Enhanced Bioremediation of Field Agricultural Soils Contaminated with PAHs and OCPs

Abstract

Effect of different concentrations of ammonium chloride (NCL) and ammonium nitrate (NN)and surfactants such as Tween-80, HPCD and rhamnolipids on the bioremediation of PAHs and OCPs wasinvestigated. The results showed that the best optimum concentration of NCL and NN was 50 g·kg-1, and thePAHs degradation rate during 60 days of remediation was enhanced to 64.6% and 62.8% for NCL and NN,respectively, which was approximately 45, 17, 10% higher than those in the control group, soil only addedmicroorganism, soil added microorganism and tourmaline. OCP removal rates were 51.7% and 50.4 % for NCLand NN, respectively, which was 34% higher than the control group, 14% higher than the soil only addedmicroorganism, 9% higher than the soil added microorganism and tourmaline. The best dose of Tween-80,HPCD and rhamnolipids was 2, 0.5 and 0.2 g·kg-1. When they were applied, the PAHs degradation rate during60 days of remediation was enhanced to 69, 70.4 and 71.5%, respectively, which was approximately 52, 24and 17% than those in the control group, soil only added microorganism, soil added microorganism andtourmaline. Similarly, OCP removal rate was 42, 26 and 16% higher than those in the control group,microorganism -added soil alone, soil added microorganism and tourmaline. Additionally, nutrients and surfactantscan promote the generation of soil hydrogen peroxidase and invertase enzyme. Hence, the present studyprovides a promising combination remediation technology for the remediation of field soils contaminated byPAHs and OCPs.