Evaluation of water quality at the source of streams of the Sinos River Basin, southern Brazil.

The Sinos River Basin (SRB) is located in the northeastern region of the state of Rio Grande do Sul (29º20' to 30º10'S and 50º15' to 51º20'W), southern Brazil, and covers two geomorphologic provinces: the southern plateau and the central depression. It is part of the Guaíba basin, has an area of approximately 800 km 2 and contains 32 counties. The basin provides drinking water for 1.6 million inhabitants in one of the most important industrial centres in Brazil. This study describes different water quality indices (WQI) used for the sub-basins of three important streams in the SRB: Pampa, Estância Velha/Portão and Schmidt streams. Physical, chemical and microbiological parameters assessed bimonthly using samples collected at each stream source were used to calculate the Horton Index (HI), the Dinius Index (DI) and the water quality index adopted by the US National Sanitation Foundation (NSF WQI) in the additive and multiplicative forms. These indices describe mean water quality levels at the streams sources. The results obtained for these 3 indexes showed a worrying scenario in which water quality has already been negatively affected at the sites where three important sub-basins in the Sinos River Basin begin to form.

Integrated Environmental Assessment of streams in the Sinos River basin in the state of Rio Grande do Sul, Brazil.

The deterioration of environmental quality in the Sinos River basin is directly associated with the impacts of intense industrialization and urbanization. An integrated environmental assessment (IEA) was conducted in July and September of 2012, in areas along the sources of the EstânciaVelha/Portão, Pampa and Schmidt streams using physical, chemical and biological methods. The water in the three sampling sites was not proper for human consumption, presented a low toxic contamination index (TCI) and mesotrophic characteristics. One site was included in Class 4, and two, in Class 3, according to current legislation. The rapid assessment protocol (RAP) indicated a natural environmental condition for habitat diversity and environmental impact in the three sites. The Tradescantia pallida (Rose) D.R. Hunt var. purpurea Boom biomarker showed water genotoxicity in two of the sites. The integrated diagnosis of water quality in these streams is fundamentally important to ensure the sustainable management of water resources and their multiple uses, as well to estimate their contribution to pollution in this river basin.

Evaluation of water quality at the source of streams of the Sinos River Basin, southern Brazil / Avaliacão da qualidade da água das nascentes de arroios da Bacia do Rio dos Sinos, região sul do Brasil

The Sinos River Basin (SRB) is located in the northeastern region of the state of Rio Grande do Sul (29º20' to 30º10'S and 50º15' to 51º20'W), southern Brazil, and covers two geomorphologic provinces: the southern plateau and the central depression. It is part of the Guaíba basin, has an area of approximately 800 km 2 and contains 32 counties. The basin provides drinking water for 1.6 million inhabitants in one of the most important industrial centres in Brazil. This study describes different water quality indices (WQI) used for the sub-basins of three important streams in the SRB: Pampa, Estância Velha/Portão and Schmidt streams. Physical, chemical and microbiological parameters assessed bimonthly using samples collected at each stream source were used to calculate the Horton Index (HI), the Dinius Index (DI) and the water quality index adopted by the US National Sanitation Foundation (NSF WQI) in the additive and multiplicative forms. These indices describe mean water quality levels at the streams sources. The results obtained for these 3 indexes showed a worrying scenario in which water quality has already been negatively affected at the sites where three important sub-basins in the Sinos River Basin begin to form.

