Decontamination of a municipal landfill leachate from endocrine disruptors using a combined sorption/bioremoval approach
2014
Loffredo, Elisabetta | Castellana, Giancarlo | Senesi, N. (Nicola)
Sorption and biodegradation are the main mechanisms for the removal of endocrine disruptor compounds (EDs) from both solid and liquid matrices. There are recent evidences about the capacity of white-rot fungi to decontaminate water systems from phenolic EDs by means of their ligninolytic enzymes. Most of the available studies report the removal of EDs by biodegradation or adsorption separately. This study assessed the simultaneous removal of five EDs—the xenoestrogens bisphenol A (BPA), ethynilestradiol (EE2), and 4-n-nonylphenol (NP), and the herbicide linuron and the insecticide dimethoate—from a municipal landfill leachate (MLL) using a combined sorption/bioremoval approach. The adsorption matrices used were potato dextrose agar alone or added with each of the following adsorbent materials: ground almond shells, a coffee compost, a coconut fiber, and a river sediment. These matrices were either not inoculated or inoculated with the fungus Pleurotus ostreatus and superimposed on the MLL. The residual amount of each ED in the MLL was quantified after 4, 7, 12, and 20 days by HPLC analysis and UV detection. Preliminary experiments showed that (1) all EDs did not degrade significantly in the untreated MLL for at least 28 days, (2) the mycelial growth of P. ostreatus was largely stimulated by components of the MLL, and (3) the enrichment of potato dextrose agar with any adsorbent material favored the fungal growth for 8 days after inoculation. A prompt relevant disappearance of EDs in the MLL occurred both without and, especially, with fungal activity, with the only exception of the very water soluble dimethoate that was poorly adsorbed and possibly degraded only during the first few days of experiments. An almost complete removal of phenolic EDs, especially EE2 and NP, occurred after 20 days or much earlier and was generally enhanced by the adsorbent materials used. Data obtained indicated that both adsorption and biodegradation mechanisms contribute significantly to MLL decontamination from the EDs studied and that the efficacy of the methodology adopted is directly related to the hydrophobicity of the contaminant.
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