Comparative Study Of Phytoremediation Efficiency Under PAHs-Cd Compound Pollution Intimidation

With the development of society and economy,the entironment and the human health is facing serious challenges from "single pollution" to "combined pollution".And repairment of composite pollution has become urgent work at today.In this study,two kinds of anti-combined pollution dominant plants were selected as the investigated object,the comparative experimental study of two plants growth tolerance was carried out in different polluted conditions.It has compared the two plants the biodegradation of PAHs(Polycyclic Aromatic Hydrocarbons,PAHs)and the removal capacity of Cd(Cadmium,Cd)in different polluted conditions,and the following results were summarized:(1)PAHs+Cd are respectively 40mg/kg+15mg/kg,when grow to 150 days,the ground height of Phoenix and Echinacea purpurea have decreased 29.93%,52.97%,the biomass of Phoenix and Echinacea purpurea have decreased 31.72%and 91.91%;PAHs+Cd are respectively 40mg/kg+15mg/kg,the ground height of Phoenix and Echinacea purpurea have decreased 31.21%and 22.84%,the biomass of Phoenix and Echinacea purpurea have decreased 37.00%and 87.67%,the two kinds of plants have tolerance to PAHs+Cd combined pollution,under the two composite soil pollution concentration Phoenix grow better,Phoenix has more patience.At the same time,under the condition of the Cd single pollution and the PAHs single pollution,Phoenix's patience and the growth condition is better than the Echinacea purpurea,Cd single pollution almost has no inhibition for the growth of fire phoenix,the inhibition of PAHs single pollution is smaller than PAHs+Cd combined pollution.(2)PAHs+Cd are respectively 40mg/kg+15mg/kg,when grow to 150 days,the degradation efficiency of chrysene,pyrene and benzo fluoranthene(k)of Echinacea purpurea was 44.05%?65.01%?67.15%?26.49%,the order of the four hydrocarbons degradation rate was obtained:chrysene>pyrene>fluoranthene>benzo fluoranthene(k);the degradation efficiency of chrysene,pyrene and benzo fluoranthene(k)of Phoenix was 71.9%?75.73%?68.53%?45.01%,the order of the four hydrocarbons degradation rate was obtained:pyrene>fluoranthene>chrysene>benzofluoranthene(k).PAHsHs+Cd are respectively 70mg/kg+15mg/kg,when grow to 150 day,the degradation efficiency of chrysene,pyrene and benzo fluoranthene(k)of Phoenix was 37.04%?66.08%?63.7%?48.64%,the order of the four hydrocarbons degradation rate was obtained:pyrene>chrysene>benzo fluoranthene(k)>fluoranthene;under the concentration the growth of Echinacea purpurea is unusual,as death.The degradative ability of two plants on the 4th ring aromatics hydrocarbons is better than 5th rings aromatic hydrocarbonsm,under two kinds of concentrations the PAHs degradation rate of Phoenix is 62.18%%and 52.15%,the PAHs degradation rate of Echinacea purpurea is 47.38%and 0%,the Phoenix have a stronger degradation ability than the Echinacea purpurea.(3)PAHs+Cd are respectively 40mg/kg+15mg/kg,when grow to 150 days,the removal rate of Cd was 40.93%with Phoenix,the removal rate of Cd was 26.55%with Echinacea purpurea(the blank control group is 13.92%);PAHs+Cd are respectively 70mg/kg+15mg/kg,when grow to 150 days,the removal rate of Cd was 25.4%with Phoenix(the blank control group is 0%);but the growth of Echinacea purpurea is unusual,as death.Under the condition of combined pollution the removal ability of Phoenix is stronger.PAHs+Cd are respectively 0mg/kg+15mg/kg,when grow to 150 days,the removal rate of Cd was 7.18%with Phoenix,the removal rate of Cd was 4.47%with Echinacea purpurea(the blank control group is 2.83%),under the condition of single pollution the removal ability of Cd with Phoenix is stronger.Under the condition of PAHs-Cd combined pollution the romeval rate of the two plants is higher than Cd single pollution,maybe in soil PAHs can enhance the removal function for Cd,showing the synergy.