Recent results obtained from a pilot plant study showed that the rate of morning temperature increase in surface water is significantly correlated with the degree of water pollution expressed as turbidity.
The aim of the present study was to validate the above findings under field conditions. Two oxidation ponds differing in their effluent quality were investigated during the summer. In clear weather and moderate winds the ponds were thermally stratified. Continuous records of subsurface temperature and parallel measurements of turbidity provided data for statistical analysis.
The variables tested appeared significantly correlated and the more polluted pond exhibited consistently a higher rate of morning temperature increase.
Temperature measurements can be carried out remotely using airborn IR radiometric equipment. The thermal method should be applied together with visible spectrum imaging, which can identify pollution components according to the specific waveband of the reflected light.