The present study shows the physical and chemical parameters collected in an urban river in the Eastern Amazon, they present the characteristics of the waters in the Neblina stream, which has its basin inserted in an urban center, in the city of Araguaína - TO. Therefore, the present study aims to investigate the water quality parameters of that stream, and thus allow deductions about the causes and effects of these changes. In this stream, sampling points were listed that contemplate environments from the springs to its mouth. Being, the quality of its waters, evaluated in two stages that envision two seasons (dry and rainy), respectively, August 2020 and March 2021. Adding a total of six sampling points, systematically visited in both seasons described, making up 12 samples, for all parameters analyzed here. In this way, the samples were explored in order to find values for the parameters: In Situ (Turbidity by turbidimeter; Dissolved oxygen; Electrical conductivity; Water temperature; Air temperature; pH); and Ex Situ (BOD; COD; Nitrogen series; Phosphate series; Fecal coliforms; Chlorophyll-α; Heavy metals). The parameters showed similar variations between the sampling points, with a notable data discrepancy between the mouth and head of the Neblina stream. These results show that there are higher concentrations for these parameters, directly related to the length of the route in the urban environment. Indicating a possible impact on the existing fauna and flora, which may conjecture a plausible toxicity and risks to organisms, as an admissible threat to biodiversity.

Even though the herpetofauna richness in the Cerrado – a vast tropical savanna ecoregion of Brazil – is one of the highest of all Brazilian biomes, it still needs to be thoroughly investigated. This study reports the first records of the emerald-eyed tree frog (Boana crepitans), amazon waterfrog (Lithobates palmipes), star-fingered frog (Pipa pipa), and hemprich’s coral snake (Micrurus hemprichii hemprichii) within the states of Maranhão in the northeastern region and Tocantins in the northern region of Brazil. The first state records of Boana crepitans, Pipa pipa and Micrurus h. hemprichii in Tocantins, and Lithobates palmipes in Maranhão, appear in highly climatically suitable areas within the Species Extent of Occurrences (EOO), as predicted in Ecological Niche Modelling (ENM). Our new records of Pipa pipa and Micrurus h. hemprichii, compared to the ENM predictions, represent their southeastern distributional range limits. Our results also suggest that the current gaps on the distributional species ranges probably result from the lack of herpetological surveys in those regions.

Este estudo apresenta os resultados da diversidade de peixes em um trecho do Rio dos Bois, um manancial de Cerrado, localizado no noroeste do Goiás, Brasil. Sendo um importante tributário das cabeceiras do rio Araguaia, bacia Araguaia-Tocantins, que possui importantes atributos na manutenção da biota deste complexo ecossistema, e parte deste mosaico do Cerrado. A região estudada, compreende a calha principal do Rio dos Bois, da sua cabeceira até a foz do Rio Formiga. As amostragens da ictiofauna foram efetuadas ao longo de duas estações climáticas da região (seca e chuvosa), realizadas em junho/2021 e novembro/2021, respectivamente. As amostragens foram realizadas em 5 pontos amostrais, distribuídos equidistantes de montante à jusante, no Rio dos Bois. Como resultado registrou-se 15.645 espécimes distribuídos em uma riqueza de 46 espécies. Neste estudo, os resultados foram avaliados por testes ecológicos, tais como, frequência de ocorrência, Dominance_D, Simpson_1-D, Shannon_H’, Evenness_e^H/S, Brillouin, Menhinick, Margalef, Equitability_J, Fisher_alpha, Berger-Parker e Chao-1. E analisados pelo teste de normalidade no Tukey test e ANOVA-One way. Sendo possível identificar os locais amostrais mais diversos, assim como os pontos que apresentaram divergência entre alta taxa de captura e baixa diversidade. Indicando que, alguns sítios apresentam maior importância de conservação que outros, vislumbrando futuras ações prioritárias a preservação ambiental.

In this study, the health and well-being of fish species Salminus hilarii, in a stretch of a headwater river in the Araguaia River basin - Tocantins, Goiás State, were evaluated. Where the objective was to identify and measure the hematological parameters (erythrogram, thrombogram and leukogram of the referred species). The specimens (n = 50) were captured using fishing nets and cast nets. Blood samples were collected by caudal puncture. The hematological data were obtained according to the methodology described in the classic bibliography. Based on the results of the hematological analysis, the relationship between them and their collection area was obtained, as well as the analyzes by microscopy in the search for morphological (genotoxic) alterations, in the micronuclei. Changes or variations in these parameters can be used as indicators of environmental contamination since these animals are inserted in the environment. Thus, the immune responses presented by the analyzed specimens where the difference between the results of these parameters, as well as the presence of genotoxic markers, are indicative of changes in the studied river water quality.

This study was conducted in dos Bois River, Araguaia-Tocantins basin, investigating the connections between physical and chemical conditions, fish diversity and well-being of Salminus hilarii in the Cerrado of northwestern Goiás. The research covered five sampling points, from upstream, before the waste from a mining company, to downstream, where it meets a tributary, in two stages: dry and rainy seasons. Dissolved oxygen, electrical conductivity, water and air temperatures, pH, BOD, COD, nitrogen series, phosphate series, fecal coliforms, chlorophyll-α and heavy metals were analyzed, according to Conama Resolution 357. The results show a relationship between the parameters analyzed and the effects on the organisms studied, with distinct data between upstream and downstream, linked to the proximity of agricultural and industrial areas. S. hilarii, through its morphological changes, evidences the intense exploitation of the Cerrado. The results suggest the need for priority actions to preserve biological diversity in the region.