Pergamon 0043-1354(93)E0023-L War. Res. Vol. 28, No. 7, pp. 1595-1600, 1994 Copyright © 1994 Elsevier Science Ltd Printed in Great Britain. All rights reserved 0043-1354/94 $7.00 + 0.00 TASTE AND ODOUR DEVELOPMENT IN WATER IN POLYETHYLENE CONTAINERS EXPOSED TO DIRECT SUNLIGHT LUCIA CALVOSA 1, GERMANA CHIODINI 2, WALTERCORETTI 3, PAOLODONAGGIO 1, MARCO ORLANDI 2, VALERIOPARATICI 2 and BRUNORINDONE2*O ~Enichem, via Iannozzi 1, 1-20097 San Donato Milanese, Italy, 2Dipartimento di Chimica Organica e Industriale, Universita' di Milano, via Venezian 21, 1-20133 Milano, Italy and 3Water Line S.A., CH 6805-Mezzovico, Lugano, Switzerland (First received March 1992; accepted in revised form November 1993) Abstract--Drinking water samples contained in Low Density Polyethylene(LDPE) and exposed to direct sunlight for 2 weeks were analysed to identify substances responsible for taste and odour development. Identical samples not exposed to direct sunlight and samples contained in glass bottles were used as reference material. The analyses were performed by passing water through a column of purified Amberlite XAD-2 resin Coolystyrene-divinylbenzene), to concentrate trace compounds. Solvent eluates from the resin were concentrated 50 times and analysed by gas chromatography and gas chromatography-mass spectrometry. Butyl vinyl ketone, deriving from the photodecomposition of LDPE, together with benzophenone, 3.5-dimethoxybenzaldehyde, n-butylphthalate and i-butylphthalate, deriving from the ink, were found in water exposed to direct sunlight. The addition of horseradish peroxidase to water stored in PE containers resulted in lower taste and odour development. Key words---drinking water, taste and odour, irradiation, solid phase extraction, GC-MS, GC-FTIR, horseradish peroxidase INTRODUCTION The increasing use of plastic films for the packaging of food and drink calls for more information con- cerning the interactions of such plastic packaging materials with food and drinks (Halek et al., 1988). During droughts it is a common practice to use transportable plants to make local water potable and to store it in LDPE bags. However, taste and odours are known to develop in these containers, especially after direct exposure to sunlight for long periods. The primary reasons for these organoleptic changes have been suggested (Flogstad, 1984): (a) photooxidation of polyethylene (PE) and the dissolution of the resulting compounds; (b) photooxidation of secondary PE components, such as residual solvents or ethylene oligomers; (c) photooxidation of external inks and migration of products through PE; (d) migration of external contaminants through PE. In fact, it is often the transfer of material from or through the packaging that is the origin of off-flavors in food (Flogstad, 1984). Furthermore, plastic pack- *Author to whom all correspondence should be addressed. ing film is often printed with inks that release residual solvents such as hydrocarbons, alcohols, ketones and esters (Mehens et al., 1984) into the plastic. These compounds then migrate to the packaged food (Kim and Gilbert, 1989) and contribute sensory defects because of their low flavor thresholds (Halek et al., 1988). This study reports on the concentration and identification of compounds released into drinking water samples from polymeric packaging, and print- ing ink. EXPERIMENTALSECTION Local well water was used for this work unless otherwise stated. Polyethylene (PE) was an Enichem product. HPLC- grade water was a Merck product. Horseradish peroxidase was a Sigma product. Samples were stored in a well aerated dark room and were analysed after 15 days. The exposition to direct sunlight occurred putting the samples on the roof of the building for 15 days in June. Extraction method The use of XAD macroreticular resins for the recovery of low concentrations of organic pollutants from water is well documented (Halek and Levinson, 1989). In this study XAD-2 resin (polystyrene~divinylbenzene) was used to ex- tract organic compounds from drinking water. The organics were then eluted with diethyl ether and the eluate was concentrated by evaporation. The organic components were 1595