Avaliação do grau de contaminação por Mercúrio no ar e na água para consumo humano em distritos da província de Tete devido à mineração de Ouro

Abstract

Water and air are vital resources for human life. The quality of water intended for human consumption and compliance with air quality levels are fundamental to guaranteeing public health. One of the main contaminants of concern is mercury (Hg). The aim of this study was to assess the quality of air and water in the province of Tete, in Mozambique, with a focus on the presence of mercury. The work was carried out as part of the project linked to the determination of mercury in air and water developed in the chemistry department. The concentration of mercury in the air was directly measured using the Lumex RA-915M mercury analyzer (a total of 28 points), based on the limit established by the WHO (World Health Organization) of 1 μg/m3. For the water samples, Cold Vapor Emission Atomic Absorption Spectrometry was adopted, using the Lumex RA-915M mercury analyzer coupled to the RP-92 based on the limit of 1 μg/L established by the Ministerial Diploma on the Quality of Water for Human Consumption (Ministerial Diploma No. 180/2004) of September 15, 2004. The highest levels of Hg in the air were recorded in the district of Cahora-Bassa with a value of 49.2 μg/m3, and in the district of Chifunde with 5 points with concentrations above the limit, in the range of 1.50 - 40.00μg/m3. In river water samples, in Chifunde there were 4 points above the limit, between 16404.70±862.02 and 23534.70±308.53 ng/L; in Chiúta and Moatize all the points were below the limit, between undetectable and 10.67±2.75 ng/L. All the well water samples were below the limit, ranging from 23.10±10.47 to 362.20±14.71 ng/L ng/L in the district of Chifunde and undetectable in Cahora Bassa and Moatize. The only water sample from the Chiúta district borehole in Machinga showed a concentration of 316.50±1.73 ng/L. In summary, this study has revealed mercury contamination in both water and air in various areas, including at levels that could pose risks to human health. Mercury's ability to bioaccumulate in the body and cause disease in vital systems such as the nervous, respiratory, digestive and urinary systems makes these results a significant concern.