Assessment of the level of heavy metals absorbed from farm soil by tomato during production and its health implications to consumers in Gida Ayana District, Ethiopia

ABSTRACT

The contamination of soil with heavy metals is common and it can be a major source of transfer metals into tomatoes and is regarded as a primary path of human exposure to these potentially toxic metals. Therefore, the purpose of this study was to assess the levels of selected physico-chemicals and heavy metals in the three representative tomatoes and their farm soils obtained from three different major tomato-producing Kebeles in Gida Ayana district, Ethiopia. The proximate analysis of tomatoes and soils obtained the pH (4.58–4.62 and 3.74–3.89), electrical conductivity (EC) (0.200–0.206 and 1.92–2.52 mS/cm), moisture content (39.38–49.793 and 91.283–94.853%), and ash content (79.40–83.067 and 9.8–18.267%) for soil and tomatoes samples, respectively. After effective wet sample digestion, the mean level of heavy metals in the tomatoes and its farm soil determined is in the range of 3.6–6.20 and 25–26.30 (Cu), 269–397, and 54779.3–58538.87 (Fe), 50.87–74.89 and 110.34–156.2 (Zn), 0.0057–0.0081 and 0.079–0.152 (Cr), 1.461–1.582 and 24.82–28.16 (Mn) mg/kg dry weight, respectively. However, Pb and Cd are below instrument detection limits for both tomatoes and soil samples. The highest and lowest transfer factors (or the major mechanism through which the consumers are exposed to heavy metals) were observed for Zn (0.637) and Fe (0.0046), respectively. The Pearson correlation analysis showed moderate to the highest positive correlations between the levels of heavy metals and pH, EC, and ash content for both samples is observed. Furthermore, the assessment of health effects showed that there is no or less probability for the non-carcinogenic health risk against the consumer following the long time consumption of tomatoes obtained from the study areas.

KEYWORDS:

• Tomato
• farm soil
• heavy metals
• Gida Ayana
• transfer factor
• health risk

Acknowledgments

The authors are grateful to the Department of Chemistry of Wollega University, Nekemte, Ethiopia for the provision of all the required materials for the experimental works.

Disclosure statement

No potential conflict of interest was reported by the author(s).