Photodegradation of the UV filter ethylhexyl methoxycinnamate under ultraviolet light: identification and in silico assessment of photo-transformation products in the context of grey water reuse
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In: The Science of The Total Environment, Vol. 572, 01.12.2016, p. 1092-1100.
Research output: Journal contributions › Journal articles › Research › peer-review
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TY - JOUR
T1 - Photodegradation of the UV filter ethylhexyl methoxycinnamate under ultraviolet light
T2 - identification and in silico assessment of photo-transformation products in the context of grey water reuse
AU - Jentzsch, Franziska
AU - Olsson, Oliver
AU - Westphal, Janin
AU - Reich, Marco
AU - Leder, Christoph
AU - Kümmerer, Klaus
PY - 2016/12/1
Y1 - 2016/12/1
N2 - To prevent water shortages in the future and to reduce domestic water consumption, decentralized grey water (GW) reuse has become increasingly important. This water has, however, to be free of pollutants. Conventional treatment of GW does not fully eliminate micropollutants such as the UV filter substance ethylhexyl methoxycinnamate (EHMC). EHMC, which is commonly used in sunscreens and personal care products, is an endocrine disruptor and shows potential to bioaccumulation, which is also reflected in its low water solubility. Photolysis has been proposed as an alternative treatment method for other micropollutants, but it is not clear yet whether it can also be used to eliminate EHMC. One goal of this study was to better understand the basic pathways involved in this process. It aimed to identify photo-transformation products (photo-TPs) by using, in the test conditions, an initial concentration of EHMC higher than those expected in the environment. Acetonitrile (ACN) was added in low concentrations to the aqueous solution to overcome the low aquatic solubility of EHMC. The influence of this co-solvent on the degradation kinetics was studied. The photolysis experiments were carried out using a medium pressure mercury lamp, which emits UV light in the range of 200–400 nm. The quantum yield of the photolysis of EHMC was 0.0042 and 0.0023 mol·Einstein − 1 (for 0.2 and 0.5% ACN (v/v), respectively), and the relative and absolute UV photon fluxes were determined. HPLC was used to monitor the elimination kinetics of EHMC, which followed first-order kinetics. The results of LC-MS n analyses revealed that beside others, several oxidized and hydroxylized EHMC isomers were formed as photo-TPs in aqueous solution. Using a set of in silico quantitative structure-activity relationship (QSAR) models, this study also offered new insights concerning the environmental fate and toxicity of the TPs of EHMC.
AB - To prevent water shortages in the future and to reduce domestic water consumption, decentralized grey water (GW) reuse has become increasingly important. This water has, however, to be free of pollutants. Conventional treatment of GW does not fully eliminate micropollutants such as the UV filter substance ethylhexyl methoxycinnamate (EHMC). EHMC, which is commonly used in sunscreens and personal care products, is an endocrine disruptor and shows potential to bioaccumulation, which is also reflected in its low water solubility. Photolysis has been proposed as an alternative treatment method for other micropollutants, but it is not clear yet whether it can also be used to eliminate EHMC. One goal of this study was to better understand the basic pathways involved in this process. It aimed to identify photo-transformation products (photo-TPs) by using, in the test conditions, an initial concentration of EHMC higher than those expected in the environment. Acetonitrile (ACN) was added in low concentrations to the aqueous solution to overcome the low aquatic solubility of EHMC. The influence of this co-solvent on the degradation kinetics was studied. The photolysis experiments were carried out using a medium pressure mercury lamp, which emits UV light in the range of 200–400 nm. The quantum yield of the photolysis of EHMC was 0.0042 and 0.0023 mol·Einstein − 1 (for 0.2 and 0.5% ACN (v/v), respectively), and the relative and absolute UV photon fluxes were determined. HPLC was used to monitor the elimination kinetics of EHMC, which followed first-order kinetics. The results of LC-MS n analyses revealed that beside others, several oxidized and hydroxylized EHMC isomers were formed as photo-TPs in aqueous solution. Using a set of in silico quantitative structure-activity relationship (QSAR) models, this study also offered new insights concerning the environmental fate and toxicity of the TPs of EHMC.
KW - Chemistry
KW - Grey water
KW - Personal care products
KW - Photolysis
KW - Quantitative structure-activity relationship
KW - UV treatment
KW - Sustainability Science
KW - Transformation
UR - http://www.scopus.com/inward/record.url?scp=84994043917&partnerID=8YFLogxK
U2 - 10.1016/j.scitotenv.2016.08.017
DO - 10.1016/j.scitotenv.2016.08.017
M3 - Journal articles
C2 - 27531468
VL - 572
SP - 1092
EP - 1100
JO - The Science of The Total Environment
JF - The Science of The Total Environment
SN - 0048-9697
ER -