Screening of Wetland Plants Subjected to Stress From Polychlorinated Biphenyls Contaminated Soils

Abstract

Soil pollution due to electric and electronic waste (e-waste) has become a major problem that is degrading environment and drawing worldwide attention. PCBs are widespread and have potential health risk so their removal from the environment has become an international priority. Phytoremediation is considered as highly accepted and good method for treatment of contaminated soils. Current study was conducted to investigate the abilities of several promising wetland plants to degrade and dechlorinate PCBs and demonstrate their advantages in disappearance of polychlorinated biphenyls. The soils samples were collected from PCB-contaminated sites at Layyari, Karachi Pakistan. Under both floody and dry condition plants including Alternanthera sessilis (L.), Bacopa moneiri (L.) Pennell, Centella asiatica (L.) Urban, Juncus articulatus L., Cyperus arenarius Retz were grown. For dechlorination of PCBs three treatments were set up in a fully randomized layout of greenhouse pots. Soil from those pots was extracted and further analyzed by Gas chromatography equipped with a 63Ni electron capture detector. The detection limits of PCBs ranged from 0.009 to 0.082 µg/kg. In total PCBs degradation ratio was 22.44% while in high chlorinated PCBs almost 15.26% of the high polychlorinated biphenyls were removed from the soil after 2 month in the wetland planted soil, while only 4.64% was removed in the drowned control and 6.54% in the unplanted control. Present study concludes that this method only has high efficiency in removal of low chlorinated biphenyls, while low efficiency even nothing in removal of high components.