Avaliação dos impactos ambientais causados pelo Mercúrio na mineração artesanal do ouro no Distrito de Cahora-Bassa Província de Tete

Abstract

This dissertation was carried out due to the observation of environmental pollution caused by heavy metals in artisanal gold mining areas in the province of Tete, specifically in the district of Cahora-Bassa, locality of Chitima, and the potential environmental impact caused by mercury during anthropogenic activities. In gold extraction, as in all-natural resource exploration, impacts are generated on society in general, in access to resources and services in terms of the physical environment, changes occur in the natural environment, such as changes in the landscape, air quality, water and soil, among other environmental factors (Bittar,2008). In this way, the study assesses the environmental impacts of artisanal gold mining in the province of Tete, district of Cahora-Bassa, in the town of Chitima. In order to assess the pollution caused by artisanal gold mining, analyzes were carried out on the concentration of mercury in the air, in the well water and in the water used to wash the ore during processing. For air analysis, mercury concentration readings were taken in the air, using the Lumex RA-915M analyzer, in which the concentrations recorded in the air were 0-500000ng/L, with this maximum concentration determined at the location being higher than the maximum permissible levels. of mercury in the air. The well water was collected locally as it is used for human consumption. When analyzing the mercury concentration in the well water, it was below the detection limit of the Lumex RA-915M analyzer, coupled to the RP-92. As for the waste water, it was collected from the drains used to deposit the ore washing water, and was taken to the laboratory in Maputo, at the Faculty of Medicine of the Eduardo Mondlane University, where laboratory tests were carried out using the Lumex RA-915M coupled analyzer. to the RP-92. Samples of ore washing water showed a maximum mercury concentration of 4553.33±57.45ng/L. This is also above the maximum allowable limit for discharge water.