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Effectiveness evaluation of glyphosate oxidation employing the H2O2/UVC process: Toxicity assays with Vibrio fischeri and Rhinella arenarum tadpoles

Author:
Junges, Celina M., Vidal, Eduardo E., Attademo, Andrés M., Mariani, Melisa L., Cardell, Leandro, Negro, Antonio C., Cassano, Alberto, Peltzer, Paola M., Lajmanovich, Rafael C., Zalazar, Cristina S.
Source:
Journal of environmental science and health 2013 v.48 no.3 pp. 163-170
ISSN:
1532-4109
Subject:
Vibrio fischeri, acetylcholinesterase, bacteria, ecotoxicology, enzyme inhibition, glyphosate, hydrogen peroxide, oxidation, photolysis, sublethal effects, tadpoles, water pollution
Abstract:
The H₂O₂/UVC process was applied to the photodegradation of a commercial formulation of glyphosate in water. Two organisms (Vibrio fischeri bacteria and Rhinella arenarum tadpoles) were used to investigate the toxicity of glyphosate in samples M₁, M₂, and M₃ following different photodegradation reaction times (120, 240 and 360 min, respectively) that had differing amounts of residual H₂O₂. Subsamples of M₁, M₂, and M₃ were then used to create samples M₁,E, M₂,E and M₃,E in which the H₂O₂ had been removed. Acetylcholinesterase (AChE) and butyrylcholinesterase (BChE) activities were measured in tadpoles to determine possible sub-lethal effects. In V. fischeri, M₁,E, which was collected early in the photodegradation process, caused 52% inhibition, while M₃,E, which was collected at the end of the photodegradation process, caused only 17% inhibition. Survival of tadpoles was 100% in samples M₂, M₃, and in M₁,E, M₂,E and M₃,E. The lowest percentages of enzymatic inhibition were observed in samples without removal of H₂O₂: 13.96% (AChE) and 16% (BChE) for M₂, and 24.12% (AChE) and 13.83% (BChE) for M₃. These results show the efficiency of the H₂O₂/UVC process in reducing the toxicity of water or wastewater polluted by commercial formulations of glyphosate. According to the ecotoxicity assays, the conditions corresponding to M₂ (11 ± 1 mg a.e. L⁻¹ glyphosate and 11 ± 1 mg L⁻¹ H₂O₂) could be used as a final point for glyphosate treatment with the H₂O₂/UV process.
Agid:
265319