Human health risk assessment of heavy metals in dust samples of quarry clusters in Umuoghara Quarry Industry, Ebonyi State, Nigeria

Abstract

Background: Heavy metals exert toxic effects on body systems with the degree of toxicity directly dependent on the daily intake. The safety of workers from heavy metal exposure has not been adequately evaluated despite the presence of many quarry industries. Objective: This study seeks to determine the inhalational risks of heavy metals in the dusts of Umuoghara quarry industry in Ebonyi state.

Methodology: Three quarry dust samples from four clusters of the study location were subjected to atomic absorption spectrometer to determine the concentrations of Cadmium (Cd), Zinc (Zn), Lead (Pb), Copper (Cu), and Nickel (Ni). The estimated daily intake (EDI), hazard quotient (HQ), hazard index (HI) and incremental lifetime cancer risks (ILCR) of the heavy metals were calculated.

Result: The results showed high concentrations of the heavy metals in the dust samples. The EDI of the heavy metals was found in the order of Ni> Pb> Cd for carcinogenic and Zn>Ni>Cu>Cd>Pb for non-carcinogenic. The HQ and HI of the heavy metals were normal (<1). The ILCR was also normal (≤ 10-5). There was no significant difference (P>0.05) in the concentration of the heavy metals in the dusts of the four clusters.

Conclusion: The result showed permissible limits of the heavy metals in the quarry dust which may not pose any non-carcinogenic or carcinogenic risk to the quarry workers. However, as toxicity is dependent on dose, duration and type of heavy metal exposure, there is a need for adherent use of personal protective measures and periodic medical check-ups by the workers with close monitoring by relevant authorities.