南黄海西部中陆架区近50年来沉积物重金属元素地球化学特征

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

    • 摘要: 以南黄海西部中陆架区SYS-0701钻孔顶部102.5 cm岩心为研究对象,通过对岩心沉积物的210Pb、137Cs同位素测年和重金属元素(Cu、Pb、Zn、Cr、Hg、As、Cd)含量分析,研究了该孔0~102.5 cm岩心的沉积速率及其重金属元素地球化学特征。结果表明,岩心沉积物的平均沉积速率为2.16 cm/a;重金属含量在1961—1970年含量较低,1970—2004年呈上升趋势,随后开始减少,这与人类活动密切相关。SYS-0701孔顶部102.5 cm岩心未明显受重金属污染,且与黄渤海其他海域相比重金属含量偏低,其原因可解释为该钻孔岩心沉积物主要为老黄河沉积物(1128—1855年)在1855年之后被海流侵蚀并搬运而来,来自苏北岸外的现代沉积含量较低。

       

      Abstract: 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.

       

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