Spatial-temporal changes and the influences of Hg sources in Jiaozhou Bay

Abstract

Using investigation on Hg in May and August 1990 in Jiaozhou Bay, this paper analyzed the spatial-temporal changes of Hg sources, and the influences on spatial-temporal changes of Hg contents. Results showed that the major Hg sources in May were atmosphere deposition in the center of the bay and the wharf in the north of the bay, whose source strengths were 0.208 μg L−1 and 0.194 μg L−1, respectively. Meanwhile, the major Hg sources in August were also atmosphere deposition in the center of the bay and the wharf in the north of the bay, yet whose source strengths were relative low as 0.055 μg L−1 and 0.053 μg L−1, respectively. In May, Hg contents in surface waters were higher than in bottom waters. After three months from May to August, a large amount of Hg was accumulated in sea bottom by means of continuous sediment process, resulting in Hg contents in surface waters in the center of the bay were lower than in bottom waters in August, while in the north of the bay mouth Hg contents were homogeneous between surface and bottom waters. At temporal scale, the source input amounts were decreasing from May to August, and Hg contents were decreasing from May to August. However, by means of sediment and accumulation effects, Hg contents in bottom waters were tending to be higher than or closed to what in surface waters. In general, the spatial-temporal changes of Hg contents in marine bay were strongly influenced by the spatial-temporal changes of the Hg sources.