Environmental impacts of abandoned dredged soils and sediments Available options for their handling, restoration and rehabilitation

Aim and background  

In the process of creating safe navigable waterways for oil exploitation, the companies operating in the Niger Delta generate tons of sulfidic spoils. These are often deposited over bank, mostly upon fringing mangroves, and abandoned. This leads to a myriad of environmental problems. The extent of these impacts is not exactly known, but was inferred from the activities of oil companies operating in the area. This paper describes the impacts following the disturbance of sulfidic sediment through dredging and by subsequent poor spoil management practices. Environmental impacts of exposed and abandoned sulfidic sediments. The practice of dumping and abandoning sulfidic dredged spoils along canal banks triggers a series of environmental problems leading to extreme acidification, heavy metal pollution, and general habitat degradation which prevent the re-colonization of the sites by native species. The resultant spoil dumps remain bare for several years and they become colonized by invasive species later. Later still they may become attractive to the local population as sites for houses, fishing camps and home gardens, which is nevertheless regarded as a positive impact.