Probabilistic sampling in the control of quality for human consumption

Several factors can interfere with water features, the distribution network, both across sectors that make up the network and over time, which in turn compromises its quality. This can happen even if the water has come from producers-distributors systems in accordance with the quality parameters required as acceptable. To ensure the quality of the produced water, water samples are collected along the distribution network and the higher concentration sites are prioritized, as well as those with greater probability of contamination. The purpose of this study is to present a monthly plan for water collection sampling, based on statistical criteria and strategic points which are representative of the water supply system to be evaluated by monitoring the results of the inspection, based on control charts and in accordance with Ordinance 518 of March 25, 2004, of the Ministry of Health. From the analyzed parameters: Chlorine, Fluoride, Turbidity, pH and color, only the turbidity and color are not under statistical control, however, they are in accordance with Ordinance 518 MS. The results show that there was a fluctuation in the concentration of the parameters analyzed during the evaluation period. The averages were: chlorine 0.86 mg / l, fluoride 0.79 mg / l, turbidity 0.49 uT, pH 6.72 and color 1.49 uH.