Controlling effects of terrestrial organic matter on metal contamination and toxicity risks in port sediments.

The contents of metals, total carbon, total nitrogen (TN), total organic carbon (TOC), and stable isotope composition (δ¹³C org and δ¹⁵N) of sediment organic matter (SOM) were investigated to explore the sources and spatial distribution of metals and SOM in the surface sediments (Kaohsiung Port, Taiwan). Results showed that TOC and metals in estuarine sediments are high, gradually decreasing toward the port entrances. The δ¹³C org , δ¹⁵N, and TOC/TN ratios indicate that SOM comes mainly from terrestrial sources. This study proposes a befitting model between metal pollution and toxicity risk index and SOM sources in port sediments by combining stable isotope composition, correlation matrix, and multiple linear regression analysis. The model indicates that the degree of metal pollution and toxicity risk in sediments are mainly affected by TOC terr content and SOM source. The results help to understand the influence of organic matter sources in port sediments on metal concentration distribution. [Display omitted] • The sediment organic matter (SOM) in port sediments mainly originated from land. • The sources and distribution patterns of SOM and metals are similar. • Estuarine sediments are enriched with metals and pose high toxicity risks. • The TOC terr , δ¹³C org and TOC/TN are the main factors affecting metal distribution. [ABSTRACT FROM AUTHOR]