Evaluation of the water quality of tidal creeks of Pontal do Paraná, Paraná, Brazil

The aim of this wat was to evaluate the water quality in four tidal creeks of Paraná, Brazil, with different anthropic influences. Samples were collected every three months. Temperature, salinity, pH, alkalinity, total CO2, dissolved O2, nitrite, nitrate, N-ammoniacal, phosphate, silicate, particulate suspended matter, humic matter, total chlorophyll, total and fecal coliform bacteria of surface water were measured in each sample and compared. For all the stations water temperature was lower in winter, but ranged within typically subtropical values. Salinity (7 - 25) and pH (7.08 - 7.91) were higher in Perequê tidal creek indicating that only this tidal creek was strongly influenced by the nearby ocean waters. Lower dissolved O2, reaching anoxic levels along with higher phosphate and N-ammoniacal concentrations and higher total (<200 - 160,000 MPN 100 ml-1) and thermotolerant coliforms (<200 - 50,000 MPN 100 ml-1) in Olho d´Água suggested euthrophication, especially in summer when rainfall was higher and tourism was at its peak. Perequê, Penedo and Barranco Creeks were characterized as meso- and oligotrophic environments.

Foi objetivo da presente pesquisa, avaliar a qualidade da água de quatro gamboas do Paraná, Brasil, que sofrem influências antrópicas distintas. Em cinco coletas trimestrais, foram obtidas, as seguintes variáveis em águas superficiais: temperatura, salinidade, pH, alcalinidade, dióxido de carbono, oxigênio dissolvido, nitrito, nitrato, N-amoniacal, fosfato, silicato, material particulado em suspensão, substâncias húmicas, clorofila total, coliformes totais e coliformes termotolerantes. Os resultados mostraram que a temperatura da água apresentou características tipicamente subtropicais com valores significativamente menores no inverno em todas as estações. A salinidade (7 - 25‰) e o pH (7,08 - 7,91) mais elevados, registrados na Gamboa Perequê, indicaram que somente este curso d´água é influenciado pelo mar adjacente. As quantidades baixas de oxigênio dissolvido, chegando a anoxia, altas de fosfato (8,11 - 208,11 µM), N-amoniacal (0,90 - 75,33 µM), coliformes totais (<200 - 160.000 NMP 100 mL-1) e coliformes termotolerantes (<200 - 50.000 NMP 100 mL-1) observadas na Gamboa Olho d´Água indicam que esta apresenta características típicas de eutrofização, principalmente no verão, época de maior pluviosidade e maior fluxo de turistas na região. As gamboas Perequê, Penedo e Barranco podem ser caracterizadas como gamboas meso- e oligotróficas.

Limnological study of Piraquara river (Upper Iguaçu basin): spatiotemporal variation of physical and chemical variables and watershed zoning

The Piraquara river basin (Upper Iguaçu River basin - Brazil) was studied as an ecological system throughout a complete seasonal cycle, comprising the rainy and dry season. Analyzes of 16 physical and chemical water variables (dissolved oxygen, biochemical oxygen demand, temperature, pH, conductivity, total nitrogen, total phosphorus, ortophosphates, nitrite, nitrate, ammonium, reagent silicate, total suspended solids, chlorophyll - a, flow velocity and depth) showed correlations between water composition and watershed physiographic features, and the Principal Component Analysis allowed to evidence spatial gradients and seasonal differences. The sampling points were clustered in patches with homogeneous behavior, according to ecologycal concepts: patch 1, with strong influence of Serra do Mar mountains; patch 2, medium course, under Piraquara Dam influence and patch 3, under wetlands influence. Two main factors of serial discontinuity were identified: the Piraquara dam effect and the influence of wetlands. The watershed zoning based on limnological characteristics seeks to subsidize research and biomonitoring for this public springs area