Document Type : Research Paper

Authors

• Mahshid Souri ¹
• Mina Bayat ²
• Saeedeh Nateghi ¹
• Parvaneh Ashouri ¹

¹ Assistant Professor, Rangeland Research Division, Research Institute of Forests and Rangelands, Agricultural Research, Education and Extension Organization (AREEO), Tehran

² Research expert, Rangeland Research Division, Research Institute of Forests and Rangelands, Agricultural Research, Education and Extension Organization (AREEO), Tehran

Abstract

Background and Objectives:
Heavy metals are major soil pollutants due to their toxicity and persistence. Mining activities are a significant source of pollution in natural ecosystems. With its numerous mines, the Khaf region is a case in point. Identifying plants capable of absorbing metals from contaminated soils is crucial for phytoremediation efforts. This study investigated the phytoremediation potential of three plant species – Artemisia sieberi, Salsola richteri, and Scariola orientalis – in the iron mine area of Khaf city, Razavi Khorasan province, Iran.
Methodology:
All plant species were first surveyed at distances 500, 1000, and 3000 meters from the mine to determine the dominant vegetation type. Three species belonging to this dominant type were then selected for heavy metal analysis. Plant samples were collected from different parts (leaves, roots) of these dominant species, along with soil samples from around their roots, at varying distances from the mine and in the direction of the prevailing wind. A total of 36 plant and 36 soil samples were analyzed for copper, iron, and lead using inductively coupled plasma (ICP) to determine metal contamination levels. Plant remediation potential was assessed using various phytoremediation indicators.
Results:
Significant differences in phytoremediation indicators were observed among the plant species. Salsola richteri exhibited the highest bioconcentration factors (BCF) for lead (1.38), iron (1.37), and copper (1.99), and the highest bioaccumulation coefficients (BAC) for lead (1.55), iron (1.72), and copper (1.95). This indicates Salsola richteri's strong ability to accumulate these metals.
The highest lead soil pollution index (2.64) was found around Artemisia sieberi, signifying moderate lead pollution exceeding natural levels in this plant's habitat. The highest iron contamination was observed in the soil around Artemisia sieberi and Scariola orientalis.
Conclusion:
Metal concentrations in shoots, roots, and soil were highest at 500 meters from the mine and decreased with increasing distance. Soil analysis revealed higher average concentrations of the studied elements compared to global soil values. Notably, high concentrations of copper (490 mg/kg), lead (343 mg/kg), and iron (49000 mg/kg) were observed.
At 500 meters from the mine, Salsola richteri displayed BCF values of 1.4, 1.5, 1.45, and 1.02 for lead, iron, copper, and BAC values of 1.7, 1.8, 1.4, and 1.34, respectively. Based on these results, Salsola richteri shows promise as a suitable plant for decontaminating soils in the Khaf mine area.
 

Keywords

• rangeland species
• heavy metals
• bioremidiation
• soil pollution
• Khaf city