Invitation for Attending Science Seminar

Organizer:             College of Natural and Computational Sciences

Date:                     14.10.2021/Thursday, afternoon 2:30PM, B-130/Room - 408.

Seminar topic:       Heavy Metals in Foods from Hawassa Industrial Zone, Hawassa, Ethiopia:

                              Health Risk Assessments.  

 Dr. Samuel Bekele, PhD in Environmental Toxicology

 Abstract: The concentrations of heavy metals (Cr, Co, Fe, Ni, Cu, Zn, As, Cd, Hg, Pb and Mn) were determined using Inductively Coupled Plasma Mass Spectrometry (ICP-MS). The human health risks due to ingestion of heavy metals through the consumption of vegetables, milk and fish were assessed based on the target hazard quotients (THQ), hazard index (HI) and target cancer risk (TCR). Mean concentrations of metals in cabbages decreased in the order Zn>Cu>Ni>Cr>Cd>Pb>As the same in potatoes revealed Zn>Cu>Ni>Cr>Pb>As>Cd. Mean concentrations of Zn, As and Cd in cabbages as well as mean concentrations of As and Cd in potatoes were above the safety limits. Assessment of THQ indicated no human health concern from consumption of both cabbages and potatoes grown in the areas, except As. However, effects of all the metals put together may affect human health as revealed by the high HI. Mean concentrations of Zn, Fe and Cu in cow milk were above the maximum tolerance limits.  Assessment of THQ indicated no human health concern from consumption of milk except for Zn. However, all heavy metals put together may affect human health as revealed by HI. In the same way, assessment of TCR revealed no human health concern from consumption of cow milk. Average concentrations of metals in muscle tissues of C. gariepinus and O. niloticus decreased in the order: Zn>Fe>Se>Cu>Hg>Hg>As>Ni>Cr>Co>Pb and Zn>Fe>Se>Cu>Hg>As>Ni>Cr>Pb>Co, respectively. Mean concentrations of Hg and As in muscle tissues of C. gariepinus and O. niloticus were above the safety limits set by WHO/FAO. Assessment of THQ indicated no human health concern from consumption of these fish species except for Hg. However, all heavy metals put together may affect human health as revealed by the high HI. Assessment of TCR revealed that there is no human health concern from consumption of these fish except for As. Consumption of food items from Hawassa Industrial Zone may leads to health risks. Therefore, regular monitoring of heavy metals level in vegetables, cow milk and fish as well as policy interventions with respect to waste disposal are recommended to protect the health of the public.