Scientific and Cleanup Response to the Idoho-Qit Oil Spill, Nigeria

Abstract

On 12 January, 1998, a 24 inch pipeline from the IDOHO platform to the Mobil Qua Iboe terminal ruptured. This resulted in the release of approximately 40 000 bbl of Qua Iboe light crude oil into the marine environment. In response to the spill, cleanup and containment equipment were immediately deployed. Dispersant application played an important role in the cleanup response because the bulk of the oil remained offshore and was transported westward by prevailing currents, thus providing an extended opportunity for treatment at sea. As a result of dispersant application, natural dispersal and evaporation, over 90% of the oil was dispersed and evaporated offshore. Heavy shoreline oiling was limited and localized, with oiling of sensitive estuarine mangrove habitats limited to a few locations. Remnants of the spill that tracked 5–10 km offshore from the spill source were observed at Lagos harbor, about 900 km west of the spill site. Most of the exposed sand beaches in the spill zone self-cleaned within 2–3 weeks and cleanup of the limited number of heavily impacted shoreline areas recovered approximately 1000 bbl of oily waste. A national and international team of scientists was convened within 24 hours and initiated scientific studies to measure the short-term impact of the spill on environmental resources important to local human activities. Elements of the short-term scientific program were (1) an offshore component, including fisheries, benthos, chemistry, microbiology; (2) a riverine/estuary component, including extensive water analyses to detect any spill input to waters used by local settlements and chemical analysis of local fish market samples. The results of the short-term scientific study indicated that any initial environmental effects were limited and localized. Based on the initial scientific program, a larger follow-up scientific program was initiated on September 15, 1998. This involved a multi-disciplinary program with the following components: offshore fisheries and benthic studies; a shoreline fate and effects program; a study of impacts to estuarine mangrove habitats; and a study of any socioeconomic and human health effects. The study plan was based on comparisons of data from spill zone and non-spill zone locations. The key elements of the study design of this comprehensive longer term study are described.