THE EFFECT OF THE PRESENCE OF IRON ON THE PHYTOREMEDIATION OF COPPER BY WATER HYACINTH (EICHHORNIA CRASSIPES) AND WATER WILLOW (JUSTICIA AMERICANA)

Contamination of streams and rivers by heavy metal ions is an increasingly common problem, as abandoned mining sites across the southeastern United States produce acid mine drainage (AMD) that poses a threat to ecosystem health. Phytoremediation presents an effective natural solution to this problem. This study examines the ability of Eichhornia crassipes (water hyacinth) and Justicia americana (American water willow) to remove copper and iron ions from contaminated water. These plants were selected because previous research has shown that both species are known hyperaccumulators of metal ions, making them ideal candidates for phytoremediation. Furthermore, both species are already widely distributed across the southeastern United States, which makes them useful for remediation of abandoned mining sites in those areas. The objective of this study was to determine which plant is most effective at removing copper and metal ions from water, as well as the conditions under which phytoremediation is most effective. Plants were exposed to prepared acidic solutions (pH 3.5-3.7) containing varying concentrations of Cu²⁺ and/or Fe²⁺ up to 25 ppm of each metal for twenty-four hours, and samples were collected at a regular interval. E. crassipes was more effective at removing metals than J. americana, especially at removing copper; E. crassipes removed a maximum of 73.94% of copper ions, whereas J. americana removed 1.12%. E. crassipes was also more effective at remediating iron, removing a maximum of 96.90% versus the 38.58% removed by J. americana. Generally, plants were more effective at absorption when only one metal was present. The data suggest that the presence of both copper and iron in the same solution negatively affects the plants’ abilities to absorb those metals, although both plants were found to be suitable candidates for phytoremediation under acidic conditions.