Phytoremediation Efficiency of Flax (Linum usitatissium L.) of Heavy Metal-Conataminated Soil in the Kwashe Industrial Region Using Soil Amendments

The study was conducted in the contaminated soils surrounding the petroleum refineries and iron scrap recycling factories in the Kwashe Industrial region, Duhok Governorate, Kurdistan Region of Iraq. Soils were taken from the surface at a depth of 0-20 cm. A pot experiment was carried out in a greenhouse to evaluate the effectiveness of using chelating agents such as humic acid and biochar at a concentration of 5 g kg⁻¹ of soil and ammonium nitrite (NH₄NO₃) at a concentration of 230 mg kg⁻¹ of soil, as well as the control. Flax (Linum usitatissium) was used to remove Zn, Cd, and Pb from the contaminated soil. The results showed a significant increase in Zn, Pb, and Cd in flax shoots and roots when treated with different amendments. The high uptake of metals with the addition of amendments was in the following order: BC > HA > AN, while for roots, the increase was in the following order: HA > BC > AN. Biochar effectively enhanced the uptake and accumulation of Zn and Pb in flax shoots, while the humic acid enhanced the uptake of Cd in flax shoots. The results also revealed that flax is successful for accumulating these metals in its shoots and roots, but the roots accumulated much more than the shoots, and the bioconcentration factor (BCF > 1) and the translocation factor (TF ˂ 1) showed that flax roots could be used as a good phytostabilizer for those soil that has been contaminated with Zn, Pb, and Cd