A Bacia Hidrográfica do Rio dos Sinos (BHRS) está localizada na região Nordeste do Estado do Rio Grande do Sul (29º20' to 30º10'S and 50º15' to 51º20'W), na região Sul do Brasil, envolvendo duas regiões geomorfológicas, o planalto Sul e a depressão central. Esta bacia faz parte da Bacia do Guaíba e tem uma área de aproximadamente 800 km 2, atingindo 32 municípios. A BHRS fornece água de abastecimento para cerca de 1.6 milhões de habitantes e para um dos mais importantes centros industriais do Brasil. Este artigo apresenta a determinação de diferentes índices de qualidade de água (IQA) para as regiões de nascente de três importantes sub-bacias pertencentes à BHRS: arroios Pampa, Estância Velha/Portão e Schmidt. Utilizando parâmetros físicos, químicos e microbiológicos, analisados em amostras coletadas bimestralmente em cada ponto próximo à nascente, foram calculados os índices de Horton (IH), de Dinius (ID) e o índice de qualidade de água da National Sanitation Foundation, EUA (IQANSF) usando os métodos somatório e produtório. Os resultados foram analisados para verificação da qualidade da água nos pontos amostrais a fim de comparar e classificar a água na região das nascentes das três sub-bacias. Uma avaliação conjunta dos índices calculados indicou que a água nos três pontos amostrais apresenta qualidade média. Os resultados dos três índices convergem a um cenário preocupante que indica que, desde os pontos iniciais de formação de três importantes sub-bacias do rio dos Sinos, já ocorrem problemas de qualidade de água.

Effects of nickel on the fern Regnellidium diphyllum Lindm. (Marsileaceae).

The heterosporous fern Regnellidium diphyllum occurs in southern Brazil and some adjoining localities in Uruguay and Argentina. Currently it is on the list of threatened species in the state of Rio Grande do Sul. Anthropic alterations such as the conversion of wetlands into agricultural areas or water and soil contamination by pollutants may compromise the establishment and survival of this species. Nickel (Ni) is an essential nutrient for plants but increasing levels of this metal due to pollution can cause deleterious effects especially in aquatic macrophytes. Megaspore germination tests were performed using Meyer's solution, at concentrations of 0 (control), 0.05, 0.5, 1, 5, 10, 20, 30, 50 and 100 mg L(-1) of Ni. The initial development of apomictic sporophytes was studied using solutions containing 0 (control) to 4.8 mg L(-1) of Ni. A significant negative relation was observed between the different Ni concentrations and the megaspore germination/sporophyte formation rates. Primary roots, primary leaves and secondary leaves were significantly shorter at 3.2 and 4.8 mg L(-1) of Ni, when compared with the treatment without this metal. At 4.8 mg L(-1), leaves also presented chlorosis and necrosis. The introduction of pollutants with Ni in the natural habitat of Regnellidium diphyllum may inhibit the establishment of plants in the initial stage of development, a problem to be considered in relation to the conservation of this species.

Germination and sporophytic development of Regnellidium diphyllum Lindman (Marsileaceae) in the presence of hexavalent chromium.

Regnellidium diphyllum Lindman is a heterosporous fern, growing in aquatic environments and surrounding wetlands, which is assumed to be threatened by increasing water pollution and disappearance of its natural habitats. Among contaminants, hexavalent chromium - Cr(VI) - is known to be present in effluents from some leather tanning factories. Megaspore germination tests were performed using Meyer's solution, at concentrations 0 (control), 0.1, 0.5, 1, 5, 10, 15, 20, 30, 50, and 80 mg.L⁻¹, from a standard solution of Titrisol® 1000 mg.L⁻¹. The primary development of apomictic sporophytes was studied using solutions containing 0.025 to 4.8 mg.L⁻¹ of Cr(VI). The experiments were conducted in a growth chamber at 24 ± 1 ºC and for a 12-hour photoperiod under fluorescent lights, providing a nominal irradiance of 77 µmol.m⁻²/s. Significant differences in megaspore germination, with subsequent sporophytic development, were verified from 0.5 mg.L⁻¹ Cr(VI) concentration onwards. Growth of primary root and primary and secondary leaves was significantly reduced at 3.2 mg.L⁻¹ Cr(VI) concentration or higher. Considering the pollution from Cr(VI) in some areas of R. diphyllum natural occurrence, these data indicate that low reproductive rates and disappearance of populations are likely to occur in these situations.