[Spatial distribution and pollution assessment of heavy metals in the tidal reach and its adjacent sea estuary of Daliaohe area, China ].

The aim of this article was to explore the pollution level of heavy metals in the tidal reach and its adjacent sea estuary of Daliaohe area. The contents and spatial distribution of As, Cd, Cr, Cu, Ph and Zn in surface water, suspended solids and surface sediments were analyzed respectively. The integrated pollution index and geoaccumulation index were used to evaluate the contamination degree of heavy metals in surface water and surface sediments respectively. The results indicated that the contents of heavy metals in surface water was in the order of Pb < Cu < Cd < Cr < As < Zn. The heavy metal contents in surface water increased from river to sea. Compared with the contents of heavy metals in surface water of the typical domestic estuary in China, the overall contents of heavy metals in surface water were at a higher level. The contents of heavy metals in suspended solids was in the order of Cd < Cu < As < Cr <Pb < Zn. Similar patterns of spatial distribution in suspended solids were observed for As, Cd, Cr,Cu and Pb, and the highest contents of Cr, Cu, Cd appeared at EM3 station. The contents of heavy metals in surface sediments was in the order of Cd <Cu < Pb < As < Cr < Zn. The highest contents of Cr, Cu, Cd and As in surface sediments also appeared at EM3 station. Temperature, pH, DO, EC and other factors affected the distribution of heavy metals in water, suspended solids and sediment. In particular, the effects of salinity and suspended solids matter were most significant. The integrated pollution index assessment showed that the water quality was good except individual stations. The geoaccumulation index assessment showed that As was the major pollution element in surface sediments.