Investigation of the Effectiveness of Oil Spill Dispersant Application in Nigerian Mangrove Creek Environments

The application of chemical dispersants to oil spills in mangrove creek environments is technically contested due to the complex hydrodynamics, biological sensitivity, and restricted water volumes characteristic of these ecosystems. This study investigates the effectiveness and environmental consequences of dispersant application in simulated spill scenarios representative of the Niger Delta mangrove creek system. Adopting an experimental laboratory methodology, the research uses mesocosm experiments to assess the dispersion effectiveness of two commercially available dispersants against crude oil of the Bonny Light and Forcados blend specifications under low-flow conditions typical of mangrove creeks. The study measures oil dispersion efficiency, droplet size distribution, dispersant-to-oil ratios, and sub-lethal biological effects on sentinel organisms including mangrove oyster larvae and mud crab juveniles. Results indicate that both dispersants achieve reasonable oil dispersion under higher energy conditions but demonstrate significantly reduced effectiveness at the low-flow conditions characteristic of mangrove creek interiors. Biological assays reveal that dispersant-treated oil mixtures induce greater physiological stress responses in test organisms than untreated oil at equivalent concentrations, suggesting ecological trade-offs. The study contributes novel experimental data to the ongoing scientific debate on dispersant use appropriateness in mangrove environments, providing a basis for evidence-based policy revision of Nigeria's National Oil Spill Contingency Plan. Keywords: oil dispersants, mangrove creeks, Niger Delta, oil spill response, ecological impact