Role of cosubstrate and bioaccessibility played in the enhanced anaerobic biodegradation of organochlorine pesticides (OCPs) in a paddy soil by nitrate and methyl...

Abstract

Abstract The present study was conducted to investigate the anaerobic biodegradation potential of biostimulation by nitrate (KNO 3) and methyl-β-cyclodextrin (MCD) addition on an aged organochlorine pesticide (OCP)-contaminated paddy soil. After 180 days of incubation, total OCP biodegradation was highest in soil receiving the addition of nitrate and MCD simultaneously and then followed by nitrate addition, MCD addition, and control. The highest biodegradation of chlordanes, hexachlorocyclohexanes, endosulfans, and total OCPs was 74.3, 63.5, 51.2, and 65.1%, respectively. Meanwhile, MCD addition significantly increased OCP bioaccessibility (p< 0.05) evaluated by Tenax TA extraction and a three- compartment model method. Moreover, the addition of nitrate and MCD also obtained the highest values of soil microbial activities, including soil microbial biomass carbon and …