Biodegradability assessment of complex chemical mixtures using a carbon balance approach

Abstract

The assessment of complex mixture biodegradability can be limited by technical issues and/or difficulties to rule on ready or inherent biodegradability.

Improving the Environmental Risk Assessment of Substances of Unknown or Variable Composition, Complex Reaction Products, or Biological Materials

“…Modifications to standard screening biodegradation tests are being explored to 1) apply such tests to UVCBs, and 2) improve the understanding of biodegradation for the constituents present in or representing those mixtures. These include the use of additional measurements, such as chemical analysis and measurement of biomass to aid interpretation, and passive dosing to establish suitable exposures of hydrophobic organic mixtures (Birch et al 2018; Brillet et al 2018; Brown et al 2018). It is recognized that further research is needed and that the influence of competitive effects, sequential degradation, cometabolism, and the conditions of screening tests on the results and their interpretation should be considered.…”

Influence of Biodegradable Release Oils on the Physical and Mechanical Properties of Light-Colored Architectural Concrete

“…Biodegradability: Biodegradability tests were performed under the conditions described in CEC Method L-33-T-82 [ 22 , 23 ]. According to the CEC methodology, 150 cm 3 of 50 mg/dm 3 solution were prepared for testing, into which 1 cm 3 of inoculum containing more than 107 CFU/cm 3 (active cells/cm 3 ) were introduced each.…”

Biodegradation kinetics testing of two hydrophobic UVCBs – potential for substrate toxicity supports testing at low concentrations

“…Analytical challenges and technical issues are some of the main limitations to biodegradation testing of UVCB substances. 2,42 In this study, the automated HS-SPME-GC/MS method used directly on the test systems ensured minimal losses and low detection limits, which made it possible to obtain primary biodegradation kinetics for many individual, and potentially diverse, mixture constituents even at the low test concentration. The method is thus highly useful for determining primary biodegradation kinetics of individual mixture constituents, whereas it cannot directly be used to determine how much of the original mixture has been degraded in total.…”

“…The total and ultimate biodegradation (mineralization) of a complex mixture can be determined by measuring a non-specic analytical parameter such as CO 2 production. 42 However, determining the overall mineralization of a mixture will not provide information on potentially persistent constituents, even if a pass criterion 43 like 60% of the theoretical CO 2 production is reached. Future biodegradation testing strategies for UVCB substances may thus require a combination of specic and non-specic approaches.…”