Study on the accumulation of heavy metals in coastal sediments in Hai Phong city

Abstract

This study aims to investigate the spatial distribution and accumulation mechanisms of heavy metals (Cu, Pb, Zn, Cd, and As) in coastal sediments of Hai Phong, Vietnam, based on sediment grain size composition, metal concentrations, and correlation analysis. The results reveal a clear spatial heterogeneity in sediment characteristics, with fine - grained sediments (silt - clay) dominating estuarine and tidal flat areas, while coarser sediments (sand) prevail in offshore zones. Among the studied metals, Zn exhibits the highest relative abundance, followed by Pb and As, whereas Cu and Cd are present at lower levels. The concentrations of heavy metals are generally higher in estuarine regions and decrease seaward, indicating significant influence from land - based sources. Pearson correlation demonstrates strong positive relationships among Pb, Zn, and As, suggesting a common anthropogenic origin and similar accumulation behavior associated with fine particles and organic matter. Overall, the accumulation of heavy metals in the study area is governed by a combination of sediment grain size, terrestrial inputs, and hydrodynamic conditions. Estuarine and tidal flat zones act as effective sinks for heavy metals and should be prioritized in environmental monitoring and management strategies.