The Sinos River basin is located Northeast of the state of Rio Grande do Sul (29° 20' to 30° 10' S and 50° 15' to 51° 20' W), Southern Brazil, covering two geomorphologic provinces: the Southern plateau and central depression. It is part of the Guaíba basin and has an area of approximately 800 km 2 , encompassing 32 municipalities. The objective of this study was to monitor water quality in the Sinos River, the largest river in this basin. Water samples were collected at four selected sites in the Sinos River, and the following parameters were analysed: pH, dissolved oxygen, biochemical oxygen demand (BOD 5 ), turbidity, fecal coliforms, total dissolved solids, temperature, nitrate, nitrite, phosphorous, chromium, lead, aluminum, zinc, iron, and copper. The results were analysed based on Resolution No. 357/2005 of the Brazilian National Environmental Council (CONAMA) regarding regulatory limits for residues in water. A second analysis was performed based on a water quality index (WQI) used by the Sinos River Basin Management Committee (COMITESINOS). Poor water quality in the Sinos River presents a worrying scenario for the region, since this river is the main source of water supply for the urban core. Health conditions found in the Sinos River, mainly in its lower reaches, are worrying and a strong indicator of human activities on the basin.Keywords: Sinos River, water resources, water quality. Avaliação da qualidade da água do Rio dos Sinos ResumoA Bacia Hidrográfica do Rio dos Sinos localizada a nordeste do Estado do Rio Grande do Sul, entre as coordenadas geográficas de 29° 20' a 30°10' de latitude Sul e de 50° 15' a 51° 20' de longitude Oeste. As províncias geomorfológicas abrangidas são o planalto meridional e a depressão. Compondo a Região Hidrográfica do Guaíba, ocupa, aproximadamente, uma área de 800 km 2 , abrangendo 32 municípios. O objetivo deste trabalho foi monitorar a qualidade da água do rio dos Sinos, principal rio da bacia hidrográfica do rio dos Sinos. Foram realizadas coletas em quatro pontos selecionados do rio, sendo realizadas análises de pH, oxigênio dissolvido, demanda bioquímica de oxigênio (DBO 5 ), turbidez, coliformes fecais, sólidos dissolvidos totais, temperatura, nitrato, nitrito, fosfato, cromo, chumbo, alumínio, zinco, ferro e cobre. Os resultados do trabalho foram analisados com base na resolução CONAMA nº 357 de 2005 em relação a suas restrições de uso. Outra análise foi feita empregando o Índice de Qualidade das Águas (IQA), índice usado pelo comitê de gerenciamento desta bacia (COMITESINOS). A baixa qualidade da água do rio dos Sinos observada deslumbra um cenário preocupante para a região que usa este rio como a principal fonte de abastecimento público. As condições sanitárias encontradas no rio dos Sinos, principalmente no trecho inferior, são preocupantes sendo forte indicativo das atividades antrópicas na bacia.Palavras-chave: Rio dos Sinos, recursos hídricos, qualidade da água.

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Polyaniline ͑PANi͒ and poly͑1,5-diaminonaphthalene͒ ͑PDAN͒ films can be deposited on iron from aqueous sulfuric acid. The films exhibit electroactive properties similar to those of PANi and PDAN generated on platinum. Electrosynthesis performed in the presence of both monomers leads to a composite film which presents excellent adhesion properties on iron. The composite film imparts a form of anodic protection for at least 9 days in pH 4 sulfate medium. Many corrosion control methods use coatings and conversion layers which contain toxic and environmentally hazardous materials, in particular, metal oxides such as chromate and phosphate. There is a great need to find a nontoxic replacement, and for the last 20 years, a great deal of attention has been devoted to organic polymers which could be used as primer coats. These polymers can be deposited on oxidizable metals by electropolymerization and are either insulating or conductive. The insulating coatings could act as diffusion barriers. [1][2][3][4][5] This is the case of poly͑phenylene oxide͒ type films studied in our laboratory.1-4 The ''functionalized polymer'' films obtained from phenol derivatives substituted by functional groups are strongly adherent on iron. They are reactive and constitute primary layers which permit the grafting of other protective layers, e.g., paints. Poly͑phenylene oxide͒ films present excellent protective properties but have the drawback of being too thin ͑thickness under 0.5 m, due to the insulating character͒.The thickness of inherently conductive polymers ͑ICP͒ is easily controlled when they are synthesized by the electrochemical method. ICP are electrically conductive owing to a system of conjugated double bonds. When deposited on iron, ICP could impart a form of anodic protection by maintaining the electrode in its passive state under aggressive conditions, in which the active passive layer alone would be destroyed in a few minutes.Among the ICP investigated for corrosion protection ͓polyaniline, 6-13 polypyrrole, 14-16 polythiophene, 17 poly͑5-amino-1-naphthol͒ 18 ͔, polyaniline has received the most attention. Nevertheless, the adhesion of electrosynthesized polyaniline films is generally quite poor.We have recently performed electropolymerization of naphthylamine derivatives bearing a functional group ͑-OH,-NH 2 ͒ on the second ring. It was demonstrated that polymerization occurred selectively via the -NH 2 group, leading to polyaniline-like films bearing a free -OH 18 or -NH 2 group in the chain. The presence of a functional group in the chain confers surface reactivity to the film which can be functionalized thereafter. In the case of 1,5-diaminonaphthalene ͑DAN͒ ͑Fig. 1͒, electroactive poly͑1,5-diaminonaphthalene͒ ͑PDAN͒ films ͑Fig. 1͒ were obtained, which can be transformed into complexed films with copper ions. 19 We have attempted in this study to electrosynthesize PDAN, polyaniline ͑PANi͒, and composite films of DAN and ANi on iron in aqueous acid. The composite films present good adhesion properties and protect iron b...

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