Multivariate analysis of selected allied chemical properties of soils close to an abandoned manganese mine

Abstract

This study aimed at understanding the statistical relationships between base saturation percent (BSP), cation exchange capacity (CEC), pH_(water) and electrical conductivity (EC) in soils within close proximity to the abandoned Kgwakgwe Mn oxide ore mine, Botswana. Four hundred soil samples were collected from a 4 km² area close to the abandoned mine. Soil pH ranged from 2.92 to 7.26 with very acidic soils located close to the mine workings. Electrical conductivity values were low, ranging from 49.1 Scm⁻¹ to 123.5 Scm⁻¹. The BSP in the soil samples varied between 33.77 and 100 with a mean of 82.10 and CEC values % (cmol_ckg⁻¹) ranged from 1.1 to 29.2, with a mean of 8.2. Relationships between the various parameters were generally poor and negative with the exception of EC/BSP and BSP/CEC which were positive. The statistical data yielded five clusters with distribution of the parameters as follows: cluster one is dominated by pH and EC, cluster two by EC, cluster three by CEC, PBS and EC, cluster four by PBS, and cluster five by none of the four parameters. The PBS and CEC values are closely associated. Comparing results obtained from the control site, it is certain that mining activities have affected the soil PBS, CEC, pH and EC of the study area.