The changes of Cd sources in Jiaozhou Bay 1979-1983

Many marine bays have been polluted due to the rapid development of economic and population. Understanding the changes of pollution sources of pollutants in marine bays is essential to pollution control. This paper analyzed the changes of Cd in Jiaozhou Bay during 1979–1983. Results showed that there were six Cd sources including marine current, river flow, island top, atmosphere deposition, overland runoff and wharf, whose source strengths were 0.12-0.25 μg L^-1, 0.07-0.85 μg L^-1, 0.48-3.33 μg L^-1, 0.14-0.55 μg L^-1, 0.38-0.53 μg L^-1 and 0.16-1.50 μg L^-1, respectively. The changes of the sources were mainly determined by human activities, and the distributions of Cd in Jiaozhou Bay were influenced by the spatial-temporal variations of the sources. In general, source control would be necessary countermeasures of pollution control in marine bay.