Dumpsites in Brazil are deposits of solid waste, without cover, without soil
impermeability and without pipe-laying for the pluvial water. They represent potential sources
of pollution and they can be a negative influence on the water quality of their surroundings and
consequently to human health and the natural environmental under their influence. At the
municipality of Matozinhos, Minas Gerais, Brazil, a dumpsite has been installed on a karst
region since the 1990s. In this context, this study aimed to assess the quality of surface and
groundwater on its surroundings, in order to verify possible contaminations. To conduct the
research, the methodology applied included field survey and exokarst prospection, in order to
support the selection of three sampling sites: two ponds for evaluation of surface water and a
stream inside a cave for groundwater quality evaluation. With reference to Joint Normative
Deliberation of COPAM/CERH-MG No. 01 of May 5th, 2008, for surface water class 2, and the
CONAMA Resolution No. 396 of April 3rd, 2008, for groundwater with human consumption
preponderant use, the results negated the preview hypotheses. Even with the dumpsite's
proximity to water bodies and its occurrence on a karst region, which is environmentally more
vulnerable, no contamination was detected in the waters by phenols, BTEX hydrocarbons,
heavy metals or inorganic compounds, elements that are typically found in leachate from
deposits of solid waste such as Matozinhos' dumpsite. The only verified contamination was by
total phosphorus, organic matter and thermotolerants coliforms. We conclude the leachate
produced by Matozinhos’ dumpsite hasn’t been reaching the nearby water bodies and the water
quality should be associated with environmentally predatory land uses by the local population.
At this region almost full conversion of natural vegetation into pastures was observed, including
riparian forests, the use of fertilizers, pesticides and chemicals in agriculture in general, and
cattle ranching, which can explain the contaminations found. Lastly, we created a new
hypothesis, supported by a qualitative evaluation from local geology and geomorphology. The
Matozinhos’ dumpsite is a source of pollution but its contaminations haven’t been found by
analysis because the contaminant plume is being retained in a compacted clay impermeable
layer existing at the bottom of the sinkhole located on East downstream from the dumpsite.
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