 Dec;29(60):90259-90271. doi: 10.1007/s11356-022-22037-5. Epub 2022 Jul 22.
Acid mine drainage (AMD) involves complex mixtures of metals and hydrogen ions that can be highly toxic to the biota. Assessing the effects of AMD to aquatic stages of amphibians is key, as this group constitutes the vertebrate class with the highest proportion of species considered as threatened. Thus, the present work aimed at assessing the sensitivity of two aquatic life stages of the green frog Pelophylax perezi to an AMD originated from a cupric-pyrite mine. Embryos (Gosner stages 10-11) and tadpoles (Gosner stages 20-21) of P. perezi were exposed, for 96 h, to six AMD dilutions (1.39% to 7.5%). Endpoints involving responses at different levels of biological organization were monitored: mortality, malformations, hatching rates, body length and growth rate, enzymatic activity related with detoxification metabolism (glutathione S-transferase), and histopathologies (anatomical structures of the digestive, respiratory, and excretory systems). Embryos presented high mortality and malformation rates at AMD levels equal or above 5.36%, as well as premature hatching at 1.95% of AMD or higher. A significant reduction in body length and growth rate occurred in embryos and tadpoles exposed to 1.95% or higher levels of AMD, respectively. At the histological level, several abnormalities were observed for AMD-exposed tadpoles in a variety of tissues. One of the most noticeable histological changes occurred in the intestine that exhibited papillary epithelial hyperplasia along with a yellowish content and was more pronounced in tadpoles exposed to higher AMD levels. FEmbryos were more sensitive to lethal levels of AMD than tadpoles, suggesting embryos as a useful model life stage when performing amphibian risk assessment of mine drainage. Furthermore, AMD was highly toxic for P. perezi aquatic life stages since levels as low as 1.95% induced lethal effects. These results emphasize the importance of implementing efficient remediation methodologies for AMD, given its high toxicity.
酸性矿山排水（AMD）含有复杂的金属和氢离子混合物，对生物群落可能具有高毒性。评估AMD对两栖动物水生阶段的影响至关重要，因为该类群是被视为受威胁物种比例最高的脊椎动物类别。因此，本研究旨在评估绿蛙泽陆蛙两个水生生活阶段对来自铜硫铁矿矿山的AMD的敏感性。将泽陆蛙的胚胎（戈斯纳10 - 11期）和蝌蚪（戈斯纳20 - 21期）暴露于六种AMD稀释液（1.39%至7.5%）中96小时。监测涉及不同生物组织水平反应的终点指标：死亡率、畸形率、孵化率、体长和生长率、与解毒代谢相关的酶活性（谷胱甘肽S - 转移酶）以及组织病理学（消化、呼吸和排泄系统的解剖结构）。当AMD浓度等于或高于5.36%时，胚胎表现出高死亡率和畸形率，当AMD浓度为1.95%或更高时出现过早孵化。分别暴露于1.95%或更高浓度AMD的胚胎和蝌蚪的体长和生长率显著降低。在组织学水平上，观察到暴露于AMD的蝌蚪在多种组织中出现了一些异常。最明显的组织学变化之一发生在肠道，表现为乳头状上皮增生以及黄色内容物，在暴露于较高AMD水平的蝌蚪中更为明显。胚胎对AMD致死水平比蝌蚪更敏感，这表明在进行矿山排水对两栖动物的风险评估时，胚胎是一个有用的模型生活阶段。此外，AMD对泽陆蛙的水生生活阶段具有高毒性，因为低至1.95%的浓度就会产生致死效应。这些结果强调了鉴于AMD的高毒性而实施有效修复方法的重要性。
