Student’s solution to microplastics just came naturally

A Christchurch high school student believes a simple wool filter could go a long way in stopping microplastics from entering our waterways – and she has evidence to back up her theory.

Millie and Holly: Millie Palmer (winner) and finalist Holly Fraser with judge Jon Hickford, and Councillors Greg Byrne and Paul Dietsche.

Millie Palmer (winner) and finalist Holly Fraser with judge Jon Hickford, and Councillors Greg Byrnes and Paul Dietsche

“A third of all microplastics found in the ocean originates from our laundry – every time we wash our clothes, tiny strands of fabric come off and get washed away with the water,” Cashmere High School Year 10 student Millie Palmer said. 

“If we could stop these microplastics from ever leaving our washing machines, then we would be doing both the environment and ourselves a huge favour. If everyone had these cartridges (filters), millions of microplastics will be prevented from reaching the water cycle.” 

Taking water samples from her local stream, Millie added equal amounts of microplastics to each sample and experimented with five different filter materials - natural wool, processed wool, bamboo cloth, woodchip cloth and coconut husk.

She discovered that wool performed best as it filtered 100 percent of the microplastics, confirming her hypothesis. 

Her efforts have won her the Wrybill Trophy, an annual science prize for school students across Canterbury named after the bird with a distinctive bent beak that is found only around braided rivers in the South Island. 

Our next wicked problem

The Wrybill Awards is backed by us and has been running since 1996.

To win the top trophy, students must exhibit outstanding projects on environmental themes relating to the Council’s portfolios or work streams, particularly around how we look after our natural resources while offering innovative solutions. 

Winners from local science fairs present their projects to a panel including Canterbury Regional Councillors, Environment Canterbury staff and an external judge. 

This year’s external judge, Lincoln University Professor Jon Hickford, said it was a tough decision, however, Millie took out the award for her work on microplastics, which he described as our “next wicked problem”.

What are microplastics?

“Microplastics have been found in the highest mountains and deepest oceans - it’s an emerging problem we’re only beginning to understand. Seventy-five percent of fish have been found to have microplastics in them, 500,000 tonnes of microplastics found in textiles enter the global marine environment each year, and we eat on average five grams of microplastics a week - the weight of a credit card,” Millie said.

“Over the past five years, microplastic filtration has begun to develop. However, no products I came across used sustainable filter materials.” 

Young scientists impress with their innovations 

The science fair presentations

The science fair presentations

Prof Hickford was “blown away” with the quality of the presentations and was impressed to see how Wakanui School students Mitchell Digby and Jack Bennet used technology for their experiment on finding the best bait to catch possums. 

He also admired the “great science” and chemistry involved in Cashmere High School student Charlie Caddilac’s project on how allelochemicals affect seed germination, and Selwyn House School student Holly Fraser’s experiment on safer weed sprays.

Environment Canterbury Chair Peter Scott said running the awards was a team effort, with teachers and parents providing support for students, along with the commitment of Councillors and staff who assisted with judging.

“But the real stars are the young people. They show so much initiative and, once they get going, their passion for the environment and enthusiasm is infectious.

“It’s such a positive thing for Environment Canterbury to be involved in, supporting and inspiring young people as they find solutions to problems our generation has caused. 

“We’ve had some interesting people at these awards over the years and it’s fascinating to see where they pop up again in the future,” he said. 

2022 Science Fair winners from Canterbury/Westland (L-R): Charlie Caddilac, Holly Fraser, Alex Withell and Millie Palmer

2022 Science Fair winners from Canterbury/Westland (L-R): Charlie Caddilac, Holly Fraser, Alex Withell and Millie Palmer

2022 Science Fair winners


  • Junior: Holly Fraser, year 7, Selwyn House School with ‘Spray Away’
  • Senior (1st equal): Millie Palmer, year 10, Cashmere High School with ‘Microplastics, Macro problem’
  • Senior (1st equal): Charlie Caddilac, year 11, Cashmere High School with ‘The Effects of Allelochemicals on Seed Germination’

Timaru/South Canterbury

  • Junior: Mitchell Digby and Jack Bennet, Wakanui School with ‘Project Possum’