Vermiremediation of Biomixtures from Biobed Systems Contaminated with Pesticides

Laura Delgado-Moreno,Rogelio Nogales,Esperanza Romero

doi:10.3390/app10093173

Laura Delgado-Moreno, Rogelio Nogales + Show 1 more

Open Access

https://doi.org/10.3390/app10093173

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Journal: Applied sciences	Publication Date: May 2, 2020
Citations: 4	License type: CC BY 4.0

Affiliation: Estación Experimental del Zaidín

Abstract

Biobeds bioremediation systems are effectively used for minimizing pesticide point-source contamination. For keeping the biobed effectiveness, its biomixture needs to be replaced every so often. The exhausted biomixtures can contain pesticide residues and so they require a special treatment before being discharged into the environment. In this study, we explore the potential of vermiremediation for cleaning up biobed biomixtures contaminated with pesticides. Two biomixtures composed of soil:peat:straw (P) and soil:vermicompost of wet olive cake: olive tree pruning (O), contaminated with high loads of four pesticides, were used. Vermicomposting was carried out by Eisenia fetida earthworms for 12 weeks. Results showed that 50% and 70% of the earthworms colonized the contaminated P and O biomixtures, respectively, but the number of alive earthworms decreased with time just as their weight. The colonization of biomixtures did not significantly affect the dissipation of imidacloprid and tebuconazole, but increased 1.4 fold the dissipation of oxyfluorfen in both biomixtures and that of diuron in biomixture P. Although the presence of high loads of pesticides and the composition of the biomixtures limited the vermiremediation, satisfactory results were obtained for diuron and oxyfluorfen. Complementing vermiremediation with other remediation practices could improve the efficiency of this technology.

Highlights

IntroductionBiobeds are biopurification systems used to minimize pesticide point-source contamination
Biobeds are biopurification systems used to minimize pesticide point-source contamination.Currently, these systems are widely expanded worldwide, accounting for more than 10,000 units, especially in European and South American countries
The biotransformation of the biomixtures for 12 weeks, using or not the earthworms of the E. fetida species, was revealed as an emergent and effective strategy to dissipate the pesticide residues contained in the assayed exhausted biomixtures

Summary

Introduction

Biobeds are biopurification systems used to minimize pesticide point-source contamination. These systems are widely expanded worldwide, accounting for more than 10,000 units, especially in European and South American countries. These systems have an active biomixture that adsorbs pesticides in organic matter and enhances their microbial degradation. Biomixtures used in the biobeds should be replaced every five to eight years (periodically) in order to maintain the overall efficiency of this biopurification system. The exhausted biomixtures can contain residues of pesticides. For that reason, they should be considered as hazardous wastes and need special treatments.

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