Fraction distribution and risk assessment of heavy metalsin sediments of Moshui Lake
LIU Honglei , LI Liqing , YIN Chengqing , SHAN Baoqing
DOI:
Received June 15, 2007,Revised September 11, 2007, Accepted , Available online
Volume 20,2008,Pages 390-397
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To examine the status and risk of heavy metal pollution in urban lakes, in China, the distribution of several heavy metals (e.g., Cr,
Cu, Ni, Pb, Zn) in the sediment of Moshui Lake, Hangyang District, Wuhan City, was characterized. The process of rapid urbanization
and industrialization of the district was also studied to find out its relationship with the metal accumulation profile in the sediment. It
was found that the total concentration of heavy metals in the sediment was higher than the severe e ect level (SEL), at all sampling
sites, except those in the riparian zone. The Cr and Cu maximum concentrations were 1,780 and 1,250 mg/kg, approximately 16 and
11 times as much as the SEL values, and they appeared as deep as 32 cm in one sample. The carbonate and exchangeable fractions of
Zn were more than 50% of the total Zn content, resulting in very high risk according to the Risk Assessment Code (RAC). For Cu and
Ni, a medium RAC value was found for carbonate and exchangeable fractions of 11%–20%. As sensitive indicators of contaminants
in aquatic systems, heavy metals in the sediment reflect the outcome of regional urbanization, industrialization, and environmental
management. With rapid urbanization, sedimentary Pb and Zn concentrations increased. The experimental results showed that high
sedimentary heavy metal concentrations had resulted from rapid urbanization and industrialization, which would absolutely lead to
substantial aquatic environmental decline in urban lakes.
