Estudo da qualidade da água distribuída à população de Macapá pelo sistema público de abastecimento

Abstract

Water is an essential element to human life, to maintain its biological activities in homeostasis. Water is a very important biological vehicle and it favors the absorption, biotransformation and elimination of various substances in the body. Contamination by heavy metals in water supply can lead to diseases due to the use of water with limits higher than those established by legislation, in this respect it is extremely important to monitor the water supply process for consumption. Therefore, the aim of this study was to evaluate the quality of the water abstracted and distributed by the public water supply system of the Companhia de Água e Esgoto do Amapá in order to verify possible changes in physical-chemical parameters and contaminations by heavy metals. The method for investigating the physico-chemical parameters was according to the standard Methods for the Examination of Water and Wastewater. And the method for the analysis of heavy metals performed by the Atomic Absorption Spectrophotometer was applied in samples of water from the Amazon River, before treatment, and in the samples at the exits of the treated water distribution reservoirs provided by Companhia de Água de Macapá-AP. Based on the results of the physico-chemical parameters it was possible to observe with respect to the pH, that the sample collection districts, were within the limits recommended by the legislation, except for the middle district that presented acidic pH of 4,2 ± 0 , 09 (n = 3). According to the results, 70% of the water in the districts of Macapá were outside the legal limits recommended for turbidity, it was verified that the majority of the water samples were above the limit of 5.0 UT. There was no significant difference (p> 0.05) between the collection points for the temperature parameter, being the lowest value found 27.9 ± 2.29 ° C. Regarding the concentration of metals in the samples, values higher than those recommended by CONAMA Resolution 357/05 were observed. The iron content in the samples showed that 100% of collection points had values above the limits recommended by CONAMA Resolution 357/2005, and according to the legislation a maximum of 0.3 mg.L-1 is allowed. In the concentration of Lead, the points ranged from 0.001 to 0.08 mg.L-1, demonstrating that 66.67% of the samples were in disagreement with the limits allowed for the lead content. At the copper concentration (Cu), the values ranged from 0.02 to 0.08 mg.L-1 at the different collection points, and the allowed limit is 0.02 mg.L-1. Thus, 100% of collection points were higher than allowed. For the values of Chromium (Cr), it was possible to observe that 100% of the samples were within the limit recommended by the legislation with an average of 0.03 ± 0.002 mg.L-1. In conclusion, it was demonstrated that both the Iron, Lead and Copper concentrations were higher than those recommended in Resolution 357/05 of CONAMA