Fish communities' organisation is a challenging task due to global, local and temporal variations related to biotic and abiotic factors, highlighting anthropic activities. The Verde River Basin (VRB) was chosen as a model to the fish community study due to its complexity, presenting a longitudinal gradient of degradation. The ichthyofauna and abiotic factors were sampled during twelve months in four sites. Analyses employed rarefaction curves with Hill numbers estimators and canonical correspondence analysis. The endemic Apareiodon sp. (not described), Hypostomus albopunctatus, H. strigaticeps, Oligosarcus paranensis, Neoplecostomus yapo and Trichomycterus diabolus were associated with structurally complex and well-preserved environments. In contrary, Astyanax aff. fasciatus, Corydoras ehrhardti, Geophagus brasiliensis, H. ancistroides and Phalloceros harpagos showed tolerance to impacted environments. The methods here employed allowed to identify and explain differences in the ichthyofauna structure, distinguishing the influence of spatial, temporal and human effects on the fish communities. K E Y W O R D Sabundance, anthropic impacts, diversity, entropy, lotic system | 1127 SILVEIRA Et AL.

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In this article, we report the results of the work carried out on the Verde River, a predominantly urban river located in the city of Ponta Grossa, Paraná, Brazil. Developed in three stages, it aimed to evaluate the water quality through physical-chemical parameters, the presence of caffeine as a chemical tracer, and the compound Triclosan (TCS), considered a pollutant of emerging concern. An attempt was made to identify possible polluting sources along the river. Samples were collected at 4 points from the spring region, with sampling upstream and downstream of a Sewage Treatment Plant (STP). The physical-chemical parameters were determined in situ, through portable analysers, as well as in the laboratory, in this case, through analyses using molecular absorption spectroscopy. For the determination of TCS and Caffeine, high-performance liquid chromatography (HPLC) was used, preceded by a pre-concentration step in the solid phase (SPE), and the techniques were implemented after validation. The physicochemical evaluations of the surface samples showed a decline in water quality after the STP. Mean total phosphorus concentrations of 1.0 mg•L −1 (±0.4), as well as dissolved oxygen (DO) levels below 5.0 mg•L −1 were verified downstream of the STP. Caffeine concentrations for Verde River were between 49.0 to 299.0 µg•L −1 , verified upstream and downstream of the STP. The results demonstrated the relationship between the presence of caffeine and impaction, either by the input of raw sewage or by treated effluent. TCS was detected by chromatographic analysis, downstream of the STP, with an average concentration of 27.6 (±1.

The objective of this work was to evaluate the physicochemical parameters that express the water quality of the Rio Verde, in the city of Ponta Grossa, Paraná. Multivariate Analysis was used, and quality indexes were obtained, such as the Trophic State Index and the Water Quality Index for Aquatic Life Protection. River samples were collected at 4 points along the  Rio Verde for 12 months. The study showed that the river presents a high trophic degree, and that it can be considered hypereutrophic, and that phosphorus concentration is determinant for this situation. The results indicated that, at point 4, downstream from the Sewage Treatment Plant, the aquatic environment is very poor for the biota. The disposal of the effluent was indicated as the cause, and it is assumed that the river has no flow capacity  to receive this contribution, without suffering impact. It was also concluded that points 1 and 2 correspond to more preserved sites, but are not totally favorable to aquatic life either because they receive surface drainage from agricultural areas in the basin. Point 3, of urban character, suffers an impact caused by irregular connections of sewers, and contribution of streams that flow into the river.