Deriving in Vivo Bioconcentration Factors of a Mixture of Fragrance Ingredients Using a Single Dietary Exposure and Internal Benchmarking

Chemicals in mixtures that are hydrophobic with Log K OW > 4 are potentially bioaccumulative. Here, we evaluate an abbreviated and benchmarked in vivo BCF measurement methodology by exposing rainbow trout to a mixture of eight test chemicals found in fragrance substances and three benchmark chemicals (musk xylene (MX), hexachlorobenzene (HCB) and PCB52) via a single contaminated feeding event followed by a 28-day depuration period. Concentrations of HCB and PCB52 in fish did not decline significantly (their apparent depuration rate constants, k T , were close to zero), whereas k T for MX was 0.022 d -1 . The test chemicals were eliminated much more rapidly than the benchmark chemicals ( k T > 0.117 d -1 ). The bioconcentration factors (BCF A ) for the test chemicals were in the range of 273 L kg -1 (8-cyclohexadecen-1-one (globanone)) to 1183 L kg -1 (α-pinene); the benchmarked BCFs (BCF G ) calculated relative to HCB ranged from 238 L kg -1 (globanone) to 1147 L kg -1 (α-pinene). BCF G were not significantly different from BCF A but had smaller standard errors. BCFs derived here agreed well with values previously measured using the OECD 305 test protocol. We conclude that it will be feasible to derive BCFs of chemicals in mixtures using a single dietary exposure and chemical benchmarking.