Preliminary study of the quality of the water of Forqueta and Forquetinha rivers, RS state

Abstract

The activities human beings have caused great impacts in the aquatic systems, either for the removal of the ciliar bush, for the construction of barrages or canalization of waters. Moreover, the oustings of effluent domestic servants and industrials cause deep modifications in these environments, for the introduction of great amounts of strange substances, in amount and quality, to the system. The majority of the diagnosis programs and control of the ambient contamination are based on the physical aspects and chemical of waters, being that the biological aspects, are normally in second plain. However, in recent years if they have given bigger attention to the biological aspects, therefore currently, is made use of a great variety of methods, which indicate the actual damages on the biological community. In order to achieve a preliminary study of two rivers in the catchment of the River Fork / RS, we proceeded with the following research, which, in addition to physical and chemical analysis (pH, water temperature, chemical oxygen demand (COD), Dissolved Oxygen (DO)), we analyzed the presence of benthic insects. The results showed that for most environmental variables, there is little difference between seasonal and not the locations studied. The environmental analysis using only these parameters provided little information regarding the ecological characteristics present. It also has shown that the use of aquatic insects in monitoring programs of water resources can complement the results obtained by measuring abiotic, suggesting the need for joint use of different methods.