Enhanced dissipation of polycyclic aromatic hydrocarbons in the rhizosphere of the Athel tamarisk (Tamarix aphylla L. Karst.) grown in saline-alkaline soils of the former lake Texcoco

Remediation of polycyclic aromatic hydrocarbons (PAHs) contaminated alkaline saline soil with phreatophyte or "water loving plants" was investigated by spiking soil from the former lake Texcoco with 100 mg phenanthrene (Phen) kg(-1) soil, 120 mg anthracene (Ant)kg(-1) soil and 45 mg benzo(a)pyrene (BaP) kg(-1) soil and vegetating it with Athel tamarisk (Tamarix aphylla L Karst.). The growth of the Athel tamarisk was not affected by the PAHs. In soil cultivated with Athel tamarisk, the leaching of PAHs to the 32-34 cm layer decreased 2-fold compared to the uncultivated soil. The BaP concentration decreased to 39% of the initial concentration at a distance smaller than 3 cm from the roots and to 45% at a distance larger than 3cm, but 59% remained in unvegetated soil after 240 days. Dissipation of Ant and Phen decreased with depth, but not BaP. The biodegradation of PAHs was affected by their chemical properties and increased in the presence of T. aphylla, but decreased with depth.