The Impacts of artisanal mining on groundwater quality around Bindura town

Author

Tavanhira, Tinashe

Title

The Impacts of artisanal mining on groundwater quality around Bindura town

Abstract

Artisanal and small-scale mining operations is a form of mining which employ basic tools and machinery, and manual labour for mineral ore excavation. It contributes to the Gross Domestic Product of many countries as well as provide a source of livelihood for many people. However, artisanal mining is usually done informally and illegally, characterized by poor technology and hazardous working conditions. Artisanal mining has been reported to cause severe environmental disruptions such as land degradation, pollution, and deforestation, whose impacts are felt long after the mining activities have ceased. As such, the study investigated the effects of artisanal mining on groundwater quality around three mining sites (Chanaka, Kitsiyatota and Makusha) in Bindura. 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 permissible limits. The groundwater quality was determined by characterizing pH, BOD, COD, DO and TDS. Also, the groundwater samples were assessed for presence of heavy metals (Cd, Fe, Hg, Pb and Zn). Thus, a complete randomized block design was employed to collect groundwater around the three artisanal mines. The groundwater samples were sourced from boreholes and wells around each mining site and collected in plastic bottles, labelled and tightly sealed. All samples were taken to to the laboratory for analysis using standard procedures. Results showed that, the groundwater had BOD, COD and TDS above the EMA and WHO permissible standards. Kitsiyatota recorded the significantly highest values for BOD (28.7±3.2 mg/L), COD (84.3±7.1 mg/L) and TDS (492.3±32.3 mg/L) respectively. All mining sites had Cd, Fe, Hg, Pb and Zn above EMA and WHO limits. The concentrations of heavy metals in groundwater decreased in the order Makusha > Kitsiyatota > Chanaka. Though the heavy metals were slightly above the set thresholds, continued consumption of the groundwater may lead to clinical effects overtime. From the study findings, it can be recommended that use of ground water from the mining sites for domestic purposes should be done after adequate treatment as it contains heavy metals. As such, artisanal mining sites should treat their effluent before disposal. Future research should focus on ways of reducing groundwater contamination by artisanal miners.

Date

May 2022

Publisher

BUSE

Keywords

Artisanal mining

Groundwater

WHO limit

Supervisor

Mr. P. Nhokovedzo