Phytoremediation of Triazophos by Canna Indica Linn. in a Hydroponic System

Abstract

The phytoremediation of triazophos (O, O-diethyl-O-(1-phenyl-1, 2, 4-triazole-3-base) sulfur phosphate, TAP) by Canna indica Linn. in a hydroponic system was studied. After 21 d of exposure, the removal kinetic constant (K) of TAP was 0.0229–0.0339 d⁻¹ and the removal percentage of TAP was 41–55% in the plant system and the K and removal percentage of TAP were about 0.002 d⁻¹ and 1%, respectively, in darkness and disinfected control. However, the K and removal percentage of TAP were 0.006 d⁻¹ and approximately 11%, respectively, in the treatment with eluate from the media of constructed wetland. The contribution of plant to the remediation of TAP was 74% and C. indica played the most important role in the hydroponic system. Under the stress of TAP and without inorganic phosphorus nutrient, the activity of phosphatase in the plant system increased and phytodegradation was observed. The production and release of phosphatase is seen as the key mechanism for C. indica to degrade TAP. C. indica, which showed the potential of phytoremediation of TAP, and is commonly used in constructed wetland, so the technique of phytoremediation of TAP from contaminated water can be developed with the combination of constructed wetland.

KEY WORDS:

• phytoremediation
• phytodegradation
• organic phosphate substance
• triazophos
• Canna indica Linn.
• hydroponics
• degradation constant
• removal percentage
• phosphatase

ACKNOWLEDGEMENT

The authors are very grateful to Prof. Dr. Wolfgang Grosse, Institute of Botany, University of Cologne, Cologne, Germany, for reading the manuscript. This work was supported by the Tenth-Five-Year Major Science and Technology Program in China (2002AA601021), KIP Key Project of CAS (KZCX2-YW-426), and the Scientific Research Foundation for the Returned Overseas Chinese Scholars, State Education Ministry, China (2005).