Study of Estuarine Processes (Adsorption and Desorption) Under the Effects of Salinity, Dissolved Organic Carbon, Nitrate and pH

Estuaries are very important aquatic systems due to importing/exporting large amounts of organic and inorganic materials from natural and anthropogenic sources to seas.

In the present study, suspended particulate matters (SPMs) were collected from Navrud River in to laboratory and sequential extraction procedure was conducted to determine element concentration. Adsorption and desorption of heavy metals (Cu, Zn, Pb, Ni, and Mn) was determined under the effect of various parameters (Salinity, DOC, pH and Nitrate).

Based on the results of adsorption and desorption testing, when SPMs enter estuarine mixing zone at different salinities, Cu, Ni and Zn adsorbed to SPMs by 6.41, 3.03 and 2.09, respectively. Mn and Pb desorbed from SPMs by 97 and 2.09 ppm. Base on cluster analysis, Nitrate and pH dominate the adsorption and desorption of Mn and Pb during experimental blending. Also, salinity and dissolved organic carbon control adsorption and desorption of Ni and there was a high correlation between this element and salinity and DOC.

Water resource managers will make better decisions with more accurate information, the actual amounts of heavy metals transported by rivers to the sea are different from those taken for absorption and desorption. Therefore, the absorption and desorption of heavy metals in the estuary is of great importance due to the possibility of different salinities.