ABILITY OF 16 PRIORITY PAHS TO BE DIRECTLY CYTOTOXIC TO A CELL-LINE FROM THE RAINBOW-TROUT GILL

Sixteen polycyclic aromatic hydrocarbons (PAHs) were screened for thei r ability to be directly cytotoxic to a cell line from the rainbow tro ut gill, RTgill-W1. Exposure times of 2 h or less were sufficient for direct cytotoxicity to be detected, which appeared to be caused by a c ommon mechanism, the general perturbation of membranes. This was judge d by the similarity of results obtained for three fluorescent indicato r dyes, alamar Blue(TM), 5-carboxyfluorescein diacetate acetoxymethyl ester (CFDA-AM) and neutral red. Among the 16 PAHs tested, just two- a nd three-ring PAHs were found to be directly cytotoxic. These were nap hthalene congruent to acenaphthylene congruent to acenaphthene > fluor ene congruent to phenanthrene. The results suggest that water solubili ty and lipophilicity are the critical properties determining the direc t cytotoxicity of PAHs and that they do so by influencing PAH accumula tion in membranes. Only naphthalene was effective at concentrations we ll below its water solubility limit. Therefore, direct cytotoxicity is likely to be most environmentally relevant only with naphthalene. (C) 1998 Elsevier Science Ireland Ltd. All rights reserved.