Phytoremediation of selenium using subsurface-flow constructed wetland

Area of Science:

• Environmental Science
• Plant Science
• Ecotoxicology

Background:

• Selenium (Se) contamination poses environmental risks.
• Constructed wetlands (CWs) offer a sustainable solution for contaminant removal.
• Phyto-remediation using aquatic plants is an emerging technology for Se-contaminated water.

Purpose of the Study:

• To evaluate the efficacy of Phragmites australis and Typha latifolia in removing Se from contaminated water.
• To compare the Se accumulation and distribution in the biomass of both plant species.
• To assess their suitability for phytoextraction and phytostabilization in subsurface-flow constructed wetlands (SSF-CWs).

Main Methods:

• Two SSF-CWs were established, one planted with P. australis and the other with T. latifolia.
• Se was continuously supplied to the inlet at 100 µg Se L⁻¹.
• Water samples and plant biomass were analyzed for Se content at various time points over 12 weeks.

Main Results:

• P. australis beds reduced Se to undetectable levels in outlet water.
• T. latifolia beds showed variable Se concentrations in outlet water (25–76 µg/L).
• P. australis accumulated Se in leaves and rhizomes; T. latifolia accumulated Se primarily in fine roots.

Conclusions:

• P. australis is highly effective for Se phytoextraction and phytostabilization in SSF-CWs.
• T. latifolia demonstrates potential for Se phytostabilization but is less effective for overall removal.
• Both species show potential for Se management in constructed wetland systems.