Department of Biochemistry, Faculty of Science, Ebonyi State University, Abakaliki, Nigeria.
Department of Medical Biochemistry, College of Medicine, Alex Ekwueme Federal University, Ndufu-Alike, Ikwo, Nigeria.
J Food Prot. 2021 Aug 1;84(8):1288-1294. doi: 10.4315/JFP-20-295.
In most developing countries, mining is one of the major sources of toxic heavy metals, some of which are a major health concern to the surrounding populace through soil pollution and food contamination. We investigated the levels of Ti, Mn, Ni, Cu, Zn, Pb, Rb, Sr, Se, Nb, and V in 64 soil samples, 320 samples of regularly consumed staple food crops and vegetables (Manihot esculenta [cassava] tubers, Dioscorea rotundata [white yam], Arachi hypogea [groundnut] seed, Telfariria occidentalis [fluted pumpkin leaf]), and leaves of the medical plant Zanthoxulum zanthoxyloides on farmlands near Enyigba mining sites in Ebonyi state, Nigeria. We also examined the possible health risks due to consumption of these staple foods. Energy dispersive X-ray fluorescence was used to determine the metals present in the samples. The mean levels of metals, except for Mn, Pb, and Zn, were below the threshold limits recommended by various institutions for agricultural soils. Our data also showed that food crops cultivated near these sites bioaccumulated toxic levels of these metals above the proposed values set by the World Health Organization, National Agency for Food and Drug Administration and Control, and Codex Alimentarius Commission, especially for Pb, Zn, Cu, Ni, Se, and Rb. These findings may have potential health implications for the local dwellers. The estimated daily intakes of the toxic metals through the consumption of the crop samples were below the maximum tolerable daily intakes, except for Pb and Ni, by eating groundnut, cassava, and white yam. Furthermore, the target hazard quotient, computed based on the estimated daily intake of the heavy metals, was above unity for the metals for cassava, white yam, and groundnut consumption, suggesting significant health risk. Elevated amounts of heavy metals in cassava and groundnut samples, as revealed by their metal extraction coefficient computed in this study, hint that they may be used as bioindicators of ecological and health hazards and phytoremediators of Mn, Zn, Cu, and Pb.
在大多数发展中国家，采矿是有毒重金属的主要来源之一，其中一些通过土壤污染和食物污染对周围人群的健康构成重大威胁。我们调查了尼日利亚埃努伊比州恩尼吉巴矿区附近农田中 64 个土壤样本、320 个经常食用的主食作物和蔬菜（木薯块茎、白薯、落花生种子、棱果番木瓜叶）以及药用植物黄皮树的叶子中 Ti、Mn、Ni、Cu、Zn、Pb、Rb、Sr、Se、Nb 和 V 的含量。我们还检查了食用这些主食可能带来的健康风险。我们使用能量色散 X 射线荧光法来确定样品中存在的金属。除 Mn、Pb 和 Zn 外，大多数金属的含量均低于各机构推荐的农业土壤阈值。我们的数据还表明，在这些地点附近种植的粮食作物生物累积了这些金属的毒性水平，超过了世界卫生组织、国家食品和药物管理局和控制机构以及食品法典委员会规定的建议值，尤其是对于 Pb、Zn、Cu、Ni、Se 和 Rb。这些发现可能对当地居民的健康产生潜在影响。通过食用作物样本，估计有毒金属的每日摄入量低于最大耐受日摄入量，除了食用落花生、木薯和白薯时的 Pb 和 Ni。此外，基于重金属的估计每日摄入量计算的目标危害系数对于食用木薯、白薯和落花生的人群来说，均高于 1，表明存在重大健康风险。本研究计算的重金属提取系数表明，木薯和落花生样本中重金属含量较高，这暗示它们可能被用作生态和健康危害的生物标志物，以及 Mn、Zn、Cu 和 Pb 的植物修复剂。
