PhD project: Sources and Fate of Microplastics in an Urban River catchment

Julia Rambacher

My project, led by NIWA scientist Dr. Amanda Valois and supervised by Dr. Olga Pantos and Dr. Sally Gaw, looks at the role of rivers in the transport and formation of microplastics.

Sampling site is the Kaiwharawhara stream in Wellington.  I will be analysing microplastics using FTIR spectroscopy from samples of a) the water column at 6 sampling sites, b) stormwater events using an autosampler and c) sediment. This will enable me to identify polymer types present in the river over time as well as determine their sources and potential entry points.

The second part of the project will investigate the environmental degradation the plastics and the processes involved. We will: a) deploy virgin plastics in the river over a period of 12 months and then analyse microbial growth on the weathered particles as well as their potential fragmentation; b) look at the degradation of washed up river plastics along a UV gradient from the North to the South of New Zealand, and; c) conduct a feeding experiment with the freshwater crayfish/koura Paranephrops sp., to see whether aquatic biota commonly found in rivers are able to fragment plastic particles and hence produce micro- and nanoplastics like their marine relatives.