Vertical Variation of Hg Content without Transport Source

The investigation data on Hg in Jiaozhou Bay in May, August and October 1992 showed the horizontal and vertical changes of Hg content and the difference of Hg content between the surface and bottom layers in the Jiaozhou Baymouth. By these data, it was shown that the magnitude and time of Hg content in transportation affected the Hg content change of the surface and bottom layers and subsidence area. The results showed that in May, August and October, there was no source of Hg content in the south and west of the bay mouth, and in the southwest, center and southeast of the bay. The settlement of Hg content in the surface layer did not depend on the Hg content transported from sources, but only depended on the Hg content in the surface layer of waters. On the spatial scale, according to the results from subtracting Hg content in the surface and bottom, the Hg content in the waters accounted for more than half, the Hg content sediment accounted for one third, and the Hg content distributed uniformly accounted for one tenth. As a result, the Hg content is abundant in the water body, without forming large deposits. On the time scale, from May to October, in the central waters of Jiaozhou Bay and the coastal waters in the southeast of the bay, during the change process of Hg content in the surface and bottom layer, it appeared that the Hg content was consistent in the surface and bottom layer. At this time, the Hg content presented the homogeneity in the water body.