ABSTRACT

Effects of kaolin mining on soil and vegetation were studied to find out how kaolin mining has impacted the soil and vegetation as well as the socio-economic livelihood of the community. The study was conducted at Agbaghara Nsu, Ehime Mbano, Imo State, Nigeria. The objectives of this study were to: assess the chemical quality of kaolin materials extracted from the mining site and to determine the effects of kaolin mining on the soil and plants in the vicinity as well as evaluate the economic impact of the mining activities on the local community. Information on the peculiarity ofthe area and economic characteristics were collected using direct interview, questionnaire, and personal observation. Samples of kaolin materials were collected from 3 different mining pits dug in Agbaghara Nsu mining site and analyzed to determine the mineral constituents and purity of the kaolin. In order to obtain information on the impact of kaolin mining on the soil and plant, the mined site was delineated into 4 concentric zones that vary with intensity of mining activity namely:- A, B, C and D (the Control). Soil and plant samples were collected from 3 replicate points within each zone for laboratory analyses. Vegetation enumeration was carried out using Line Intercept Transect Method. The results indicated that kaolin mined from Agbaghara Nsu, Ehime Mbano is composed ofsilica (Si) 0.01%, aluminum (Al) 0.04%, potassium (K) 23% and sodium (Na) 46.0% and impurities such as lead (Pb) 5.0%, cadmium (Cd) 0.4%, manganese (Mn) 10.0% and iron (Fe) 15.0%. The soils closest to the mine epicenter have higher levels of Av.P%, Ca and organic carbon. Av.P%, Ca and OC are higher in soils of Zone A than the Control by 66.5%, 12% and 58.9% respectively. They are higher in soils of Zone B than the Control by 34.4%, 12% and 48.9% respectively and higher in soils of Zone C than the Control by 40.4%, 11.6% and 42% respectively. In terms of heavy metals, the levels of Cd, Pb and Fe where higher in soils ofZone A than the Control by 47.5%, 57% and 59.3% respectively, higher in Zone B than Control by 32.5%, 29.6% and 58.8%, respectively and higher in Zone C than Control by 46.5%, 26.3% and 13.95 respectively. Their levels decrease with increasing distance from the epicenter. Similarly the plant samples closest to the epicenter of mining have more levels ofmacronutrients and heavy metals than the Control samples. The Cd, Pb and Fe levels in the plant samples collected from Zone A were significantly higher than the Control samples by 68.4%, 17.8% and 45% respectively. They are higher in plants of Zone B than the Control by 68.5%, 14.7% and 58% respectively and higher in plants of Zone C than the Control by 68.7%, 5.5% and 10% respectively. The total population of plant species is 1888 plants/0.036 hectare, 1632 plants/0.036hectare, 1712plants/0.036hectare and 3424plants/0.036hectare for Zones A, B, C and D respectively. The kaolin mining activity impacted on the people in the form of job creation. Human consumption and use of kaolin from Agbaghara should be done with great caution as the possibility of having Pb and Cd toxicity with prolonged exposure is high. Rehabilitation and future use of the mining site should recognize the changes introduced already in the soil ofthe area particularly with regard to Cd and Pb toxicity.