Resumen de Pesticide residues in washing water of olive oil mills: effect on olive washing efficiency and decontamination proposal
Maria Guardia-Rubio, Antonio Ruiz-Medina, Antonio Molina Díaz, María José Ayora-Cañada
BACKGROUND: Washing olives in the olive oil mill (a commonly used preliminary step to remove foreign materials and leaves) can help to remove pesticide residues, especially herbicides that are present in olives due to contamination either during application or as a consequence of contact with contaminated soil. The aim of the present work was the study of washing efficacy during washing cycles, i.e., from the beginning of the cycle until the water was changed. RESULTS: Four active ingredients, namely diuron, oxyfluorfen, terbuthylazine and endosulfan (α and β isomers) as well as the latter's degradation product endosulfan sulfate, were the most frequently found pesticides in raw olives after harvest. At the beginning of the washing cycle, diuron, terbuthylazine and oxyfluorfen residues were effectively removed from olives. However, progressive water contamination with pesticide residues decreased the efficiency of the washing step, specially for diuron and terbuthylazine residues. CONCLUSION: A decontamination method to enable water recycling in olive oil mills was proposed and optimized. It employed FeCl3 as coagulant and active charcoal as adsorbent, and was effective in removing both suspended solids and pesticide residues. Copyright © 2008 Society of Chemical Industry
