Abstract

JIMENEZ CARTAGENA, Claudio; GIRALDO AGUIRRE, Ana Liliana; LEON PEREZ, Daniel Esteban  and  PENUELA MESA, Gustavo Antonio. Hotolytic degradation of carbofuran in waters from the Rionegro river and in ultra-pure water under different pH conditions. Rev. P+L [online]. 2013, vol.8, n.2, pp.39-50. ISSN 1909-0455.

Introduction. The use of pesticides in agriculture has generated important impacts:on one side, the increase of agricultural production and, on the other, a big source of environmental pollution. This fact has brought the consciousness of the importance of studying the dynamics of such pollutants in the environment and the possible alternatives to degrade them. Objective. To study the carbolysis of carbofuran in waters confluent to the crops from the East of Antioquia, by the use of a sun radiation simulator, toxicity tests and determination through liquid chromatography -with an ultra-violet detector with a diode array-. Materials and methods. To establish the best photolytic degradation conditions a 3x2x2 factorial design was used, evaluating three variables: pH (5, 7 and 9), types of water (ultra-pure and surface water) and carbofuran concentration. The response factor defined was de degradation percentage. Results. As pH increases the carbofuran's degradation percentage is more significant, with 30% and 20% of degradation at a pH of 9 during 90 minutes of irradiation in ultra-pure water and surface water, respectively. It can also be seen that under natural pH conditions -represented by water from the Ríonegro river- the removal percentages of a 10 mg L^-1 and 30 mg L^-1 samples, when irradiated, 9,5% and 21% of degradation are respectively obtained, which means that with low carbofuran concentrations the effect of neutral pH tends to have a lower influence on the degradation. Conclusions. The photolytic processes as primary degradation mechanisms in the environment have a significant contribution to the degradation of carbofuran when this carbofuran is at relatively high concentration rates. For the Rio Negro river waters, neither the dissolved organic matter nor a neutral pH value, had an effect on the carbofuran's degradation. Nevertheless, basic or acid pH values tend to increase the degradation of the carbofuran.

Keywords : carbofuran; pesticide; degradation; contamination; photolysis.

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