Abstract:
The content and distribution characteristics of heavy metal elements in marine sediments are key indicative parameters for measuring the status of marine environmental pollution and tracing the process of environmental evolution. In this study, surface sediment samples were analyzed for six heavy metals and organic carbon (OC), which were collected from the adjacent sea area of Lanshan Port, Rizhao Port between 2021 and 2024, and the temporal and spatial distributions as well as geochemical characteristics of each element were discussed. The content ranges of six heavy metals (Cu, Pb, Cd, Cr, Zn, Hg) in the surface sediments of the study area were 10.4-27.9, 10.5-26.3,
0.0366-0.160, 23.8-75.9, 41.4-122, and (0.008 50-
0.0938) µg/g, which were generally at the level typical of port marine areas . In the time series, although the contents of Cu, Pb, Cd, and Zn exhibited interannual fluctuations, they tended to be stable overall; the contents of Cr and Hg showed a decreasing trend year by year. Affected by mixed anthropogenic activities closely associated with port operations and industrial activities, the heavy metals in port-area sediments generally exhibit a spatial distribution characterized by high concentrations in the nearshore zones of the port, while also showing certain interannual variations. The levels of Pb, Cr and Hg in the sediments were at a clean level; Cu and Zn ranged from clean to slightly polluted; while Cd, although generally slightly polluted, showed locally moderate pollution in 2024; Overall, the marine sedimentary environment was at a low to moderate ecological risk level of heavy metals.