Multi-laboratory Validation of a New Marine Biodegradation Screening Test for Chemical Persistence Assessment
Amelie Ott, Timothy Martin, Kishor Acharya, Delina Y. Lyon, Nik Robinson, Bob Rowles, Jason Snape, Ian Still, Graham Whale, Vurtice C. Albright, Petra Bäverbäck, Nicola Best, Ruth Commander, Curtis Eickhoff, Sarah Finn, Björn Hidding, Heiko Maischak, Katherine A. Sowders, Masanori Taruki, Helen E. Walton, Aina Charlotte Wennberg, Russell J. Davenport
Abstract
Current biodegradation screening tests are not specifically designed for persistence assessment of chemicals, often show high inter- and intra-test variability, and often give false negative biodegradation results. Based on previous studies and recommendations, an international ring test involving 13 laboratories validated a new test method for marine biodegradation with a focus on improving the reliability of screening to determine the environmental degradation potential of chemicals. The new method incorporated increased bacterial cell concentrations to better represent the microbial diversity; a chemical is likely to be exposed in the sampled environments and ran beyond 60 days, which is the half-life threshold for chemical persistence in the marine environment. The new test provided a more reliable and less variable characterization of the biodegradation behavior of five reference chemicals (sodium benzoate, triethanolamine, 4-nitrophenol, anionic polyacrylamide, and pentachlorophenol), with respect to REACH and OSPAR persistence thresholds, than the current OECD 306 test. The proposed new method provides a cost-effective screening test for non-persistence that could streamline chemical regulation and reduce the cost and animal welfare implications of further higher tier testing.