Effect On Growth Of Microcystis Aeruginosa,chlorella Vulgaris And Spirogyra Communis Of Nine Algicides And Three Composite Algicides

Water eutrophication is getting more and more general at home and abroad,which has been bringing about blooms of algae and deterioration of water quality.In addition,in many waters,an explosion in growth of filamentous algae in spring and summer affects the growth of submerged plants.When filamentous algae die,it will appear as masses and float on the water,which will destruct the ecological landscape.So,studies of algae removal has important practical value.Physical method,biological method and chemical method is the current main methods to remove algae.Chemical method,which has the highest efficiency among the three methods,and utilized to remove pervasive algae rapidly,is a very important way to governance environment and restore the polluted aquatic ecosystem.Nowadays,there are many sorts of algicides in China,but the effect of then is uneven.So we are blind to select suitable algicide in a real world application.Besides,most algicide are mainly for planktonic algae.That there is little reseach about control of filamentous algae,which is one of the great demands in the field of water pollution repair.This article has summarized and selected nine efficient and short period algicides(ClO2,CuSO4,Diuron,SDIC,Bromogeramine,Glutaraldehyde,Cinnamic acid,Siwananluohedian and H2O2)with few side effects published in many literatures and patents.Then taken Microcystis aeruginosa,Chlorella vulgaris and Spirogyra communis as research objects and conducted many toxicity experiments to estimate the algae-inhibition effect of each algicide.Afterwards,summarized the order of algae-inhibition effect to different algae and the optimal use concentration of each algicides.On this basis,we selected three algicides from the nine which have better inhibition effects to do pair combination toxicity experiments,including “Diuron-Cu SO4”,“ClO2-Cu SO4” and “ClO2-Diuron”,summarize and compare their effects and the optimal use concentration,hoping to provide fundamental basis for practical application of algicides.(1)Effect of nine algicides on M.aeruginosaAmong the nine algicides,inhibiting effect of ClO2 and CuSO4 was the best.When the concentration was 0.5 mg/L at 5 d the algal inhibiting rate was 80.16% and 79.07% respectively and when 1 mg/L-10mg/L the algal inhibiting rates were all above 100% at 5 d.According to the IR and of ClO2 and CuSO4,the best working concentrations are 0.5 mg/L-1.5 mg/L(ClO2)and 0.5 mg/L-1 mg/L(CuSO4).When theconcentration was 2 mg/L and 5 mg/L,the IR of Diuron,Bromogeramine,Glutaraldehyde and SDIC had good algae-inhibition effect,all about 100%.Siwananluohedian and Cinnamic acid had little effect on M.aeruginosa When the concentration was 0.5 mg/L-10 mg/L,IR of the former was all under 50% at 5 d and the latter was under 0,which were unsuitable to control cyanobacterial blooms.(2)Effect of nine algicides on C.vulgarisAmong the 9 algicides,when 0.5 mg/L and 1 mg/L,CuSO4 had the best algae-inhibition effect on C.vulgaris,the IR at 5 d was 98.61% and 98.15%.When 2 mg/L,5 mg/L and 10 mg/L,IR of ClO2,Bromogeramine,CuSO4 and Diuron were all about 100%.ClO2 killed C.vulgaris completely and needed litte time,whose IR was above 50% within 15 min.Bromogeramine,Diuron,and SDIC had good inhibition effect on C.vulgaris,but their effective concentration.Cinnamic acid,Glutaraldehyde and Siwananluohedian had little effect on C.vulgaris,unsuitable to control green algae blooms.(3)Effect of nine algicides on S.communisAmong the nine algicides,when the concentration was 10 mg/L,Diuron,ClO2 and Cu SO4 had better inhibition effect and their IR was all about 30%.The other six algicides had little effect on S.communis and the IR of them all under 22%.There was no obvious difference compared with control group when the concentration were under 10 mg/L.On the whole,inhibition effect on S.communis is poor.(4)Effect of three composite algicides on M.aeruginosa,C.vulgaris and S.communisFor M.aeruginosa and C.vulgaris,the algae-inhibition effect of Cu SO4-Diuron and ClO2-Diuron were better,whose IR were above 100%.The best working concentration is 0.5 mg/L;IR for M.eruginosa of CuSO4-ClO2 all under IR of Cu SO4 and ClO2 at all concentrations.IR for C.vulgaris of CuSO4-ClO2 were above 100% only when the concentration were above 5 mg/L and it had no significant difference compared with CuSO4 and ClO2(P>0.05).The effective concentration is high.So Cu SO4-ClO2 is not suggested.For S.communis,the sequence of algae-inhibition effect of the three composite algicides was:ClO2-Diuron,CuSO4-ClO2 > CuSO4-Diuron.Compared with algicides used alone,the three composite algicides had higher IR at 5 d.When the concentration was 10mg/L,IR of ClO2-Diuron was above 50%.The best working concentration suggested is about 10 mg/L.