Assessment of the potential of Sunflower in Treating Some Contaminated Soils with Heavy Metals in Northwest Syria

Abstract

Agricultural soils in Northwestern Syria are among the most affected areas by heavy metal pollution due to various anthropogenic activities, posing significant threats to agricultural productivity and environmental health. This study aimed to evaluate the ability of three sunflower cultivars (Helianthus annuus L.) — American, Spanish, and Local — to accumulate and translocate heavy metals (chromium and cobalt) in three different locations in Idlib Governorate (Daraat Azza, Harim, and Sarmada). The physical and chemical properties of the soils were analyzed, and the cultivars were grown under controlled conditions for 45 days. Heavy metal concentrations in the roots were measured using Inductively Coupled Plasma Optical Emission Spectrometry (ICP-OES) following wet digestion with aqua regia. The Bioconcentration Factor (BCF), Translocation Factor (TF), and Removal Efficiency (RE%) from the soil were calculated.

The results revealed that BCF values for both elements were less than one across all treatments, indicating that sunflower exhibits excluder behavior rather than accumulative behavior. Most TF values were also below one. The removal efficiency was very low, ranging from 0.166% to 1.781% as a maximum during a single growing season. The Harim site significantly outperformed the other two sites in most parameters. Additionally, the death of the Local cultivar was observed in Daraat Azza soil, which may be attributed to the high accumulation of heavy metals in its roots.

The study concluded that sunflower, under the conditions of this study, is more suitable for phytostabilization than for phytoextraction, particularly for chromium. The Spanish and Local cultivars at the Harim site demonstrated the best overall performance across most indicators.