Wildfires are an environmental concern due to the loss of forest area and biodiversity, but also because their role as drivers of freshwater systems contamination by metals. In this context, the fish Gambusia holbrooki was used as a model, deployed for in situ exposure in watercourses standing within a recently burnt area and further assessment of toxic effects. The fish were exposed during 4 days at four different sites: one upstream and another downstream the burnt area and two within the burnt area. Biochemical biomarkers for oxidative stress and damage were assessed. The extent of lipoperoxidative damage was monitored by quantifying malondialdehyde and DNA damage evaluated through erythrocyte nuclear abnormalities observation. Chemical analysis revealed higher metal levels within the burnt area, and exposed fish consistently showed pro-oxidative responses therein, particularly an increase of gill glutathione peroxidase and glutathione reductase activity, the records doubling compared to samples from sites in the unburnt area; also the activity of glutathione-S-transferases comparatively increased (by 2-fold in the liver) in samples from the burnt area, and malondialdehyde was produced twice as much therein and in samples downstream the burnt area reflecting oxidative damage. Consistently, the frequency of erythrocyte nuclear abnormalities was higher at sites within and downstream the burnt area. This study supports the use of sensitive oxidative stress and genotoxicity biomarkers for an early detection of potentially noxious ecological effects of wildfires runoff.

由于森林面积和生物多样性的丧失，野火是一个环境问题，也是因为它们作为淡水系统被金属污染的驱动因素。在这种情况下，鱼Gambusia holbrooki被用作模型，部署用于在最近被烧毁的区域内的水道中进行原位暴露，并进一步评估毒性效应。这些鱼在四个不同的地点暴露了 4 天：一个在燃烧区域的上游，另一个在燃烧区域的下游，两个在燃烧区域内。评估了氧化应激和损伤的生化生物标志物。通过量化丙二醛和通过红细胞核异常观察评估的 DNA 损伤来监测脂质过氧化损伤的程度。化学分析显示，燃烧区域的金属含量较高，暴露的鱼始终表现出促氧化反应，尤其是鳃谷胱甘肽过氧化物酶和谷胱甘肽还原酶活性增加，与未燃烧区域的样本相比，记录翻了一番；此外，来自烧伤区域的样品中谷胱甘肽-S-转移酶的活性相对增加（在肝脏中增加了 2 倍），其中和烧伤区域下游的样品中产生的丙二醛是氧化损伤的两倍。始终如一地，在烧伤区域内和下游的部位，红细胞核异常的频率更高。这项研究支持使用敏感的氧化应激和基因毒性生物标志物来及早检测野火径流的潜在有害生态影响。在烧伤区域内和下游的部位，红细胞核异常的频率较高。这项研究支持使用敏感的氧化应激和基因毒性生物标志物来及早检测野火径流的潜在有害生态影响。在烧伤区域内和下游的部位，红细胞核异常的频率较高。这项研究支持使用敏感的氧化应激和基因毒性生物标志物来及早检测野火径流的潜在有害生态影响。