Purpose

This work investigated the levels, ecological and potential human health risk of heavy metals in soils and crop plants of an abandoned open municipal solid waste dumpsite being used for agricultural crop planting at Ugwuaji in Enugu, Nigeria.

Method

Samples of soils and plants were collected from the site and heavy metals (Pb, Cr, Cd, Zn, Al and Fe) contents and some soil physicochemical parameters were determined after wet digestion with Nitric acid/perchloric acid mixture. The digested samples and all the supernatants were analyzed for heavy metals using Atomic Absorption Spectrophotometer (Shimadzu AA7000 made in Japan) fitted with deuterium lamp for background correction.

Results

The heavy metal concentrations in the soils (mg/kg) ranged from 20.825 to 62.501; 7.25 to 11.806; 54.074 to 275.559; 10.861 to 40.139; 1835.751 to 2225.768; and 7166.724 to 11,601.940 for Pb, Cd, Cr, Fe, Al and Zn respectively. The Cr, Fe, Al, and Zn contents (mg/kg) in the plants samples were within the recommended limits but Cd levels were higher.

Conclusion

The ecological and health risk assessments revealed contamination and high human health risk associated to Cd. Apart from Cd, other heavy metals under investigation in the soil posed low ecological risk. The target hazard quotient (THQ) values for Cd in the plants samples were all above one except for for Ocimum gratissimum, indicating that people consuming the plants cultivated in the vicinity of the dumpsite may experience adverse effects due to Cd toxicity.

中文翻译：

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废弃城市露天垃圾场土壤和粮食作物中重金属的生态和潜在健康风险评估

目的

这项工作调查了尼日利亚埃努古 Ugwuaji 用于农作物种植的废弃露天城市固体废物垃圾场的土壤和农作物中重金属的水平、生态和潜在的人类健康风险。

方法

从现场采集土壤和植物样品，用硝酸/高氯酸混合物湿消化后测定重金属（铅、铬、镉、锌、铝和铁）含量和一些土壤理化参数。使用配备用于背景校正的氘灯的原子吸收分光光度计（日本制造的 Shimadzu AA7000）分析消化的样品和所有上清液中的重金属。

结果

土壤中的重金属浓度（mg/kg）在 20.825 到 62.501 之间；7.25 至 11.806；54.074 至 275.559；10.861 至 40.139；1835.751 至 2225.768；Pb、Cd、Cr、Fe、Al 和 Zn 分别为 7166.724 至 11,601.940。植物样品中的 Cr、Fe、Al 和 Zn 含量 (mg/kg) 在推荐限度内，但 Cd 含量较高。

结论

生态和健康风险评估揭示了与 Cd 相关的污染和高人类健康风险。除 Cd 外，土壤中正在调查的其他重金属具有较低的生态风险。植物样本中镉的目标危害商（THQ）值除罗勒外均高于1 ，表明人们食用在垃圾场附近种植的植物可能会因镉毒性而受到不利影响。