EVALUATION OF ELEMENTAL COMPOSITION OF ALGAL BIOMASS AS TOXICAL END-POINT

Freeze dried algal biomass was analysed with an organic elemental anal ysis (CHNS) in order to determine whether chemical stress could be det ected as changes in gross cellular composition. Results showed that an LOEC for potassium dichromate of 0,21 mg/l was statistically differen t from a NOEC of 0,10 mg/l. The elemental analysis method could be imp roved if the final algal density in the batch cultures was kept low (< 10(5) cell/ml). The remaining problem is to get sufficient biomass to perform the elemental analysis. The study demonstrates the potential o f elemental analysis applied as endpoint for algal toxicity and define s the optimal conditions for simultaneous CHNS determination, furtherm ore proposals for future investigations are given. (C) 1998 Elsevier S cience Ltd. All rights reserved.