Bioconcentration of Organophosphorus Insecticides by the Ciliate Protozoan, Tetrahymena thermophila

Tetrahymena thermophila, a freshwater riliate shswed d aarked dbility to accumulate fenthion, parathion and methylparathion from the medium initially containing 1 ppm of each insecticide. The pattern of accumulation of the three organophosphorus insecticides in T. thermophila was sifferent and the amount of each insecticide (in ppm) acccumulated by the organism ranged from 199 to 833 for fenthion, 9 to 862 for parathion and 7 to 15 for methylparathion.