The Effects of Toxicants on the Health of Victorian Waterbirds

Anthropogenic disturbances are increasingly threatening the health of wildlife populations globally. One such threat is chemical pollution. With the advent of the Anthropocene, negative impacts from pollution are escalating in all ecosystems. Indeed, the United Nations has recently declared pollution to be the third global catastrophe (along with climate change and biodiversity loss). However, the urgency of this threat has not always been widely appreciated in Australia. This knowledge gap was addressed in this thesis by providing a contemporary account of exposure to pollutants in Australian waterbirds. This was achieved by opportunistically sampling birds from across the state of Victoria and focusing on three species: Pacific black ducks (Anas superciliosa), grey teal (Anas gracilis), and black swans (Cygnus atratus). I examined two contaminant types in these species: heavy metals (lead, copper, chromium, iron, manganese, mercury, and zinc) and persistent organic pollutants (POPs), and five tissue types: bone, feather, muscle, blood and adipose. The physiological impacts of these pollutants on birds were explored by characterising associations with metabolites in muscle and biochemistry parameters in blood. One key finding of this thesis is that exposure levels to critical contaminants are currently not as high in Australian ducks as in equivalent species inhabiting heavily industrialised areas of other continents. Additionally, there was little evidence that the quantified toxicants had obvious deleterious effects on the health of Victorian waterbirds. This research project has provided new information relevant to waterbird ecotoxicology in an under-studied global region. It has also allowed me to develop several key skills in field biology, laboratory methods, statistical analysis, and science communication. The crucial recommendation for future research is to conduct further investigations on other environmental contaminants in other Australian ecosystems and taxa.