Occurrence and Diagenetic Evolution of Perylene in the Sediments of Oginigba Creek, Southern Nigeria

Abstract

Perylene and penta-aromatic hydrocarbons were determined in sediments as part of a study that was dedicated to the aquatic ecosystem of Oginigba Creek (southern Nigeria) in order to carry out a critical corroboration of occurrence and diagenetic evolution of perylene in the sediments of the creek. The results show that the annual mean levels of perylene ranged from 396.27– 507.19 mg/g dry weight at the various Stations. The observed values for total penta-aromatic hydrocarbons were high (867.3-1243.14mg/g dry weight) in all the stations sampled One origin index or concentration ratio of Ip/Ip+BghiP was also used to evaluate the suitability of the penta-aromatic hydrocarbons as a tracer to distinguish between contaminations arising from different sources. The values for the sampling stations therefore ranged from 0.41 to 0.81. A critical appraisal of the PAH index, consequently, suggested that petroleum combustion is the major penta-aromatic hydrocarbon source in the sediments of the creek. The PAH group profile shows that perylene was high in the sediments and would pose apparent effects in fauna. The high concentration of perylene in the sediments was also indicative of an in situ biogenic derivation. Furthermore, a concentration of perylene ³ 31.88% of total penta-aromatic hydrocarbons established a credible diagenetic origin.