Assessment of Century Plant (Agave americana) for Remediation of Chromium Contaminated Soils

Abstract

Agave americana was evaluated for its tolerance to different levels of Cr (0, 25, 50, 100 and 200 mg kg−1 soil) and its suitability for the remediation of Cr contaminated sites. The pot culture experiment was carried out for 3 months in clay soil which was collected from 0 to 30 cm depth from the nearby agricultural field. The partitioning of Cr between roots and shoots and its uptake by the plant, bio-concentration factor, translocation factor, translocation efficiency etc. were used to determine the remediation potential of the crop. Overall, the plant could tolerate up to 200 mg Cr kg−1 soil, but a concentration of 81 mg Cr kg−1 soil caused a reduction in the dry weight of the plant by 50 %. The highest total uptake of Cr (2286 µg g−1 plant) and bio-concentration factor (6.59) was found at Cr 200 mg kg soil−1. However, the translocation factor values were found to be <1 (0.18–0.13) indicating that Cr was mainly located in the roots exhibiting an exclusion mechanism. Based on these findings, it was concluded that A. americana could not be considered as a hyperaccumulator for Cr. Nevertheless, as shown by the accumulation ratios the plant has a massive potential for phytostabilization of Cr.