Bioconcentration for Ionizable Organics (BIONIC)
The BIONIC model estimates the bioconcentration factor (BCF, L/kg) of neutral organic and ionizable organic chemicals (IOCs) in fish and is an outcome of the CEFIC-LRI ECO21 project which ended in 2015. The main features and modelling approaches for the BIONIC model are described in Armitage et al. 2013. In short, BIONIC is a modification of the Arnot and Gobas 2004 AQUAWEB model for neutral organic chemicals such that the model can be applied to IOCs as well. The most important modifications are to the description of partitioning to phases in the organism (distribution ratios rather than partition coefficients) and to the gill uptake sub-model.
The gill uptake model was revised in BIONIC V1 such that resistance to transport of the chemical across organic diffusion layers (i.e., membranes) is scaled by a factor driven by the ratio of the neutral to charged form of the chemical in the gill. The gill uptake model from V1 was replaced with a new formulation in BIONIC V2 such that transport of the charged form of the chemical is explicitly considered in the model calculations. BIONIC V2 is recommended for simulating the BCFs of IOCs that lie at the extreme range of typical acidic and basic IOCs, i.e., organic acids with pKa < 3 and organic bases with pKa > 12. Full details of the model are available in the following publication:
– Armitage, J. M.; Arnot, J. A.; Wania, F.; Mackay, D. 2013. Development and evaluation of a mechanistic bioconcentration model for ionogenic organic chemicals in fish. Environ. Toxicol. Chem. 32, (1), 115–128. DOI: 10.1002/etc.2020
The BIONIC models are implemented (coded) in Visual Basic for Applications (VBA) and the Graphical User Interface is designed in Excel™. A User Manual is embedded within the Excel file. The BIONIC models will only function properly on a Windows operating system. The computer must use the period (.) as the decimal separator rather than the comma (,) to ensure accurate results.