Paleoecological perspectives of anthropogenic impact in Seocheon, on the west coast of the Korean Peninsula

Abstract

Abstract

Paleoecological study was conducted in the Yonghwasil-mot to reconstruct human activities in Seocheon, Korea. Yonghwasil-mot is a reservoir constructed for the purpose of irrigating paddies. Sediment core was collected and dated using the 210Pb method. The average dry mass accumulation rates from 1863 to 2011 was 1.80 kg m-2 yr-1. The 210Pb flux rate of the study area was 42.4 mBq cm-2 yr-1 and seemed to be affected by wind from China. There was a big increase in the accumulation rate in 1956 and the amount of organic matter, total carbon, nitrogen and phosphorus also increased. This indicates significant input of soil and organic particles into the Yonghwasil-mot and a less decomposed state because of increased water levels. The concentrations of Pb, Cu, As, Cd, and Zn reflect the influences of the Janghang smelter located around 6 km away and Janghang station located around 300 m away. The concentrations of As, Cu, and Pb have decreased slowly since the mid-1990s and the decrease of lead contents is attributed to the government policy banning the sale of leaded gasoline. Pollen analysis revealed that Gramineae and Pinus spp. were high in this area. Alnus spp. dominated below 44 cm depth and abruptly decreased around 1894. This may be related to the expansion of farmland around the study area. Relationship between human activities and changes of water level of Younghwasil-mot was reconstructed through pollen, LOI, C/N stratigraphy. Also, influence of Janghang smelter, Janghang station and the industrialization of Korea on environment was able to identified using heavy metal contents. The 210Pb flux rate suggests that Seocheon is affected by dust from China because of westerlies.