Zhikang Wang

Influence of rising tide and falling tide on settling process of Cd in Jiaozhou Bay

Settling is one of the important transporting processes of pollutants in marine bay. Based on the analysis on the distributions of Cd in bottom waters in Jiaozhou Bay 1988, this paper defined the settling process. Results showed that Cd contents in bottom waters in Jiaozhou Bay in April and July 1988 were 0.08-0.10 μg L and 0.09-0.61 μg L, respectively, indicated that the pollution level of Cd in bottom waters in this bay was still very slight in 1988. By means of vertical water’s effect, there were high settling regions from the bay mouth to the bay center in April 1988, and there were high settling regions in the inner side of the bay mouth in July 1988. By means of rising tide and falling tide, Cd from different sources was settling the moving path, resulting in high settling regions along with the moving path. As a result, during the settling process of Cd, drifting phenomenon was occurring.

Temporal variations of Cu in Jiaozhou Bay 1982–1986

This paper analyzed the temporal variations of Cu in Jiaozhou Bay during 1982–1986. Results showed that Cu contents in study years were 0.15–5.31 μg L−1, 0.77–20.60 μg L−1, 0.11–4.00 μg L−1, 0.10–0.43 μg L−1 and 0.18–0.77 μg L−1, respectively. The Cu pollution level in this bay was moderate during 1982–1983, yet for temporal variations Cu contents in surface waters were showing decreasing trend. Cu contents in spring, summer and autumn were 0.11–20.60 μg L−1, 0.10–4.86 μg L−1 and 0.11–3.56 μg L−1, respectively. This bay was moderate pollution in spring in 1982–1983, while in other seasons in study years was still slight. These indicated that the temporal variations of Cu pollution in this bay should be taken in to account in decision-making of pollution control practice.

Spatial-temporal changes of Cr sources in Jiaozhou Bay

Cr pollution in marine bay is one of the environmental issues in many countries and regions, and the understanding of the spatial-temporal variation of Cr sources in marine bay is essential to pollution control. Based on investigation on Cr in surface waters, this paper analyzed distributions and spatial-temporal variations of Cr sources in Jiaozhou Bay, eastern China during 1979-1983. Results showed that for spatial variations, the strong Cr sources were in estuaries of the major inflow rivers (i.e. Haibo River, Licun River and Loushan River), and the source strengths were 4.17-112.30 μg L−1. For temporal variations, the source strengths were changing from moderate stage (1979-1981) to slight stage (1982-1983),whose source strengths were 32.32-112.30 μg L−1 and 4.17-19.76 μg L−1, respectively. In general, the spatial-temporal variations of Cr sources in Jiaozhou Bay were significant, which should be taken into account for the countermeasures for pollution control.

Settling Process of Cd and the Origin in Jiaozhou Bay

This paper analyzed the settling process of Cd and the origin in Jiaozhou Bay based on investigation data during 1979 — 1983. Results showed that the distributions of Cd contents in bottom waters were determined by the spatialtemporal variations of the Cd source inputs, and the transports of Cd from land/atmosphere to ocean. The seasonal-spatial variations of the settling of Cd resulted in the variations of high Cd content regions in bottom waters. During 1979-1983, the source strengths of were increasing, and were extending the high Cd content regions and increasing the Cd contents in bottom waters.