The Polychlorinated Biphenyls, Aroclors 1248 and 1260: Effect on and Accumulation by Tetrahymena pyriformis*

SYNOPSIS. Effects of 2 polychlorinated biphenyls, Aroclor 1248 and 1260, on axenic Tetrahymena pyriformis strain W were investigated and compared with published data on Aroclor 1254. Aroclors 1248 and 1260 at 1 mg/liter in the presence of 0.1% (v/v) polyethylene glycol 200 reduced significantly (P < 0.005) growth rates and 96‐hr populations of T. pyriformis grown at 26 C. Both toxicants were ∼ 0.001 as toxic as Aroclor 1254. Ciliates were exposed for 7 days to concentrated Aroclors 1248 40X, 1254 60X, and 1260 79X over initial concentrations in the media. Accumulation of Aroclors increased with increased chlorination. It is suggested that if levels in the environment reached those used in these studies, the chief ecologic effect of Aroclor 1254 would be reduction of availability of the ciliates as food and as nutrient regenerators, but with Aroclors 1248 and 1260, this effect would be secondary to accumulation of the toxicants by the ciliates. Accumulation of polychlorinated biphenyls by ciliates would permit the toxicants to enter aquatic food chains. Thus the compounds could exert toxic effects at higher trophic levels.