Determination and risk assessement of heavy metals via intake of spinach (Amaranthus Caudatus) from wastewater used for irrigation in Bauchi suburb
Rilwan Zakiyya Musa, Auwalu Lamido, Sale Aisha, Suleiman UA
This research determined the concentration of some selected heavy metals (Zn, Mn, Cd, Cu, Cr and Pb) in irrigation and non-irrigation soil, wastewater used for irrigation, and irrigated and non-irrigated Spinach (Amaranthus caudatus) using Atomic Absorption Spectrophotometer (AAS). The research reveals that, the heavy metal concentrations in wastewater (0.01-0.39 for Zn, 1.36-1.27 for Mn, Cd ND, 0.05-0.07 for Cu, 0.05-0.42 for Cr and 0.01 for Pb in mg/dm3 at Gwallaga, and 0.0-0.04 for Zn, 0.17-0.23 for Mn, Cd ND, 0.05-0.09 for Cu, 0.0-0.11 for Cr and 0.0 for Pb in mg/dm3 at Gombe road ) were within the permissible limits of World Health Organization [WHO] (2001), except Mn and Cr of Gwallaga wastewater. The concentrations in soil (50.0-83.0 for Zn, 508.0-554.0 for Mn, Cd ND, 13.5-17.0 for Cu, 17.5-23.0 for Cr and 0.0-1.0 for Pb in mg/kg at Gwallaga irrigation soil, 56.5-64.0 for Zn, 513.0-556.55 for Mn, Cd ND, 10.0-11.5 for Cu, 8.5-12.5 for Cr and 0.0-0.5 for Pb in mg/kg at Gombe road irrigation soil) were within the permissible limits of WHO (2001). The concentrations in Amaranthus caudatus (23.5-35.7 for Zn, 35.5-63.5 for Mn, Cd ND, 11.0-17.7 for Cu, 0.0 for Cr and 0.0-0.5 in mg/kgat Gwallaga irrigation site, and 24.0-75.5 for Zn, 52.5-133.0 for Mn, Cd ND, 8.5-13.0 for Cu, 0.0 for Cr and 0.0-0.5 for Pb in mg/kg at Gombe road irrigation site, and 25.0-25.5 for Zn, 74.5-75.5 for Mn, Cd ND, 5.0-5.5 for Cu, 0.0 for Cr and 0.0 for Pb in mg/kg at non-irrigation site) were within the permissible limits of WHO (2007). The enrichment factor (EF) shows that, Cu has the highest EF value (1.6727 and 1.4450) while Cr and Pb have least EF value (0.0000). Therefore there is high translocation of Cu from soil to the Amaranthus caudatus plant. The Metal Pollution Index (MPI) reveals that, the Amaranthus caudatus cultivated during rainy season (non-irrigation) have higher MPI, therefore may pose hazards to human health. The Health Risk Index (HRI) for metals of this research were found to be less than 1. This research recommended to be monitoring plants cultivated during rainy season (non-irrigation).