Remediation Of Cu-pyrene Combined Pollution In Water By Rygrass

Hydroponic experiments were conducted to investigate the phytoremediation of copper and pyrene in water by ryegrass. It included the following aspects:remediation efficiency of cu-pyrene combined pollution in water by ryegrass, the accumulation of copper and pyrene in ryegrass, the influence of co-existed pollutants on physiological, biochemical and morphological characteristics of ryegrass, and rhziofiltration mechanism of copper.Pyrene and Cu were well remediated by ryegrass in water, and the removal ratios of O.1mg.L-1 pyrene and 5mg.L-1Cu were up to 95%in 96h. When the initial concentrations were 5-40mg.L-1, the removal ratios of copper were between 53%and 95%, and the relationship of them was a negative linear. The removal of pyrene was fast at first and then became slowly. In 24h, the concentration of pyrene decreased from 0.1mg.L-1 to 0.029mg.L-1, and the removal ratios reached 71.3%. While in 96h, the concentration of pyrene was decreased to 0.009mg.L-1, only 11%of the control. It was indicated that hydroponically grown plant ryegrass could effectively remove copper and pyrene from aqueous solution, exhibiting a good application prospect in phytoremediation of cu-pyrene combined pollution in water.Ryegrass had a strong tolerance on pyrene, while copper had physiological and biochemical toxic effects.on ryegrass. High concentrations of copper would reduce the biomass and chlorophyll contents of ryegrass, and increase the contents of free proline and malonyl dialdehyde in ryegrass. Compared with sole Cu pollution, under Cu-pyrene combined pollution, there was no obvious difference in physiology and biochemistry of ryegrass.The accumulation of pyrene by root and shoot of ryegrass was 4.65-5.39mg.kg-1and 0.81-1.08 mg.kg-1, respectively. There was no remarkable relevance between the initial copper concentration and the accumulation of pyrene. The accumulation of pyrene in root and shoot were slightly decreased under different copper treatment, because the presence of copper would reduce the biomass and biological activity of ryegrass.It could be know from chemical forms and subcellular distribution analysis that ethanol extractable copper was predominant in root, which accounted between 44.6%to 79.5%for the total quantity, and this may be one of the reasons why massive copper could be accumulated by shoot of ryegrass. While a variety of chemical forms were coexist in shoot, the chemical forms of copper could be transferred to stable and low poisonous form by ryegrass, so the ryegrass could well grow under high concentrations of copper. Most of Cu was bound to the cell wall fraction and secondly cytoplasm fraction and only a small quantity of Cu was bound to organelle fractions.A larger number of hair roots were grow on the main root under the stimulation of copper, which would promote the accumulation of copper by ryegrass. The proportion of copper in ryegrass root were:hair root> sample root> control root, this also proved that, a lot of copper could be absorbed on hair root because of the large surface area of it.The removal ratios of copper by fresh roots and dry roots of ryegrass were 95%and 58%, respectively, which conformed that the adsorption and active absorbtion of roots were important ways of ryegrass to accumulate copper.