The land surface mildly contaminated by Hg

Abstract

The Hg content in the waters of Jiaozhou Bay was within 0.010-0.060μg/L in May, September and October 1993, which conforms to the seawater quality standards of Class I and II. It indicates that in the entire waters of Jiaozhou Bay, there were some water areas that did not get contaminated by Hg while some areas got mild contamination by Hg in May, September and October. In May, the variation range of Hg content in the waters of Jiaozhou Bay was 0.010-0.046μg/L. In September, it ranged within 0.007-0.011μg/L. And in October, the content of Hg detected in the waters of Jiaozhou Bay was 0.060μg/L. There were three sources to transport Hg content, open sea currents, Licun river and the surface runoff. The Hg content from the transportation of open sea currents was 0.046μg/L, from the Licun river was 0.011μg/L and from the surface runoff was 0.060μg/L. This paper builds a model block diagram to present the different paths and Hg contents that were input in the Jiaozhou Bay. In May, the open sea currents did not get any contamination of Hg; in August, the Licun river did not get any contamination of Hg as well; while in September, the surface runoff was mildly contaminated by Hg. The author concluded two points about the migration of Hg content: 1) Human activities discharge Hg to the land so that the Hg content could directly run to the ocean through the surface runoff. As the Hg content transported by surface runoff was relatively high, it resulted that the nearshore waters got mild contamination of Hg content. On the other hand, the surface runoff transported Hg to rivers, resulting relatively low content of Hg. Then rivers delivered the Hg content to nearshore waters, leading to a non-contaminated condition of rivers. 2) Human activities input Hg content to the ocean in a long period, resulting the increase of Hg content in the ocean. As the accumulation of Hg content in the ocean, the ocean got close to the mild contamination status.