Oral Presentation Society of Environmental Toxicology and Chemistry Australasia 2021

The impacts of a common agricultural pollutant on behaviour and growth in the spotted marsh frog (Limnodynastes tasmaniensis) (#146)

Jack Orford 1 , Shiho Ozeki 1 , Jake Martin 1 , Lesley Alton 1 , Bob Wong 1
  1. Monash University, Melbourne

Endocrine-disrupting chemicals (EDCs)—compounds that interfere with endocrine system function at extremely low levels—are a class of environmental pollutants of increasing concern. Given EDCs act on receptors that are evolutionarily conserved across diverse taxa, and have a propensity to bioaccumulate, exposed wildlife are highly likely to be affected. Detrimental impacts on development and reproduction due to EDC exposure have been well documented, however, their potential impacts on behaviour have received far less attention. Concern over the extensive use of hormonal growth promotants (HGPs) in the cattle industry has been mounting, as these powerful anabolic steroids, used to increase meat yields for farmers, contain known EDCs. Detected repeatedly in aquatic habitats, 17β-trenbolone is a particularly potent androgenic endocrine-disrupting compound entering the environment due to HGP use. Here, we investigated the impacts of 28-day exposure to two environmentally realistic levels (average measured concentration: 9.46 ng/L and 66.13 ng/L) of 17β-trenbolone on behaviour and growth of spotted marsh frog tadpoles (Limnodynastes tasmaniensis). We found no evidence of 17β-trenbolone induced changes in the time taken for tadpoles to commence foraging behaviour. Similarly, we found no effect of 17β-trenbolone on tadpole morphology. However, we did find that the relationship between body size and activity was dependent on 17β-trenbolone exposure, with larger tadpoles being significantly more active within our lower 17β-trenbolone treatment. Overall, our results suggest that tadpoles may be less susceptible to detrimental effects of 17β-trenbolone exposure than other taxa, whilst also providing tentative support for a nonmonotonic dose-response to 17β-trenbolone. These findings provide pivotal insight into the effect of sub-lethal levels of agricultural pharmaceuticals on behavioural processes in amphibians.