Phytoavailability and bioaccumulation of cadmium in duckweed plants (Spirodela polyrhiza L. Schleid)

Abstract

The aquatic vascular plant Duckweed (Spirodela polyrhiza L. Schleid) was investigated as a potential biological filter for wastewater Cd removal. Duckweed plants were grown in and harvested weekly from 0.10 M Hoagland nutrient solutions containing 0.04–7.63 μg Cd/mL. Dry weights of plants significantly decreased when exposed to 7.63 μg Cd/mL. For both the 1.03 and 7.63 μg Cd/mL treatments the greatest Cd accumulation in plants occurred during week 1 and decreased through week 4. It was also interesting to note that tissue P was observed to be suppressed for one week at higher Cd treatments, and thereafter increased as the tissue Cd levels decreased. Frond production was decreased by the lowest Cd treatments by the second week. These results suggest that Duckweed can tolerate and accumulate Cd for one week even when exposed to 7.63 μg Cd/mL. However, after one week the plants needed to be removed from the Cd solution to avoid tissue Cd loss and to achieve maximum removal from solution.

Notes

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