Spatial Distribution Characteristics of Heavy Metals Cu and Zn in Coastal Wetland Sediments

The content of Cu,Zn in the sediments from coastal wetlands of the Yellow River Delta was determined.The results showed that:(i)The content of Cu,Zn range was 16.70-50.40 mg/kg,18.15-48.80 mg/kg,respectively.The mean content of Cu,Zn was 31.12mg/kg,36.74 mg/kg,respectively.Compared with the soil environmental background values of Shandong Province,the content of Cu was excessive,while the content of Zn was below the background.(ii)The concentrations of Cu,Zn in sediment in the coast of the Yellow River Delta were higher than in the other two areas.(iii)Vertical distribution characteristics of the concentrations of Cu,Zn were increasing with depth.The maximum content of Cu,Zn was 80-100 cm,in general,the content of Cu,Zn in the bottom sediments was higher than that in the surface sediments.The growth and decline trends of Zn in Tamarix and Suaeda areas were much the same and all higher than in the Phragmites communis area.(iv)The distribution characteristics of Cu concentration in different vegetation cover in sediment is Suaeda>Phragmites communis>Tamarix,which reflected different effects on retention of Cu in the sediments because of the different vegetation types.The highest content of Zn in the 0-20 cm sediments in Tamarix area was 44.07 mg/kg.

The content of Cu,Zn in the sediments from coastal wetlands of the Yellow River Delta was determined.The results showed that：（i）The content of Cu,Zn range was 16.70-50.40 mg/kg,18.15-48.80 mg/kg,respectively.The mean content of Cu,Zn was 31.12mg/kg,36.74 mg/kg,respectively.Compared with the soil environmental background values of Shandong Province,the content of Cu was excessive,while the content of Zn was below the background.（ii）The concentrations of Cu,Zn in sediment in the coast of the Yellow River Delta were higher than in the other two areas.（iii）Vertical distribution characteristics of the concentrations of Cu,Zn were increasing with depth.The maximum content of Cu,Zn was 80-100 cm,in general,the content of Cu,Zn in the bottom sediments was higher than that in the surface sediments.The growth and decline trends of Zn in Tamarix and Suaeda areas were much the same and all higher than in the Phragmites communis area.（iv）The distribution characteristics of Cu concentration in different vegetation cover in sediment is Suaeda＆gt;Phragmites communis＆gt;Tamarix,which reflected different effects on retention of Cu in the sediments because of the different vegetation types.The highest content of Zn in the 0-20 cm sediments in Tamarix area was 44.07 mg/kg.