Chromium Removal in Constructed Wetlands and Physiological Response of emergent macrophytes from Argentina

DANIELA ARAN; ALICIA FERNÁNDEZ CIRELLI; MAGDALENA MONFERRAN; CARLOS HARGUINTEGUY; MARIA LUIS PIGNATA

Congreso; 8th Young Environmental Scientists Meeting; 2019

SETAC-Europa

Leather tanning generates liquid effluents with high contents of organic matter, sulfides and trivalent chromium. The discharge of these untreated effluents in aquatic environments generate serious problems with ecological risks. The use of constructed wetlands is considered a reliable technology for the treatment of wastewater with metals, and aquatic plants have a fundamental role in these systems. Schoenoplectus californicus, Juncus effusus and Eleocharis palustris are native aquatic plants, of interest for their use in the phytoextraction of Cr. These macrophytes are perennial, rooted, rhizomatous and are part of the emergent vegetation in many lakes and estuarine areas of the Argentine Republic. Experimental work was developed to test the hypothesis that the aquatic species Schoenoplectus californicus, Juncus effusus and Eleocharis palustris are resistant to chromium exposure and can accumulate this metal in the root. Methodology Schoenoplectus californicus, Juncus effusus and Eleocharis palustris were exposed for four weeks to increasing concentrations of Cr (Control treatment T0: 0 mg L-1, Treatment T1: 1 mg L-1, Treatment T2: 10 mg L-1) in constructed wetlands. The indicators of physiological damage that were analyzed were parameters of the photosynthetic system (chlorophyll, pheophytin, carotenoids), and also indicators of oxidative stress in stem and root, such as conjugated hydroperoxydienes and malondialdehyde. In addition, the removal of Cr from the solution and the accumulation of the metal in the root and stem were measured. Results and interpretation The macrophytes Schoenoplectus californicus, Juncus effusus and Eleocharis palustris exposed to increasing concentrations of Cr showed to be tolerant to the metal and not to affect the photosynthetic system. The removal of the metal from the solution was 99% in all cases and the largest accumulation of the metal occurred at the base of the stem and the root of the plants. Taking into account the tolerance of the macrophytes S. californicus, J. effusus and E. palustris at increasing concentrations of Cr, it could be determined that they are plants of interest for their use in phytoremediation of water contaminated with chromium.