Levels of Heavy Metals and its Health Risk Estimation in Calyces of Red and White Roselles Purchased from Monday-Market, Borno State

Document Type : Research Article


1 Department of Pure and Applied Chemistry, Faculty of Science, University of Maiduguri, Borno State, Nigeria

2 Department of Pure and Applied Chemistry, University of Maiduguri


Heavy metals accumulation in vegetables and their jeopardous health effects have been on increase especially after a long-term exposure. This study examines the levels of some heavy metals in calyces of red and white roselle obtained from Monday-Market, Maiduguri, Borno state, Nigeria. Furthermore, the study estimates the health risk associated with consumption of the calyces. The calyx samples were prepared in accordance with standard procedures and subjected to smart spectrophotometer for heavy metal analysis. The variation trend of the heavy metals in the red roselle was Cu > Zn > Cr > Cd while in the white roselle was Zn > Cu > Cr > Cd. However, Hg was not detected in both samples. The Health Quotient (HQ) calculated for the heavy metals showed that Cd and Cu were greater than unity indicating that consumers may be exposed to potential non-carcinogenic health risk due to Cd and Cu intoxication. The Target Cancer Risk (TCR) values (2.26 × 10-4 - 1.34 × 10-1) recorded in the present study were all above the allowable range of 1 × 10-6 – 1 × 10-4 by United Nations Environmental Protection Agency (USEPA) indicating cancer risk through ingestion of these calyces. The risk of cancer among the metals for both samples followed the sequence Cu > Cr > Cd.


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