Phytoremediation of arsenic‐contaminated soil as affected by the chelating agent CDTA and different levels of soil pH

Abstract

Elevated levels of arsenic can pose a major threat to both human health and the environment. The phytoremediation of heavy metals from soil is emerging as a cost‐effective technology for the remediation of contaminated soils. The present greenhouse study was undertaken to identify plants capable of tolerating and accumulating high concentrations of arsenic. Asparagus fern and rye grass were found to tolerate and accumulate more than 1,100 ppm of arsenic in plant tissue. Arsenic uptake as affected by different levels of the chelating agent trans‐1, 2‐ cyclohexylenedinitrilotetraacetic acid (CDTA) and soil pH were also studied. The application of 5 mmol kg−1 of CDTA to arsenic‐contaminated medium loam field soil enhanced the accumulation of arsenic by the test plants. Under these conditions, plants accumulated up to 1,400 ppm of arsenic as compared to 950 ppm by the plants grown in soil containing 1,200 ppm of arsenic but without any amendment of the chelating agent. Plants grown in field soil of pH 5 containing 300 ppm of arsenic absorbed higher concentrations of arsenic than at other tested pH levels. Corresponding reductions in arsenic content of soil after plant harvests were observed. © 2001 John Wiley & Sons, Inc.

Phytoremediation of contaminated soils and groundwater: lessons from the field

“…The levels of As in plants are generally less than 12 mg kg −1 DW, but P. vittata was found to accumulate As at levels of more than 7,000 mg kg −1 DW in its fronds, which is hundred times more than any other plant species tested (Ma et al 2001). High capacity for As accumulation was also reported for asparagus fern (Bagga and Peterson 2001). The capacity for As accumulation of brake fern together with its ability to cope and survive in many areas with a mild climate as well as its considerable biomass, fast growing, etc.…”

The Use of Plants for Remediation of Metal-Contaminated Soils

“…The levels of As in plants are generally less than 12 mg kg -1 DM, but P. vittata was found to accumulate As at levels of more than 7000 mg kg -1 DM in its fronds, which is hundred times more than any other plant species tested [38]. High capacity for As accumulation was also reported for asparagus fern [57]. The capacity for As accumulation of brake fern together with its ability to cope and survive in many areas with a mild climate as well as its considerable biomass, fast growing, etc.…”

Arsenic speciation driving risk based corrective action

“…Arsenic has not been shown to be an essential plant nutrient (Carbonell et al, 1998;Bagga and Peterson, 2001). The availability of arsenic for plant metabolism is mediated by the oxidation state.…”