Evaluation of the capability of Robinia pseudoacacia and Pinus eldarica for bioremediation of heavy metals (Pb, Cr and Ni) in urban areas of Hamedan, west of Iran

Monitoring of pollutants in urban ecosystems is of particular importance. Therefore, this study was conducted to evaluate the capability of Robinia pseudoacacia and Pinus elderica for biomonitoring of Pb, Cr and Ni in urban areas of Hamedan in 2023.

A total of 36 soils and 72 plant samples were collected from 12 sites. The contents of elements were determined using ICP-OES. Also, the values of PI, PLI, BAF, and CR indices were computed. 

The highest values of Pb, Cr, and Ni (mg/kg) in soil samples with 72.2, 67.5 and 101 values belonged to the commercial, industrial, and commercial sites, respectively. The highest average content of analyzed elements in unwashed and washed leaves/needles for Pb both belonged to the commercial areas; for Cr and Ni, all belonged to the industrial areas. The average values of PI followed the descending order of Cr > Ni > Pb. The average values of PLI varied from 1.22 to 1.34. Moreover, BAF values of Pb, Cr, and Ni of R. pseudoacacia leaves and P. elderica needles were found to be in the range of 0.100-1.00. Also, the highest mean values of CR of Pb and Cr were both found in P. elderica; and the highest mean value of CR of Ni was found in R. pseudoacacia.

R. pseudoacacia and P. elderica could be used as suitable and efficient species for monitoring and remediation of toxic elements from soil and air in polluted ecosystems.