1 research outputs found
Predicting the Bioconcentration of Fragrance Ingredients by Rainbow Trout Using Measured Rates of <i>in Vitro</i> Intrinsic Clearance
Bioaccumulation in aquatic species
is a critical end point in the
regulatory assessment of chemicals. Few measured fish bioconcentration
factors (BCFs) are available for fragrance ingredients. Thus, predictive
models are often used to estimate their BCFs. Because biotransformation
can reduce chemical accumulation in fish, models using QSAR-estimated
biotransformation rates have been developed. Alternatively, biotransformation
can be measured by <i>in vitro</i> methods. In this study,
biotransformation rates for nine fragrance ingredients were measured
using trout liver S9 fractions and used as inputs to a recently refined <i>in vitro-in vivo</i> extrapolation (IVIVE) model. BCFs predicted
by the model were then compared to (i) <i>in vivo</i> BCFs,
(ii) BCFs predicted using QSAR-derived biotransformation rates, (iii)
BCFs predicted without biotransformation, and (iv) BCFs predicted
by a well-known regression model. For fragrance ingredients with relatively
low (<4.7) log <i>K</i><sub>OW</sub> values, all models
predicted BCFs below a bioaccumulation threshold of 1000. For chemicals
with higher (4.7–5.8) log <i>K</i><sub>OW</sub> values,
the model incorporating measured <i>in vitro</i> biotransformation
rates and assuming no correction for potential binding effects on
hepatic clearance provided the most accurate predictions of measured
BCFs. This study demonstrates the value of integrating measured biotransformation
rates for prediction of chemical bioaccumulation in fish