Department of Forest and Wood Science, Stellenbosch University, Bag X1 Matieland, Stellenbosch, 7602, South Africa.
Department of Biomaterials Science and Technology, Copperbelt University, P. O. Box 21692, Kitwe, Zambia.
Environ Monit Assess. 2021 Dec 7;194(1):8. doi: 10.1007/s10661-021-09656-0.
Heavy metal contamination in the soil and the subsequent accumulation in Brachystegia longifolia were investigated as a function of the wind direction and distance from a copper mine in Mufulira, Zambia. Soil and leaves of B. longifolia were collected along transects up to 12 km downwind and 19 km upwind. The total concentration of trace elements in the soil and leaves was determined through XRF. Plant-available Cu, Fe, Mn, and Zn were extracted in a Mehlich III solution and analyzed using ICP-AES. The degree of soil contamination illustrates that Cu and Fe from the copper mine strongly pollute Mufulira and the surrounding forests. Bioavailable Cu, Fe, Mn, and Zn reduced with increasing distance from the mine. An average of 296 mg/kg Cu, 2337 mg/kg Fe, 1101 mg/kg Mn, and 109 mg/kg Zn were recorded in leaves at the most polluted site. Similarly, 55.21 mg/kg Cu, 516.4 mg/kg Fe, 3196 mg/kg Mn, and 154 mg/kg Zn were recorded at an unpolluted site 19 km upwind. The concentration of Cu and Fe reduced significantly with increasing distance, while Mn and Zn increased significantly. It was further established that B. longifolia leaves accumulated Mn (× 38) and Zn (× 15) more than their respective total concentration in the soil. The concentrations of Cu and Fe found in leaves near the mine, as well as the Mn concentration in leaves across the study sites, could be stressful for B. longifolia tree growth.
研究了赞比亚穆富利拉一座铜矿下风方向和距离对土壤重金属污染及 Brachystegia longifolia 积累的影响。沿 12 公里下风方向和 19 公里上风方向的样带采集土壤和 B. longifolia 叶片。通过 XRF 测定土壤和叶片中微量元素的总浓度。采用 Mehlich III 溶液提取植物有效态 Cu、Fe、Mn 和 Zn，并用 ICP-AES 进行分析。土壤污染程度表明，铜矿中的 Cu 和 Fe 严重污染了穆富利拉及其周边森林。随着距离的增加，生物可利用的 Cu、Fe、Mn 和 Zn 减少。在污染最严重的地点，叶片中 Cu、Fe、Mn 和 Zn 的平均值分别为 296 mg/kg、2337 mg/kg、1101 mg/kg 和 109 mg/kg。同样，在 19 公里上风处无污染地点，叶片中 Cu、Fe、Mn 和 Zn 的平均值分别为 55.21 mg/kg、516.4 mg/kg、3196 mg/kg 和 154 mg/kg。随着距离的增加，Cu 和 Fe 的浓度显著降低，而 Mn 和 Zn 的浓度显著增加。进一步证实，B. longifolia 叶片积累的 Mn（×38）和 Zn（×15）多于其在土壤中的总浓度。在离矿较近的叶片中发现的 Cu 和 Fe 浓度，以及在整个研究地点叶片中的 Mn 浓度，可能对 B. longifolia 树木的生长造成压力。
