Metropolitan urban. The Whau River catchment is located in Auckland, Aotearoa-New Zealand's largest city. This catchment includes urban and industrial areas and contains some of metropolitan Auckland’s highest anthropogenic pollutant concentrations, reflecting a range of inputs (urban stormwater, commercial/industrial site runoff, combined sewage overflows, urban litter).
Mixed productive land use. A catchment will be selected in the Nelson-Tasman region to provide a “mountain-to-sea” study site with headwaters originating in DOC estate and exotic forest before entering the plains, one of Aotearoa-New Zealand's most productive horticultural areas.
Determining microplastic pollution risks
To address microplastic impacts, we will focus on how microplastics act as a direct chemical contaminant source, adsorb contaminants and make them bioavailable, and microbial interactions in these processes.
This work will link to studies defining the ecotoxicology and ecological effects of microplastics in representative ecosystems.
Interactions between plastics and the environment
The way plastics interact with the environment can affect their risk to ecosystem and animal health. To look at the some of the ways plastics can affect our marine environment we are running a series of experiments where we put plastics out into the sea and look at what starts living on their surface, and what chemicals become associated with them. We are also look at how these things can affect the plastics themselves, for example are the things that grow on them assisting with their breakdown.
Between March and August 2019 a pilot study was conducted at the Port of Lyttelton, Christchurch, to look at the biofilms that develop on two different plastics, Nylon and oxo-PE, which are commonly found in marine litter. The samples from this experiment are currently being analysed.
What are microplastics ?
Microplastics are pieces of plastic less than 5mm in size. They are either made for purpose (primary microplastics) such as those used in industrial processes, personal and domestic care products, glitter or the preproduction pellets (nurdles) that is how plastics is transported around the world. Microplastics can be the breakdown products (secondary microplastics) of large plastic items, from food packaging to car lights. There is estimated to be >15 trillion pieces of microplastic debris in the world’s oceans, 80% of which originate from land-based activities.
Worldwide there is increasing public and regulatory concern about the impact of microplastics on our environment, food, and health. International research demonstrates microplastics are pervasive in the environment. This problem has been likened to climate change due to its global scale and the magnitude of potential risks it poses to ecosystem health and resilience, human health, and the economy.