BILE FLUORESCENCE AND SOME EARLY BIOLOGICAL EFFECTS IN FISH AS INDICATORS OF POLLUTION BY XENOBIOTICS

Simple measurement of bile fluorescence in fish has been proposed as a means for determining exposure to certain waterborne chemicals. This proposal was based on the data obtained by chemical determination of metabolites of compounds to which fish were exposed. Because exposures to most of these compounds cause some profound biological effects in fish, we studied the correlation between the increase in bile fluorescence, the induction of liver benzo[a]pyrene monooxygenase (BaPMO) activity, and the increase in the potential of liver to bioactivate promutagenic benzo[a]pyrene to Salmonella typhimurium TA100 mutagens. Carp exposed to diesel-2 oil, crude oil, or to a flow of polluted river water simultaneously increased severalfold the levels of all three parameters in a dose- and time-dependent manner. During the recovery from exposure, the levels of bile fluorescence and the BaPMO activity declined and by day 15 reached their natural, preexposure levels. The level of bioactivation potential, however, remained at the higher, induced level throughout the recovery period of 15 d. Seven fish species living in polluted Sava River (near Zagreb, Croatia) revealed severalfold increased levels of these parameters, as compared to their levels in fish living in the reference Korana River (near Karlovac, Croatia) or to their levels in control carp. These results give qualitatively new support to the idea of using simple measurements of fluorescence of diluted bile as a rapid and cheap complementary investigative tool for monitoring and assessment studies.