Importance of the study of atrazine toxicity to amphibians in the Australian environment

Global amphibian declines have been of great concern over recent years due to a number of increasing natural and anthropogenic stressors. Reproductive and developmental abnormalities in amphibians have been reportedly linked to pesticide exposures and atrazine is one such pesticide that is of particular concern. Studies have shown gonadal deformities in frogs exposed to atrazine concentrations as low as 0.1 μg/L. The majority of amphibian toxicity tests have been run using the African clawed frog, Xenopus laevis; however, the use of Australian native frogs in toxicity testing is limited. Differences in sensitivity to environmental contaminants may exist between Australian amphibians compared to overseas frog species. Atrazine is one of the most widely applied herbicides and is commonly detected in surface and groundwater samples. Australian native frogs usually breed during late spring and summer, which is the peak time for applying atrazine to agricultural fields. Therefore, their breeding sites adjacent to the agricultural fields can potentially become contaminated with atrazine. The Australian Pesticides and Veterinary Medicines Authority has reviewed atrazine several times due to its concern for human and animal health after frequent detection in surface and ground waters; however, most of the reviews were based on mammalian and/or overseas studies. Therefore, the aim of this review was to: 1) detail the present scenario of atrazine in Australia, particularly in Queensland where agriculture is an important industry, and 2) assess likely atrazine toxicity to amphibians in order to highlight the potential harm in the Australian environment.