The Effect Of Organic Phenol In Urban River Stresses On The Engineered Plants And Its Phytoremediation Ability

With the accelerated process of urbanization, urban river eutrophication and organic pollution problem has become increasingly evident. Such problems have currently become one of the main China's water environment issues. In recent years, people began to study on riverway ecological recovery technique from ecological point, and committed to eliminate the adverse effects of human activities on the river systems, people have done a lot of research work on it. In this paper, we discuss some factors such as the plain areas of the city river's eutrophication degree, organic phenol and the surrounding buildings shading stress on the engineered plants and effect on the purification law of plant. This has an important theoretical guidance meaning on using bioremediation technologies to restore river ecosystem and get some rationalization proposals for improving the reasonable architectural composition around the city river.Through experiments, the following important conclusions as follow:In the absence of phenol pollutants in water, with the weakening of light intensity, H.reticulatum optimum growth of the nutritional state would decreasing, It nutrition demand at 30000lx light intensity is 0.17mg/L and at 6000lx is declined to 0.085mg/L, respectively. In the same nutrients conditions, due to the increase light intensity H.reticulatum can increase the growth and the nitrogen and phosphorus absorption and removal efficiency rising. Under 30000lx illumination conditions nitrogen and phosphorus removal rate up to the 69.8%, 49.9%; and light intensity of 6000lx, nitrogen and phosphorus'highest removal rate is only 39.9% and the 30.8%. In the same circumstances with the light intensity becoming weakened, the total sugar content was evidently decline. Under the same nutrients conditions, increased light intensity is conducive to promoting the growth of algae, increasing the synthesis of chlorophyll accumulation, promote algae absorb nutrients, so that enabling its phytoremediation ability. And it will also greatly improve the engineering plants'ecological adaptation.When the concentration of organic phenol is low, it can produce hormesis-effect on H.reticulatum. In the 30000lx light intensity group, the experimental group without phenol algae's growth maximum rate at 27%. But when existing 15mg/L phenol, the experimental group maximum growth rate is rising to 37%.At the light intensity of 6000lx, the law was same. In none phenol group, highest growth rate was 21%; while within 15mg/L phenol, the largest growth rate of 31%. Increase Light intensity can also rising H.reticulatum's removal rate of nitrogen and phosphorus. At 30000lx light intensity for the group containing 15mg/L phenol, the highest nitrogen and phosphorus removal rate reached 78.6% and 52.8%, and these more than the none phenol group 6.8% and 2.9%. In light intensity of 6000lx, nitrogen and phosphorus maximum removal rate is 57.8% and 41.6%, higher than the experimental group without phenol 25.8% and 10.7%.In the water-body with adequate light, the largest degradation rate of phenol by H.reticulatum reached 86%, while less than its best light degradation rate was only 64%. Therefore, the light radiation is also advantageous to raising the repairing plants'purification ability of organic phenol pollution. So the buildings around the plain areas of the city river should reduce effective illumination to river ecosystem, and that has a negative impact on application engineering plants for restoration eutrophication rivers. That should be attached importance to highly at present.At the best adequate nutrient condition and within different concentrations of phenol, experiments found that the group received adequate illumination, algae can bear 50mg/L organic phenol, and when the concentration less than 60mg/L, phenol takes a significant role to promote H.reticulatum grow. While the light intensity weaker, H.reticulatum can tolerate less than 20mg/L phenol, and the phenol stimulate affection obviously less than the former.Malondialdehyde (MDA) as a regular typical molecular markers (biomarkers) can show aerobic biological membrane lipid oxidative damage, which in this experiment has been very good proof. Not only manifestation on the growth rate of plants, resistance phenol's stress, its polysaccharides metabolism and membrane permeability changes in line with the law also proved it, and so on.When the light intensity at 30000lx, H.reticulatum MDA metabolism level below 16000nmol/g (fresh weight). Once MDA content was detected more than 19800nmol/g (fresh weight), at this time the role of phenol's stress can caused algae death. Under 6000lx, as MDA content below 11000nmol/g (fresh weight), the algae can grow normally, while the content of MDA reached at 13000nmol/g (fresh weight), the toxic effects of phenol should lead to algae died.The Spartina Anglican's leaf surface has the good adsorption effect on hydrozybenzene. On still water and lucifuge condition, the process of adsorption was chosen to describe with Freundlich isotherms: q = 1.3×10-8 C0.08314. Besides that the population density, deepness, flow turbulence and concentration are also the main facts in such process. In the same conditions, increase light intensity should produce degradation of photosensitive, that can improve the removal rate of phenol higher in sunny than at night and cloudy day by Spartina anglica. So it should be viewed the ecological functions of Spartina anglica from various angles, but also attaches importance to its characteristics as alien species.