Anilines: selective toxicity to blue-green algae.

The blue-green alga Agmenellum quadruplicatum (strain PR6) was very sensitive to aniline and p-toluidine (potential environmental toxicants) in an algal lawn assay (the growth of the algal lawn was inhibited with as little as 1 microgram of p-toluidine per disk). Assays with seven other species of blue-green algae showed that they had varying sensitivities ranging from 1 to 100 micrograms of p-toluidine. Under comparable conditions, 0.5 milligram or more of p-toluidine was needed to inhibit a green alga, a diatom, or two species of bacteria. p-Toluidine had no immediate effect on the photosynthesis or respiration of A. quadruplicatum, although growth was arrested and viability declined.