Trace Metals in Surface sediments 

Grain size and TOC content are two important parameters in controlling the behavoirs of trace metals contaminations.

 

Concentrations of metals are positivly and highly correlated with silt and clay contents while they are negatively correltated with sand contents.    

The results shows that TOC contents in sediment with coarser components are notably lower. TOC contents in sand and silty sand sediments have an average of 0.41% of the dry sediment weight and in clayey silt sediments 1.22% of the dry sediment weight.

 

Organic matter plays an important role in controlling the physicochemical behaviors of metals and has an influence of the bioavailability, reactivity and mobility of metals in sediment. In this study, TOC shows a significant correlation with all the metals studied, but it might not be a major factor affecting the spatial distribution of metals in the surface sediments in this area. It is more likely that the distribution of TOC in the sediments itself is governed by grain size.