Sorption of triazoles to soil and iron minerals Yu Jia a, * , Per Aagaard a , Gijs D. Breedveld a,b a Department of Geosciences, University of Oslo, P.O. Box 1047, Blindern, 0316 Oslo, Norway b Norwegian Geotechnical Institute, P.O. Box 3930 Ullevaal Stadion, 0806 Oslo, Norway Received 9 June 2006; received in revised form 1 October 2006; accepted 8 October 2006 Available online 22 November 2006 Abstract Triazoles, additives in runway de-icers, are found in soil and groundwater at airport sites. To better understand the fate and transport of benzotriazole (BTA) and methylbenzotriazole (MeBTA) and to assess possible remediation options of contaminated groundwater, sorption to various soils and ferrous sorbents has been studied. In batch experiments, limited non-linear sorption of BTA to mineral subsoil from the Oslo International Airport, Gardermoen was observed. The sorption to soil could be described using a Freundlich isotherm. pH affected sorption of BTA to subsoil, although the effect was not strong. Increased sorption was observed to zerovalent iron (Fe 0 ). MeBTA showed similar sorption behaviour as BTA although the sorption coefficient was generally higher. Sorption to Fe 0 seems to be controlled by multi-layer coverage. Our data suggest that sorption of triazoles to Fe 2 O 3 is negligible. However BTA sorption to 2-line and 6-line ferrihydrites showed strong sorption. The results demonstrate that triazoles are highly mobile in the subsurface envi- ronment, however zerovalent iron can be an effective medium for groundwater remediation. Without remediation, wide distribution of triazoles in the environment can be expected due to its extensive application and limited degradability. Ó 2006 Elsevier Ltd. All rights reserved. Keywords: Benzotriazole; Zerovalent iron; Ironoxides; Subsoil; Specific surface area; Freundlich isotherm 1. Introduction Spills of hazardous organic compounds in the environ- ment can result in extensive contamination. Soil is a natu- ral barrier which prevents chemicals from polluting groundwater aquifers. Both abiotic and biotic processes in soil may contribute to natural attenuation of a chemical compound. Sorption is one of the primary processes in soils which affect the transport of nutrients and contami- nants. In addition, it influences the bioavailability of com- pounds for uptake by soil living organisms as well as biodegradation. The present study focuses on sorption of triazoles especially benzotriazole (BTA) and methyl-benzotriazole (MeBTA) to soil and mineral sorbents. BTA is generally known as a corrosion inhibitor reacting with metal surfaces (Babic ´ et al., 1999). Moreover, BTA is used in a number of applications including as additive in antifreeze and deicers (Cancilla et al., 1997; Hart et al., 2004). BTA derivatives are used as lubricant additive, stabiliser for plastic mate- rials, UV stabilisers for polymers, automotive surface coating, photographic papers, and pigments (see e.g. Breedveld et al., 2003). Aircraft deicing/antiicing fluids (ADAF) are extensively used at airports in the winter season under cold climates to ensure safe take-off and landing of aircraft. There exists considerable concern that ADAFs may contaminate soil and groundwater (Cornell et al., 2000; Breedveld et al., 2003; Jia et al., 2006). BTA/MeBTA is used as an additive in ADAF as flame and corrosion inhibitor. Although the concentration of BTA/MeBTA is typically low, from 0.5% to 0.6% (Cornell et al., 2000), it has been identified to contribute significantly to the acute toxicity of ADAF (Cancilla et al., 1997; Gruden et al., 2001). As a result of the wide spread application, BTA and MeBTA have been 0045-6535/$ - see front matter Ó 2006 Elsevier Ltd. All rights reserved. doi:10.1016/j.chemosphere.2006.10.021 * Corresponding author. Tel.: +47 22 85 66 88; fax: +47 22 85 42 15. E-mail address: yu.jia@geo.uio.no (Y. Jia). www.elsevier.com/locate/chemosphere Chemosphere 67 (2007) 250–258