Four types of attenuation of phenol and cresols in microcosms under simulated marine conditions: A kinetic study

Abstract

Phenol, o-cresol, m-cresol, and p-cresol were selected to conduct microcosm experiments to examine their attenuation under simulated marine conditions, aiming at estimating natural attenuation and the contribution of oxidation, photolysis, biodegradation, and volatilisation to total attenuation of phenol and three cresols in the marine environment. The development of attenuation in microcosms showed the relevance of the pseudo-first-order kinetic for all phenols. The half-lives of phenol, o-cresol, m-cresol, and p-cresol attenuation under optimal conditions were 7.9, 4.3, 5.3, and 4.4 d, respectively. Attenuation kinetics was proposed to analyse the natural attenuation of phenol and cresols. The leading attenuation type of phenol, o-cresol, and p-cresol was volatilisation, and the attenuation rate constants (K_v) were 0.0356, 0.0687, and 0.0710 d^-1. Photolysis (K_p: 0.0584 d^-1) was the major attenuation type for m-cresol. Biodegradation of phenol (K_b: 0.0021 d^-1) and m-cresol (K_b: 0.0049 d^-1) were extremely inhibited. The rank between the contributions of the four types of attenuation to total attenuation differed between phenol and the three cresols. The attenuation kinetics proposed in this study possibly demonstrated the attenuation of the phenol and cresols in microcosm. This new reaction kinetics can be used in the analysis of natural attenuation of chemical substances.

Keywords: Attenuation; Kinetics; Marine; Microcosm; Phenols.