CADMIUM REMOVAL BY AQUATIC MACROPHYTE (NASTURTIUM OFFICINALE) AND POTENTIAL FOR OIL PRODUCTION FROM THE BIOMASS

Abstract

Toxic metal pollution of water bodies is a major environmental problem and has accelerated drastically since the beginning of industrial revolution. Aquatic plants are known to accumulate metals and other toxic elements from contaminated water. This study was carried out to investigate short term uptake of cadmium (Cd) by Nasturtium officinale^, and Cd effects on chlorophyll contents and oil production. Plants were exposed to 1, 5 and 10 mg L^-1 of Cd in hydroponics and sampling was done after 3, 6, 9 and 12 days to check accumulation and toxicity patterns. A control treatment (without Cd) was also included in the experiment to compare the results. The plants treated with 10 mg L^-1 of Cd at day 12 had the highest concentration in shoots (35.7 mg kg^-1 Cd) and roots (18.8 mg kg^-1). The chlorophyll contents decreased from 0.25 to 0.82 mg g^-1 fresh weight at levels of Cd from control to highest level of Cd at day 12, respectively. Oil contents dropped from 258±11.5 to 218±3.5 mL kg^-1 of fresh biomass over an exposure period of 12 days at 10 mg L^-1 of Cd. Keeping in view the bioaccumulation capacity and oil production potential, this technique appears as environmentally and economically sustainable.