Photodegradation of pesticides in float system effluent from tobacco plantation

Abstract

Several crops can generate liquid effluent containing pesticide residues. In the region of the Vale do Rio Pardo, RS, Brazil, one type of effluent results from the float system used in the tobacco seedling plantation. This system is an alternative that substitutes for the conventional seedbeds of tobacco production. The tobacco is germinated on polystyrene tray beds on a water blade that may contain pesticides residues following the transplant of seedlings to the farm. In this paper, we have simulated in the laboratory, the photo-degradation of the pesticides present in the effluent of the float system, including the pesticides metalaxyl, iprodione and imidacloprid. Photolysis and photoperoxidation were the methods used. The experiments were performed with a mercury vapor light bulb of 80, 125 and 250 W. The obtained results show that the photodegradation of the metalaxyl, iprodione and imidacloprid in an optimized system presents considerable reproducibility and high degradation, requiring less time.