EFFECTS OF A NONIONIC SURFACTANT (C-14-15 AE-7) ON FISH SURVIVAL, GROWTH AND REPRODUCTION IN THE LABORATORY AND IN OUTDOOR STREAM MESOCOSMS

The effects of a nonionic surfactant (C-14-15 AE-7) on survival and gr owth of juvenile bluegill sunfish and on survival and reproduction of fathead minnows were investigated in the laboratory and in outdoor str eam mesocosms. In the laboratory, where the fish were exposed for 10 d , the 96-h LC50 values for bluegill sunfish and fathead minnows were 6 50 and 770 mu g/L, respectively. The no-observed-effect concentration (NOEC) for survival and swimming performance of bluegill sunfish and f or survival of fathead minnows was 160 mu g/L. The lowest-observed-eff ect concentration (LOEC) for these toxic responses was 460 mu g/L. In the stream mesocosms, where the fish were exposed for 30 d, the NOEC f or bluegill sunfish survival and growth was >330 mu g/L. The LOEC for fathead minnow survival was 330 mu g/L, and the NOEC was 280 mu g/L. D ecreased egg laying by fathead minnows was noted in the streams at con centrations of 330 mu g/L or greater. Close correspondence between the results of laboratory tests and those obtained under field conditions in the mesocosms indicates that for this surfactant, it may not be ne cessary to apply ''safety factors'' to extrapolate results from the la boratory to the field.