Abstract:
This paper is the result of marine and environmental geological survey engineering.
Objective The environmental quality of surface sediments in Quanzhou Bay faces great ecological risks caused by heavy metals, but the researches focused on the influencing factors and potential sources were relatively weak.
Methods By collecting surface sediment samples in offshore area of Quanzhou Bay, the distribution characteristics and enrichment degree of heavy metals were summarized based on element and grain size analysis, and the potential ecological risk was assessed using Hakanson method in study area. Positive definite matrix factor analysis (PMF) and principal component analysis (PCA) were further used to apportion the sources of heavy metals contamination.
Results Grain size of surface sediments was low at the converging area of Jin river and Luoyang river, which were prone to enrich heavy metals. The order of surface sediments heavy metals enrichment factors was Hg > As > Cd > Pb > Zn > Cu > Cr > Ni. Overall ecological risk of surface sediments in Quanzhou Bay was moderate, and contribution of Cd to potential ecological risk was the highest (37.90%), followed by Hg (29.38%). Cr and Ni were mainly from rock weathering. Besides rock weathering, Cu, Zn and Pb were strongly affected by mining smelting. Cd and As were contributed by sewage disposal and fuel combustion, respectively. However, the sources of Hg were relatively complicated. Main sources of heavy metals in study area were mining smelting, rock weathering, sewage disposal and fuel combustion, and the contribution of them were 33.95%, 31.16%, 22.26% and 12.21%, respectively.
Conclusions The transport of land substances with surface water runoff was the main cause for the ecological risk of surface sediments in Quanzhou Bay, and furthermore it is necessary to strength the research on the fate and environmental behavior of Hg in different media in the future.
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