Seabed Pollution Near Industrialized Seaports: An Enhanced Multivariate Technique to Explore Trace Element Dynamics

Abstract

[EN]This work focuses on the coastal ecosystem of the Gijón bay, located in Asturias, Northern Spain. This bay area is the site of a large, industrialized port and as such its coastal ecosystems are vulnerable to anthropogenic damage due the accumulation Potentially Toxic Elements (PTEs) in marine sediments. To assess the levels of industrial pollution in Gijón’s coastal ecosystem, we collected sediment samples from the three main zones of its port-area beach system: swash (subaerial); surf; and wave-shoaling (nearshore) zones. A total of 41 elements and RREE were analyzed using advanced statistical techniques, including CUR decomposition, PCA, Sparse PCA, Clustering Disjoint Biplot, and Empirical Bayesian Kriging. Results show elevated concentrations of As (up to 22.3 ppm), Zn (up to 60.1 ppm), Pb (up to 22.1 ppm), and Hg (up to 1130 ppb) in localized areas, with pollutants being enriched near the port mouth. Principal components associated with mainly natural processes while the contribution of anthropic sources is explained by over 13.7% of the cumulative variance. These findings reveal three dominant geochemical profiles: detrital inputs (alkali and silicate elements), sedimentary processes (e.g., Ti, Fe), and industrial pollution (notably Pb, Zn, and Cu), whose spatial distribution were studied with geostatistics. This comprehensive approach highlights the spatial variability and anthropogenic origin of PTE contamination in the seabed sediments of Gijón Bay and serves as a guideline for similar researches.