Evaluation of elemental composition of algal biomass as toxical endpoint

Freeze dried algal biomass was analysed with an organic elemental analysis (CHNS) in order to determine whether chemical stress could be detected as changes in gross cellular composition. Results showed that an LOEC for potassium dichromate of 0.21 mg/l was statistically different from a NOEC of 0.10 mg/l. The elemental analysis method could be improved if the final algal density in the batch cultures was kept low (<105 cell/ml). The remaining problem is to get sufficient biomass to perform the elemental analysis. The study demonstrates the potential of elemental analysis applied as endpoint for algal toxicity and defines the optimal conditions for simultaneous CHNS determination, furthermore proposals for future investigations are given.