IDENTIFICATION OF TOXIC METALS IN AFFECTED ALGAL CELLS IN ASSAYS OF WASTEWATERS

Chlorella fusca was the test species used in assays of two wastewaters , one characterized by a high concentration of free metal ions, and th e other by high concentrations of free metal ions and chlorinated orga nic compounds. Fine structural damage in cells exposed for six days to the effluents was examined using an electron microscope. In the prese nce of organic toxicity, the affected cells displayed a characteristic ally large build-up of starch grains. At high metal concentrations, th e chloroplasts were the only organelles altered. Within the chloroplas t, there were disruptions of the thylakoidal membranes and enlargement of interthylakoidal spaces. Excess metals, detected by X-ray microana lysis in the polyphosphate (poly-P) bodies of cells where chloroplast damage was observed, were regarded as harmful. X-ray scanning of parti culate material in effluent samples is proposed as a useful and low co st addition to surveillance programmes.