论文部分内容阅读
The chemical forms of Fe,Mn,Zn,Cu,Cr,Pb and Cd in the Huanghe River sedimentshave been studied by sequential extraction techniques and the comparison with data from theRhine River sediments has been made.In the Huanghe River sediments the average contentsof metals,without exception,are below their respective contents in average shales and veryclose to their levels in Ca-poor granites.The major portion of metals is combined with thedetrital and moderately reducible phases.Both in the Huanghe River and in the Rhine Riversediments the distribution ratios of metals between the moderately reducible and the easilyreducible phases are generally more than unity.However,the distribution ratios of Mn,Znand Cd are obviously lower than those of Fe.Cr,Cu and Pb.As a result of contamination,the ratios of Fe,Cr,Cu and Pb show an apparent increase,but no remarkable ratio varia-tion is observed for Mn,Zn and Cd.Metals in the Huanghe River sediments,especially Cuand Zn,show a tendency to be associated with the organic phase.The effect of carbonateon metal association preference seems to be less important than that in the Rhine Riveralthough there is higher content of carbonate in the Huanghe River sediments.Cd has a greaterpercentage of the exchangeable phase,which is similar to the result from the Rhine Riversediments.
The chemical forms of Fe, Mn, Zn, Cu, Cr, Pb and Cd in the Huanghe River sediments have been studied by sequential extraction techniques and the comparison with data from the Rhine River sediments has been made. In the Huanghe River sediments the average contents of metals , without exception, are below their respective contents in average shales and veryclose to their levels in Ca-poor granites. major part of metals are combined with the detrital and moderately reducible phases. Both in the Huanghe River and in the Rhine Rivers editments distribution distribution ratios of metals between the moderately reducible and the easilyreducible phases are more than unity. However, the distribution ratios of Mn, Znand Cd are obviously lower than those of Fe.Cr, Cu and Pb.As a result of contamination, the ratios of Fe , Cr, Cu and Pb show an apparent increase, but no remarkable ratio varia-tion is observed for Mn, Zn and Cd. Metals in the Huanghe River sediments, especially Cu and Zn, show a tendency to be associated w ith the organic phase. The effect of carbonateon metal association preference seems to be less important than that in the Rhine Riveralthough there is higher content of carbonate in the Huanghe River sediments. Cd has a greaterpercentage of the exchangeable phase, which is similar to the result from the Rhine Riversediments.