The influence of sulphite mill effluents on heterotrophic activity as measured by glucose assimilation

The influence of sulphite mill effluents on the heterotrophic activity of natural populations in the recipient water was studied during the summer of 1979. A single concentration method (3-H-glucose, 0.05 µg 1^–1) was used to measure the heterotrophic activity. The influence of the effluent was studied by adding it in concentrations varying from 0.001 to 10% to water samples derived from different sections of the watercourse. Adaptation to rather high concentrations of the effluent was observed near to the point of discharge. Low concentrations of the effluent had a stimulatory effect on heterotrophic activity. Short turnover times (5–20 h) of glucose and inhibition of primary productivity demonstrated the influence of effluents on planktonic populations.The single concentration method allows rapid and simple detection of horizontal and vertical effects of effluents on natural bacterioplankton in the recipient water.