The effects of Artisanal Mining On Soil physicochemical properties Around Kwekwe District

Author

Nyasha Munhondo

Title

The effects of Artisanal Mining On Soil
physicochemical properties Around Kwekwe District

Abstract

The study investigated the impacts of artisanal mining on soil physicochemical properties around three mining sites (Battlefield, Sherwood and Melvin) in Kwekwe District. This was necessitated by the mining activities’ disposal of toxic substances containing heavy metals with potential to cause detrimental effects if they do not adhere to EMA and WHO/FAO permissible limits. The soil parameters to be determined included bulk density, pH, CEC, EC and nutrients, as well as presence of trace elements (Cd, Cu, Hg, Pb and Zn).The soil samples were collected in triplicate from 3 random points around each artisanal mining site using a soil auger at a depth of 0-20cm after removal of surface litter. The samples were placed in polythene samples bags, labelled and properly sealed. All samples were taken to BSR laboratory at Trojan Mine for analysis using standard procedures. Results showed that, soils around the artisanal mining sites were slightly acidic pH, high CEC and EC, low soil nutrients and presence of significant concentrations of trace elements than those required by EMA and WHO. Battlefield recorded the highest soil bulk density (1.64±0.06 g/cm3). All mining sites had a slightly acidic pH ranging from 5.99 to 6.89, whereas the pH for Sherwood was outside the EMA and WHO limits. The CEC was highest in the Control (11.37±0.26 cmols) and all mining sites had EC values above EMA and WHO thresholds. All sites were significantly different in soil N and P content whereas Battlefield and Melvin were not significantly different in soil K content. Battlefield recorded the significantly highest concentrations of Cd (0.016±0.004 ppm) and Pb (0.02±0.01 ppm) whereas, Sherwood had the highest concentrations of Hg (0.045±0.03ppm) and Zn (0.029±0004 ppm), with Melvin recording the highest Cu (0.04±0.002 ppm) concentrations. Comparison of trace element concentration in soils around artisanal mining sites with EMA and WHO guidelines showed that, Cu, Pb and Zn were within both EMA and WHO threshold levels. However, all sites had Hg above both EMA and WHO limits whereas Cd was above EMA limits but within WHO standards. Overall, the total trace element concentrations in the soil around the artisanal mining sites declined in the order Cu > Hg > Zn > Pb > Cd whereas by site comparison it was in the order Control < Melvin < Sherwood < Battlefield. From the study findings, it can be recommended that artisanal miners sites should treat their effluent before disposal, and they should exploit resources sustainably so as to reduce ecosystem 7 disruption. Future research should incorporate the impacts of artisanal mining on ground water and surrounding vegetation quality as well

Date

August 2024

Publisher

BUSE

Keywords

EMA

physicochemical properties

WHO

artisanal mining
Kwekwe District
Zimbabwe

Supervisor

Mr A Kundhlande