Environmental Biochemistry, Health and Toxicology Research Unit, Department of Medical Biochemistry, Alex Ekwueme Federal University Ndufu-Alike, Ndufu-Alike Ikwo, Ebonyi State, Nigeria.
Plant Ecology Research Unit, Department of Science Laboratory Technology, Akanu Ibiam Federal Polytechnic, Unwana, Ebonyi State, Nigeria.
Environ Monit Assess. 2020 Apr 18;192(5):292. doi: 10.1007/s10661-020-08280-8.
This study evaluated the level of metals in edible plants, their chemical forms in the soil, and the associated health risk in Enyigba lead-zinc mining vicinity in Ebonyi State, Nigeria. Soil sample, Telfairia occidentalis and Amaranthus hybridus were collected from mining sites (Ishiagu-Enyigba and Elinwobvu-Enyigba) and non-mining site (Ekawoke-control) and analyzed using standard protocols. The results showed that a high percentage of Cd, Pb, Fe, and Zn were associated with non-residual fraction, while Cu, Cr, and Ni were bounded with residual fraction. The order of mobility and bioavailability of the metals was as follows: Pb > Cd > Fe > Zn > Cr > Ni > Cu. Geoaccumulation index (I) indicated moderate to strong pollution of the mining sites with Cd Cu, Pb, and Zn. The most significant contributor to hazard index (HI) was ingestion of edible plants; followed by ingestion, dermal-contact, and then inhalation of soil particles. HI values for Cd (1.32), Cr (1.05), and Pb (1.97-2.04) for children in the sites exceeded United States Environmental Protection Agency (USEPA) safe limit (HI > 1). Total cancer risk (TCR) for adults and children via soil inhalation or soil ingestion were below USEPA safe limit (TCR < 1.0 × 10). TCR for adults and children via consumption of T. occidentalis or A. hybridus exceeded USEPA safe limit (TCR > 1.0 × 10). These results strongly indicated associated noncarcinogenic and carcinogenic health risk of these metals from the soil and the edible plants around Enyigba mining sites vicinity to humans especially children, this calls for concern.
本研究评估了尼日利亚埃邦伊州恩尼伊巴铅锌矿区可食用植物中的金属水平、土壤中金属的化学形态以及相关的健康风险。从矿区（伊希阿古-恩尼伊巴和埃林沃布武-恩尼伊巴）和非矿区（埃卡沃克-对照点）采集了土壤样本、台尔菲利亚西方菜和苋菜混合种，并使用标准协议进行了分析。结果表明，高比例的 Cd、Pb、Fe 和 Zn 与非残留部分有关，而 Cu、Cr 和 Ni 则与残留部分有关。金属的移动性和生物有效性顺序如下：Pb>Cd>Fe>Zn>Cr>Ni>Cu。地质累积指数（I）表明矿区存在中度至重度 Cd、Cu、Pb 和 Zn 污染。危害指数（HI）中，食用植物的摄入量对 HI 影响最大；其次是土壤颗粒的摄入、皮肤接触和吸入。矿区儿童的 HI 值（1.32），Cr（1.05）和 Pb（1.97-2.04）超过美国环保署（USEPA）安全限值（HI>1）。通过土壤吸入或土壤摄入，成人和儿童的总癌症风险（TCR）低于 USEPA 安全限值（TCR<1.0×10）。通过食用台尔菲利亚西方菜或苋菜，成人和儿童的 TCR 超过 USEPA 安全限值（TCR>1.0×10）。这些结果强烈表明，来自恩尼伊巴矿区周围土壤和可食用植物的这些金属对人类，尤其是儿童，存在非致癌和致癌健康风险，这令人担忧。
