Phytoremediation of barium, copper, zinc and arsenic contaminated soils by sunflower and alfalfa
By: Jamil Zargan, Massood Fakharyfar
Key Words: Phytoremediation, Heavy metals, Contaminated soil, Sunflower, Alfalfa.
J. Bio. Env. Sci. 8(6), 171-180, June 2016.
The existing remediation techniques of heavy metal-contaminated soils are expensive, time consuming and environmentally destructive. Unlike organic compounds, metals cannot degrade, and thus effective cleanup requires their immobilization to reduce or remove toxicity. Phytoremediation is a developing technology for cleaning up contaminated sites, which is cost effective, and has aesthetic advantages and long term applicability. The main aim of this study was to screen the accumulation and distribution of barium (Ba), copper (Cu), zinc (Zn) and arsenic (As) in 30 cultivars of alfalfa (Medicago sativa L.) and giant sunflower (Helianthus giganteus) for their possible use in phytoremediation. Soil samples were collected from Saghand and Bandar Abbas which are closed to industrial complexes. Also, loam soil was used as a blank sample for comparing results. Among these species, alfalfa samples could not grow in these soils, hence, it was removed from experiments. Furthermore, influence of adding nitric acid, acetic acid, citric acid and oxalic acid on performance of sunflower was investigated. Results proved that sunflower could be used for phytoremediation, as, they showed the ability of toleration high concentration of heavy metals and they exhibited the capability of barium, copper, zinc and arsenic uptake. Moreover, outcomes from experiments ascertained that adding acid to soils increased bioavailability of heavy metals, since, adding acids to soils increased bioavailability of barium, copper, zinc and arsenic and these samples showed higher heavy metals uptake.