Seasonal and Temporal Distribution of Arsenic

International Journal of Research and Scientific Innovation (IJRSI) | Volume VII, Issue IX, September 2020 | ISSN 2321–2705

Seasonal and Temporal Distribution of Arsenic

 Alexander Kwaku Banson¹, Richard Kwasi Amankwah², and Samuel Agyarko Ndur^3
1Perseus Mining Ghana Limited, Ghana,
^2,3University of Mines and Technology, Ghana 

Abstract:- In this study seasonal and temporal distribution of arsenic was assessed over a period of one year.During the study water and soil samples were taken from streams, rivers, old and active process ponds, tailings dams, tailings footprints, heap leach sites, arsenic trioxide storage sites, waste rock dumps as well as gold processing plants which treat arsenic ores. The study concluded the temporal distribution of arsenic in surface water follows a linear seasonal trend whereas all year round it generally follows a polynomial trend. It is not advisable to attempt to predict the concentration of arsenic in groundwater on the basis of the Fe contents alone. However, the presence of high Fe is a possible indication of high arsenic in groundwater. It is noted however that wells with low Fe will tend to have low arsenate concentration. There is a temporal nonlinear relationship between As and Fe concentrations which proposes a natural remediation of the polluted water source and indicates how long it may take for the water to revert to a compliant concentration when measures are taken to stop activities that mobilize arsenic. This suggests that if the current anthropogenic activities releasing arsenic is halted and with the appropriate concentration of iron in solution, the surface water may demobilize arsenic back into the host mineralogy. There are seasonal changes in arsenic content of the monitoring boreholes in Arsenic-trioxide Storage Area (ASA) suggesting the mobility of arsenic with infiltrating water as an important transport pathway to groundwater.

I. INTRODUCTION

Obuasi Municipality is a historic gold mining tropical community that has a massive cocktail of old and active liquid and solid arsenic storage facilities (Banson et al., 2016). Small scale and illegal mining has become a significant gold producing activity in almost every community in the Obuasi Municipality (Banson et al., 2018a).Large scale gold mining in the historic Obuasi community begun since 1890 and it has left behind geochemical dispersion from arsenic mineralization which has resulted in arsenic contaminated water, plants and soils at Obuasi (Ahmad and Carboo, 2000). There are massive old and active liquid and solid arsenic storage facilities such as process ponds, tailings dams and tailings footprints, heap leach sites, arsenic trioxide storage sites, waste rock dumps as well as gold processing plants which treat arsenic ores (Banson et al., 2018b). Likewise, in the past there was airborne gaseous dispersion of arsenic through the arsenic dust/fumes that exited from the exhaust stack of the Ashanti Goldfields Ashanti (AGA) Obuasi Mine’s sulphide roaster plant(Golowet al., 2010).

Read More