Soil characterization is a vital activity to develop appropriate and effective restoration protocols for mine wastelands while insights into the total content of heavy metals in the soil is an important step in estimating the hazards that the metals may pose to the vital roles of soil in the ecosystem. This study addressed the following research questions: (1) To what extent do the physico-chemical characteristics vary between mine waste sediments and the nearby forest soil? (2) Are the concentrations of heavy metals high enough to be considered as toxic? and (3) Are heavy metals present in mine waste sediments potential sources of pollution? We hypothesized that the physico-chemical characteristics of mine waste sediments are less favorably for plant establishment and growth while the concentrations of heavy metals are very high, thus restricting the success of revegetation of mine waste lands. Mine waste sediments were sampled following a diagonal transect across tailings dams, overburden dump sites and the local forest soil from the top layer (0–20 cm) using a closed auger. Samples were analyzed for arsenic, barium, lead, cadmium, cobalt, copper, chromium, nickel, vanadium, and zinc as well as for soil physico-chemical properties. The mine waste sediments were dominated by silt whilst the forest soil by sand particles, with significantly high bulk density in the former. Both the forest soil and overburden sediments were acidic than the alkaline tailings dam sediment. Total organic carbon and nitrogen contents were significantly low in mine wasteland substrates but the concentration of Ca and Mg were significantly higher in tailings dam substrate than the forest soil. The concentrations of available P, K and Na were similar across sites. The mean concentrations of heavy metals were significantly (p < 0.01) higher in mine waste sediments than the forest soil; except for cadmium (p = 0.213). The order of contamination by heavy metals on the tailings was Cu > Co > Ba > Ni > As > Zn > Pb > Cr > V > Cd, and that on the overburdens was Cu > Co > Ba > Ni > Zn > Cr > Pb > V > As > Cd. The pollution load index (PLI) was nearly twice higher for the tailings dam (8.97) than the overburden (5.84). The findings show that the copper mine wastes (the tailings dams and overburden waste rock sites) are highly contaminated by heavy metals; which, in turn, might pose serious hazards to human health and agricultural productivity. In addition, poor macro-nutrient availability, substrate compaction and soil acidity (particularly on overburden sites) coupled with toxic level of heavy metals would be the main challenges for successful phytostabilization of copper mine wastelands.

对土壤进行表征是为矿山荒地制定适当而有效的恢复方案的一项重要活动，而洞察土壤中重金属的总含量是评估金属可能对土壤在生态系统中的重要作用构成危害的重要步骤。这项研究解决了以下研究问题：（1）矿山废物沉积物和附近森林土壤的理化特性在多大程度上变化？（2）重金属的浓度是否高到足以被认为有毒？（3）矿山废物沉积物中是否存在重金属潜在的污染源？我们假设矿山废渣沉积物的理化特性不利于植物的建立和生长，而重金属的浓度非常高，从而限制了矿山荒地植被恢复的成功。使用封闭式螺旋钻，在对角线横穿尾矿坝，覆土堆放场和顶层（0–20 cm）的当地森林土壤后，对矿山的废物沉积物进行采样。分析了样品的砷，钡，铅，镉，钴，铜，铬，镍，钒和锌，以及土壤的理化性质。矿山废渣的沉积物以淤泥为主，而森林土壤则以沙粒为主，前者的堆积密度明显较高。森林土壤和上覆沉积物均比碱性尾矿坝沉积物酸性。矿山废弃地基质中的总有机碳和氮含量显着较低，但尾矿坝基质中的Ca和Mg浓度显着高于森林土壤。不同地点的有效磷，钾和钠的浓度相似。重金属的平均浓度显着（p  <0.01）矿山废物中的沉积物高于森林土壤；除镉（p = 0.213）。重金属在尾矿上的污染顺序为：铜>钴>钡>镍>砷>锌>铅>铬>钒>镉，覆盖层上的重金属为铜>钴>钡>镍>锌>铬>铅>铅> V>砷> Cd。尾矿坝（8.97）的污染负荷指数（PLI）几乎是表土（5.84）的两倍。研究结果表明，铜矿废物（尾矿坝和上覆废石场）受到重金属的高度污染。反过来，可能对人类健康和农业生产力造成严重危害。此外，不良的宏观养分利用率，基质压实度和土壤酸度（特别是在上覆地带）以及重金属的毒性水平将是成功地稳定铜矿荒地的主要挑战。