Study On Stress Effects Of Heavy Metals On Pavlova Viridis And Its Biosorption Capability

This paper studies the effects of copper, zinc, lead, cadmium on the growth of Pavlova viridis and study the accumulation of heavy metal on Pavlova viridis . It also discussed some regularity of their physiology and biochemistry.The Pavlova viridis is exposed to various concentrations of four kinds of heavy metal and cultured for ten days. Then, reports the toxicity effect of heavy metal ion in growth. The density was analyzed in the course of culture. The content of chlorophyll-a , soluble carbohydrate and SOD were analyzed after ten days culture. In the experiment of biosorption, Pavlova viridis is exposed to stabilized heavy metal concentration. And analyze the concentration of the solution after time. The experiment results show that: the cell density of Pavlova viridis was restrained in high concentration algae solution. With the concentration increased the cell density will be decrease. It was found that the safety concentrations of Cd2+,Cu2+, Pb2+, Zn2+ for Pavlova viridis are 0.7777, 0.1192, 3.301, 0.3548mg/L and 96-h EC50 are 7.777, 1.192, 33.01, 3.548mg/L. So the toxic sequence of these heavy metals from low to high is Cu2+,Zn2+,Cd2+,Pb2+. It shows that the content of chlorophyll-a , soluble carbohydrate and SOD is low when the ion concentration is higher. The mechanism of the action was suggested and it is believe that the balance of availability of nutrients for optimum growth was disturbed with the presence of metals at high ion concentration.The accumulation of four kinds of heavy metal ion also been investigated. After 5-hour biosorption, the removal concentration of Pb ion is reach to 80 percent. The accumulation sequence of these heavy metal from high to low is Pb2+,Zn2+,Cd2+, Cu2+.Investigation in into the stress of heavy metals to Pavlova viridis and the their absorption abilities is key to treatment of environmental contamination, and significant in understanding the transferring and transforming behaviors of heavy metals, the results from obtained from such research can prove useful in establishingthe standards for wastewater release and provide a framework for water qualityevaluation.