The Degradation of O-ethyltoluene and 1,3,5-Trimethylbenzene in Lake Naivasha Wetland, Kenya

Abstract

The primary degradation of benzene derivatives in aquatic environments occurs via microbial and chemical processes. This study investigated the kinetic degradation of o-ethyltoluene and 1,3,5-trimethylbenzene in the wetland of Lake Naivasha. Sediment samples were collected from 6:00 AM to 6:00 PM at intervals of 3 h during the dry season of December 2017. The sediment samples were air dried, ground into powder, followed by soxhlet extraction in a binary mixture of methanol and hexane in the ratio of 1:1. The extract was analyzed using gas chromatograph with mass selective detector. Variation in the concentrations of o-ethyltoluene and 1,3,5-trimethylbenzene with time was monitored kinetically. Accordingly, the half-lives for the degradation of o-ethyltoluene and 1,3,5-trimethylbenzene were 4.9 and 5.4 h, respectively, and their corresponding decay rate constants were 3.93 × 10^-5 and 3.56 × 10^-5 S^-1. 1,3,5-Trimethylbenzene was the most persistent contaminants in the wetland.

Keywords: Benzene derivatives; Contaminants; Decay rate; Degradation; Wetland; o-Ethyltoluene.