Microcystins (MCs) are hepatotoxins that have been considered to be a worldwide problem due the effects that they can cause to environmental and human health systems. The Iraí Reservoir, located in the South of Brazil, is used as a water supply and MCs concentrations have been reported in this ecosystem. This study aims to determine the MCs concentrations in the Iraí Reservoir and to evaluate the MCs depuration time and the health of Geophagus brasiliensis using biomarkers. Water and fish samples were collected in the Iraí Reservoir from August 2015 to May 2016. Phytoplankton and chemical analyses were conducted using water samples and the fish were divided into two groups; the Immediate Group (IMM) and the Depuration Group (DEP). In the IMM group, the blood, liver, muscle, brain and gills were collected, in order to evaluate the genotoxic, biochemical and chemical biomarkers. The DEP group was used in the depuration experiment for 90 days, and after this period the fish were submitted to the same procedure as the IMM group. Our results suggested that fish accumulated MCs and it may have caused oxidative stress, neurotoxicity and molecular damage. Furthermore, MCs concentrations increased during the depuration time and it resulted in molecular damage over the first 30 days. After 90 days, the recovery of the antioxidant system occurred. The depuration started on the 15th day, however, the toxins were still present in the samples. Therefore, the effects and the persistence of MCs are a risk to environmental systems and human health.

微囊藻毒素（MC）是肝毒素，由于它们可能对环境和人类健康系统造成影响，因此被认为是全球性的问题。位于巴西南部的伊拉克水库被用作供水，并且据报道该生态系统中的MC浓度较高。这项研究旨在确定伊拉克水库中的MC浓度，并评估MC净化时间和巴西格氏噬菌体的健康状况。使用生物标志物。从2015年8月至2016年5月在伊拉克水库中收集了水和鱼样本。使用水样本进行了浮游植物和化学分析，并将鱼分为两组。直接小组（IMM）和净化小组（DEP）。在IMM组中，收集了血液，肝脏，肌肉，大脑和g，以评估其遗传毒性，生化和化学生物标志物。DEP组在净化实验中使用了90天，在此之后，将鱼接受与IMM组相同的程序。我们的研究结果表明，鱼类体内积累了MC，可能引起氧化应激，神经毒性和分子损伤。此外，MCs浓度在净化期间会增加，并在开始的30天内导致分子损伤。90天后，发生了抗氧化剂系统的恢复。净化开始于第15天，但是样品中仍存在毒素。因此，多氯联苯的影响和持久性对环境系统和人类健康构成威胁。