HEAVY METAL TOXICOLOGICAL STATUS OF WHEAT SAMPLES FROM DISTRICT SWABI, PAKISTAN

Z. Khan*, E. Tariq and S. Hadi

Department of Chemistry, Women University, Swabi, 23430

*Corresponding Author’s Email: zahid.khan@wus.edu.pk

ABSTRACT

Wheat is the primary food requirement of Pakistan. Wheat flour is used to make the bread that is nearly irreplaceable for almost everyone who use it as a daily staple. With an average 339-gram per capita consumption, it can potentially become a serious source of food-based toxicity if the wheat crop is contaminated. In order to establish a toxicology profile of wheat crop for heavy metal contamination, seventy-six samples of wheat grains were collected from the markets across the district Swabi, Pakistan and were analyzed for eight common toxic heavy metals including Nickle (Ni), Cadmium (Cd), Lead (Pb), Copper (Cu), Cobalt (Co), Iron (Fe), Zinc (Zn) and Chromium (Cr) by employing the flame atomic-absorption spectrophotometry. The mean concentration level of all metals was used to calculate dietary exposure by wheat consumption in the local residents. These values were in turn used to establish the toxicological status in terms of potential health risks by assessing (a) “Target-Hazard-Quotient (as THQ)”, (b) “Health-Risk-Index (as HRI)”, and (c) the percentage of metals to the corresponding reference toxicological standards i.e., “Provisional-Tolerable-Daily-Intake (as PTDI)”, “Tolerable-Daily-Intake (as TDI)” and “Provisional-Maximum-Tolerable-Daily-Intake (as PMTDI)”. Among eight metals, HRI and THQ values were found to be less than 1, i.e., for Cd, Cu, Zn and Cr while greater than 1 for Pb and Ni. The percentage contribution of dietary exposure to their respective toxicological reference values for Cu, Co, Zn and Cd were found to be less than 100% and greater than 100% for Fe, Pb and Ni.