Reduced plant uptake of PAHs from soil amended with sunflower husk biochar

Abstract

Biochar effect on the polycyclic aromatic hydrocarbons (PAHs) uptake by spring barley (Hordeum Sativum) was studied in model experiment conditions with Haplic Chernozem spiked by the high doses of benzo[a]pyrene (BaP) (400, 800 and 1200 µg kg-1), as the main marker of PAHs contamination. The relevance of the study is due to the BaP stability in natural environments and its carcinogenicity in relation to all living organisms. The express method of subcritical water extraction was used for BaP extraction from samples. The soil contamination by BaP contributed to the PAHs accumulation in soil and plants uptake from the polluted soil. It was found the 1% biochar application dose in the variant with 400 µg kg-1 contamination decreased the alone BaP and total PAHs content in soil and spring barley up to 50% compared to the contaminated variant. In soil contaminated with 800 µg kg-1 the 5% of biochar application led to the BaP content decreasing in the soil up to 56% and in the plants to 40-60%. Application of 5% biochar in the soil polluted with 1200 µg kg-1 led to the BaP and total PAHs content decreasing in soil up to 47% and 30%, respectively, plants the BaP content decreased up to 37-48%. Biochar 5% amendment effectiveness has been shown on the plants grown on the highly toxic variant contaminated with 1200 µg kg-1 BaP. The earing phase was inhibited in the spring barley plants growth at the most contaminated soil of the model experiment, whereas biochar application into the soil promoted the successful formation of the corn. The used biochar showed a high sorption capacity and its effectiveness under the soil remediation contaminated with BaP.

Keywords

• carbon sorbent
• vegetation experiment
• remediation of soil
• plant uptake
• pahs