Evaluation of Sixteen Priority Polycyclic Aromatic Hydrocarbons in Sediment and Impacts on Benthic Marcoinvertebrate Community Structure of the Lagos Lagoon

Abstract

The Lagos lagoon in Nigeria, receives myriads of organic wastes containing Polycyclic Aromatic Hydrocarbons (PAH). Sixteen (16) PAHs in the sediment and their effects on community structure of the macrobenthic organisms in Apapa, Commandor Channel and Okobabaof the Lagos lagoon were monitored. PAH levels were determined using Hewlett Packard Gas Chromatograph 6890 with flame ionization detector. The levels of PAHs in the sediment samples from Commandor Channel and Okobaba ranged from 0.030- 0.493 mg/kg and 0.010- 0.490 mg/kg, respectively. The highest total PAHs was recorded in the Commandor channel station (0.201 mg/kg). The results of the marcobenthic community structure showed that the species richness was 2.509 in Okobaba. 2.950 in Apapa and 2.911 in Commandor Channel. The highest (178) and lowest (82) number of organisms was recorded in the Okobaba and Apapa respectively. Capitella capitata was the main hydrocarbon pollution indicator species identified in the impacted aquatic stations. There was generally high levels of hydrocarbon, low biodiversity which indicated stressed and contaminated study areas. Continuous monitoring of the level of PAHs and its effects on benthic community is necessary for proper management and containment of organic pollution within the Lagos lagoon