This study was executed to: (i) evaluate the ability of sunflower (Helianthus
annuus), sorghum (Sorghum bicolor) and elephant grass (Pennisetum purpureum
Schum) to accumulate Co in their tissues. (ii) and define to what extent these plants
can clean-up a Co-contaminated sandy soil. Two experiments were conducted, the
first was nutriculture (hydroponics) experiment and a pot sandy soil one. Sunflower
absorbed appreciable quantities of cobalt in both experiments. Elephant grass was
superior in accumulation of cobalt to the other plants particularly in the soil
experiment. Sunflower and elephant grass could be considered hyperaccumnulator
plants for cobalt and could be used to remedy Co-contaminated soils. Using
phytoremediation may be of less cost as compared with other remediation
techniques. Using chemical extraction in sequences may remove high amounts of
cobalt and be most effective as compared with phytoremediation. Extraction of heavy
metals with EDTA was more effective than using AB-DTPA extraction.