The Doce River basin has suffered the largest environmental accident ever occurred in Brazil with the influx of tailings from Fundão and Santarém, belonging to Samarco mining company, due to the disaster in Mariana. A spill between 50 and 60 million m3 of tailings was estimated by the company. According to Samarco, the wastewater was composed mainly of clay, silt and heavy metals like iron, copper and manganese. Thereby, the objective of the present study was evaluated the genotoxic damage in juvenile of Geophagus brasiliensis (Quoy e Gaimard, 1824) exposed to Doce river water before (DRWBA – Doce River water before acident) and after (DRWAA – Doce River water after acident) the influx of tailings from the Germano and Santarém Dam disasters in Mariana, MG, Brazil. For this, 24 individuals of the species G. brasiliensis (obtained on IFES/ALEGRE fish culture) were submitted to a bioassay with three treatments and eight replicates. The treatments were: 1) Control water (water from the urban water supply system, filtered with a 0.45 µm membrane), 2) DRBA and 3) DRAA. After 96 h, these fishes were anesthetized to remove blood for evaluation of genotoxic damage (micronucleus and comet). For the bioassay, a total of 80 L of The Doce River water were collected before the influx of tailings and after the influx and then submitted to metal quantification analysis. Fish exposed to DRWBA and DRWAA treatments showed a significant increase in both the number of erythrocyte micronuclei and the DNA damage index in relation to the control fish; however, they did not present any differences between the two treatments. The results demonstrate that the DRWBA treatment was already genotoxic for the fish, mainly due to dissolved Cu concentrations in the water. The DRWAA treatment probably presented genotoxicity due to the increase in the dissolved fraction and synergistic effects of several metals found in the tailings of the Mariana accident.

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RESUMO.-Os elementos químicos, em sua maioria, encontram-se em ciclos bioquímicos e geoquímicos fechados e em concentrações que não causam efeitos nocivos aos or- Chemical elements are mostly involved in biochemical and geochemical cycles in concentrations which are harmless for organisms. However, accelerated human actions promote environmental changes such as the increase in contaminant intake. With this information, this study aimed to characterize the presence of trace elements in two snake species common in Southeastern Brazil, Boa constrictor and Bothrops jararaca. Copies of B. constrictor (n=18) were from pedestrian accidents which occurred on Highway stretch ES-060 from Km 0 to Km 67.5. Copies of B. jararaca (n=18) were captured by farmers in a rural mountainous area of Espíirito Santo State, Brazilo. They were analyzed 1 kidney fragment grass, autopsied specimens. Harvested kidneys were digested with acid mixture (HNO3 e HCl 1:1) at 300°C, 40 min and quantification of microelementos (Cd, Co, Cr, Cu, Fe, Mn, Ni, Pb and Zn) were determined by spectrometric optical emission with inductively coupled plasma (ICP OES). significant differences between males and females were observed, except for Chrome in B. constrictor (p=0.03), with an average of 1.6595 in Cr concentration of females and 0.2896 in males. However, when different species of snakes were compared, different concentrations were found for all elements, especially iron with a concentration of 106.2mg/g in B. constrictor and 120.3mg/g in B. jararaca; probably these animals came from areas near iron ore ports. The concentration of zinc in B. constrictor was 1261.8mg/g and in B. jararaca 28,4mg/g. This study indicates that the analyzed snakes, which inhabit the regions of Greater Victoria and the mountainous region of the State of Espírito Santo have high concentrations of the microelements Zn and Fe. Concentração