Comprehensive Evaluation of some Heavy Metals in Dust Deposited on Eucalyptus Tree Leaves and their Health Effects in Erbil City, Northern Iraq

In Erbil City, Northern Iraq, an evaluation was conducted to determine the pollution level and health effects caused by heavy metals found in dust collected from tree leaves. Throughout June and July 2022, thirty samples of dust were taken from eucalyptus leaves. These samples were collected from various locations including industrial areas, streets, parks (green areas), and residential sites. The concentration of heavy metals including As, Cd, Co, Cr, Cu, Mn, Ni, Pb, V, and Zn was determined using Inductively Coupled Plasma – Mass Spectrometry (ICP-MS). To assess the contamination level of the dust with heavy metals, various indices and models were utilized; these included the geo-accumulation index (Igeo), enrichment factor (EF), contamination factor (CF), and pollution load index (PLI). In addition, the Potential Ecological Risk Index (RI) and health risk assessment model were evaluated using the Hakanson and USEPA methods, respectively. The findings revealed that the metals' concentrations followed a descending order of Mn> Zn> Ni> Cr> Cu> V> Pb> Co> As> and Cd. The Igeo data showed that the dust in the area of study was clear of As, Co, Cr, Mn, Pb, and V pollution, unpolluted to moderately polluted with Cd, Cu, while moderately polluted with Ni, and Zn. The CF results indicated that the degree of dust pollution was low for V, moderate for As, Cd, Co, Cr, Cu, Mn, and Pb, and considerable for Ni and Zn. According to the EF calculation results, As, Cd, Co, Cr, Cu, Mn, Pb and V all have deficiencies or very minimal enrichments, but Ni has a moderate enrichment and Zn has a moderate to significant enrichment. The Er values exhibited that the Er was classified as low potential risk for As, Co, Cr, Cu, Mn, Ni, Pb, V and Zn except Cd which indicate moderate potential ecological risk. The RI value is classified as low ecological risk for heavy metals in all sampling sites. The results of the health risk assessment revealed that the examined heavy metals pose no non-carcinogenic danger to children and adults, while Cd, Co, Ni, and Pb do not represent a carcinogenic danger to children or adults. The risk of As and Cr on human being is within acceptable limits.