Soil Chemical Characteristics in Wet and Dry Season at Iva Long Wall Underground Mined Site, Nigeria

Abstract

In a bid to diversify the sources of revenue generation in Nigeria, the Government of the Federation has initiated plans to resuscitate coal mining. This study, therefore, assessed the impact of previous mining activities on soil chemical characteristic of the abandoned site. A single factor experiment was conducted in a randomized complete block design (RCBD) with three replications to obtain information on soil status of Iva mined site. Soil samples were collected randomly from ten different sampling points at 0-10, 10-20, and 20-30 cm soil depth in four cardinal points at north (N), south (S), east (E), west (W), and at the centre (c) of crest, middle slope, and valley of Iva mined site. The samples were analysed for heavy metals, macronutrient, soil pH, and organic matter content. The organic matter values ranged from 0.00 ± 0.00 to 1.14 ± 0.02% in dry season and 0.00 ± 0.00 to 1.04 ± 0.06% in wet season, with higher levels of organic matter in the valley (OM ≤ 1.14 %). Soil pH values ranged from 3.98 to 6.00 in wet season and 3.82 to 5.34 in dry season, with higher levels of acidity in the middle slope (pH ≤ 4.37). The range of values of soil macronutrients (K, Mg, N and P) were higher in wet season than in dry season with higher levels of K, Mg, N and P, at middle slope. Similarly, the values of the concentration of heavy metals (Ni and Pb) in soil were higher in wet season than in dry season with higher levels of Ni and Pb at middle slope. The levels of Ni, Pb and Cd in this study are above their allowable limits in Austria, Germany, France, Netherlands, Sweden, and United Kingdom. The high concentrations of Cd and Ni in soils could be taken up in plants via the roots, thus, exposing both man and herbivores to serious health risks.