Abstract: The ability of water hyacinth for accumulating heavy metals,such as Cu,Zn,Ni, Cr inelectroplate waste water and its effects on water environmental factors were studied through staticand dynamic experiments. The results showed that water hyacinth had significant accumulatingand purifying functions. Under dynamic experiment, average quantity(mg穔g^-1,dry)ofaccumulation in a 24hr-peried was Cu:135. 09 Zn:436.58 Ni:50.29 Cr:89.14. The static studyindicated that the ability of water hyacinth for accumulating heavy metals was significantlydifferent under the same initial concentration of different heavy metals, in the sequence of Cr>Cu>Zn>Ni.pH values of Cu, Zn,Ni and Cr were 5,6, 6 and 3,respectively,at whichmaximum accumulat ion quantity was detected. The restraining functions of organic substanceswere the most significant under BOD₅<60(mg穕^-1). In addition, it was found that cultivationdensity of water hyacinth had no significant effects.

Key words: desert steppe, grazing disturbance, specific leaf area, leaf dry matter content.