Distribution of Mercury in Sediments of Shihwa Lake, Korea

Abstract

Contamination levels of mercury in surface sediments of Shihwa Lake were assessed at 16 stations from 1997 through 2000 by investigating the distribution patterns and by comparing mercury concentrations with those of other regions in Korea. In addition to total mercury, the reactive and pyrite mercuries in surface and core sediments were also analyzed in 2000. The Shihwa Lake can be divided into three zones according to spatial distribution patterns of mercury concentrations in surface sediments. Zone Ⅰ (Sts. 1-6) in the vicinity of Banweol and Shihwa Industrial Complexes showed the highest mean concentrations of mercury, followed by Zone Ⅱ (Sts. 7-12), and Zone Ⅲ (Sts. 13-16) near the watergate of the Shihwa Dike exhibited the lowest mercury levels. The sediment mercury levels in Zone Ⅰ of Shihwa Lake were comparable to those of Masan Bay, while Zone Ⅲ showed the low mercury levels similar to the outer sea of Shihwa Dike and the Yellow Sea. The spatial distribution trend of Hg-DTMP (degree of mercury pyritization) was also similar to that of total mercury concentrations. The mean Hg-DTMP values in surface sediments were shown the highest in Zone Ⅰ (0.80), while those of Zone Ⅱ and Ⅲ were below 0.5. The mercury concentrations in surface sediments showed good correlations with organic carbon, sulfur and mean grain size of sediments.