Sources and Mixing of Dissolved Salts in Estuaries

Prior to discussing the factors that control concentrations of the major dissolved components in rivers, estuaries, and oceans, it is important to discuss the operationally defined size spectrum for different phases (dissolved, colloidal, and particulate) of an element. The conventional definition for dissolved materials is the fraction of total material that 

The sources of salts in rivers are primarily derived from the weathering of rocks in the drainage basin of rivers and estuaries, in addition to human activities (e.g., agriculture) 

River Sediment discharge (106 ty 1) Sediment discharge rank Water discharge (109 m3 y 1) Water discharge rank Drainage basin area (106 km2) 

Element Surficial rock concentration (mg g 1) Soil concentration (mg g 1) Particulate concentration (mg g 1) Dissolved concentration (mg L-1) Particulate load (106 tons y-1) Dissolved load (106 tons y-1) River particulate/ rock Particulate/ (particulate+ dissolved) 

Elements with no gaseous phase only. Particulate and dissolved loads based, respectively, on the total loads, 15.5 x 10 tons solids y-1 and 37,400 km3 water y 1. Data sources Martin and Meybeck (1979) Martin and Whitfield (1981) Meybeck (1979, 1982). 

---