Determination of the biological effect of water pullutants in protozoa. III. Saprozoic flagellates. As a completion of the toxicological method developed by Bringmann and measuring cell multiplication inhibition to determine the toxicity threshold (TGK) of water pollutants for bacteriovorous flagellate protozoa (model organism: Entosiphon sulcatum Stein) and for bacteriovorous ciliate protozoa (model organism: Uronema parduczi Chatton-Lwoff), respectively, an analogous but modified test procedure using saprozoic flagellates as test organisms (model organism: Chilomonas paramaecium Ehrenberg) is described. This test was used to determine the TGK of 171 potential water pollutants. In this test procedure, the flagellate saprozoic protozoon Chilomonas paramaecium Ehrenberg cultured in a bacteria-free standardized organic mineral nutrient medium serves as model organism. The test period required for determination of the TGK is 48 h. An electronic cell counter (Coulter) is used for quantitative determination of the protozoa inoculated and of the multiplication of protozoan cells within the test cultures after addition of a suitable electrolyte. If cell counts in the test cultures are 5% below the average of the counts in test cultures free of toxic influence, this may be considered as an initial inhibition of protozoan cell multiplication by a pollutant and thus serve for determining the toxicity threshold (TGK) of that particular pollutant.
With regard to the inorganic pollutants studied toxicologically, the TGK was 0.0001 mg/l for the effective ions of chromate, 0.003 mg/l for the effective ions of silver, 0.002 mg/l for hydrazine hydroxide (80%), 0.02 mg/l for the effective ions of mercury, between 0.1 and 1 mg/I for the effective ions of selenite as well as for the effective ions of cadmium, lead, beryllium, and nickel, between 1.0 and 10mg/I for the effective ions of cyanide as well as the effective ions of copper. As to the organic pollutants studied toxicologically, the TGK was between 0.1 and 1 mg/l for furfuryl alcohol, monofluoro acetic acid, acrylic acid, and cumene hydroperoxide, between1.0 and 10 mg/l for 1 .3-dinitro benzene, 2.4-dinitrophenol, acrolein, ethylene imine, 2.3-dinitro toluol, ethylene glycol monomethyl ether, acrylic acid-2-ethyl hexyl ester, o-nitrophenol, salicyl aldehyde, acrylic acid n-butyric ester, propargyl alcohol, furfural, pyridine, formalin (35%), 1.2-diethyl benzene, 4-nitroaniline, 4.6-dinitro-o-cresol, 2.4.6-trinitro toluol, cyclo heptene, 4-nitro-m-cresol, 2.4-dichioro-phenol, allylamine, heptene-(1),2-nitro-p-cresol, allyl chloride, vinyl acetate, and methyl acrylate.