THE PURIFICATION EFFICIENCY OF AQUATIC VASCULARPLANTS TO THE POLLUTED WATER IN DIANCHILAKE, KUNMING
Wu yushu Li Senlin (Yunnan University, Kunming)
This paper deals with the purification efficiency of five hydrophytes growing in natural ponds and estuaries to the eutrophic ation (nitrogen and phosphorus) and heavy-metals polluted water of Dianchi Lake. Kunming.The results show that these hydrophytes can eliminate N,P and heavy metals six elements-Pb,Cd,Cr, Ni, Zn, Cu have been studied) from the water and the mud through absorption and accumulation . As the content of pollutants in water and mud is reduced, the pH value, COD value and the turbidity of the water are also reduced in different degrees, so the water quality has been improved obviously. It indicates that some hydrophytes have obvious purification efficiency.Among the five test species, Eichhornia crassipes is the best both on the accumulation coefficient and the purification efficiency to N, P and heavy metals, so it is a superior species with great cleaning capacity.The contents of N, P and heavy metals among the water-plant population--mud show the correlative change tendency. Therefore , when the biomass and coverage of population reach to a certain degree, drag away the hydrophytes proportionally at regular intervals as to get rid of the pollutants from the water and the mud.If the quantity of pollutants entering the water is counter-balanced by the pollutants output with plants dragged, then the enrichment process can be controlled and the heavy metals pollution can be reduced.Those hydrophytes dragged from the water can be efficiently used as regenerative bio-energy resources.It has practical significance to exploit the natural ponds and estuaries used for developing oxidation ponds system.