O PROCESSO DE EUTROFIZAÇÃO ARTIFICIAL NO LAGO PARANOÁ, BRASÍLIA, DF

This paper represent an academic exercise dealing with some index parameters of water quality usinganalytical field methods. In first instance it aims to demonstrate the praticalness of the methods as well asits level of precision. It was possible to estimate the influence of parameters like NO3, pH, OD (dissolvedoxygen), etc. for the determination of water quality of the Paranoa Lake wich serves as recipient of sewagefrom Brasilia and satellite towns of the Federal District/Brazil, with an estimated influx rate of 140 litersper second. Treatment of this quantity of sewage (during the time of our study) is very simple: just passingby a fence system. Conditions of eutrophication of this water body have become worse due to the inflowof clandestine sewage from houses along the the lake-side, wich contributes much to the increase ofnutrients, especially phosphorus and nitrogen.The obtained results were promising and served to stimulate further studies in the course "Practice ofField Studies", even not serving for a definite characterization of the waters. It is important to emphasizethat neither results nor the analysis of the data are focused in this paper.The high rate of eutrophication at the sampling stations can be observed using NO3 e PO4 as parameters.In that sense the following measures are recommended in order to maintain chemical and physicalcharacteristics of the habitat:1 - dredging of organic mud from the bottom of the lake, since it contains 80% of the phosphates ofthe slop, besides other nutrients;2 - expansion or construction of new sewage treatment plants in order to prevent the inflow ofsewage in natura in the lake and to satisfy the demand of the population;3 - control of clandestine sewage of the houses at Lake South and North by the official environmentalprotection agencies punishing house owners with application of heavy fines;4 - development of environmental education programs for scholars of all levels in order to arouse theconscience for preserving of water resources.