CONTAMINAÇÃO POR NITRATO EM ÁGUAS DE POÇOS RASOS DESTINADAS AO CONSUMO HUMANO EM ICOARACI, MUNICÍPIO DE BELÉM, ESTADO DO PARÁ

Abstract

The research aims to assess the water quality of shallow wells utilized by the local inhabitants of the Parque Guajará neighborhood, located in the Icoaraci District of Belém Municipality, State of Pará. This assessment was conducted in accordance with the criteria delineated by Ordinance GM/MS nº 888, an edict established by the Ministry of Health. In the year 2016, a series of samples were collected from 15 specifically chosen shallow wells. This sampling was arranged to align with the distinct climatic patterns of the region, spanning the rainy season (January and May) and the drier period (August and October). The investigation analyzed the following parameters: pH, electrical conductivity, nitrite, ammonium, and nitrate content. During the time of the sample collection phase, recorded pH values oscillated between 3.93 and 6.42, while the measurements of electrical conductivity exhibited a peak at 527 µS/cm. Notably, ammonium concentrations peaked during the rainy season at 6.01 mg/L, whereas nitrite levels reached their peak during the less rainy season at 0.44 mg/L. High nitrate levels were particularly observed, predominantly during the rainy season, increasing up to 64.03 mg/L. Signs of a nitrification process could be seen within the samples from two wells under investigation. Statistical analysis highlighted positive correlations between electrical conductivity and nitrate levels, as well as between pH and ammonium concentrations. Based on these data, it became evident that nitrate contamination was pervasive in the residual groundwater of the shallow wells. This nitrate contamination, a fundamental concern throughout the sampling period, under scored the significant influence of septic tank systems on the analyzed water. This contamination, in turn, threatens the well-being of the people who depend on these water sources for consumption, thereby requiring urgent attention.