Amphibian Malformations and Environmental Contaminants
Environmental contaminants have been linked to several types of amphibian malformations. Heavy metals are one type of contaminant that has been shown to cause eye, pigment, and jaw defects in frogs (Hopkins 2000). Agricultural pesticides have also been of primary interest to researchers due to frequent reports of malformations from agricultural sites where pesticides are likely to have been used. For example, Ouellet and colleagues (1997), studying malformation reports from south-central Canada, concluded that there was an association between the prevalence of malformations and proximity to agricultural regions that used pesticides. Laboratory studies have also shown that exposing frogs to water collected from field sites where malformations are known to occur produces a variety of developmental malformations in amphibians (Burkhart et al. 1998). The role of pesticides or other contaminants in producing the complete array of malformations reported from wild amphibian populations remains unclear. Although prior work provides reason for concern over possible environmental health impacts of contaminants, there is an ongoing need to definitively identify individual compounds or interactive mixtures responsible for many of the observed malformations.

Amphibian Malformations and Environmental Contaminants