Study On The Purification Of Myriophyllum Verticillatum L. To Cadmium And Microcystis Aeruginosa Polluted Water

China is rich in mineral resources,but overexploitation and poor clean-production technology make the water around the mining area prone to heavy metal pollution.At the same time,a lot of high nitrogen and phosphorus waste water is discharged into the water without proper treatment,which makes the water environment eutrophicate gradually,Algaes which cause algal bloom propagate rapidly under the suitable conditions.It is easy to cause algal bloom in this condition.For a long time,physical and chemical methods are mainly used to repair water environment,but there are obvious defects such as high cost or easy to cause secondary pollution.Nowadays,biological methods to control polluted water bodies through the production of various biological agents and the planting of aquatic plants have become a hot research topic.This method has the advantages of low price and no secondary pollution.Some pollutants can realize resources recovery and other huge advantages.In this paper,Myriophyllum verticillatum L.which has strong adaptability and ecological remediation function,was used as experimental material to study the removal of cadmium,a heavy metal,and microcystis aeruginosa,a characteristic algae which cause algal bloom.The following results are obtained:?1?The adsorption of heavy metal cadmium between Myriophyllum verticillatum L.and Microcystis aeruginosa was similar in the range of 0.05¹0mg/L concentration,the adsorption amount was negatively correlated with cadmium concentration.The the adsorption of heavy metal cadmium by the two algae was in accordance with the quasi-second-order kinetic equation.The removal of heavy metals was mainly achieved by adsorption on the surface of the cells,and the reaction reached equilibrium within 30minutes.?2?Myriophyllum verticillatum L.has a very strong inhibitory effect to Microcystis aeruginosa,and the inhibition strength has positive correlation with dosage quantity.By measuring the cell number,chlorophyll a content,MDA content and SOD activity of Microcystis aeruginosa,combined with the relevant literature,it was proved that the inhibition was allelopathy.Myriophyllum verticillatum L.can secrete allelochemicals to destroy the membrane structure and cause oxidative damage,which can destroy the algal cells and make Microcystis aeruginosa die.?3?Myriophyllum verticillatum L.has strong absorption to nitrogen and phosphorus in water,and its fixation ability to nitrogen is stronger than that to phosphorus.The addition of heavy metal cadmium will change its ability to fix nitrogen and phosphorus.0.5mg/L concentration Cd²⁺can slightly promote its nitrogen fixation ability,and nhibit phosphorus fixation abilit.1mg/L and 2mg/L concentration Cd²⁺can weaken its nitrogen fixation and phosphorus fixation ability,and the degree of weakening is positively related to Cd²⁺concentration.?4?Myriophyllum verticillatum L.has apparent inhibition to Microcystis aeruginosa under background conditions of cadmium in the range of 0.5²mg/L concentration.The inhibition ability is basically the same as that of alga ihibion experiment.The adsorption capacity of Cd²⁺in solution is basically consistent with that of single factor cadmium adsorption.