Relationships between formation of micronuclei and DNA adducts and EROD activity in newts following exposure to benzo(a)pyrene

The aim of this study was to determine whether the micronucleus test, using the larvae of a lower invertebrate, the newt Pleurodeles waltl, is suitabl e for evaluating the overall genotoxicity of polluted water (AFNOR Standard , 1992). The study used the pollutant model benzo(a)pyrene (BaP). After hav ing shown that BaP is metabolized by the larvae, the test was carried out u nder standard AFNOR conditions. We investigated the relationship between th e BaP concentration, spectrofluorometric measurement of liver EROD activity , and two genotoxicity biomarkers: DNA adduct production (P-32-postlabeling detection) and micronucleus formation in red blood cells (RBCs) (number of micronucleated RBCs per 1,000). A dose effect was found for all three biom arkers, which were seen to be linearly correlated showing that the biochemi cal mechanisms occurring in the newt larvae exposed to BaP are similar to t hose described in higher vertebrates. This result confirms the utility of t he test for the evaluation of the overall hazard of a given aquatic environ ment. Environ. Mol. Mutagen. 32:397-405, 1998 (C) 1998 Wiley-Liss, Inc.