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Study on impact of microplastics resumes post-lockdown

23 July 2020

Impact of microplastics

An important study on how microplastics are interacting with New Zealand’s marine ecosystems, has been restarted after lockdown delays.

Just days before New Zealand went into level four lockdown, scientists at ESR deployed structures into the sea, not knowing when they could check on them again.

The study deployed five different plastics in coastal waters around New Zealand to study how microplastics are interacting with New Zealand’s marine ecosystems. The plastics, held in place by large steel frames, are being deployed at marine sites in Auckland and Nelson, and at the Port of Lyttelton for one year.

The full-scale experiment follows a pilot study at the Port of Lyttelton between June and August last year, which looked for biofilms that developed on two different plastics. The samples from this experiment are currently being analysed.

The first samplings from these structures took place in Nelson last month.

Project co-lead ESR scientist Dr Olga Pantos says it is exciting for the large project team to get back to the sites.

“We did get the structures out at all the locations three marine sites across the country, but obviously we went into lockdown abruptly halting plans. The whole time we are thinking, we have to get back in and sampling as soon as possible, but there was uncertainty about the levels. We have found that a fantastic world has formed as we all stayed home.”

The five plastics used in the new experiment are both new and artificially aged, and include two commonly found in plastics bags (polyethylene and oxo-polyethylene), one commonly found in drink bottles (polyethylene terephthalate), one commonly used for food and liquid containers (polylactic acid) and one used in materials like fishing lines (nylon). Polylactic acid in particular is marketed as “compostable plastic” but these conditions are not found in the ocean. 

The deployment of the plastics in the coastal environment will allow the researchers to study changes to the plastics over time and chemicals and organisms that become associated with them.

 “By establishing the relationship between different plastics, the chemicals and microbes that become associated with them, we can better understand the risks they may pose the environment,” Dr Pantos says.

The team spent lockdown making new sampling plans to suit different scenarios for when and in what form they’d be able to access the experiment again. Whilst lockdown meant that short-term time points had to be missed, the experiment will continue for a year and new plastics will be deployed to capture what was missed.

The work is part of a five-year research programme looking at contemporary microplastic pollution in New Zealand called Aotearoa Impacts and Mitigation of Microplastics (AIM²). The project is the first comprehensive research investigating the impact of microplastics and the threat in New Zealand, and brings together a multidisciplinary team of researchers, community groups and iwi, from across the country to assess the risk microplastics present to our environment, economy and well-being.

The information gained from these experiments will be used to determine the level of risk posed by different plastics. This will be used in combination with the information gained on the distribution and levels of plastics in the coastal ecosystem, to determine the potential impact on New Zealand.

This team includes eleven students from the Universities of Auckland and Canterbury. The students will be looking for the chemical contaminants that become associated with the plastics in the environment, and/or that are released into the environment, the microbes’ ability to fully degrade the plastics, plastics in soils, their sources and their impacts on soil health, the effects of plastics on marine biosecurity, plastics in freshwater systems, and potential impacts on the ecology, and the ecotoxicological effects of plastics and their associated chemicals, inherent or acquired.

The Ministry of Business, Innovation and Employment funded study is 18 months in and is led by Dr Pantos and Dr Grant Northcott of Northcott Research Consultants. It includes scientists from University of Auckland, University of Canterbury, Scion and the Cawthron Institute.