Influence of novel lignocellulosic residues in a biobed biopurification system on the degradation of pesticides applied in repeatedly high doses

• Published in: Electronic Journal of Biotechnology Vol. 16; no. 6
• Main Authors: Diez, M. Cristina, Tortella, Gonzalo R, Briceño, Gabriela, Castillo, Maria del Pilar, Díaz, Jorge, Palma, Graciela, Altamirano, Carolina, Calderón, Carolina, Rubilar, Olga
• Format: Journal Article
• Language: English
• Published: Universidad Católica de Valparaíso 07-07-2014
• Subjects: biomixture; biopurification system; lignocellulosic materials; pesticide degradation
• ISSN: 0717-3458; 0717-3458

Background: The biobed is a simple biopurification system used to
prevent the point-source pesticide contamination that occurs at farm
level. The typical composition of the biomixture used in this system is
soil, peat and straw in volumetric proportions of 1:1:2. The principal
component is straw due to its positive effects on biological activity
and thus pesticide degradation. However, access to straw can be limited
in some regions, so it must be replaced by other more readily available
lignocellulosic residues. Results: Therefore, two alternate
lignocellulosic materials (barley husks and pine sawdust) were
evaluated as partial substitutes for straw. The degradation of a
repeatedly applied mixture of six pesticides by these alternates was
assessed. The microbial respiration and fluorescein diacetate (FDA)
hydrolysis activity were also assessed. The results showed that the
highest degradation efficiency was found in mixtures containing straw
and barley husks. Each biomixtures tested achieved a high degradation
(50 to 90%) of all the pesticides used except iprodione. Repeated
applications of pesticides resulted in a slowing of the degradation
rate of all pesticide types in all biomixtures. FDA activity and
microbial respiration were higher in the biomixtures containing barley
husks and straw compared to the mixture with pine sawdust, a result
consistent with the pesticide degradations observed. Conclusions: This
paper demonstrates that the straw in the traditional biomixture can be
partially replaced by other lignocellulosic materials to efficiently
degrade a mixture of pesticides, even when the pesticides are added in
successive applications and high concentrations.