Algal test using chlorococcal algae Desmodesmus subspicatus was used to determine single acute toxicity of either diclofenac or cadmium and to assess acute toxicity of their binary mixtures. The test confirmed significant acute toxicity of both diclofenac and cadmium; diclofenac with acute toxicity ErC50 60.44 ± 0.20 mg/L and cadmium with acute toxicity ErC50 2.14 ± 0.02 mg/L. This study of acute toxicity of binary cadmium-diclofenac mixtures confirmed their negative effects on aquatic producers and it also proved influence of the above substances on acute toxicity of their mixtures. Normalization method was applied to predict acute toxicity of binary mixtures composed of chemicals with significantly different acute toxicities. Normalization method used molar ratio (R) of chemicals in binary mixtures as their composition descriptor.
Keywords: Binary mixtures; Cadmium; Desmodesmus subspicatus; Diclofenac; Normalization method.