| Most freshwater lakes in China confronted with environmental problems such a-s water eutrophication,some lakes simultaneously affected by different degree of hea-v y metal pollution.The toxicity of arsenic and its biological transformation mechanis-m is related to the forms of arsenic closely.Phytoplankton as an important link of the f-ood chain in water ecological environment,and biotransformation of arsenic run throu-gh every link of the entire environmental system,the effect of the phytoplankton cann-ot be ignored in the meantime.Arsenic in the environment under the action of phytopl-ankton,its transformation way should roughly as the As(?)into the As(?),the A s(?)into MMA and DMA.To explore migration rule of arsenic pollutin by phytopla-nkton under different environmental factors.This study takes Chlorella vulgaris for r-esearch objection and investigation migration transformation of arsenic affected by Ch-lorella vulgaris in different concentrations of arsenic level,pH and N/P condition.To examine the effect of Chlorella vulgaris on the conversion of arsenic under di-fferent concentrations of arsenic level,this study respectively selected four different concentration gradient of the As(?)and four different concentration gradient of the As(?)to cultivate Chlorella vulgaris,then respectively using liquid chromatograp-hy atomic fluorescence spectrometer to make analytic determination of total arsenic a-nd the form in the culture liquid and Chlorella vulgaris.The experiments were conduc ted for thr-ee weeks(20d).The results show that the ordinary Chlorella vulgaris to ab sorb arsen-ic more as arsenic concentration increases,and compared with the A s(?),Chlorella vulgaris absorbed more easily with the existence of the As(?);Th e change of the valence state of As(?)in the body is not obvious,and the As(?)in c hlorella was almo-st oxidezed to the As(?),though the whole term organic arsenic do es not detected.To examine Chlorella vulgaris in different pH conditions,the experimental set up four gradient.Experimental process with 0.1 mol/L sodium hydroxide and hydrochloric acid to adjust pH,to remain it to keep unchanged,in the proce-ss of control experiment set the background value of arsenic concentration as t-he As(V),by liquid chromatography with atomic fluorescence spectrometer,re-spectively for different pH and the arsenic concentration of nutrient solution cu-Iture and Chlorella vulgaris analysis determination of total arsenic and arsenic form in the body.The whole experiment were done three weeks(20d).The resu-Its showed that when the pH between 7.0 and 8.0 normal chlorella to the abs-orption of arsenic from pH between 8.0 and 9.0;When the pH is 6.0,Chlore-lla vulgaris arsenic in the body mainly exists in the form of As(?);As(?)under the background concentration of medium,to detect small amounts of DMA,algae in the body at the same time As(?),the As(?),organic DMA,including organic ars-enic content is 1.8 to 5.3 ?g/g.To examine Chlorella vulgaris in different N/P conditions form transformat-ion of arsenic,the experimental set Chlorella vulgaris on arsenic transformation,in the form of the experimental set up five groups of N/P,and set up four ar-senic concentration gradient of As(V),by liquid chromatography with atomic fluorescence spectrometer respectively for each group of culture and Chlorella vulgaris analysis determination of total arsenic,the whole experiment were do-ne three weeks(20d).The results show that under different concentrations of a-rsenic levels,Chlorella vulgaris organic arsenic levels in the body under the hi-gher N/P group than low N/P high arsenic content in the body.Under various pH levels,along with the increase of the concentration of arsenic content in t-he cells increased significantly;With the increase of arsenic concentration,arse-nic levels in the body also increases accordingly,when the concentration of As(V)for more than lmg/L,the body of Chlorella vulgaris trace organic arsenic(DMA),its concentration in the range of 1.1 to 6.8 p,g/g. |
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