Screening Of Aquatic Enriched Plants For Uranium And Associated Heavy Metals

This paper is about the key technical problems of screening ou t aquatic h-yperaccumulation plant with uranium and its associated heavy metals by hydroponics experiments,and studies the aquatic p lants such as Oenanthe javanica(Blume)DC,Hydrocotyle vulgaris L.,Nymphaea tetragona L and Hydrocharis dubia(Bl.)Backer under the stress of uranium and its associated heavy metals,which showe d that Nymphaea tetragona L.has the best accumulation ability.It also analyzes the physiological and biochemical indexes and change s of photosynthetic characteristics of Nymphaea tetragona L under a single pollution treatment of uranium and its associated heavy met als,and the accumulation characteristics of Nymphaea tetragona L t o each element under a compound pollution treatment of uranium a nd its associated heavy metals,which provides certain references fo r the application in the ecological treatment of radioactive water.T he results are as follows:(1)The accumulation of aquatic plants increased with the in crease of treatment concentration,and the TF(transfer factor)of th e Nymphaea tetragona L.was more than 1 under different concentra tions of Mn,Pb,Hg and As.Under 55mg/L U treatment,the U con centration of the whole Nymphaea tetragona L.was highest,reachin g 1885.67mg/kg.The biomass enrichment coefficient of Nymphaea te tragona L.was the highest at 0.61 under 30mg/L U treatment.The biomass accumulation coefficient of the Nymphaea tetragona L.was1.06 under 2mg/L Hg treatment.The Mn and Pb biomass accumula tion of the whole Hydrocharis dubia(Bl.)Backer were 6407.47mg/kg and 1300.00mg/kg under 110mg/L Mn and 55mg/L Pb treatment.U nder 10 mg / L Mn and 5mg / L Pb treatment,the biomass enrichm ent coefficient of Hydrocotyle vulgaris L.was 1.63 and 0.80,respe ctively.The Hg and As biomass accumulation of whole Oenanthe ja vanica(Blume)DC were 112.67mg/kg and 136.36 mg/kg under 2 mg/L Hg and 4 mg/L As treatment,and the biomass accumulation co efficient of Oenanthe javanica(Blume)DC was 1.98 under 2 mg/L As treatment.(2)The trend of the activity of hydroxygenase in aquatic plant s rose first and then decreased under the U,Pb,and As concentrati on,and rose gradually under the Mn and Hg treatment.The activity of SOD under the coercion of 30mg/L U was highest,75.03% hig her than the contrast,and the activity of POD under the coercion o f 30mg/L Pb was highest,134.54% higher than the contrast.The ac tivity of CAT under the coercion of 5mg/L Pb was highest,275.95% higher than the contrast.The content of soluble protein and M DA became gradually lower and higher respectively both in plant under the coercion of 4mg/L As,which increased 55.48% and decre ased 73.43% compared to the contrast.The Chlorophy A,Chlorophy B and Carotenoid decreased 19.50%,20.30% and 19.34% compared to the contrast under 55mg/L U treatment,and the photosynthetic r ate of Nymphaea tetragona L.under 4mg/L As treatment decreased19.50%,20.30%,19.34%.Under 55mg/L U and Pb treatment,Fv/Fm(maximum photochemical efficiency)declined 11.55% and 10.35%respectively.PIabs(light and performance)declined 19.13%,24.39%and 21.33% respectively undue 5mg/L U and Pb,4mg/L As treatm ent.(3)The enrichment of uranium and its associated heavy metals of Nymphaea tetragona L.increased significantly with the increase of concentration.The concentration of U per plant in Nymphaea te tragona L.was significantly correlated with the concentration of U(r=0.7778**),which showed promotion effect.The concentration of Mn per plant under U(r=0.5264*)and Mn(r=0.8328**)treatment s howed significant and highly significant promotion effect,which wa s significantly inhibited by Pb(r=-0.5349*)treatment.The concentr ation of Pb per plant was significantly inhibited by U treatment(r=-0.5161*),which was significantly promoted by Pb(r=0.9086**)tre atment.The concentration of Hg per plant was significantly and highly significantly promoted under the treatment of U(r=0.5034*)an d Hg(r=0.7044**).The concentration of As per plant was significan tly promoted by As treatment(r=0.5188*).