The Temporal And Spation Variation Of Cyanobacteria Which Caused Water Bloom And The Assay Of Toxicity Study In Aha Rerservoir And Hongfeng Rerservoir

This paper studies on Aha Reservoir and Hongfeng Reservoir,which are two dominant water supply reservoirs of Guiyang.The water sample was collected in March,June, September and December at Aha Reservoir, and in March,May,June,Audest, September,November and December at Hongfeng Reservoir.The water quality ,phytoplankton communities,the communities of cyanobacteria water bloom, the temporal and spation variation were investigated. Microcystins was detected by biology experiment and High Performance Liquid Chromatography. By discussing Cyanobacteria water bloom influence to the safety of drinking water, some suggestions are put up for the factors and control of cyanobacteria water bloom.There are 107 species(include variants) of phytoplankton in Aha Reservoir,They belong to 54 genera 29 families 18 orders 10 classes and 7 divisions. Cyanophyta have 16 species belong to 9 genera 3 families 3 orders 2 classes, occupy 14.95%.On quantitatively,the average quantity is 8.974×106cell·L-1 of the whole year,the variety is 1.372×106cell·L-1 to 23.856×106cell·L-1, Cyanophyta is dominant in the whole year,next are Chlorophyta,Bacillariophyta,Cryptophyta,Euglenophyceae,Pyrrophyta,Chrysophyta is the least.The mostly variety of phytoplanktonis Cyanophyta, the order is March>September>December>June.The proportion of Cyano- phyta in phytoplankton is changed from 1.90% to 92.43%,the average of the year is 46.44%.The highest is 1# 78.13%, the least is 3# 61.13%. The quantitaty proportion of M. aeruginosa in phytoplankton is 0～4.23%, the order of spation variation is 3#>2#>1#. The quantitaty of Aphanizomenon Morr in phytoplankton is 0～89.05%,the order of spation variation is 1#> 2# > 3#.The dominant species of cyanobacteria water bloom is Aphanizomenon flos-aquae,the Aphanizomenon flos-aquae water bloom biology text demonstrated that the symptom of mouse poisoning is not obvious.For the PSP standard sample is confined by National Security Agency ,it can not be tested in China for the while. The algea sample has already sent to Institute of Hydrobiology Chinese Academy of Sciences waiting for text.There are 252 species(include variants and derivative) of phytoplank- ton in Hongfeng reservoir, They belong to 78 genera 38 families 19 orders 9 classes and 6 divisions. Cyanophyta have 65 species belong to 14 genera 5 families 3 orders 2 classes, occupy 14.95%.The order is Chlorophyta,Cy- anophyta, Bacillariophyta,On quantitatively,the average quantity is 72.508×106cell·L-1 of the whole year,variety is 7.194×106cell·L-1to 255.596×106c- ell·L-1, Cyanophyta is dominant in the whole year,next are Chlorophyta, Bacillariophyta, Cryptophyta,Pyrrophyta,Euglenophyceae is the least.The mostly variety of phytoplankton is Cyanophyta,the order is June>Novem- ber>Augest>May >September > March >December.The quantitaty propo- rtion of M. aeruginosa in phytoplankton is 30.95%～79.54%, the average is 53.78%,the first is Augest,second is June 69.09%,the last is March, Cyanophyta is dominant in phytoplankton.The quantitaty of Aphanizomen- on Morr in phytoplankton is 0～22.61%,the average of year is 6.41%,the order of spation variation is March,May17.96%,September.November and December have not been detected.Distribution on spation variation, The quantitaty proportion of cyanobacteria water bloom is 59.22%～82.22%,the average of year is 72.45%.The first is 3#,second is 5# 76.57%,the last is 2#. The quantitaty proportion of M. aeruginosa is 51.89%～80.68%,Distribution on spation variation is 5#>3#>4#>2#>1#. The quantitaty proportion of Aphanizomenon Morr is 2.05%～6.05%,Distribution on spation variation is 4#>3#>1#>2#>5#.The result of experimentation of toxicity study demonstrated that cyanobacteria water bloom in Augest have MC,the first is 3# 0.66μg.mg-1,second is 4# 0.64μg.mg-1,the last is 1# 0.37μg.mg-1.By calculation,if all of the MC was released into Hongfeng Reservoir,it will be 34.7393μg.L-1of MC in 1#, 300.9072μg.L-1 of MC in 3#, 199.6864μg.L-1 of MC in 4# , 186.4352μg.L-1 of MC in 5#.There are many factors causing cyanobacteria water bloom,the domi- nant factor is the increment of nutrition.But to once cyanobacteria water bloom,factors of influence is complex, not only have physics factor,such as temperature,suspend of stormy waves,illumination etc,but also have chemistry factors,such as limit of phosphorous,transform of phosphorous, and also have biology factors,such as competition of populations and control of food chain. The excessive nutrition in Aha Reservoir and Hongfeng Reservoir is the reason of cyanobacteria water bloom ,which lead to the higher proportion of phosphor-nitrogen,so we should prevent nutrition inputing to two reservoirs,particulary phosphorus.There are many methods to control cyanobacteria water bloom,such as chemistry method,biology method.Too much nutrition and high level of phosphor-nitrogen is the main reason of cyanobacteria water bloom.So we should take action to control nutrition,especially the input of phosphors.After all,a single method to control cyanobacteria water bloom is difficult,associate with many methods can make cyanobacteria water bloom at a low-level homeostasis and prevent cyanobacteria water bloom from breaking out effectively.