This research aimed at developing the Trophic Water Quality Index (TWQI) for subtropical temperate Brazilian lotic systems based on a review of the indicative values of diatom species obtained using multivariate analysis techniques and considering the environmental gradient defined by a series of measured physical, chemical, and microbiological variables. Sampling was conducted from 2005 to 2009 in the Pardo River Hydrographic Basin, Rio Grande do Sul (RS), Brazil, and in the Andreas Stream Hydrographic Basin, RS, from 2012 to 2013. A total of 140 biological samples and 211 abiotic samples were collected. Data were analyzed by cluster analysis based on the Ward method and canonical correspondence analysis (CCA). The results indicated that total phosphate, turbidity, ammonia nitrogen, electrical conductivity, dissolved oxygen, and thermotolerant coliforms showed a significant correlation with the sample ordination made by CCA, in relation to a gradient of eutrophication. Eutrophication was operationally defined in a broad sense, including the problem of organic pollution and eutrophication of the water. The determination of the different tolerance degrees to eutrophication of the diatom taxa was used to assign trophic values of 1, 2.5, and 4 to species, corresponding to levels of low, medium, and high tolerance, respectively. By using the trophic values obtained for each diatom species, the TWQI constituted a new technological tool for environmental monitoring studies and showed a consistent, robust, and objective database for water quality assessment in subtropical temperate Brazilian lotic systems.

The Castelhano Stream Hydrographic Basin, located in the city of Venâncio Aires, RS, Brazil, shows an area of 675.3 km 2 , highlighting the Castelhano Stream as their main water course. The stream is the main responsiblity for the local water supply; however, there are no published studies in the literature regarding their water quality. In this context, the present research aimed to assess the water quality of Castelhano Stream in terms of organic pollution and eutrophication, applying the Biological Water Quality Index (BWQI), which uses epilithic diatoms communities as bioindicators. Biological samples were collected at three sampling stations along the stream in the months of September, November and December 2012. The results showed 81 identified species, distributed in 30 genera. The water pollution levels detected ranged from "strong" (66.7%) and "very strong" (33.3%), with differences in species composition between sampling stations. The sampling station S1 in the upper reaches was characterized by the presence of indicative species of acidophilus and lentic environments with large amounts of organic matter. The sampling stations S2 and S3, in the intermediate and lower reaches, respectively, showed a substitution of species in the community, with the presence of highly tolerant taxa to organic pollution and eutrophication. The high pollution levels detected along the basin are related to the nutrients and high organic load originating from livestock, domestic and industrial waste, as well as excess fertilizers and agricultural inputs used in farming. The results demonstrate the necessity to implement mitigation measures to contain the processes of organic pollution and eutrophication detected due to the dangers offered to public health and the environment.

AIM: This study aimed to assess the quality of water and sediment of urban streams (Lajeado, Preto, Pedras and Lewis-Pedroso) located in Santa Cruz do Sul County, RS, Brazil, using the microcrustacean Ceriodaphnia dubia as test-organism. METHODS: Quarterly scientific excursions to the streams were held on August and November 2011, February and May of 2012 in order to collect water and sediment samples, in the upper reaches (P1, P3, P5, P7) and lower reaches (P2, P4, P6, P8), totalizing 8 points. To evaluate the toxicity (acute and chronic), the microcrustacean C. dubia was used. RESULTS AND CONCLUSION: The results indicated high toxicity levels detected in samples P2, P6 and P8 (lower reaches), as they caused the mortality of 100% of organisms in the water samples (P6 and P8) and sediment samples (P2 and P8), denoting acute effect. Yet, all upstream sites showed chronic effects in sediment samples, at least for one collection period, with the highest significant toxicity level among all samples (55.2%), which indicates the presence of contamination even in upper areas. These results indicated a strong degradation of the water and sediment quality of urban streams coming from the wastewater and industrial discharges of the urban area, which can cause damage to the biota as well as the public health, due to the multiples uses of water that the local population does, highlighting many of them as inappropriate to the water quality detected, such as the primary contact recreation (balneability).

Informação científica atualizada sobre comunidades de aves é essencial para permitir uma avaliação ambiental das condições necessárias para manter a biodiversidade local, como forma de evitar extinções futuras e garantir a integridade dos ecossistemas. Áreas com ambientes de mata e áreas abertas podem contribuir para a manutenção das aves em ambientes urbanos, destacando o papel de parques, áreas verdes e campi universitários que podem atuar como “ilhas” e corredores de grande importância como locais de abrigo e alimentação. Neste contexto, o presente estudo teve por objetivo realizar um levantamento qualitativo das espécies de aves que ocorrem no Campus Universitário da UNISC, zona urbana do município de Santa Cruz do Sul, RS, Brasil. O inventário de campo foi realizado entre janeiro a dezembro de 2013. Seis transectos foram percorridos (três com fragmentos florestais e três em área abertas). As amostragens foram realizadas no período matutino e vespertino, e as espécies foram identificadas pela morfologia externa e reconhecimento de suas vocalizações. Os resultados indicaram a ocorrência de 101 espécies de aves pertencentes a 38 famílias, o que representa 15,3 % das espécies registradas para o Rio Grande do Sul. Em relação à estrutura trófica, oito guildas ecológicas foram identificadas, destacando as espécies com hábitos alimentares insetívoros e onívoros como as mais representativas, 46,5% e 21,8%, respectivamente. 13 espécies migratórias Neotropicais foram registradas. Não foram observadas espécies ameaçadas de extinção. Os resultados indicaram que apesar da ocorrência de espécies predominantemente generalistas, o campus universitário serve como área de abrigo, além de descanso e alimentação.

AIM: The main objective was to evaluate the efficiency of the sewage treatment plant (STP) of UNISC, through the ecotoxicological characterization and the analyses of the physical, chemical and microbiological variables from the raw and treated effluent. METHODS: Samples were collected during 2008 and 2009 for performing acute toxicity (Daphnia magna), chronic toxicity (Ceriodaphnia dubia), as well as the determination of environmental variables. RESULTS: The results indicated acute toxicity with an EC(I)50 48 hours average of 64.1 ± 9.9%, characterized as moderately toxic, and an average chronic toxicity CI(I)25 of 8,1 ± 2.6%, characterized as highly toxic. The total phosphorus (3.6 ± 1.4 mg L-1) and the ammonia nitrogen (77.8 ± 22.5 mg L-1) showed high concentration in the treated effluent, highlighting the STP inefficiency and, specially, the large amount of nutrients that the system is introducing into the receiving waterbody, the Lajeado Stream, condition that characterizes a large potential environmental impact known as eutrophication. The treated effluent showed high levels of thermotolerant coliforms, reaching an average of 6.4 × 10(5) ± 8.6 × 10(5) NMP 100 mL-1, corresponding to a potential pollution load of high impact in the receiving waterbody, characterizing therefore a public health problem. CONCLUSIONS: The Lajeado Stream has no supporting capacity for preventing acute and chronic effects on biota.