Vertical Water's Effect on Pb Contents in Jiaozhou Bay 1987

This paper analyzed the seasonal variation, vertical change, and horizontal distributions of Pb contents in Jiaozhou Bay, China. Results showed that Pb contents in surface waters in May, July and November in Jiaozhou Bay 1987 were 1.95-3.02 mu g L-1, 18.76-22.02 mu g L-1 and 3.98-24.64 mu g L-1, respectively, while in bottom waters were 1.87-2.60 mu g L-1, 15.11-19.68 mu g L-1 and 11.08-15.18 mu g L-1, respectively. The pollution levels of Pb in May, July and November 1987 in Jiaozhou Bay were slight, moderate and heavy, respectively. Pb contents in surface waters were in order of autumn>summer>spring, while in bottom waters were in order of summer>autumn>spring. Pb contents in bottom waters would be relative low/high if Pb contents in surface waters were relative low/high. The seasonal variations of Pb contents in surface waters were mainly determined by the seasonal changes of Pb sources, while in bottom waters were mainly determined by the changes of vertical water's accumulation and dilution effects. The horizontal distributions of Pb contents in surface and bottom waters were consistent in case of only one major Pb source, while were reverse in case of two different major Pb sources.