Assessment of Trace Metal Contaminants and Consumer Preference in Tomato Varieties Produced in Two Mining Communities of Nigeria

Abstract

Tomato varieties (Solanum lycopersicum L) produced in areas prominent for mining activities contribute more deposits of metal contaminants. In turn, affects the quality and value of the products. Highlighting the level of metal contaminant in consumer's most preferred tomato variety is also necessary for health and well-being. This study specifically aimed to investigate, i) the variability between six metal contaminants in UTC, Yowlings, and Derica tomatoes; ii) we also explored the relationship between the metal contaminants and tomato quality, and lastly, we ascertained which socioeconomic factor specifically determined preference for a particular variety of the tomatoes. The metal contaminants examined and found present using ICP-OES were nickel (Ni), chromium (Cr), lead (Pb), arsenic (As), cadmium (Cd), and mercury (Hg). We found a good agreement between most of the analyte and the National Institute of Standards and Technology (NIST) Certified Reference Material 1573a (CRM 1573a) values. Although this study's recovery for the analyte was between 83.22% and 111.00%, we also found contrary to our prediction that Cr, Ni, and Cd concentrations were higher in Derica, UTC, and the Yowlings varieties during the rainy season. A two-way ANOVA between tomatoes and planting seasons was not statistically significant (P > 0.05) in contrast to the mixed model (GLMMs) analysis that indicated a significant (P < 0.05) relationship between lycopene concentration, size of tomatoes, and concentration of metals screened. We also found using a principle component analysis (PCA) and correlation matrix that the concentration of Pb in the tomato varieties was significantly related to the As level. Despite As and Cr concentrations being higher in the Derica tomato variety, most consumers preferred it. Derica tomato contained metal contaminants that could be harmful to human health. Therefore, there is need to monitor the production procedures involved prior to supply of the tomato product.

Keywords: Ascorbic acid; Beta-carotene; Farmers and consumer preference; Lycopene; Toxic elements.