Pollutants in sediments such as heavy metals, organic matters and nutrients affect on the water quality. The transport and transfer of the pollutants was due to the physical, chemical and biological processes. These pollutants were identified as a potential source for contamination in the water column. Recently, the Korean government initiated the four major river restoration project and developed a total of 16 weirs to promote and secure water quality and resources in the four major rivers. This project expanded the storage space and produced reliable water resources by reducing the sediments that will later be a potential contamination source. However, since sediment accumulation can naturally occur, water management is needed to prevent the water pollutioin from sediments.
In order to find the sources of pollutants in the sediments, the sediments were collected from different landuses. River sediments were collected from Mankyung and Dongjin rivers in Jeonbuk province. Also sediments originated from nonpoint sources were collected from a paved area in KNU campus and livestock areas in Chunam province. The disturbed and undisturbed samples collected in monitoring locations were moved to the laboratory for the analysis of water content, ignition loss, chemical compounds, etc. The sieve analysis show the sediments from paved areas were larger and were mostly composed of sand compared to other sampling locations while sediments from the livestock were mostly made up of sand and silt. The ignition loss, COD and Pb of metals were higher in paved areas while nutrient concentrations were higher in livestock areas. The ratios of COD:TN:TP: shows TP concentration in paved areas was low (66:8:1) and TN in livestock was evidently higher (21:5:1) while organics in streams were low (12:1:1) due to the natural process of self-purification in streams. However, it can also be seen that TP concentration was comparably high in streams based from the ratio. The water quality data shows Mankyung river have the highest pollutant concentration followed by Geum river then Dongjin river. The most dominant form of phosphorus except the livestock area was Residual-P. NAI-P was dominant in livestock, while in streams, Residual-P and Apatite-P were almost the same in proportion. Finally, comparing this study’s metal concentration with American and Canadian soil quality standard it can be observed that metal concentration in this study was lower.
The results of this study can be used to make the sediment management plans in different landuses. In paved areas, road cleaning activities and nonpoint sources management can be helpful to reduce the sediment discharges. In order to reduce the impact of sediments to the river water quality, the ecological wetlands can be proposed for streams. The reduction of manure, composting and wastewater management may be implementation methods for livestock areas to reduce sediment discharges.