Ecological Risk Evaluation of Heavy Metals in Soils near a Water Dam in Baljurashi, KSA, and Their Accumulation in Dodonaea viscosa

Abstract

Soil’s contamination with heavy metals is a serious issue, and assessing their levels, regulating their sources, and finding cost-effective technology to limit their toxic effect and soil cleanup are of high priority. The focus of this study was to find out the extent of priority hazard heavy metal contamination in soils close to the Al-Janabeen water reservoir dam in Baljurashi, KSA, and the extent of their accumulation in the Dodonaea viscosa Tacq plant. Soil and plant samples were analyzed for heavy metal concentration using inductively coupled plasma spectroscopy (ICPS). Quantitative single and integrated contamination indices were used to characterize and evaluate the degree of heavy metal contamination in soils. The biological concentration factor (BCF) and the translocation factor (TF) were utilized to determine the extent of transfer and accumulation of heavy metals in the D. viscosa plant. Soil analysis showed the presence of Mn, Cu, Zn, Co, Cr, and Pb among the prioritized heavy metals with Cu, Zn, and Pb values being higher than those in natural background levels. The mean concentration order was Fe > Mn > Zn > Cu > Pb > Cr > Ni > Cr > Co. The single contamination indices’ quantification indicated marked contamination due to Mn, Zn, Cu, Co, Cr, and Pb elements. While integrated contamination factors’ computation showed low ecological risk due to accumulative metals of concern, Nemerow’s index (NI) showed that Cu, Zn, and Pb were the three most abundant pollutants in the examined soils. Analysis of plant parts showed the presence of Mn, Cu, Ni, Zn, Co, Cr, Cd, and Pb at varying quantities in various plant sections. Both BCF and TF factors were less than one, indicating that the D. viscosa plant was limited in its ability to phytoextract and accumulate the metals from the soil. This study suggests more research to locate suitable native plants for phytoremediation and soil cleaning is required in addition to the appropriate planning and management of landfills in order to ensure agricultural sustainability.