The spreading process of Pb in Jiaozhou Bay

This paper analyzed the contents, horizontal distributions, sources and spreading process of Pb in Jiaozhou Bay, China based on investigation data on Pb in surface waters in 1985. Results showed that Pb contents were 11.4-42.8 μg L, and were confirmed with Grade IV in according to Chinese Sea Water Quality Standard (GB 3097-1997), indicated that the pollution level of Pb was very heavy. Overland runoff and stream flow were the two major sources of Pb, and the source strength of overland runoff was stronger. Even the pollution source was playing a role of ‘point source’, Pb could be spreading to the whole bay, and to the open waters. The loss of Pb during the spreading process in the bay was 44.8%, and from the bay to the open waters was 23.5%. The spreading processes confirmed the point of view that the ocean had the characteristic of homogeneity. We found that the Pb contents were easy to be spreading, under same time and same conditions, the bigger spreading space the higher spreading rate. Hence, the reduction of emission of Pb was necessary, and the transfer process of Pb should be given close attention to.