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

摘要

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{sup}(-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 infield soil of pH5 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.