The Studies Of Three Aquatic Species On The Potential Phytoremediation Of Copper Tailing Leachate

Higher ornamental value and high viability of three aquatic plants,Nelumbo nucifera Gaertn,Iris sanguinea Donn ex Hornem.and Hydrocotyle sibthorpioidesLam.Encycl.were used as the experiment materials and cultivated in Cu tailing leachate obtained from Dexing,Jiangxi,China.The aims of the research were to study the effect of Cu tailing leachate(CuL)on the plant growth index,tolerance index,Cu accumulation and translocation factors,and the effect of cultivation of these plants on CuL remediation potential.The results would provide theoretical and technical support for water environment remediation of heavy metal pollution,especially the water containing Cu.The main results are as follows:(1)The effects of Cu tailings leachate on the growth index and Cu accumulation and translocationof N.nucifera and I.sanguinea were studied by pot culture.The results showed that under CuL stress,the length and diameter of lotus petiole were 13.69% and 5%,respectively,lower than that in the control.The height of I.sanguinea growing in 50%CuL decreased 22.77% compared with control.Compared with the control,the root dry mass of N.nucifera was 1.59 times higher than that of the control,and the tolerance index was increased 1.17 times,and the Cu accumulation in the underground of N.nucifera was the highest and was up to 90.92 ?g/g.Cu content in the shoot of I.sanguinea treated with 75%CuL was highest,45 ?g/g.translocationfactors of N.nucifera and I.sanguinea treated with 75%CuL were 1.32 times and 3.34 times,respectively,of the control.The results indicated that the adaptability of N.nucifera was stronger than I.sanguinea,and N.nucifera could be used to remediated Cu tailings leachate or Cu polluted water.(2)The effect ofcultivation of N.nucifera and I.sanguinea on the quality index of CuL tailings leachate was studied.The results showed that Hydrogen ion concentration(pH)value in the the pure CuL tailings leachate cultivated with N.nucifera decreased by 25% compared with control.Electrical Conductivity(EC)values of CuL tailings leachate cultivated with N.nucifera and I.sanguinea were 15.9 times and 4.08 times,respectively,and Dissolved Oxygen(DO)values were 1.05 times and 1.01 times,respectively,of the control.The Oxidation-Reduction Potential(ORP)of pure Cu tailings leachate cultivated with N.nucifera was 1.28 times higher than that of control,and was significant difference(P<0.05)and Biochemical Oxygen Demand(BOD)increased by 1.05.Planting N.nucifera and I.sanguinea made phosphate in the pure tailings leachate to decrease by 94% and 89%,respectively.The ammonia nitrogen concentration in the pure Cu tailings leachate planted with N.nucifera increased 128 times of the control,while,that in 75%CuL cultivated with I.sanguinea was 4.55 times of the control.The content of Cu concentration in 75%CuL cultivated N.nucifera was 1.09 times higher than that of control.The results indicated that N.nucifera was more conducive to improve the index of water pollution compared with I.sanguine and conducive to the remediate of CuL.(3)The effect of pure CuL on the growth indexes of three aquatic plants,N.nucifera,I.sanguinea and H.sibthorpioides in compound cultivation was studied.Results showed that the petiole length,leaf diameter and root number of N.nucifera in compound cultivation decreased compared with monoculture;leaf number,stem length and root length of N.nucifera in the N.nucifera and I.sanguinea compound cultivation were significantly higher than that of monoculture;exept to the underground parts dry weight of N.nucifera and I.sanguinea compound cultivation,dry weight of above-and underground parts and tolerance index of N.nucifera showed a declining trend.The leaf number and aboveground parts dry weight of I.sanguinea in compound cultivation decreased compared with single planting.The leaf diameter,root number,root length and shoot dry weight of H.sibthorpioides in composund cultivation decreased compared with monocultre;above-andunderground parts dry weights in the compound cultivation with N.nucifera and I.sanguinea were different significantly compared with monoculture(P<0.05).The results indicated that N.nucifera was more suitable for the monoculture;I.sanguinea and H.sibthorpioides in compound cultivation would promote bilateral growth index,tolerance index and H.sibthorpioides could be single or compound cultivated.(4)The effects of the compound cultivation of three aquatic plants on the CuL quality index showed that the pH of each treatment was acidic,the pHin the cultivation leachates of N.nucifera,I.sanguine,N.nucifera+H.sibthorpioides and N.nucifera+I.sanguinea+H.sibthorpioides treatments were higher than that of not cultivated any plants(control).The electrical conductivity(EC)of all treatments was lower than that of control.The redox potential(ORP)in the Cu tailings leachate of H.sibthorpioides treatment increased by 1.77 times compared with the control,while,the ORP in the leachae of N.nucifera was decreased by 34.21% compared with the control.The dissolved oxygen(DO)decreased by 45.11% under N.nucifera treatment,and the H.sibthorpioides treatment increased by 1.06 times compared with the control.The values of biological oxygen demand(BOD)in the treatment of H.sibthorpioides and I.sanguine+ H.sibthorpioides were 1.06 and 1.04 times,respectively,that of the control.There was no significant difference in the values of phosphate in the different treatments(P>0.05).The ammonia nitrogen treatments of three aquitic plants were lower than the control.Cu concentrations in N.nucifera+I.sanguinea,N.nucifera+H.sibthorpioides and N.nucifera+I.sanguinea+H.sibthorpioides treatments were lower than the control.