Abstract
The effect of initial concentrations of manganese on the overall removal efficiency of Mn by wool grass, soft rush, broad leaved cattail and soft stem bulrush plants was investigated under laboratory conditions. The translocation of Mn in the roots, stems, leaves and flowers of each plant species was determined and the fraction of Mn removed by precipitation was calculated. The overall manganese removal efficiencies of the system during the first period were 97.66, 94.09, 98.51 and 98.44 %, 90.94, 95.47, 96.83 and 85.51 % and 92.65, 75.55, 97.56 and 75.55 % which decreased to 82.22, 89.94, 95.26 and 95.85 %, 87.78, 91.85, 90.49 and 84.16 % and 38.88, 61.61, 31.54 and 71.64 % by the end (after 72 days) of the experiment for soft stem bulrush, wool grass, soft rush and cattail in the compartments receiving tolerance concentration, landfill leachate and the control, respectively. The removal of manganese was a function of the initial Mn concentration and the higher the initial concentration the higher the removal efficiency. The results showed the addition of manganese (from wastewater) to the soil by precipitation at average rates of 2.17 and 17.19 mg/kg/day, 2.11 and 15.75 mg/kg/day, 1.71 and 15.86 mg/kg/day and 1.17 and 15.29 mg/kg/day for soft stem bulrush, wool grass, soft rush and cattail in the compartments receiving landfill leachate and tolerance concentration, respectively. The leaves of wool grass, soft rush and cattail accumulated significantly greater concentrations of manganese than the roots with translocation factors > 1 indicating high translocation of Mn from root to shoot for the control, landfill leachate and tolerance concentration, respectively.
Highlights
Living plants can be compared to solar driven pumps which can extract and concentrate elements from their environment
Soft stem bulrush Wool grass Soft rush Cattail (b) Leachate concentration manganese in the soils of soft stem bulrush, wool grass, soft rush and cattail increased to 639 and 1721 mg/kg, to 645 and 1627 mg/kg, to 635 and 1654 mg/kg and to 586 and 1603 mg/kg by the end of the experiment (72 days) in the compartments receiving the landfill leachate and tolerance concentration, respectively. These results showed the addition of manganese to the soil by precipitation at average rates of 2.17 and 17.19 mg/kg/day, 2.11 and 15.75 mg/kg/day, 1.71 and 15.86 mg/kg/day and 1.17 and 15.29 mg/kg/day for soft stem bulrush, wool grass, soft rush and cattail in the compartments receiving landfill leachate and tolerance concentration, respectively
The highest amount of manganese accumulated in the total plant tissues was in soft stem bulrush with concentrations of 1202, 957 and 709 mg/kg and the lowest was in wool grass with concentrations of 921, 649 and 370 mg/kg for the compartments receiving tolerance concentration, landfill leachate and control, respectively
Summary
Living plants can be compared to solar driven pumps which can extract and concentrate elements from their environment. All plants have the ability to accumulate heavy metals such as Mg, Fe, Mn, Zn, Cu and Mo which are essential for their growth and development[1,2]. Excessive accumulation of essential and nonessential heavy metals can be toxic to most plants. Plants distribute metals internally in many different ways They may localize selected metals mostly in roots and stems, or they may accumulate and store other metals in nontoxic form for latter distribution and use. A mechanism of tolerance or accumulation in some plants apparently involves binding potentially toxic metals at cell walls of roots and leaves away from sensitive sites within the cell or storing them in a vacuolar compartment[6,7]
Sign-in/Register to view highlights & summary Sign-in/Register to access full text options 
Free) 
Talk to us
Join us for a 30 min session where you can share your feedback and ask us any queries you have
Schedule a call
