Oil Spill Impact on Benthic Fauna in Ogoniland Coastal Creeks, Rivers State

Decades of oil spill incidents in Ogoniland, Rivers State, South South Nigeria, have caused severe and persistent contamination of coastal creek ecosystems, with well-documented consequences for human health, agriculture, and aquatic biodiversity. This study assesses the current impact of oil contamination on benthic macrofaunal communities in three creeks within the Ogoniland remediation zone: Bodo, K-Dere, and Gokana creeks, three years following commencement of the Hydrocarbon Pollution Remediation Project remediation activities. Sediment cores are collected from contaminated and reference stations and analysed for total petroleum hydrocarbon concentrations, polycyclic aromatic hydrocarbon profiles, grain size, and organic matter content. Benthic macrofauna are extracted by wet sieving through 0.5-millimetre mesh sieves and identified to species level. Community structure metrics including abundance, species richness, diversity, and the AMBI biotic index are compared between contaminated and reference sites. Isotopic analysis of sediment organic carbon and nitrogen provides insights into trophic linkages. Findings are expected to reveal persistent depression of benthic fauna diversity and abundance at heavily contaminated stations, even after remediation, relative to upstream reference sites. The study evaluates remediation effectiveness and recommends continuation and intensification of remediation activities aligned with UNEP environmental assessment recommendations. Keywords: oil spill, benthic fauna, Ogoniland, biotic index, remediation assessment