The Challenge of Microplastics in Aotearoa
An invisible threat is silently accumulating in New Zealand's pristine waters. Microplastics, tiny plastic particles less than 5mm in size, are now found everywhere from the peaks of the Southern Alps to the depths of the Kermadec Trench. These fragments originate from two main sources: primary microplastics, such as microbeads in cosmetics, and secondary microplastics, which result from the breakdown of larger plastic items like bottles and fishing nets. A 2022 study by the University of Canterbury revealed that some urban rivers in Christchurch contain over 400 microplastic particles per square metre of riverbed.
The impact of these particles is a growing concern for scientists. Due to their small size, microplastics are easily ingested by marine life. Plankton, the base of the marine food web, consume these plastics, which then travel up the food chain to fish, birds, and eventually, humans. Research from NIWA (National Institute of Water and Atmospheric Research) has found microplastics in over 75% of commercially caught fish species in New Zealand. While the full health effects on humans are still being investigated, chemicals in plastics and the toxins they absorb from the water are known to be harmful.
Tackling this issue is a complex challenge. While New Zealand banned the sale of products containing plastic microbeads in 2018, the larger problem of secondary microplastics from single-use plastics and industrial waste remains. Community-led initiatives, such as beach clean-ups, play a vital role, but scientists argue that systemic change is needed. This includes investing in advanced wastewater treatment plants, which could potentially filter out more than 90% of microplastics, and promoting a circular economy where plastic waste is significantly reduced and repurposed. The future of New Zealand's clean, green image may depend on how we confront this microscopic menace.