Abstract:
The behavior of dissolved and particulate iron and manganeses were studied as a function of salinity in the Bangpakong Estuary. Field samplings were made during the flood (November, 1984) and dry (May, 1985) seasons, and experiments concerning mixing of river water and seawater were made in various rations to create mixtures of varying salinities as sampled in the field. The influence of micro-organisms and heavy metals such as copper, zinc, cadmium and lead over iron and manganese were also studied. Iron showed removal behavior, between salinity 0-10 ppt., during the flood season similar to the results from the mixing experiments, but the trend for dry season was less clear. In contrast, dissolved manganese showed addition behavior during those two seasons, while the results from the mixing experiments showed removal behavior between salinity 0-10 ppt. Laboratory experiments showed that micro-organisms and heavy metals had no influence on behavior of iron and managanese. However, the formation of particulate iron was decreased by the addition of other heavy metals into the water for all salinity, while the formation of particulate manganese was increased when the salinity was between 0-10 ppt. and then decreased when the salinity was higher than 10 ppt.