Function of Nitrate Ion and Tea Saponin Application Rates in Anerobic PAH Dissipation in Paddy Soil

Abstract

Abstract In the present study, KNO 3 and tea saponin (TS) were applied to investigate systematically the potential impact of their concentrations on dissipation of anerobic polycyclic aromatic hydrocarbons (PAH) in paddy soils. After 150 days of incubation, the highest removals for total, 3-, 4-, and 5 (+ 6)-ring PAHs were 84.3, 92.3, 85.6, and 69.3%, respectively, with the simultaneous application of 50 mM KNO 3 and 2% TS, w/w. Moreover, using response surface methodology, the theoretical maximum removal for total PAHs in the 80–100% range can be achieved at> 35 mM KNO 3 and> 1.5% TS, w/w. Meanwhile, Tenax® TA extraction and a first-three-compartment model method demonstrated that TS (w/w, 2%) could serve as an effective bioaccessibility-enhancing agent to increase the rapidly and slowly desorbing fractions of PAHs from 6 and 12% in the control to 29 and 42 …