Phytoremediation And Enhancement For Heavy Metal And PAHs Contaminated Soils Form Wastewater Irrigation Area

Wastewater irrigation is the most important way of wastewater reused by far, but theenvironmental problems caused by wastewater irrigation has become very severely.So, it isvery important to remediation single and co-contaminated soils caused by PAHs and Cd.Pyrene was selectd as the representative of PAHs to study phytoremediation and enhancementfor Cd and pyrene contaminated soils from wastewater irrigation area.(1)When Sudangrass was used to remediate the single pyrene contaminated soils,≤10mg/kg pyrene in soils could promote the growth of Sudangrass, while≥50mg/kg pyrene insoils would inhibit the growth of Sudangrass; along with the increasing of pyreneconcentrations in soil,the inhibition caused by pyrene enhanced; high concentrations ofpyrene in soil caused more severe effects to roots than to shoots;the removal rates of pyrenedecreased significantly by the increasing of pyrene in soil; Sudangrass can promote theremoval rate of pyrene in soils.(2)When Sudangrass was used to remediate the single Cd contaminated soil,1mg/kgcadmium in soils can promote the growth of Sudangrass,while when the Cd concentration insoils≥6mg/kg,the growth of Sudangrass would be inhibited; with the addition of Cdconcentration in soil (≥6mg/kg) the inbibition caused by Cd increased; high concentrationsof Cd in soils caused more severe effects to roots than to shoots.(3)When Sudangrass was used to remediate the co-contaminatd soils,5mg/kg pyrenealleviated the toxicity caused by Cd, but high concentrations of pyrene (50,300mg/kg)exacerbated the toxicity caused by Cd;Sudangrass could extract Cd from pyrene-Cdco-contaminated soils, the total accumulation of Cd in plants increased with the increasing ofCd concentration in soil;the translocation factor of Cd in co-contaminated soil differ from Cdconcentration in soils；the removal rates of pyrene decreased with the increasing of pyrene insoils;Sudangrass could significantly improve the removal rates of pyrene in soil; theremediating efficiency of Cd and pyrene influenced by the interaction of pyrene and Cd,andthe interaction of pyrene and Cd might change when the concentraction of contaminateschanged; in the treated with no plants,the removal rates of pyrene not changed by the concentractions of pyrene and Cd.(4) EDTA promoted Cd accumulation and translocation in Sudangrass,and thepromotion effects increased with the increasing of EDTA concentration;differentconcentrations of (NH4)2SO4has no influence in Cd concentration in the shoots of plants,but itshowed that (NH4)2SO4could inhibited the transportating of Cd in plants;1mmol/kg EDTAcan increase the Cd removal rates;EDTA inhibited the removal rates of pyrene,but the(NH4)2SO4play a reverse role.(5) After planting rape and wheat, Cd and Cr concentration in soils decreased,itdemonstrated that the plants coule used to remediate polluted soils,but the Cd and Crconcentration in seeds of rape and wheat could not eat,while could be used to producebiodiesel. It also be proofed that wheat could translocate more than5.91times heavy metalsthan rape.