CHRONIC BIOASSAYS OF RAINBOW-TROUT FRY WITH COMPOUNDS REPRESENTATIVE OF CONTAMINANTS IN GREAT-LAKES FISH

To evaluate the hazard of organic compounds detected in Great Lakes fi sh by gas chromatography/mass spectrometry, we tested compounds repres entative of heterocyclic nitrogen compounds, polycyclic aromatic hydro carbons, and cyclic alkanes and alkenes. Sixty-day bioassays on the ef fects of nicotine, phenanthrene, pinane, and pinene on the behavior, g rowth, and survival of rainbow trout fry, Oncorhynchus mykiss, were co nducted in a large, constant-flow, temperature-controlled water system . The following 60-day LC50's were determined (mg/L): nicotine 5.0, ph enanthrene 0.2, pinane 0.8, and pinene 1.2. Values of lowest observed effects level (LOEL) and no observed effects level (NOEL) showed that growth was generally as sensitive an endpoint as behavior and was more sensitive than time of swim-up. The 60-day LC50 values for rainbow tr out were compared with earlier acute bioassays with Daphnia pulex and rainbow trout and chronic bioassays with D.pulex conducted at the Grea t Lakes Science Center. Rainbow trout fry were less sensitive than dap hnids in all tests, indicating that toxicity tests with daphnids shoul d be protective of salmonid fry for these types of compounds. The resu lts for representative compounds indicate that these classes of compou nds should be included in aquatic risk assessments at sites in the Gre at Lakes.