An investigation into the long-term effects of rhine water on rainbow trout

Rainbow trout were maintained in Rhine water for a period of 18 months in order to determine the chronic toxicological quality of this water. An equal number of trout were kept in ground water of drinking water quality under identical experimental conditions. Compared to this control group, the rainbow trout in Rhine water showed growth inhibition, enlarged liver and kidneys, reduced hemoglobin content, increased blood glucose level and a significant accumulation of chlorinated hydrocarbons in adipose tissue. Moreover, histological changes were observed in the liver and spleen at the end of the experiment. The effects mentioned are of a nature and extent such that it may be concluded that Rhine water is chronically toxic to rainbow trout.