EFFECTS OF 2 HERBICIDAL WASTEWATERS ON CHLORELLA SP AND PHAEODACTYLUM-TRICORNUTUM

The effects on Chlorella sp. and Phaeodactylum tricornutum of two indu strial wastewaters known to contain the herbicide residues of Triflura lin and Propanil have been determined by monitoring the number of cell s, the chlorophyll fluorescence and the carbon dioxide assimilation si multaneously for a period of 14 days. The growth of the diatom, Phaeod actylum tricornutum, was inhibited by concentrations of herbicidal was te of the order of 0.1-0.5%, apparently because the rate of reproducti on was reduced. Chlorella sp. cells, on the other hand, whilst dramati cally inhibited by 1% concentrations of herbicidal waste, were able to recover over a period of 14 days. If discharged at concentrations bel ow 0.01%, the industrial wastes appeared not to affect phytoplankton.