title: Development and application of screening tools for biodegradation in water-sediment systems and soil.
abstract: Two new screening-test systems for biodegradation in water-sediment systems (WSST; Water-Sediment Screening Tool) and soil (SST; Soil Screening Tool) were developed in analogy with the water-only test system OECD 301C (MITI-test). The test systems could be applied successfully to determine reproducible experimental mineralization rates and kinetics on the screening-test level for fifteen organic chemicals in water (MITI), water-sediment (WSST) and soil (SST). Substance-specific differences were observed for mineralization compared among the three test systems. Based on mineralization rate and mineralization half-life, the fifteen compounds could be grouped into four biodegradation categories: substances with high mineralization and a half-life <28 days in (1) all three test systems, (2) only in the MITI test and in the WSST, (3) only in the SST, and (4) none of the test systems. The observed differences between the MITI results and the WSST and SST biodegradation rates of the compounds do not reflect their (reversible) sorption into organic matter in terms of experimental K(oc) values and log D values for the relevant pH range. Regarding mineralization kinetics we recommend to determine the lag-phase, mineralization half-life and mineralization rate using a 5-parameter logistic regression for degradation curves with and without lag-phase. Experimental data obtained with the WSST and the SST could be verified by showing good agreement with biodegradation data from databases and literature for the majority of compounds tested. Thus, these new screening-tools for water-sediment and soil are considered suitable to determine sound and reliable quantitative mineralization data including mineralization kinetics in addition to the water-only ready biodegradability tests according to OECD 301.
authors.affiliation: ECT Oekotoxikologie GmbH, Boettgerstr. 2-14, 65439 Flörsheim, Germany. Electronic address: th-junker@ect.de.
authors.forename: Thomas
authors.initials: T
authors.lastname: Junker
authors.affiliation: ECT Oekotoxikologie GmbH, Boettgerstr. 2-14, 65439 Flörsheim, Germany.
authors.forename: Anja
authors.initials: A
authors.lastname: Coors
authors.affiliation: UFZ Helmholtz Centre for Environmental Research, Department of Ecological Chemistry, Permoserstr. 15, 04318 Leipzig, Germany; Institute for Organic Chemistry, Technical University Bergakademie Freiberg, Leipziger Str. 29, 09596 Freiberg, Germany.
authors.forename: Gerrit
authors.initials: G
authors.lastname: Schüürmann
mesh_terms: D001673:Biodegradation, Environmental; D004784:Environmental Monitoring / Q000379:methods*; D019015:Geologic Sediments / Q000737:chemistry*; D006207:Half-Life; D007700:Kinetics; D009930:Organic Chemicals / Q000032:analysis*; D012987:Soil / Q000737:chemistry; D012989:Soil Pollutants / Q000032:analysis*; D014874:Water Pollutants, Chemical / Q000032:analysis*
chemical_list: D009930:Organic Chemicals; D012987:Soil; D012989:Soil Pollutants; D014874:Water Pollutants, Chemical
keywords: Biodegradation; Degradation kinetics; Environmental fate; Persistent compounds; Soil; Water-sediment