Effects of pond water, sediment, and sediment extracts from Minnesota and Vermont, USA, on early development and metamorphosis of Xenopus

In recent studies, a high incidence of amphibian mortality and malformation has been reported in the field, suggesting that toxic and/or bioactive age nts are present in the environment of the affected amphibians. This study p rovides evidence for this hypothesis, because it applies to several affecte d ponds in Minnesota and Vermont, USA. Three developmental bioassays were c arried our on samples from three reference and three test sites in Minnesot a and one reference and three test sites, in Vermont. The bioassays utilize d Xenopus as a model system, measuring altered developmental patterns durin g the first 4 d of development (frog embryo teratogenesis assay-Xenopus [FE TAX]), hind-limb development over a 30-d period, and tail length resorption over a 14-d period. Strong correlations were observed among the results fo r all three in vitro bioassays, as well as between adverse developmental ef fects in vitro and in the field.