Typha domingensis ability to accumulate and tolerate high concentrations of Cr, Ni, Zn and P

MUFARREGE, M. M.; DI LUCA, G. A.; HADAD H. R.; MAINE, M. A.

Conferencia; 13th International Conference Wetland Systems for Water Pollution Control; 2012

The tolerance and the removal efficiency of Typha domingensis exposed to high concentrations of metals and phosphorus in separated and combined solutions were studied. The plants were collected from a natural wetland belonging to Paraná Medio River system (Argentina). Two plants and 4 Kg of sediment were dispossed in each container. The solutions were added as follows: 100 mg l-1 and 500 mg l-1 Cr, Ni, Zn and P (in separated solutions: Cr100, Cr500, Ni100, Ni500, Zn100, Zn500, P100, P500), 500 mg l-1 Cr + 500 mg l-1 Ni + 500 mg l-1 Zn (in a combined solution: Comb500), and a control (without metals). The relative growth rate and chlorophyll percentage increase were calculated. Metal and P concentration in water were measured periodically. At the beginning and at the end of the experiment the metals and TP concentrations were determined in sediment and in roots, rhizome and leaves. The leaves were separated in aerial and submerged parts because the last ones are in direct contact with the experimental solution. The final removal of Cr was 99.9, 65.7 and 90.5 % for Cr100, Cr500 and Comb500, respectively. The Ni removal was 95.1, 61.2 and 66.5% for Ni100, Ni500 and Comb500, respectively. The Zn removal was 95.1, 86.6 and 55% for Zn100, Zn500 and Comb500, respectively. The P removal was 68 and 61% for P100 and P500, respectively. The highest concentration treatments and the combined metal treatments showed the lowest metal removal from water. The highest concentrations of Cr, Ni, Zn and P observed in the submerged parts of the leaves were due to sorption processes. Despite that the sediment showed a lower metal and P concentrations than the plant tissues, mass balances showed that this compartment was the main contaminant accumulator. The relative growth rates were positive for P, Cr and Zn treatments, while the Ni treatments showed negative values. In the P treatments the percentage of chlorophyll increase was significanlty higher than that of the control and the other treatments. The chlorophyll increase in the Cr and Zn treatments were not statistically different than that of the control. The Ni and combined metal treatments showed a decrease in the chlorophyll concentration. Because of the studied contaminant concentrations are extremely higher than the concentrations found in natural and constructed wetlands for the treatment of industrial effluents, our results would demonstrate the capacity of T. domingensis to survive after a fortuitous dump of high concentrations of contaminants in an aquatic system.