关键词: 膨润土, Cu(Ⅱ )形态, 生物有效性, pH 值, 相关性

Abstract: The form of heavy metals in soil reflects the bioavailability and potential harm of heavy metals. In order to discuss the influence of bentonite on the form distribution of Cu( Ⅱ ) and bioavailability,a pot experiment were carried out to study the characteristics of the Cu(Ⅱ ) forms through simulating Cu contaminated soil and Tiesser method,and the correlation between pH value of soil and Cu(Ⅱ ) forms were studied. The results showed that:bentonite significantly reduced the concentration of exchangeable form of Cu( Ⅱ ) in the cultivated soil,increased the concentration of Fe-Mn oxide form and organic form,and had little effect on carbonate form and residual form. Bentonite significantly reduced the concentration of exchangeable form of Cu(Ⅱ ) in the virescence soil,increased the concentration of the carbonate form,Fe-Mn oxide form and organic form,and had little effect residual form. Bentonite decreased the biological activity coefficient and migration coefficient of Cu (Ⅱ ) in soil,and decreased the bioavailability of Cu(Ⅱ ) in soil. The correlation analysis of Cu(Ⅱ ) forms with soil pH value showed that there is a proven negative correlation between exchangeable form of Cu(Ⅱ ) with pH value in the cultivated soil, and there is a proven positively correlation between Fe-Mn oxide form,organic forms of Cu(Ⅱ ) with soil pH value,and there is little correlation between carbonate form and residual form of Cu(Ⅱ ) with soil pH value. There is a proven negative correlation between exchangeable form of Cu(Ⅱ ) with pH value in the virescence soil,and there is a proven positively correlation between carbonate form,Fe-Mn oxide form,organic forms of Cu(Ⅱ ) with soil pH value,there is little correlation between residual form of Cu(Ⅱ ) with soil pH value. The study shows that bentonite reduces the exchangeable concentration of Cu(Ⅱ ) mainly by changing soil pH value,thus reducing the bioavailability of Cu(Ⅱ ).

Key words: bentonite,Cu(Ⅱ ) form,bioavailability,pH value,correlation