GEOCHEMICAL CHARACTERISTICS OF HEAVY METAL ELEMENTS IN THE SEDIMENTS OF LAST 50 YEARS IN THE WESTERN MIDDLE SHELF OF SOUTH YELLOW SEA

This paper documents the sedimentation rate and geochemical characteristics of heavy metal elements in the sediments from 0-102.5 cm of the core SYS-0701 taken from the western middle shelf of the South Yellow Sea, based on the data from ²¹⁰Pb and ¹³⁷Cs isotopic analyses and contents of heavy metals (Cu,Pb,Zn,Cr,Hg,As,Cd). Our results suggest that the sedimentation rate of the uppermost 102.5 cm of the core SYS-0701 is 2.16cm/yr, and for most of the heavy metal elements there exhibit low concentration from 1961 to 1970. A rising trend was observed from 1970 to 2004 and then it falls again until 2007. Obviously the change is closely related to human activities. The sediments in the upper 102.5 cm of the core are not evidently polluted by the heavy metals, and most of the heavy metal elements are low in concentration comparing to the other sea areas of the Yellow Sea and Bohai Sea. It may suggest that the core sediments were derived mainly from the old Yellow River sediments (AD 1128—1855), which were eroded and transported to the core site by marine currents after 1855, and the modern sediments from outside of the Jiangsu coast are not significant.