Determinant factors for rehabilitation and solutions for sustainable development of Hann Bay (Dakar, Senegal)

The degradation of Hann Bay (Dakar, Senegal) has reached extremely high levels with serious environmental, health and social consequences. The presence of inorganic pollutants and microplastics in the habitants represent a threat to wildlife and human beings. Thus, this study, which looked at the key factors for rehabilitating Hann Bay, also proposes solutions for the sustainable development of this area of Dakar region. The target area includes about 500,000 residents and hundreds of industrial units, most of which do not have a suitable sanitation system. Socioeconomic surveys and sediment sampling were carried out in 2022 on eleven sites across the communes of Hann-Bel Air, Dalifort Foirail, Thiaroye-sur-Mer, Sicap Mbao and Mbao. The analysis of the collected sediment samples indicated that the limit values for lead and zinc set by Ministerial Order of August 9, 2006, have been exceeded at several sampling points, revealing that chemical pollution is still present in the bay and can lead to contamination of fishery resources or the escape of fish to the open sea. This alteration of the ecosystem may also explain frequent fry deaths noticed along the sites of Hann Marinas, Hann Pêcheurs and Cité ISRA. Further to socio-economic surveys carried out among residents and workers in local industrial units, the recommendations for the rehabilitation and the sustainability of the bay focus essentially on the implementation of protective and preventive measures, the application of regulations, the development of communication and sensitization strategies, the acquisition of equipment and the reinforcement of the monitoring/surveillance.