Assessing bioaccumulation with biomagnification factors from dietary bioaccumulation tests.

Despite the fact that the UN Stockholm Convention on persistent organic pollutants specifically acknowledges that Arctic ecosystems and Indigenous communities are particularly at risk due to biomagnification of contaminants in traditional foods, the bioconcentration factor (BCF) of substances in fish remains the preferred metric for identifying the biomagnification potential of organic substances. The BCF measures uptake of substances from water in water-breathing organisms, but not biomagnification of contaminants from food sources. The purpose of this study is to investigate how the biomagnification factor (BMF) can be used in bioaccumulation assessments.

Predicting Hydrocarbon Primary Biodegradation in Soil and Sediment Systems Using System Parameterization and Machine Learning.

Technical complexity associated with biodegradation testing, particularly for substances of unknown or variable composition, complex reaction products, or biological materials (UVCB), necessitates the advancement of non-testing methods such as quantitative structure-property relationships (QSPRs). Models for describing the biodegradation of petroleum hydrocarbons (HCs) have been previously developed. A critical limitation of available models is their inability to capture the variability in biodegradation rates associated with variable test systems and environmental conditions.

Comprehensive Two-Dimensional Gas Chromatography with Peak Tracking for Screening of Constituent Biodegradation in Petroleum UVCB Substances.

Petroleum substances, as archetypical UVCBs (substances of unknown or variable composition, complex reaction products, or biological substances), pose a challenge for chemical risk assessment as they contain hundreds to thousands of individual constituents. It is particularly challenging to determine the biodegradability of petroleum substances since each constituent behaves differently. Testing the whole substance provides an average biodegradation, but it would be effectively impossible to obtain all constituents and test them individually.

Improved closed test setup for biodegradation testing of slightly volatile substances in water-sediment systems (OECD 308).

Standardized biodegradation testing methods, like the OECD 308 Aerobic and Anaerobic Transformation in Aquatic Sediment Systems, generate data on biodegradation required during environmental risk and hazard assessment of chemicals under different European and international regulations. However, difficulties arise when applying the OECD 308 guideline for testing hydrophobic volatile chemicals. Especially the use of a co-solvent (like acetone) as a measure to facilitate the application of the test chemical in combination with a closed setup to reduce losses due to volatilization tend to deplete/restrict the amount of oxygen in the test system.