Spatial distribution of dissolved Pb, Hg, Cd, Cu and As in the Bohai Sea
WANG Chang-you , WANG Xiu-lin
DOI:
Received November 23, 2006,Revised March 03, 2007, Accepted , Available online
Volume 19,2007,Pages 1061-1066
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Characteristics of the spatial distribution of selected dissolved heavy metals were analyzed during large scale surveys from August
12 to 25, 2003 in the Bohai Sea. Dissolved Pb was the only element with average concentrations higher than the grade-one sea water
quality standard of China. The spatial distribution of dissolved Pb in surface water was similar to those of Cd, Cu and As, where the
isopleths generally indicated decreasing values from the bays to the central areas. Only for Hg did the high concentrations not only
appear in Liaodong Bay, Bohai Bay and Laizhou Bay, but also in the Central Area, viz. not only in inshore but also in o shore areas.
Vertical distributions of dissolved Pb, Cd, Cu and As were largely uniform, while that of dissolved Hg increased with depth. We infer
that the input of pollutants from land was the main influencing factor for the detected distribution patterns of dissolved heavy metals,
followed by the dynamics of sea water, release from bottom sediments and biochemical processes. Comparing with historical data,
average concentrations of dissolved heavy metals appear to decline in recent years.
