Diagnóstico das condições ambientais segundo os parâmetros do IQA em um corpo hídrico lêntico - Lago Igapó I

Abstract

In order to control the quality of urban, periodic monitoring should be carried out regarding the parameters physical, chemical and biological parameters should be done, this being possible through analysis of the Water Quality Index (WQI), which makes possible to gauge the actual conditions of the water body more clearly. This paper aims to analyze the water quality of the lake Igapó I, located in Londrina, through two distinct methodologies of WQI analysis, which are the graphic method and by the use of Qualigraf software. The WQI parameters analyzed were: Total Phosphorus, Total Nitrogen, Biochemical Oxygen Demand (BOD), Temperature, Turbidity, Total Solids, pH, Term Tolerants Coliforms and Dissolved Oxygen (OD). Among the methods used, there was variation between the results because of the magnitude od the values involved, in some parameters there was difference between the data and results, referring to the same points. The lake was divided into ten collection points, theses points being equally spaced, about 180 m from one point to another, along the length of the lake, and at each point a sample was collected at approximately 50% of the total depth. The samples were collected in three days, distributed in the months of August and September. The results were satisfactory, since among all calculated WQI, about 83% had values classified as good. Among the samples collected, a pattern was found between the values of samples 1 and 3, differing only from the values of sample 2, as a function of rainfall occurred at this time. Therefore, it can be said that despite being an urban lake with relatively high anthropogenic interference, Lake Igapó I has good conditions of quality and fits the standards required by current legislation (CONAMA 357/2005) since the results found for the three trials ranged from medium / acceptable to great. Therefore, it is concluded that the ecosystem in question is in equilibrium, since there was compatibility between the data and the days in which the collections were performed.