Oxidative Removal of Selected Endocrine-Disruptors and Pharmaceuticals in Drinking Water Treatment Systems, and Identification of Degradation Products of Triclosan

Abstract

The potential occurrences of endocrine-disrupting compounds (EDCs), as well as pharmaceuticals, are considered to be emerging environmental problems due to their persistence and continuous input into the aquatic ecosystem, even at only trace concentrations. This study systematically investigated the oxidative removal of eight specially selected ECDs and pharmaceuticals by comparing their relative reactivity as a function of different oxidative treatment processes (i.e., free chlorine, ozone, monochloramine, and permanganate) under various pH conditions. For the oxidative removal study, EDC and pharmaceutical standards were spiked into both deionized water and natural water, followed by treatment using common oxidants at typical water treatment concentrations. Liquid chromatography-tandem mass spectrometry (LC-MS/MS) was used for identification and quantification. The removal efficiency of the EDCs and pharmaceuticals varied significantly between oxidation processes. Free chlorine, permanganate, and ozone treatments were all highly effective at the elimination of triclosan and estrone, while they were not effective for removing ibuprofen, iopromide, and clofibric acid. Monochloramine (at a dose of 3. mg/L) was mostly ineffective in eliminating any of the selected EDCs and pharmaceuticals under the tested conditions. pH also played an important role in the removal efficiency of the EDCs and pharmaceuticals during free chlorine, permanganate, and ozone treatments. Additionally, the study identified the oxidation products of triclosan by permanganate, and 2,4-dichlorophenol was identified as the major oxidation product of triclosan by permanganate in drinking water system treatment. Furthermore, 2,4-dichlorophenol was further degradated to 4,5-dichloro-2-(2,4-dichlorophenoxy)phenol and/or 5,6-dichloro-2-(2,4-dichlorophenoxy)phenol. The kinetics for this reaction indicated that the reaction was first order in the drinking water system.

Department(s)

Chemistry

Second Department

Civil, Architectural and Environmental Engineering

Keywords and Phrases

2 ,4-Dichlorophenol; Ammonium Chloride; Aquatic Ecosystem; Biodegradation; Chemical Reaction Kinetics; Chlorine; Chromatography; Clofibrate; Clofibric Acid; Continuous Input; Controlled Study; Degradation Products; Deionized Water; Drinking Water Systems; Drinking Water Treatment; Drug Products; Endocrine Disrupting Compound; Endocrine Disruptor; Environmental Problems; Estradiol; Estriol; Estrone; Ethinylestradiol; First Order; Free Chlorine; Ibuprofen; Iopromide; LC-MS/MS; Liquid; Liquid Chromatography; Manganese Compounds; Mass Spectrometry; Missouri; Monochloramine; Natural Waters; Oxidants; Oxidation Process; Oxidation Products; Oxidation-Reduction; Oxidative Removal; Oxidative Treatment; Oxides; Ozone Treatment; Personal Care Products; PH; Pharmaceutical Preparations; Pharmaceuticals; Phenols; Pollutant Removal; Potable Water; Quantitative Analysis; Reaction Kinetics; Relative Reactivities; Removal Efficiencies; Sodium Hypochlorite; Tandem Mass Spectrometry; Trace Concentrations; Triclosan; Various PH; Water Pollutants; Water Purification; Water Quality; Water Treatment; Waterworks

International Standard Serial Number (ISSN)

0048-9697

Document Type

Article - Journal

Document Version

Citation

File Type

text

Language(s)

English

Rights

© 2012 Elsevier, All rights reserved.

Publication Date

01 Nov 2012

Link to Full Text

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