Potentially toxic elements concentration and distribution in soils around artisan workshops in Ago-Iwoye, Southwestern Nigeria

Abstract

Background/Introduction

Anthropogenic activities, including those carried out by artisans, have been confirmed to be one of the various means by which potentially toxic elements (PTE) are introduced into the soil. This study aims to determine the PTE concentration and distribution in soils around artisans workshops in Ago-Iwoye, southwestern Nigeria.

Methods

Twenty (20) soil samples comprising ten (10) samples from soil around auto-mechanic workshops, six (6) from soils around vulcanizer workshops and four (4) from soils around welder workshops were collected and analyzed for elemental concentration using Inductively Coupled Plasma Mass Spectrometry (ICP-MS).

Results

Elemental analysis revealed the following trend for selected metals in auto-mechanic, vulcanizing and welding workshops, respectively: Ba (60–100, 100–200 and 130–590 mg.kg⁻¹); Co (10–47, 8–19 and 15–37 mg.kg⁻¹); Cr (29–161, 22–95 and 57–272 mg.kg⁻¹); Cu (28–123, 16–100 and 88–486 mg.kg⁻¹); Ni (11–33, 7–29 and 34–112 mg.kg⁻¹); Pb (17–75, 12–77 and 36–677 mg.kg⁻¹); Sc (2–16, 1–7 and 2–8 mg.kg⁻¹); Sr (13–55, 17–72 and 33–91 mg.kg⁻¹); V (35–212, 20–117 and 40–103 mg.kg⁻¹) and Zn (82–684, 70–548 and 314–3240 mg.kg⁻¹). Geochemical assessment using contamination factor, and geo-accumulation index showed that the artisanal workshops exhibited significant contamination levels for metals such as Ba, Cu, Ni, Pb, Sr, and Zn and the contamination level varied across the artisan workshops with soils around welders workshops showing highest contamination.

Conclusion

Contamination indices revealed the artisan workshops have varying contribution to the metal load in the area and Pollution Load Index (PLI) indicated a decline in soil quality across all artisanal workshops with welding workshops revealing the highest anthropogenic contribution of PTE to the soil.