Degradation of UV filters 2-ethylhexyl-4-methoxycinnamate and 4-tert-butyl-4'-methoxydibenzoylmethane in chlorinated water

Environmental context The increasing use of sun-creams containing UV-filtering chemicals has led to increased inputs of these compounds to the aquatic environment. Chlorinated waters can convert these chemicals into chlorinated products whose toxic effects are of primary concern. To better understand the environmental fate of sun-cream chemicals, we studied the stability of two UV-filtering compounds under varying conditions of pH, chlorine concentration, temperature, dissolved organic matter and solar irradiation. Abstract The stability of the UV filters 2-ethylhexyl-4-methoxycinnamate (EHMC) and 4-tert-butyl-4′-methoxydibenzoylmethane (BDM) in chlorinated water was studied. High-performance liquid chromatography (HPLC)-UV-diode array detection (DAD) was used to follow the reaction kinetics of both UV filters and HPLC-tandem mass spectrometry (MS/MS) was used to tentatively identify the major transformation by-products. Under the experimental conditions used in this work both UV filters reacted with chlorine following pseudo-first order kinetics: rate constant k=0.0095±0.0007min–1 and half-life t1/2=73±4min for EHMC and rate constant k=0.006±0.001min–1 and half-life t1/2=119±14min for BDM (mean±standard deviation). The chemical transformation of the UV filters in chlorinated water led to the formation of chlorinated by-products that were tentatively identified as mono- and dichloro-substituted compounds that resulted from substitution of the hydrogen atoms in the benzene rings by one or two chlorine atoms. Experimental Box–Behnken designs were used to assess the effect of experimental factors: pH, temperature, chlorine concentration, dissolved organic matter and artificial sunlight irradiation on the transformation of the UV filters.

[1]  J. C. D. Silva,et al.  Factorial analysis of a chemiluminescence system for bromate detection in water , 2001 .

[2]  B. Blount,et al.  The good, the bad, and the volatile: can we have both healthy pools and healthy people? , 2010, Environmental science & technology.

[3]  Amparo Salvador,et al.  UV filters : From sunscreens to human body and the environment , 2007 .

[4]  G. B. Buck Louis,et al.  Urinary concentrations of benzophenone-type UV filters in U.S. women and their association with endometriosis. , 2012, Environmental science & technology.

[5]  Damià Barceló,et al.  Chemical analysis and ecotoxicological effects of organic UV-absorbing compounds in aquatic ecosystems , 2009 .

[6]  M. C. Antunes,et al.  Factorial analysis of the trihalomethanes formation in water disinfection using chlorine. , 2007, Analytica chimica acta.

[7]  Interaction of Fulvic Acids with Al(III) Studied by Self-Modeling Curve Resolution of Second-Derivative Synchronous Fluorescence Spectra , 1996 .

[8]  Kees Meliefste,et al.  What’s in the Pool? A Comprehensive Identification of Disinfection By-products and Assessment of Mutagenicity of Chlorinated and Brominated Swimming Pool Water , 2010, Environmental health perspectives.

[9]  M. Wittassek,et al.  Exposure patterns of UV filters, fragrances, parabens, phthalates, organochlor pesticides, PBDEs, and PCBs in human milk: correlation of UV filters with use of cosmetics. , 2010, Chemosphere.

[10]  D. Barceló,et al.  Organic UV filters and their photodegradates, metabolites and disinfection by-products in the aquatic environment , 2008 .

[11]  J. C. D. Silva,et al.  Self-modelling curve resolution analysis of synchronous fluorescence spectroscopy data for characterization of acid mixtures and study of acid–base equilibria , 1995 .

[12]  P. M. Pinheiro,et al.  Detection of 2,4,6-trichloroanisole in chlorinated water at nanogram per litre levels by SPME–GC–ECD , 2005, Analytical and bioanalytical chemistry.

[13]  M. S. Miranda,et al.  The degradation products of UV filters in aqueous and chlorinated aqueous solutions. , 2012, Water research.

[14]  A. Salvador,et al.  Development of a fully automated sequential injection solid-phase extraction procedure coupled to liquid chromatography to determine free 2-hydroxy-4-methoxybenzophenone and 2-hydroxy-4-methoxybenzophenone-5-sulphonic acid in human urine. , 2010, Analytica chimica acta.

[15]  N. Negreira,et al.  Study of some UV filters stability in chlorinated water and identification of halogenated by-products by gas chromatography-mass spectrometry. , 2008, Journal of chromatography. A.

[16]  H. Ribeiro,et al.  In vitro exposure of Acer negundo pollen to atmospheric levels of SO₂ and NO₂: effects on allergenicity and germination. , 2012, Environmental science & technology.

[17]  R. Tauler,et al.  Factorial analysis of the trihalomethane formation in the reaction of colloidal, hydrophobic, and transphilic fractions of DOM with free chlorine , 2010, Environmental science and pollution research international.

[18]  T. Albanis,et al.  Aqueous photolysis of the sunscreen agent octyl-dimethyl-p-aminobenzoic acid. Formation of disinfection byproducts in chlorinated swimming pool water. , 2003, Journal of chromatography. A.

[19]  S. Tanabe,et al.  Analysis of five benzophenone -type UV filters in human urine by liquid chromatography-tandem mass spectrometry , 2010 .

[20]  J. C. D. Silva,et al.  Study of the interaction of a soil fulvic acid with UO22+ by self-modelling mixture analysis of synchronous molecular fluorescence spectra , 1996 .

[21]  U. von Gunten,et al.  Reactions of chlorine with inorganic and organic compounds during water treatment-Kinetics and mechanisms: a critical review. , 2008, Water research.

[22]  T. Kawakami,et al.  Aquatic Fate of Sunscreen Agents Octyl-4-methoxycinnamate and Octyl-4-dimethylaminobenzoate in Model Swimming Pools and the Mutagenic Assays of Their Chlorination Byproducts , 2009 .