Phytoremediation of perchlorate by native and exotic riparian phreatophytes of the Las Vegas Wash, Nevada

The potential to use native (Salix exigua) and exotic (Tamarix ramosissima) phreatophytes to remediate perchlorate from arid riparian environments was investigated by conducting a hydroponic greenhouse experiment. Salix exigua and Tamarix ramosissima exposed to ammonium perchlorate at concentrations of 10 mg L -1 and 100 mg L-1 removed 15 to 22% perchlorate mass from hydroponic solution, with 55 to 64% of removal being taken up into plant tissue. Total perchlorate taken up by plants or removed from solution was not significantly different between species on a mass or oven dry plant weight concentration basis. Significant differences in tissue specific uptake, however, were detected, with Salix exigua accumulating 78 to 87% of perchlorate in the leaf and Tamarix ramosissima exuding 84 to 87% of uptake onto leaf surfaces. Burning leaf tissue resulted in no detectable perchlorate in ash.