Potential ecological and health risks of toxic metals associated with artisanal mining contamination in Ijero, southwest Nigeria

Abstract

This investigation was done to decide the concentrations, sources and potential risks of metals in media around Ijero area. A total of 80 samples including topsoils, sediments, tailings and whole plants were gathered from this territory while control samples were taken from zone with less human exercises. Samples were pounded, sieved and chemically analyzed utilizing Agilent High Plasma Liquid Chromatography Inductively Coupled Plasma-Mass Spectrometer. Results demonstrated that the mean concentrations of lead (Pb) and zinc (Zn) in soils are 30.61 and 123.71 µg/g individually. In tailings the mean distribution of Pb and Zn are 33.16 and 22.44 µg/g each. Toxic units in all media were less than 4, indicating low effect on the ecosystem. Bivariate correlation, hierarchical cluster and principal component analyses revealed that metals in media from this area originated from mining and mineral processing activities, mixed and geogenic sources. Study revealed that metals in the media pose high degree of contamination and moderate to high ecological hazard. Also, there is high cancer-causing hazard index (HI) (10⁻⁶–10⁻⁴) and non-cancer-causing (HI > 1) dangers which is more articulated in kids than the grown-ups. It is important to introduce measures that will decrease the negative impacts associated with mining in the area.

Keywords:

• Artisanal mining
• ecological risk
• health risk
• heavy metals
• Ijero Ekiti

Acknowledgements

We are grateful to Professor Xiao Tangfu, Dr. Ning Zengping, Dr. Liu Yizhang, Dr. Atta Ratsool, Mr. Ma Liam and Mr. Oyebamiji Abiola for their supports during the sample analysis. Also we appreciate the assistance of Mr. Oladoyin Ayodeji and Mr. Haske during the collection of samples on the field.

Additional information

Funding

This work was supported by opening grant of the State Key Laboratory of Environmental Geochemistry, Institute of Geochemistry, Chinese Academy of Sciences, Guiyang, Ghizhou Province, China. The grant number is SKLEG2017910.