Afolabi Olubukola O, Olatunji Akinade S
Department of Geology, Afe Babalola University, Ado-Ekiti, Nigeria.
Department of Geology, University of Ibadan, Ibadan, Nigeria.
Environ Geochem Health. 2023 May;45(5):1525-1536. doi: 10.1007/s10653-022-01274-0. Epub 2022 May 5.
In this study an attempt was made to determine the source(s) and nature of Pb in environmental media of Ibadan, one of the largest cities in west Nigeria. Seventy-three samples comprising forty stream sediments, twenty-five soils and eight rocks samples were used for the study. Mineralogical compositions of the samples were determined by X-ray diffraction. The elemental constituents were determined using ICP-MS; while the Pb isotopes were determined using Sector-field ICP-MS. Sequential analysis of selected samples was carried out using a modified Tessier's five-step method. The dominant minerals identified were quartz, kaolinite, k-feldspar, and plagioclase. The concentrations (mg/kg) of Pb in soils, sediments, and rocks ranged from 13.00-470.00; 89.00-3288.00 and 2.90-20.30, respectively. The Pb, Pb, Pb, Pb ranged from 1.72-47.41; 30.69-779.68; 27.00-664.46 and 65.67-1642.27 in the soils and sediments, respectively, while they ranged from 0.02-0.07; 0.56-2.33; 0.38-1.56 and 1.19-4.13 in the rocks. Further evaluation of Pb concentration in the soils and sediments revealed high to extreme Pb pollution status, while the calculated Pb isotopic ratios (IRs) in the soil and sediments varied from that of the underlying bedrocks. The IRS in soils and sediments were characterized by low (1.161-1.172 and 1.127-1.200, and 2.281-2.444 and 2.276-2.474) Pb and Pb, while those of the rocks were high (1.456-1.753 and 2.647-3.149), indicating additional anthropogenic sourcing of Pb in the soils and sediments. The analyzed Pb revealed fractions more partitioned in the reactive geochemical phases with the Pb partitioned in the exchangeable (0.11-0.23%), carbonate (9.00-43.58%), reducible (8.32-13.53%) and organic/sulfides (42.78-82.45%) phases. This implies that there may be enhanced mobility of Pb in the environmental samples and ultimately bio-adsorption into living tissues in the environment.
在本研究中，我们试图确定尼日利亚西部最大城市之一伊巴丹环境介质中铅的来源和性质。本研究使用了73个样本，包括40个河流沉积物样本、25个土壤样本和8个岩石样本。通过X射线衍射确定样本的矿物组成。使用电感耦合等离子体质谱仪（ICP-MS）测定元素成分；同时使用扇形场电感耦合等离子体质谱仪测定铅同位素。使用改良的 Tessier五步法对选定样本进行顺序分析。鉴定出的主要矿物为石英、高岭石、钾长石和斜长石。土壤、沉积物和岩石中铅的浓度（mg/kg）分别为13.00 - 470.00；89.00 - 3288.00和2.90 - 20.30。土壤和沉积物中Pb、Pb、Pb、Pb的含量分别为1.72 - 47.41；30.69 - 779.68；27.00 - 664.46和65.67 - 1642.27，而岩石中的含量分别为0.02 - 0.07；0.56 - 2.33；0.38 - 1.56和1.19 - 4.13。对土壤和沉积物中铅浓度的进一步评估显示，铅污染程度为高到极端，而土壤和沉积物中计算出的铅同位素比值（IRs）与下伏基岩的不同。土壤和沉积物中的IRs特征是Pb和Pb含量低（分别为1.161 - 1.172和1.127 - 1.200，以及2.281 - 2.444和2.276 - 2.474），而岩石中的含量高（分别为1.456 - 1.753和2.647 - 3.149），这表明土壤和沉积物中的铅有额外的人为来源。分析的铅显示，其在反应性地球化学相中分配的部分更多，其中铅在可交换相（0.11 - 0.23%）、碳酸盐相（9.00 - 43.58%）、可还原相（8.32 - 13.53%）和有机/硫化物相（42.78 - 82.45%）中分配。这意味着环境样本中铅的迁移性可能增强，最终会生物吸附到环境中的生物组织中。
