Enhanced disappearance of dicofol by water hyacinth in water.

The efficiency and primary mechanism of phytoremediation of water contaminated with dicofol, an organochlorine pesticide, by water hyacinth (Eichhornia crassipes) was investigated. After 10 days of incubation in nutrient solution at 25 +/- 1 degree C, the remaining dicofol which was spiked initially at 1 mg l(-1) was 0.05 and 0.26 mg l(-1) in the non-sterile planted and non-sterile unplanted, 0.07 and 0.31 mg l(-1) in the sterile planted and sterile unplanted treatments, respectively. The half-life of dicofol in nutrient solutions was reduced to 59-68 h in the planted treatments from 118-137 h in the unplanted treatments. The accumulated dicofol in water hyacinth plant decreased by 41-53% after the plant had grown for 7 days in dicofol-free nutrient solution. Two phytoprocesses were found to be most important in the remediation of dicofol contaminated water: (i) uptake, accumulation and phytodegradation of dicofol by the plant, accounted for 50% of the removal of the spiked dicofol, and (ii) microbial degradation associated with the rhizosphere, contributed about 7% to dicofol removal. Water hyacinth may thus be a good candidate for development as a phytoremediation system for dicofol-contaminated water.