Abstract:
The effects of ethylenediaminetetraacetic acid (EDTA) and citric acid (CA) on cadmium (Cd) uptake by water hyacinth, (Eichhornia crassipes) in 0.5 mg/L Cd contaminated water were studied. The experimental design was separated into 4 groups: 1) contaminated water without chelating agent (Control), 2) contaminated water with EDTA added at concentrations of 0.5, 1 and 2 mg/L, 3) contaminated water with CA added at concentration of 0.5, 1 and 2 mg/L, and 4) contaminated water with both EDTA and CA added at concentration of 0.5, 1 and 2 mg/L. Plants were harvested at 15, 30, 45, 60, 75 and 90 days. Cd levels were measured in the water samples and two parts of the plant: shoot (stem and leaves) and root. The results showed that Cd accumulation in the shoot in all groups was significantly higher than that in the root and was (P<0.05). Cd concentration in plants grown in all EDTA and CA added groups was higher than that in the control samples which indicates that EDTA and CA addition inceases cadmium uptake by water hyacinth. The highest Cd concentration was found in shoot with EDTA and CA added at 2 mg/L and were 156.7 and 105.4 mg/kg at 15 days, respectively. The highest Cd concentration in root was 645.8 mg/kg in EDTA added group at 15 days and 603.2 mg/kg in CA added group at 75 days. This result implies that EDTA has more influence than CA on bioconcentration factor (BCF). The highest score of BCF for EDTA added groups was 802.5 at 15 days and for CA added groups was 682.1 at 90 days. Translocation factor (TF) of plants in EDTA added groups was 0.24, 0.24 and 0.23 at 15 days, respectively. That show EDTA added groups were more cadmium uptake effect than CA added groups.