Effects of Five Synthetic Surfactants on the Red Tide Organisms and Cultured Fish

Abstract

This research examines the effects of mixtures of synthetic surfactants (C₁₄EO₁₄, C₁₈F₁EO₁₄, Tween80, C₁₄FA and Oleyl EO₂₀) on red-tide causing organisms and red sea bream. Surfactant (1 to 50 ppm) was added to media containing Chattonella marina or Heterocapsa circularisquama and examined every 30 minutes for swimming, immobile, and lysed cells for a total of 2 hours. The lowest concentration to immobolize or lyse the cells (LC₅₀, 2h) was calculated. The LC₅₀ (24h) of surfactants was also calculated for the ichthytoxicity of red sea bream juveniles. The LC₅₀ (2h) of C₁₄EO₁₄, C₁₈F₁E0₁₄ and Tween80 for C. marina was 1, 5 and 20 ppm, respectively; and for C₁₄FA and Oleyl EO₂₀, it was 30 ppm. Conversely with respect to H. circularisquama, approximately 30% of the cells showed sings of deformation at concentration of 50 ppm, Ichthyotoxicity (LC₅₀, 24h) for Tween80 was the strongest at 55 ppm, the other surfactants were ichthyotoxic from 125 to 150 ppm.