Temporal Decrease of Trivalent Chromium Concentration in a Standardized Algal Culture Medium: Experimental Results and Implication for Toxicity Evaluation

The behavior of two chromium(III) salts in standard algal medium, was examined. Total concentrations were determined by ICP-MS at m/z 53 using external calibration and internal standard correction. The pH of the chromium solutions was measured at 0, 24, 48, and 72 h. In the 72 h-experiments in ISO medium, total chromium concentrations decreased by 60-90% of their initial values over 72 h. In ancillary experiments performed in Erlenmeyer flasks under agitation, Cr concentrations decreased by 70-80% in 72 h; in good agreement with results for microplates. Chromium concentration in AAP medium decreased by 85% in 72 h and was in good agreement with observations in ISO medium.