Mankar; Shilpa, P. and Roychoudhury, K.
Arsenic is being a toxic metal for all living form. The uptake of arsenic is not identical for all plant varieties, its extents depends upon the plant species. The three species of Cyanobacteria namely, Anabaena, Nostoc and Leptolyngbya were grown in BG11 medium supplemented with soil and the effect of arsenic (250µg/L) on plant growth of marigold were observed. The parameters of the plant growth namely, height of the plant in cm., average leaf length in cm., number of branches and perimeter of the stem in cm. were considered for overall growth of the plant. The residual arsenic is 24.4 µg suggesting thereby that Anabaena must have removed considerable arsenic from the soil. In case of Nostoc and Leptolyngbya the residual value was found to be 20.4 µg, 37.6 µg respectively. Thus all the three species removed arsenic from the soil.
Keywords: Arsenic | Cyanobacteria | plant growth | remediation of arsenic
Arsenic is widely distributed toxic element that is found in the Earth crusts. This metal has a tendency of contaminating underground water resulting in its re-distribution not only along multidimensions of Earth but also among the plants and animals. The presence of arsenic in drinking water thus becomes a serious water pollution problem in many countries including India and Bangladesh. Arsenic pollution is a serious problem which not only occurs through contaminated drinking water but also from human solid food chain when the crops and fodder become contaminated with arsenic. The Indian subcontinent is primarily facing this problem where contaminated drinking water acts as a principle source of arsenic pollution (Nordstrom, 2002). The metalloid arsenic can also enter into the farming systems through natural geochemical processes partly due to many agencies namely, use of arsenic based pesticides, mining operations, use of arsenic containing groundwater for irrigation and the use of municipal solid waste for fertilization (Smedley and Kinniburgh, 2002; Meharg et al., 2009). Among the various food crops, rice grain is significantly important as it acts as a major source of arsenic contaminated crop. Apart from rice, beet-root, potato, orchaids, blue-berry and tobacco have been reported to be containing a sufficiently high level of arsenic. Apart from these, peas, beans, soya beans, cotton have also been reported to be contaminated with arsenic (Walash et al., 1977).