HEAVY METALS EVALUATION AND HUMAN HEALTH RISK ASSESSMENT OF FOUR BRANDS OF NIGERIAN PORTLAND CEMENT SOLD IN ZARIA, NIGERIA

Abstract

This study investigated the concentration of some select heavy metals (Cd, Cu, Fe, Pb, Zn, Ni, Mn and Co) in four cement samples, Bu, Da, Ak and Sk and assessed their health risks to potential users. Samples were collected from Samaru market, Zaria; and processed using Atomic Absorption Spectrophotometric method, following acid (aqua reggia) digestion. Fe reported highest concentration (542.99 mg/kg) in sample Ak, while Zn gave the lowest concentration value (1.016 mg/kg) as detected in Da). Cd concentration ranked in the order Da ˃ Ak ˃ Sk ˃ Bu; Cu ranked Da ˃ Ak ˃ Sk ˃ Bu; Fe ranked Ak ˃ Da ˃ Sk ˃ Bu; Pb ranked Da ˃ Ak ˃ Sk ˃ Bu; Zn ranked Ak ˃ Sk ˃ Bu ˃ Da; Ni ranked Ak ˃ Sk ˃ Da ˃ Bu; Mn ranked Sk ˃ Ak ˃ Da ˃ Bu and Co ranked Ak ˃ Sk ˃ Da ˃ Bu. Human risk assessment arising from exposure to heavy metals was validated from the result by estimating daily heavy metal intake and then computing the cancer and non-cancer risks (ILCR and THQ). Hazard Quotient HQ) and Health Index (HI) for adult and children exposure pathways was also determined. Metals under consideration were found to be below the threshold limit (10-6-10-4) and similar result was recorded for the cumulative cancer risk (ΣILCR) of the studied Portland cement. Metal content in all samples in the immediate does not pose cancer or non-cancer risks.