Rapid determination of polycyclic aromatic hydrocarbons (PAHs) in zebrafish eleutheroembryos as a model for the evaluation of PAH bioconcentration

A simple and fast approach for a novel bioaccumulation test by exposing zebrafish eleutheroembryos to fluorene and anthracene (PAHs) at two concentration levels below 1% of their LC50 is presented. This alternative protocol sets an uptake period of 48 h at 26 °C for bioconcentration of the compounds tested and an additional 24 h for depuration. Two different methods to estimate bioconcentration factors (BCFs) of PAHs were used. The first consists in the ratio between concentrations of the tested compounds in the zebrafish eleutheroembryos and the exposure media when a steady state during exposure is reached (BCFss). The second employs the concentration–time profile with the use of a least-square fit to a non-linear model (BCFk). A steady state (ss) was reached after 12 h and 22 h for fluorene and anthracene exposure, respectively. Uptake and depuration rate constants obtained were similar for the two exposure levels tested, hence toxicokinetic rate constants appeared to be independent of the exposure level. Bioconcentration factors of 1164 and 817 for fluorene exposure at 0.99 ng mL−1 and 7.9 ng mL−1 and of 2089 and 2344 for anthracene at 0.63 ng mL−1 and 6.1 ng mL−1 were assessed. The good agreement of the obtained results with those reported in the literature proves the feasibility of the proposed method for estimation of both toxicokinetic parameters and bioconcentration factors. Furthermore, this protocol, has potential to be an alternative to the Organisation for Economic Cooperation and Development (OECD) 305 method, considerably reducing time and associated costs of the test suggested by European legislation.