TITLE:
Geochemistry of Potentially Toxic Elements in Soil and Sediments of a Tanzanian Small-Scale Gold Mining Area
AUTHORS:
Johnbosco Karungamye, Mwemezi Rwiza, Juma Selemani, Janeth Marwa
KEYWORDS:
Environmental Pollution, Pollution Indices, Ecological Risk, Geo-Accumulation Index, Sediment Quality
JOURNAL NAME:
Journal of Geoscience and Environment Protection,
Vol.11 No.11,
November
17,
2023
ABSTRACT: Small-scale gold mining is linked to significant environmental pollution
by potentially toxic elements (PTEs). However, research on the pollution caused
by such mining activities remains insufficient especially in developing
countries. In the present study, a systematic investigation assessed the pollution and level of ecological
risk of PTEs in soil and stream sediments in an active small scale gold mining
area of Isanga, in Nzega, Tanzania. Samples amounting to 16 soil and 20 sediment were gathered from the
study area and analyzed for five PTEs concentrations (As, Cd, Cr, Hg and Pb)
using the AAS method. The contamination level and ecological risk were assessed
using several pollution indices. The results suggest
that the assessed environmental systems of the Isanga mining area and its
vicinities are lowly contaminated by PTEs and have a low potential to pose
ecological risks. Hg and Cd with mean concentrations of 0.09 mg/kg and 0.26
mg/kg respectively were found to be the most enriched PTEs in soil, compared to
their average continental crust concentrations (0.056 mg/kg and 0.102 mg/kg
respectively). The levels of the evaluated PTEs in the study area are
susceptible to increase over time if proactive steps are not taken to control
mining and waste disposal activities.