Evaluation of Spatiotemporal Variations in Water Quality Along the Chungnam Province Coast and Inner Estuary (West Coast of Korea).

Yoon, J.-J.; Lee, S.-W., and Song, H.-Y., 2023. Evaluation of spatiotemporal variations in water quality along the Chungnam Province coast and inner estuary (West Coast of Korea). In: Lee, J.L.; Lee, H.; Min, B.I.; Chang, J.-I.; Cho, G.T.; Yoon, J.-S., and Lee, J. (eds.) Multidisciplinary Approaches to Coastal and Marine Management. Journal of Coastal Research, Special Issue No. 116, pp. 333-337. Charlotte (North Carolina), ISSN 0749-0208. The coast of Chungnam Province is one of the leading fishery production sites on the west coast of Korea. In this study, we analyzed the coastal water quality along the coast of Chungnam Province and identified the causes of water pollution. The sea Water Quality Index (WQI), which integrated five physiochemical parameters (transparency, Dissolved Oxygen (DO), Dissolved Inorganic Nitrogen (DIN), Dissolved Inorganic Phosphorus (DIP), and Chlorophyll-a (Chl-a)) of water quality from 2016 to 2020, was calculated not only to evaluate the spatiotemporal distribution of water quality but also to assess the effect of water quality on contaminated water discharged from land. The WQI was relatively high in waters near the inner bay-shaped coast of the estuary lake. Moreover, the water quality in this area was greatly affected by the release of contaminated freshwater into the sea. Higher WQI values were observed near the outfall of estuary dikes in coastal areas. Further, water pollution in the estuary lake significantly affected the regeneration of internal pollutants owing to the discharge of pollutants from agricultural areas and the contaminated bottom sediments of the stagnant estuary lake. Water quality worsened, especially during summer, when the discharge of estuary lakes was caused by heavy rainfall. During winter, the water quality improved owing to the low impact from the discharge of water. WQI in summer reduced to "very poor" levels, and polluted sediment from inner estuary could be widely deposited in the sea area in front of the estuary bank. Additionally, high concentration of organic contaminants distributed in the seafloor sediments in the inner bay area had terrestrial origins. Thus, this study indicated that to improve the overall water quality in the inner bay, improving the water quality of the estuary is imperative. [ABSTRACT FROM AUTHOR]