The Distributing Characteristic Of Heavy Metals From River To Sea In Huanghe

Investigations were carried in three water periods in November 2004, May 2005 and September 2005 in Huanghe estuary. 66 surface and bottom water samples and 27 surface sediment samples were gathered. Content of Cu, Pb, Zn, Cd, Cr, As, Hg and other environment factors were determined. The space-time variances of metals analyzed to research the transport of metals and the influences of heavy metals in water and sediment were discussed. The results indicate that:1. The average concentration of total heavy metals is high water period > low water period > level period. Most heavy metal content in bottom water is slightly higher than that in surface layer. The tendency of every heavy metal of the surface and the under water is similar.2. Most heavy metal content takes on overall downward trend from river to sea. In the area mixed between the salt and fresh water, the concentration of heavy metals in every season near the sand bar is very high under the influence of the hydrological and chemical conditions, and the ratio of dissolved to particulate heavy metal in most point increases,decreases then increases.3. The suspended solids and ion concentration are the main reason for the change of the heavy metal content in water. Most heavy metals show a negative correlation between content and salinity at different significant levels. In high water period, most heavy metals takes on a significantly positive correlation between content and pH value, in others periods that are not obvious. Heavy metal content in the water shows poor correlation with the organic carbon, it is less affected by organic carbon.4. The heavy metal content in sediments is low. The average concentration of heavy metals is: level period>low water period>high water period. The tendency of heavy metal content in sediments is decrease, increase, decrease, then increase from river to sea. The highest heavy metal content appears in the vicinity of the river and sea blended region.5. The correlation of these heavy metals content in sediment in level water period is more clear than other periods, which reflects similar source of metals. The sediment granularity is the main factor affecting the content of heavy metals in sediments. The smaller sediment particle is, the higher heavy metal content is.6. The assessment of heavy metal pollution in the water shows that the content of Hg is higher in river and Pb is higher in sea. The metal content is higher in the river and sea blended region than other places. The content of As and Cd is low. The pollution of heavy metals in sediments shows slight ecological hazard.