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


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.

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Scheme 1

(Reproduced with permission from Weelink et al. 2010 and Eggen et al. 2010)

Scheme 2

(Reproduced with permission from Kibet et al. 2016 and Weelink et al. 2010)


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The authors are grateful to Prof. Vincent Nyamori of the University of KwaZulu-Natal, College of Engineering and Science for facilitating the GC-MS data reported in this work. NRF Kenya is thanked for partially funding this study.

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Correspondence to Joshua K. Kibet.

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Laurence, M., Kibet, J.K. & Ngari, S.M. The Degradation of O-ethyltoluene and 1,3,5-Trimethylbenzene in Lake Naivasha Wetland, Kenya. Bull Environ Contam Toxicol 101, 288–293 (2018).

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  • Benzene derivatives
  • Contaminants
  • Decay rate
  • Degradation
  • o-Ethyltoluene
  • Wetland