Distributions of Chemical Species of Han River Estuary and Tidal Front Area

초록

Salinity fluctuation was largest near the Kangwha Island where was mostly dominated by the freshwater discharge from the Han River. Esutuarine mixing occurred at the channel between the Kangwha Island and Seo Island, where the biogeochemical removal processes were most apparent. Palmi Island area showed a typical coastal water characteristic. From the relationships between the salinity and nutrients, nitrite showed non-conservative property that could be explained by nitrification and uptake by phytoplankton (Sharp, 1983). On the other hand, nitrate showed conservative property with simple mixing pattern. This fact does not necessarily mean that there are no biogeochemical removal processes even though recent extensive reclamation activity might have diminished the removal function of tidal flats. Probably, large amounts of nitrate loading from neighboring industrial complex and waste treatment facilities counterbalance the biogeochemical removal processes. Phosphate showed near-conservative property with a slight concave curvature versus salinity. Phosphate might have been released from suspended solids by ionic interaction during the mixture of river and seawater. Geomacromolecules, humic substance of land origin, in FDOM showed near-conservative property, which implies a relative inert organic fraction. Concentrations of DOC were higher than other temperate coastal waters, which indicates the effect of organic pollutants discharged from neighboring industrial complex and coastal towns. DOC showed non-conservative property in the study area. Most of trace metals, partly in the form of organo-metallic complexes, have been removed by neutralizations of their surface charges (Sholkovitz and Copeland, 1981). Organo-metallic complexes could be easily formed by abundant geomacromolecules in the estuarine mixing area. In the out side of the Kyonggi Bay area, tidal fronts have been developed by horizontal density gradient resulting from different distribution of salini