REDOX ENVIRONMENT EFFECT ON THE REDOX SENSITIVE ELEMENTS IN SURFACE SEDIMENTS FROM THE YANGTZE ESTUARY HYPOXIA ZONE

The grain sizes and element concentration, including redox-sensitive elements(RSE) and terrigenous elements of the sediments from the Yangtze Estuary hypoxia zone and its contiguous sea area were measured. Based on these data,the hypoxic environment's influence on the distribution of elements in surface sediments was studied and it is believed that the "redox environment effect" has important influence on the distribution of the RSE from the Yangtze Estuary hypoxia zone. Redox-sensitive elements Cd,Mo,U,and V and detrophile elements K,Sc and Al belong to different element associations and have distinct distribution and regularity characteristics.These two kinds of elements are controlled by different factors in the study area.Detrophile elements are mainly affected by provenance and "granularity effect",and the high value area goes nearshore in banded way.RSEs(such as Cd,Mo,U,and V)are less controlled by the "granularity effect" but evidently affected by hypoxic environment,and the high value area is distributed in patches and away from the shoreline.