Oral bioaccessibility of potentially toxic elements (PTEs) in urban dusts of Abakaliki, Ebonyi State, Nigeria

N I Elom,J R Dean,J A Entwistle

doi:10.4314/jasem.v18i2.13

Abstract

A literature survey has shown that no study has investigated the oral bioaccessibility of PTEs in Nigeria dusts. Studies on human health risk of PTEs from urban Nigeria dust have been based only on total elemental concentrations. Whilst this protocol is useful in assessing human health of PTEs, it could lead to an over estimation of the risk considering the elemental sequestration in the dust samples. This study deviated from previous studies by examining the total concentrations as well as the oral bioaccessibility of 8 PTEs in 15 urban dust samples collected from Abakaliki, Ebonyi State, Nigeria. The result showed that high concentrations of Pb (ranging from 236 – 1815 mg/kg) were observed in 5 locations. The Unified Bioaccessibility Method (UBM) was used to investigate the oral bioaccessibility of these PTEs in the urban dust samples. The result revealed that all the PTEs were more bioaccessible in the gastric phase that the gastric + intestinal phase. The lead tolerable daily intake (TDI), as well as the bioaccessible TDI, was computed and results compared with a guideline value.Keywords: Urban dust; PTEs; oral ingestion; bioaccessibility; ICP-MS; Abakaliki

Highlights

The occurrence and distribution of high concentration of PTEs in urban dusts have been widely reported (Okorie et al, 2012; Xinwei et al, 2009; Al-Khashman, 2007)
To check the quality control of the method employed in this work, a CRM (BCR 143R) was analysed for total elemental concentration as well as oral bioaccessibility
Excellent results were obtained for the total PTE determination compared to certificate values (Table 1), with adequate results for the oral bioaccessible PTE determination (Table 1)

Summary

Introduction

The occurrence and distribution of high concentration of PTEs in urban dusts have been widely reported (Okorie et al, 2012; Xinwei et al, 2009; Al-Khashman, 2007) They sources are well documented (Wei et al, 2010; Manasreh, 2010). The presence of these PTEs in urban dusts is a potential threat to human health and the ecosystem in general. It has been reported that these PTEs have irreversible adverse effects on humans children due to their pica behaviour, physiology, unique exposures and special vulnerabilities (Landrigan et al, 2000). This makes children at a higher risk as their immature organs tend to be more susceptible to PTEs than other contaminants (Egeghy et al, 2011)

Methods

Results

Conclusion