Short Communication Clay mineral type effect on bacterial enteropathogen survival in soil Fiona P. Brennan a,b, ⁎, Emma Moynihan a , Bryan S. Griffiths a,c , Stephen Hillier b,d , Jason Owen b , Helen Pendlowski b , Lisa M. Avery b a Teagasc Environmental Research Centre, Johnstown Castle, Wexford, Ireland b The James Hutton Institute, Cragiebuckler, Aberdeen AB158QH, United Kingdom c SRUC, Crop and Soil Systems Research Group, West Mains Road, Edinburgh, EH9 3JG, United Kingdom d Department of Soil and Environment, Swedish University of Agricultural Sciences (SLU), Box 7014, SE-750 07 Uppsala, Sweden HIGHLIGHTS • Clay mineral types differentially alter physicochemical parameters in soil. • Different clay mineral types have differential effects on enteropathogen survival. • The effect of clay type on pathogen survival in soil is enteropathogen specific. abstract article info Article history: Received 4 April 2013 Received in revised form 13 August 2013 Accepted 13 August 2013 Available online 12 September 2013 Editor: Charlotte Poschenrieder Keywords: Clay mineral Pathogen survival Salmonella Listeria Escherichia coli Enteropathogens released into the environment can represent a serious risk to public health. Soil clay content has long been known to have an important effect on enteropathogen survival in soil, generally enhancing survival. However, clay mineral composition in soils varies, and different clay minerals have specific physiochemical prop- erties that would be expected to impact differentially on survival. This work investigated the effect of clay mate- rials, with a predominance of a particular mineral type (montmorillonite, kaolinite, or illite), on the survival in soil microcosms over 96 days of Listeria monocytogenes, Salmonella Dublin, and Escherichia coli O157. Clay mineral addition was found to alter a number of physicochemical parameters in soil, including cation exchange capacity and surface area, and this was specific to the mineral type. Clay mineral addition enhanced enteropathogen sur- vival in soil. The type of clay mineral was found to differentially affect enteropathogen survival and the effect was enteropathogen-specific. © 2013 Elsevier B.V. All rights reserved. 1. Introduction Enteropathogens released into the environment can represent a serious risk to public health. A wide range of sources exist, including grazing and domestic animals, environmental reservoirs, wildlife, and land-spreading of animal manures/slurries and sludge (Brennan et al., 2010; Gerba and Smith, 2005). Soil, in particular, can act as a reservoir for, or a mitigator against, further contamination of disease vectors such as water and food sources. A wide range of physical, chemical and biological factors are known to impact on the fate and transport of enteropathogens within soil (Crane and Moore, 1984; Jamieson et al., 2002; van Elsas et al., 2011). In the particle size sense, clay content has long been known to have an important effect on enteropathogen sur- vival in soil, generally enhancing survival (Garcia and McKay, 1970; Santamaría and Toranzos, 2003). However, the clay size fraction of dif- ferent soils can consist of drastically different clay mineral types each type having its own specific physiochemical and mineralogical proper- ties (particle size, shape, surface area, cation exchange capacity (CEC), moisture absorption, swelling potential, elasticity, and provision of mineral nutrients among many others) that may be anticipated to im- pact differentially on enteropathogen survival (England et al., 1993; Höper et al., 1995). Kaolinite, montmorillonite and illite represent some of the main groups of clay minerals found within soils (Marshall, 1975; Soil Science Society of America, 1989). Montmorillonite and illite are 2:1 (3 layer) clays, while kaolinite is a 1:1 clay (2 layer) with a smaller ex- pansion and absorption capacity. While a number of studies have investi- gated the impact of clay type on survival of bacteria such as Rhizobium, Agrobacterium and Pseudomonas sp. (Heijnen et al., 1993; Heynen et al., 1988; Stutz et al., 1989) in soil, there is limited knowledge on the nature or extent of any effect on enteropathogen survival. This is a surprising omission as the behaviour of bacteria within soil is known to be Science of the Total Environment 468–469 (2014) 302–305 ⁎ Corresponding author at: The James Hutton Institute, Cragiebuckler, Aberdeen AB158QH, United Kingdom. Tel.: +44 1224395342; fax: +44 8449285429. E-mail address: Fiona.brennan@hutton.ac.uk (F.P. Brennan). 0048-9697/$ – see front matter © 2013 Elsevier B.V. All rights reserved. http://dx.doi.org/10.1016/j.scitotenv.2013.08.037 Contents lists available at ScienceDirect Science of the Total Environment journal homepage: www.elsevier.com/locate/scitotenv