This paper analyzed the annual change and seasonal variation of Cd in Jiaozhou Bay during 1979-1983. Results showed that the highest values of Cd contents in 1979-1982 were confirm to Grade I (1.00 μg L~(-1)) of National Sea Water Quality Standard (GB 3097-1997), yet in 1983 were Grade II. For temporal changes, Cd contents were showing increasing trends during 1979-1983, indicating the increasing of Cd input to the bay from human activities. For seasonal variation, Cr contents in spring during 1979-1983 were relative low and were confirm to Grade I, while in summer and autumn were relative high and the highest values of Cd contents were confirm to Grade II. These indicated that the input of Cr to the bay was different in different season. In general, the pollution level of Cd were increasing after reform and opening-up due to the rapid increase of industry.
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