Article

Environmental Monitoring and Assessment

, Volume 173, Issue 1, pp 397-407

First online:

Morphological abnormalities in frogs from a rice-growing region in NSW, Australia, with investigations into pesticide exposure

  • Nicholas SpolyarichAffiliated withCentre for Ecotoxicology, Department of Environmental Sciences, University of Technology-Sydney Email author 
  • , Ross V. HyneAffiliated withCentre for Ecotoxicology, Ecotoxicology and Environmental Contaminants Section, Department of Environment, Climate Change and Water
  • , Scott P. WilsonAffiliated withCentre for Environmental Management, Central Queensland University
  • , Carolyn G. PalmerAffiliated withCentre for Ecotoxicology, Department of Environmental Sciences, University of Technology-Sydney
  • , Maria ByrneAffiliated withSchools of Medical and Biological Sciences, University of Sydney

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Abstract

Three frog species (Limnodynastes tasmaniensis, Limnodynastes fletcheri and Litoria raniformis) were surveyed in rice bays of the Coleambally Irrigation Area (CIA), NSW, Australia, during the rice-growing seasons of 2005/2006 and 2006/2007. A total external morphological abnormality index of 7.0% was observed in frogs of the CIA (n = 1,209). The types and frequencies of abnormalities were typical of reports from agricultural areas with ectrodactyly being the most common aberration. A relatively low abnormality index of 1.2% was observed in L. raniformis (n = 87) compared to indices of 7.1% and 8.2% observed in L. fletcheri (n = 694) and L. tasmaniensis (n = 428), respectively. No conclusive evidence was found of unnaturally high rates of intersex, gonadal maldevelopment or unbalanced sex ratios in any species. Rice bay surface waters differed significantly in mean pesticide concentrations of atrazine and metolachlor on farms growing rice and corn compared to farms with rice as the sole crop. However, the similar abnormality indices observed in recent metamorphs emerging from these two farm types provided no evidence to suggest a link between larval exposure to the measured pesticides and developmental malformations.

Keywords

Atrazine Metolachlor Anuran malformation Intersex Frog deformity