Heavy Metals Content in Kaolin Mined Soil and Water Body at Ohiya, Umuahia South, Abia State, Nigeria

Abstract

Heavy metals (HM) have been a global concern for its toxic and detrimental effect on the environment especially when it exceeds the permissible limit through anthropogenic activities like kaolin mining. Kaolin mining has improved the economic wellbeing of the local people through employment and otherwise; and at the same time attached with environmental consequences that threatens the livelihood of the community members. This study was carried out to ascertain the concentrations of selected heavy metals in kaolin mined soils and water body and its pollution density using single pollution indices such as contamination factor (CF), geo-accumulation (Igeo) and ecological risk factor (Er ). Soil sample were collected from three different kaolin mined sites labelled (A,B and C) also surface water samples were collected from upper and down streams of Iyi-ugbohoroAmaudara, both samples were digested and elemental analysis was carried out using Atomic Absorption Spectrophotometer (AAS UNICAM 919 model). The concentration of the metals in three different kaolin mined soil samples ranges from Pb(40.00, 52.00 and 55.09 mg/kg) Cr(45.01, 70.00 and 71.00 mg/kg) Ni( 32.10, 50.50 and 51.00 mg/kg) Cd( 2.16, 6.25 and 6.15 mg/kg) Co( 19.68, 57.06 and 56.00 mg/kg) Se(1.06, 0.50, and 1.00 mg/kg) Mn(0.001, 0.01 and 0.01 mg/kg) Hg( 2.01, 2.00 and 2.50 mg/kg) As( 1.07, 1.10 and 1.05 mg/kg) and Cu(33.01, 60.00 and 57.5 mg/kg). Results from single pollution indices used for the selected heavy metals from kaolin mined soil, samples (A,B and C) showed that Mn, As, Cr, Ni and Cu indicated low to moderate contamination factor while Cd, Se, Co and Hg indicated high to very high contamination factor in all the samples. The distribution trend of heavy metals concentrations in the upper and down streams of the river body during wet season, showed that there were significant difference between upper and down streams while dry season showed variations in significant differences between the upper and down streams of some of the heavy metals. The study therefore concludes that kaolin soils are contaminated with heavy metals as a result of kaolin deposit and its mining activities. The single pollution indices used for the study pointed out that Cd, Se, Co and Hg are very high in the kaolin soils. The surface waters of Iyi-ugbohoroAmaudara River at the study area are polluted with heavy metals as a result of kaolin mining activities in the area; more especially during wet season of the study. Consequently, these outcomes would pose a toxic effect to both fauna and flora and possibly threatens the aquatic lives and the local populace.