Review Refinement of biodegradation tests methodologies and the proposed utility of new microbial ecology techniques Agnieszka Kowalczyk a,n , Timothy James Martin b , Oliver Richard Price c , Jason Richard Snape d , Roger Albert van Egmond c , Christopher James Finnegan c , Hendrik Schäfer a , Russell James Davenport b , Gary Douglas Bending a a School of Life Sciences, University of Warwick, Coventry CV4 7AL, United Kingdom b School of Civil Engineering and Geosciences, Newcastle University, Newcastle upon Tyne NE1 7RU, United Kingdom c Unilever, Safety & Environmental Assurance Centre, Colworth Science Park, Sharnbrook MK441LQ, United Kingdom d AstraZeneca, Mereside, Alderley Park, Macclesfield SK10 4TF, United Kingdom article info Article history: Received 30 April 2014 Received in revised form 22 September 2014 Accepted 23 September 2014 Keywords: OECD tests Biodegradation Persistence Chemical risk assessment Microbial ecology Omics abstract Society's reliance upon chemicals over the last few decades has led to their increased production, application and release into the environment. Determination of chemical persistence is crucial for risk assessment and management of chemicals. Current established OECD biodegradation guidelines enable testing of chemicals under laboratory conditions but with an incomplete consideration of factors that can impact on chemical persistence in the environment. The suite of OECD biodegradation tests do not characterise microbial inoculum and often provide little insight into pathways of degradation. The present review considers limitations with the current OECD biodegradation tests and highlights novel scientific approaches to chemical fate studies. We demonstrate how the incorporation of molecular microbial ecology methods (i.e., ‘omics’) may improve the underlying mechanistic understanding of biodegradation processes, and enable better extrapolation of data from laboratory based test systems to the relevant environment, which would potentially improve chemical risk assessment and decision making. We outline future challenges for relevant stakeholders to modernise OECD biodegradation tests and put the ‘bio’ back into biodegradation. & 2014 Elsevier Inc. All rights reserved. Contents 1. Introduction ......................................................................................................... 10 2. OECD biodegradation tests ............................................................................................. 10 2.1. Historical aspects and principal design of OECD test................................................................... 10 2.2. Overview of current tests ........................................................................................ 11 2.3. Limitations of current tests ....................................................................................... 13 2.3.1. Ready biodegradability tests ............................................................................... 13 2.3.2. Enhanced and modified screening tests within REACH .......................................................... 16 2.3.3. Inherent biodegradability tests ............................................................................. 16 3. Environmental realism of tests .......................................................................................... 17 3.1. Effect of environmental factors on biodegradability assessment .......................................................... 17 4. Microbial ecology in biodegradation testing ............................................................................... 17 4.1. Advantages and disadvantages of ‘omics’ ............................................................................ 19 5. Conclusions ......................................................................................................... 19 Contents lists available at ScienceDirect journal homepage: www.elsevier.com/locate/ecoenv Ecotoxicology and Environmental Safety http://dx.doi.org/10.1016/j.ecoenv.2014.09.021 0147-6513/& 2014 Elsevier Inc. All rights reserved. n Corresponding author. Present address: SC Johnson, Frimley Green, Frimley, Camberley, Surrey GU16 7AJ, United Kingdom. Tel.: þ44 7758572996. E-mail address: AKowalcz@scj.com (A. Kowalczyk). Ecotoxicology and Environmental Safety 111 (2015) 9–22