Structure-activity relationships for diorganotins, chlorinated benzenes, and chlorinated anilines established with bluegill sunfish BF-2 cells.

The bluegill sunfish (Lepomis macrochirus) BF-2 cell line, propagated at 34 degrees C, served as target for evaluation of the acute toxicities of various classes of aquatic pollutants, using the neutral red cytotoxicity assay. For a series of chlorinated benzenes and anilines, the sequence of cytotoxicity was dependent on the degree of chlorination and on their hydrophobicity, as described by their logarithmic octanol/water partition coefficients (log P values). With increasing numbers of chlorine atoms in the ring structure or with increasing log P values, greater cytotoxicity was observed. For a series of diorganotins, the sequence of cytotoxicity was dependent on the length of the carbon chain and upon their hydrophobicity, as described by Hansch pi parameters. Thus, increasing the chain length or increasing the Hansch pi parameter resulted in greater cytotoxicity. Similar structure-activity relationships for these classes of test agents have been previously established using acute toxicity LC50 assays with aquatic species. The ability of the neutral red in vitro cytotoxicity assay, with cultured fish cells as the bioindicators, to mimic the acute toxicity data obtained from the LC50 assays suggests its utility as a tool for preliminary screening (tier I testing) of aquatic pollutants.