Characterization of artisanal gold mining activities in the tropics and their impact on sediment loading and stream flow in the Okame River catchment, Eastern Uganda
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Date
2016
Journal Title
Journal ISSN
Volume Title
Publisher
Environmental Earth Sciences
Abstract
Artisanal gold mining activities continue to
degrade water resources in the tropical watersheds. In this
study, we examined the spatial distribution of artisanal gold
mining activities and their impact on sediment and mercury
concentration in the Okame River catchment, Eastern
Uganda. The spatial distributions of mining activities were
assessed using both a TerraSAR-X radar satellite image of
2008 and Landsat image of 2013. Water samples and river
bed deposits were collected on a monthly basis for a period
of 1 year to assess the impact of mining activities on the
streamflow variations and sediment concentration. Our
results showed that the distribution of gold mining activities
increased from 4.5 km2 in 2008 to 19.9 km2 in 2013.
Human-induced sediment loading due to gold stone
washing in the sampled tributaries of Okame River was
responsible for the high concentration of suspended sediments
(CSS), mercury and low water levels than prior to
gold stone washing. River Omanyi (0.0191 mg l-1) was
the most highly contaminated stream with mercury followed
by Nankuke River (0.0163 mg l-1) and Nabewo
River (0.0158 mg 1-1) in the Okame. There was also a
significant concentration and trend of soluble mercury
contamination from the sampled rivers (R2 = 0.8). The
average concentration of mercury was found to be
0.004 ± 0.0009 mg l. This paper notes that artisanal mining
activities have led to the reduction in streamflow rates,
change of streamflow course and colonization of stream
banks by riparian vegetation.
Description
Keywords
Artisanal gold mining, Sediments, TerraSAR-X, Mercury, Streamflow
Citation
Barasa, B., Kakembo, V., & Karl, T. (2016). Characterization of artisanal gold mining activities in the tropics and their impact on sediment loading and stream flow in the Okame River catchment, Eastern Uganda. Environmental Earth Sciences, 75(14), 1-13. DOI 10.1007/s12665-016-5876-y