Assessment of aquatic and flowering plants for phytoremediation of arsenic contamination
Student name: Ms Nishtha Saxena
Guide: Dr Sudipta Chatterjee
Year of completion: 2016
Host Organisation: Banaras Hindu University, Varanasi
Supervisor (Host Organisation): Dr Sudhakar Srivastava
Abstract: Arsenic (As) contamination is a worldwide problem turning a serious threat to
plants, animals and humans. It is a non-threshold carcinogen and is known for
causing several ailments in humans. It is largely found in groundwater that is
being consumed by population for irrigation and drinking. It enters into the food
chain through crop plants and vegetables etc. Various approaches based on
physico-chemical remediation have been proposed to tackle this issue. In this
context, the use of As accumulating plants capable of significant removal in a
short duration has been proposed as a promising phytoremediation strategy.
Phytoremediation is a cost efficient solar energy based effortless and ecofriendly
approach. Considering the need to identify suitable As tolerant plants
and/or appropriate strategies for As removal, the present experiments were
planned on following two objectives: (1) testing of selected flowering plants for
As tolerance and (2) novel strategy for practical use of well known As
accumulator aquatic plants. For the first objective, three flowering plants
namely, Marigold (Calendula officinalis), Sunflower (Helianthus annuus), and
Zinnia (Zinnia angustifolia) were subjected to As stress (100 mg Kg-1 soil) in
field conditions for 60 days and their tolerance was evaluated through growth
and antioxidant assays. For the second objective, three aquatic plants, Hydrilla
verticillata, Ceratophyllum demersum and Eichhornia crassipes were selected
and used in a successive application approach to evaluate As removal in 21 days
from medium containing 500 / 2500 ïg L-1 As. The flowering plants showed
good growth in As contaminated soil and demonstrated changes in antioxidant
enzymes, which probably contributed towards tolerance. In the second
experiment, the successive application of Lemna-Hydrilla-Ceratophyllum gave
the best results with a total of about 14% As removed in 21 days.
(Key words: phytoremediation, aquatic plants, arsenic accumulation, arsenic
tolerance, flowering plants)
