The Siderurgia Nacional, S.A. (National Steelworks) is located in Seixal, on the left bank of Coina’s creek, one among several of River Tagus’ inlets, where silt build-ups (aggradation) prevent navigability for transporting this company’s materials and products.

Environmental laws required the characterization of the sediments for the degradation process of the River Tagus’ inlet which leads to the Siderurgia Nacional and which must be cleared in order to enable the navigation of the sea transportation for the Steelworks materials.

Nemus carried out, in collaboration with Consulmar, three separate field surveys to characterize the sediments deposits to be dredged, collecting sediment samples along the canal, on the seabed surface and in greater depth, for physico-chemical and toxicity analysis. The results of the physical and chemical analysis were subjected to statistical interpolations in order to assess the sediment contamination status. Based on this information, Nemus drafted distribution charts of the main parameters indicating contamination on the floor surface, between surface and maximum dredging reach, and below dredging maximum surface.

In addition to the field surveys for collection and analysis of sediments integrated in bigger studies, Nemus has conducted more than two dozen similar projects for different clients.