Microplastics are a ubiquitous pollutant. Most research has focused on contamination of marine environments with wastewater treatment plants as sources of microplastics. However, freshwater ecosystems are also at risk, especially in urban areas. A recent study of urban wetlands in Melbourne found wetland sediments were heavily contaminated by microplastics. The main source was urban stormwater runoff and preliminary investigations showed that most microplastics came from the breakdown of larger plastic items, especially in industrial catchments. Urban wetlands are important habitats for aquatic organisms in an otherwise hostile landscape, yet it is not known whether wetland biota is affected by microplastics.
The primary purpose of this project involves continued investigations of sources of microplastics to wetlands and how contamination may be linked to local and catchment scale features such as gross pollutant traps, proximity to commercial areas, local pollution issues (e.g. illegal dumping) and surrounding land use. In addition, factors influencing the spatial distribution of microplastics in wetland sediments will be investigated, along with how disturbance events (e.g. wetland flushing) affect microplastic distribution and pose a risk to downstream aquatic ecosystems. A secondary component will be beginning investigations on how wetland biota might be affected by microplastics. This will begin with understanding if benthic biota are interacting with microplastics (such as through ingestion or bioaccumulation) and could potentially lead to further studies on the effects of microplastics on wetland biota, including in situ and laboratory toxicity assays.
