Different stages of Cd's transporting process in waters in Jiaozhou Bay

Cd pollution in marine bays is one of the critical environmental issues, and understanding the stages of transporting process of Cd in marine bays is essential to pollution control. This paper analyzed the stages of Cd's transporting process in waters in Jiaozhou Bay during 1979–1983. Results showed that the transporting process in waters in Jiaozhou Bay included seven different stages of 1) the sedimentation of Cd content was beginning, 2) the sedimentation of Cd content was increasing, 3) the sedimentation of Cd content was increasing greatly, 4) the sedimentation of Cd content was beginning to decrease, 5) the sedimentation of Cd content was decreasing stably, 6) the sedimentation of Cd content was beginning to stop, and 7) the sedimentation of Cd content was beginning to fully stop. In according to the different stages of Cd's transporting process in waters, the changing trends of Cd contents in surface and bottom waters and their relationships could be defined and predicted.