A Comparative Study on the Phytoextraction of Five Common Plants against Chromium Toxicity

Phytoextraction is a remediation technology that uses plants to remove heavy metals from soil. The success of a phytoextraction process depends on adequate plant yield (aerial parts) and high metal concentrations in plant shoots. A paper towel experiment was conducted to investigate the effects of plants sunflower (Helianthus annuus), maize (Zea maize), pearl millet ( Sorghum bicolour), green gram (Vigna radiata) and ground nut (Arachis hypogaea). Seeds of these plants were exposed to five different concentrations (10, 20,30,40,50 ppm ) of Cr as potassium dichromate. The ecotoxicological effects of hexavalent Chromium (Cr) on germination, early seedling growth and chlorophyll content of five plants were investigated. Cr accumulating capacity of those plants was compared. Different species showed different levels of tolerance to Cr pollution. Total chlorophyll content declined progressively with increasing concentrations of heavy metals. The maximum chromium accumulation capacity of roots was in the order of Zea mays > Sorghum bicolour > Helianthus annus > Arachis hypogaea > Vigna radiata and the amount is 5.56 , 3.65, 3.56, 0.8 and 0.08 ppm respectively.