Ecotoxicological soil evaluation by FETAX Mariangela Prati a , Elia Biganzoli b , Patrizia Boracchi c , Marina Tesauro a , Claudio Monetti a , Giovanni Bernardini a, * a Department of Structural and Functional Biology, Universit  a dellÕInsubria, 3 Via Dunant, 1-21100 Varese, Italy b Division of Medical Statistics and Biometry, Istituto Nazionale per lo Studio e la Cura dei Tumori, Milano, Italy c Institute of Medical Statistics and Biometry, Universit  a di Milano, Milano, Italy Received 12 August 1999; accepted 18 January 2000 Abstract The frog embryo teratogenesis assay-Xenopus (FETAX) is a powerful and ¯exible bioassay that makes use of the embryos of the anuran Xenopus laevis. FETAX satis®es the requirements of low cost, reliability and reproducibility and, thanks to its three endpoints (i.e., mortality, teratogenicity and growth inhibition) can detect the xenobiotics that aect embryonic development. In this paper, we have used FETAX to evaluate samples of soils collected in an oil-con- taminated area. Embryos were exposed directly to the soil to be tested. Particular attention was devoted to provide a statistical procedure for analysing mortality and malformation data as well as growth retardation. Ó 2000 Elsevier Science Ltd. All rights reserved. 1. Introduction The frog embryo teratogenesis assay-Xenopus (FE- TAX) (Dumont et al., 1983) is a powerful and ¯exible bioassay for developmental toxicants. FETAX appears to satisfy requirements of low cost, reliability and re- producibility (Dawson and Bantle, 1987a; Bantle et al., 1990, 1994, 1996; Fort et al., 1998) and it represents a good alternative to the use of mammalian species for screening chemicals (Dawson and Bantle, 1987a,b; Fort et al., 1989; Bantle et al., 1990; DeYoung et al., 1991; Brown et al., 1995). It makes use of the embryos of the anuran Xenopus laevis, an animal model well known in the laboratories all over the world. Thanks to its three endpoints (i.e., mortality, teratogenicity and growth in- hibition), FETAX can detect the xenobiotics that aect embryonic development, a weak link in the life circle of an organism. FETAX has been used to study the eects of single compounds (Dawson et al., 1988a, 1989; DeYoung et al., 1991; Hopfer et al., 1991; Dresser et al., 1992; Fort et al., 1992, 1993; Bernardini et al., 1994) or their joint action (Dawson and Bantle, 1987b; Dawson, 1991; Dawson and Wilke, 1991a,b; Rayburn et al., 1991a,b; Friedman et al., 1997) FETAX turned out to be ®t also for eco- toxicological studies and therefore has been used for evaluating industrial solvents or detergents (Presutti et al., 1994; Kononen and Gorski, 1997), pesticides (Schuytema et al., 1994; Bernardini et al., 1996; Morgan et al., 1996; Vismara et al., 1996; Laclair et al., 1998), surface and ground waters (Dawson et al., 1985; Bruner et al., 1998; Ciccotelli et al., 1998), sediment extracts (Dawson et al., 1988b; Fort et al., 1995; Hutchins et al., 1998) or the ecotoxicological eciency of a water pro- cessing plant (Vismara et al., 1993). In some cases, the survey of contaminated areas by FETAX can also be performed with an in situ exposure of the Xenopus em- bryos. Alternatively, soil samples can be directly tested in the laboratory by a bulk sample analysis. In this paper, we describe a bulk sample analysis performed on soils collected in an oil contaminated area. Particular attention was devoted to provide statistical Chemosphere 41 (2000) 1621±1628 * Corresponding author. E-mail address: giovanni.bernardini@unimi.it (G. Bernar- dini). 0045-6535/00/$ - see front matter Ó 2000 Elsevier Science Ltd. All rights reserved. PII: S 0 0 4 5 - 6 5 3 5 ( 0 0 ) 0 0 0 3 4 - 5