Cleanup and Restoration of 1000-ha of Oiled Mangroves, Bodo, Eastern Niger Delta, Nigeria

Abstract

A 1000 ha (2471 ac) area around the community of Bodo in Rivers State, Nigeria, was affected by two large pipeline spills in 2008 and numerous smaller discharges between 2009 and present, primarily related to oil theft, transport and indigenous refining. This paper describes the remediation of affected environments which represents the largest cleanup and restoration of a mangrove ecosystem due to oil-related damage ever undertaken and serves as a potential model for other areas of the Niger Delta similarly affected.Cleanup activities include: (1) raking / mixing of surface sediments to break up a thick algal mat and removal of heavily polluted dead mangrove debris while lesser-oiled (most common) debris is broken up and left in place to aid re-establishment of mangrove plants and animal life used as a food source by the Bodo Community; (2) pressure flushing using ambient water from adjacent channels; (3) compressed air with water from a barge-mounted system, (4) use of hard boom and sorbents around the work area to capture off-floating oil, and (5) manual collection of floating oil using sorbents and hand bailers, followed by transfer to a central collection point and disposal at a government approved facility. High-volume low-pressure flushing system proved effective in releasing much of the deeply penetrated oil without damaging the sedimentary structure of the mangrove platform. Innovative methods are continually being sought. After confirmation of cleanup requirements, former mangrove areas (~860 ha, 2125 ac) will be planted with mangrove seedlings to phytoremediate remaining oil. Close-out criteria are based upon visual assessment followed by chemical sampling to meet government approved risk-based site-specific target levels. Potential major impediments to the successful completion of this Project are community unrest, security issues and reoiling from illegal activities and pipeline operations.