Environmental implications of spatial and temporal distributions of multiple metallic elements in marginal marine sediments from Eastern Hainan Island, South China Sea

PurposeThis study investigated the spatial and temporal changes of elemental concentrations and their influencing factors, based on geochemical analysis of four sediment cores collected from the eastern shelf of Hainan Island, South China Sea, with different distance gradients from the coast.MethodsSamples used in the study, the four sedimentary cores C1, C2, C3, and C4, were all collected from the eastern Hainan shelf in the South China Sea. The concentrations of trace elements were measured by inductively coupled plasma-mass spectrometry (ICP-MS). We use X-ray fluorescence spectrometer (XRF) to measure concentrations of major elements. Combined with MS, TN, TOC, and particle size data, and then, multiple statistical analysis methods including correlation, principal component, and cluster analyses, these are comprehensively used.ResultsSpatially, the contents of metallic elements are closely related to offshore distance. In terms of temporal distribution, the concentrations of Cu, Zn, As, Pb, Ni, and Cr overall increase from the bottom toward the surface.ConclusionThe cores show a simultaneous increase with the economic and social development of Hainan Island and the implementation of related policies. The metallic and metalloid elements in the sediments are mainly affected by the input of terrigenous debris and maritime materials. Redox conditions may also influence the geochemical characteristics of some elements such as As and Cr.

Automated summary

This study investigated the spatial and temporal changes of elemental concentrations and their influencing factors in sediment cores collected from the eastern shelf of Hainan Island, South China Sea. The results showed that the contents of metallic elements were closely related to offshore distance, and the concentrations of Cu, Zn, As, Pb, Ni, and Cr increased from the bottom toward the surface. The metallic and metalloid elements in the sediments were mainly influenced by the input of terrigenous debris and maritime materials, and redox conditions may also affect the geochemical characteristics of some elements such as As and Cr.