Iranian Journal of

Background and Objective: Monitoring of traffic emissions is a good way to build a safe ecosystem for living organisms. Therefore, the present study was conducted to assess the feasibility of using Achillea wilhelmsii and Cardaria draba located along the suburban roads of Hamadan for Zn, Pb and Ni removal by their aerial and underground organs in 2020.
Materials and Methods: In this descriptive study, after selecting 3 sampling stations, a total of 126 plant samples and 63 soil samples were collected. In the laboratory, the samples were prepared, and were then digested with acid. Subsequentely, the concentration of each heavy metal was measured by inductively coupled plasma-optical emission spectroscopy (ICP-OES). Moreover, bioconcentration factor (BCF), bioaccumulation factor (BAF), transfer factor (TF) and metal accumulation index (MAI) were also calculated. Statistical analyses of the results were performed using SPSS statistical software.
Results: The mean values of BCF and BAF in both A. wilhelmsii and C. draba for all tested elements were greater than 1. On the other hand, A. wilhelmsii showed TF greater than 1 for zinc while C. draba showed TF greater than 1 for zinc and lead. The highest mean values of MAI in unwashed and washed shoots and roots of A. wilhelmsii were 98.48, 64.87 and 72.38, respectively.
Conclusion: Based on the calculated average values of BCF, BAF and TF of each elements, it can be argued that A. wilhelmsii and C. draba species have the potential of phytoextraction and Phytostabilization of the measured heavy metals and can be used for biomonitoring and bioremediation from soil and air in the heavy metals polluted areas.

Background and Objective: Evaluating the chemical speciation and bioavailability of heavy metals, along with identifying the effective parameters influencing their bioavailability, plays a key role in soil management and the improvement of agricultural lands. Therefore, this research was conducted to determine the origin, chemical speciation, and bioavailability of potentially toxic elements (PTEs) in the agricultural soils of the southern cities of Hamedan province.
Materials and Methods: In this study, 90 surface soil samples were randomly collected from a depth of 0–20 cm in agricultural lands. After preparing the samples in the laboratory, the elemental content was measured using an atomic absorption device. Texture characteristics, acidity (pH), salinity (EC), calcium carbonate content, organic matter, and exchangeable cations were determined using methods proposed by the Environmental Protection Organization. The relationships between the bioavailability of heavy metals and these characteristics were investigated using Spearman's correlation test.
Results: The average concentrations of manganese, cadmium, iron, cobalt, chromium, copper, nickel, antimony, and arsenic in the three studied cities were 267.63, 0.19, 4.20, 20.65, 90.49, 35.86, 70.84, 3.78, and 17.82 mg/kg, respectively. Sequential extraction results showed that manganese, copper, and nickel had the highest bioavailability, with concentrations of 6.76, 2.91, and 3.77 mg/kg, respectively. More than 70% of the bonds between heavy metals and soil were in resistant and residual fractions, indicating that heavy metals in the soil have a natural background.
Conclusion: The bioavailability of heavy metals in the soil environment is low, suggesting minimal potential for these metals to enter water, soil, and crops, and thus does not pose significant concern.