Bioremediation for water purification· A case study at St. Coombs Lake, Talawakelle

Abstract

Phytorernediation is one of the most eco friendly and innovative techniques to remove pollutants fromsoi I and water in agricu Itural areas. Th is study explored potentials ofbioremediation for water purificationat Tea Research Institute of Sri Lanka through monitoring water quality of St. Coombs lake andthrough several glasshouse and laboratory experiments for validating the resu Its during the period ofNovember 2004- February of2005.

The water qual ity parameters such as pH, nitrate, phosphate, iron and total col iforrns at 35 DC / 100 rnland Escherichia coli at 44° C / 100 ml were monitored during dry and rainy periods. The possiblecauses for water pollution of the lake were also monitored. Nitrate pollution was greater during rainyperiods since higher contribution of erosion and runoff. Higher levels of total coliforms and Escherichiacoli were observed in both seasons. Five plant species traditionally known to have phytorernedialproperties i.e. Kang kong (Ipomea aquaticai, Giant reed (Arunda danax), Water hyacinthiEichhornia cracipesi, Bulrush (Scirpus lacustris) and Kurnbuk (Terminalia arjuna) wereevaluated for nutrient absorption. The histology of Kumbuk and Tea roots were assessed for theiranatomical attributes to the biorernediation properties.

The differences in root anatomical traits in different plant species lead to differences in nutrient andwater absorption. Kang kong, Water hyacinth and Bulrush showed better performances in nutrientabsorption. The results supported the potentials and technical attributes to common biorernediationplant species in purification of water. These attempts would be environmentally and user friendly, costeffective as well as aesthetic advantages and long-term applicability compared to chemical treatments.