The main goal of this study was to avaluate the quality of surface waters of the area
influenced by the mining companies of iron and gold, in the area of Serra do Navio
and Pedra Branca do Amaparí, state of Amapá, and to stablish the relationships
between mining and environment. This study will contribute to the improvement of the
population life quality, once the quality of the waters has a direct relationship with
public health. For that, 16 samples of water were collected and analyzed from the
small rivers William, Mário Cruz, Taboca, Jornal, Mata Fome, Taperebá and
Silvestre. It could be interpreted, by the result of the analyses, that the mining
companies had significant influence at the studied area, mainly in what concerns the
color and turbidity values, since the extraction of the ores needs to remove the
vegetable covering, resulting in an intense leaching process, responsible for a great
amount of sediments to the water courses, reducing the penetration of the light,
disabling the photosynthesis and harming the aquatic life, and decreasing the
amount of fishes, base of the area population feeding. The element cyanide showed
concentrations below 0,001 mg / L, what seams to point to a very efficient control by
the MPBA Company toward the discard ore treated waters to the rivers. However, the
cyanide should has been liberated to atmosphere in the gaseous form (HCN), leading
serious environmental problems. That still needs more detailed study, mainly on the
quantification of the concentrations liberated by the mining process, avoiding
environmental problems that affect the area flora and fauna. Another important
aspect was the high value of the pH in the sample collected in the confluence of
William and Taboca rivers. This can facilitate the precipitation of toxic chemical
elements as heavy metals and also effect nutrient solubility. For a better evaluation of
the real influence of those mining companies toward the environment and the water
resources, it is necessary to monitor the water quality during an entire water cycle
with at least four sampling.
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