PRELIMINARY STUDIES ON DISTRIBUTION OF COPPER, LEAD AND CADMIUM IN INTERSTITIAL WATER OF THE BOHAI BAY
渤海湾间隙水中铜、铅、镉分布规律的初步研究

In recent years, attention has been drawn to environmental protection of the Bohai Bay, and a great number of investigations has been made on environmental pollution of the Bay area.This article deals preliminarily with distribution of heavy metals Cu, Pb and Cd in interstitial water of the Bohai Bay, and with equilibration of stable solid phases of these metals probably present in sediments in accordance with Eh-pH diagrams.Work to collect samples of surface sediments in situ and measure Eh and pH of the samples was conducted in August 1979. Interstitial water was obtained by using contamination-proof hydraulic piston sampler, and contents of metal ions therein were analysed by means of anodic stripping voltam-metry. Values of C1- in interstitial water were also determined by titration with AgNO3 solution.Results show that regions of high content of these heavy metals exist in estuary of the Haihe and Beitang Rivers and in the northeast part of the Bay, while the low content region stays in the central section. Distribution of the metals and Cl- in circular shape is in relation with movement of circulation in the Bohai Bay.According to regression analysis of correlations of these metals and chlorinity in interstitial water, it follows that metal contents above the lines are controlled by drainage of continental runoff, and those below the lines by motion of coastal circulation in the Bohai Bay, while some points near the lines show occurrence of both actions.Use of Eh-pH stability field diagrams may help analyse solid Cu, Pb and Cd stable phases to be in equilibrium with interstitial and sea waters at given Eh and pH.