Effect of Nitrification Inhibitors on Degradation of Surfactants in Soils

Abstract

Abstract This study investigated the effects of nitrification inhibitors (NIs) on the degradation of two selected surfactants, an anionic surfactant, linear alkylbenzene sulfonates (LAS), and a nonionic surfactant, Brij 30, in soils. Soils were treated with different NIs, mixed with LAS or Brij 30 and incubated. Results revealed that the addition of NIs, such as thiourea (TU), dicyandiamide (DCD), and hydroquinone (HQ), could significantly inhibit the degradation of surfactants and expand their half-lives in soil. When the initial concentration of NIs was 2.5 mmol/kg soil, their inhibition effects followed the order of HQ > TU > DCD for LAS and HQ > DCD ≈ TU for Brij 30. In addition, significant differences between nonsterile and sterile treatments demonstrated that microorganism activity degradation plays a major role in the degradation of surfactants. Degradation efficiency of surfactants in soils varied with initial NIs concentration and environmental factors such as culture temperature and soil moistu...