Influence of Sediment Grain Size and Land Use on the Distributions of Heavy Metals in Sediments of the Han River Basin in Korea and the Assessment of Anthropogenic Pollution Tien M. Lai & Wonkyo Lee & Jin Hur & Younghun Kim & In-Ae Huh & Hyun-Sang Shin & Chan-Kook Kim & Jong-Hyun Lee Received: 4 October 2012 / Accepted: 27 May 2013 # Springer Science+Business Media Dordrecht 2013 Abstract The influence of sediment grain size and land use was examined on the distribution of Cr, Ni, Zn, Pb, Cd, Cu, As, and Hg in the sediments collected from 19 subbasins of the Han River Basin, Korea. The degree of anthropogenic pollution of the heavy metals was also evaluated using the enrichment factor and geoaccumulation index based on local geochemical background concentrations. Except for Zn and Al, all the metals investigated showed significant correlations with the fine silt fraction of the sediments, suggesting that grain size distribution may contribute to the en- richment of the metals. Close association of the metal concentrations with a percentage of urban area in the subbasin was exhibited only for Cd, Cu, Hg, and Pb. The two pollution indices revealed that most of the sed- iments could be classified into a category of “unpolluted to moderately polluted,” except for a subbasin with the highest percentage of urban area, which was highly pol- luted with Cu, Hg, and Pb. No relationship was observed between agricultural land use and the enrichment of metals. Principal component analysis showed that a com- bination of grain size distribution and percent urban area were responsible for 55 % of the variance of the metal distribution. Cluster analysis revealed that the sources of As might be different from the other metals. Multiple regression analyses based on fine silt fraction and percent urban area resulted in a good estimation of the concen- trations of Cd, Cu, Hg, and Pb (r >0.7, p <0.005). Keywords River sediments . Metal pollution . Geochemical background . Enrichment factor . Land use . Multivariate statistical analyses 1 Introduction Heavy metal pollution in aquatic ecosystems creates critical problems because of its toxicity, persistency, and Water Air Soil Pollut (2013) 224:1609 DOI 10.1007/s11270-013-1609-y T. M. Lai : W. Lee : J. Hur (*) Department of Environment and Energy, Sejong University, Seoul 143-747, South Korea e-mail: jinhur@sejong.ac.kr Y. Kim Department of Environmental Engineering, Andong National University, Andong 760-749, South Korea I.<A. Huh National Institute of Environmental Research, Incheon 404-708, South Korea H.<S. Shin Department of Environmental Engineering, Seoul National University of Science and Technology, Seoul 139-743, South Korea C.<K. Kim : J.<H. Lee NEO Environmental Business Corporation, Bucheon 420-806, South Korea