Physicochemical characteristics of the soil around the quarry sites in Ogun State, Nigeria

Abstract

Quarrying of rock for construction purposes is a significant industry in Nigeria thus enhancing the economy. This study aimed at assessing the physicochemical parameters of the soil around the quarry sites across selected Local Government Areas in Ogun State. Geographic Information System approach was used to map the various quarry locations in Ogun State, from which eight sites were selected namely Isara, Idode, Iwaye, Ogbere, Ilagbe, Adelokun, Baaki Ake and Igodo. A total of 48 soil samples (topsoil and subsoil) were collected for cation exchange capacity (CEC), electrical conductivity (EC) and Particle size distribution using standard procedures. Sampling was done in dry and wet seasons. Data were subjected to descriptive and inferential statistics using SAS package (9.4 version). However Variable Quality Control Package was used to determine the Control Limit for the soil parameters. Sixty quarries were identified. The electrical conductivity of 505.1±0.6 μS/cm of the topsoil at Igodo in the wet season was above the Upper control limit (UCL) of 501.6 μS/cm. The CEC of topsoil and subsoil in all locations (dry and wet seasons) were lower than the control, with the exception of Isara and Baaki Ake in subsoil (wet season). The sand sizes and percentage weights of sizes (topsoil) of Idode and Adelakun were higher than the control (75 – 150 μm with 74.0%) in dry season; while in wet season, Adelokun (180 μm and 62.4%) was higher than the control (75 – 150 μm and 15.1%). In the subsoil during dry season Idode and Baaki Ake were higher than the control (75 – 150 μm and 71.5%); while during wet season Baaki Ake and Adelokun were higher than the control (75 – 150 μm and 19.4%). In conclusion, quarries had polluted the surrounding soils with sandy particle, EC and reduce CEC values.