Investigating the Effects of Salicylic Acid and Rice Husk Ash on Pb and Cd Concentration in Pinto Bean Plants Grown in Soil Contaminated with Diesel Oil and Heavy Metals

Background:  This study was conducted to investigate the effects of salicylic acid and rice husk ash on Pb and Cd concentration in pinto bean plants grown in soil that was contaminated with both diesel oil and heavy metals. Methods: The treatments in this study included the application of rice husk ash to soil at concentrations of 0 %, 4 %, and 8 % (W/W) as well as the foliar application of salicylic acid to pinto bean plants grown in soil contaminated with diesel oil, Cd, and Pb at concentrations of 0 %, 4 % and 8 % (W/W). After a growth period of 90 days, the pinto bean plant was harvested and the concentration of Pb and Cd in the plants was measured using Atomic absorption spectroscopy. In addition, the extent of diesel oil bio-degradation in the soil was determined.  Results: The results indicate a significant reduction in the concentration of Cd and Pb in pinto bean plants (by 11.7 and 15.4 %, respectively) due to the application of rice husk ash (8 % (W/W)) in the soil. Furthermore, the bio-degradation of diesel oil in the soil was found to be significantly enhanced, while the activity of plant enzymes APX and POX was observed to be decreased. Conclusion:  The interaction between rice husk ash and salicylic acid The reduction in Pb and Cd concentration was significantly influenced by, while the bio-degradation of diesel oil in the soil increased.