The reality that plastic debris ‘breaks up’ into smaller pieces and enters the food chain without ever breaking down was a hot topic at a recent forum on emerging issues in waterway health.

Wet Tropics Waterways hosted the Cairns forum which featured microplastics specialist Dr Michelle Blewitt and ranged in topics from plastic pollution and PFAS to climate change and aquatic pests.

Dr Blewitt said plastic pollution was so prevalent that it was entering the food chain, with the average person ingesting an estimated credit card-sized amount of plastic each week.

“Every piece of plastic that has ever been made is still on this earth, and it’s getting into our food and water,”  Dr Blewitt said.

The main sources of plastic that breaks up into microplastics (pieces less than 5mm in size), are:

• Drink litter – disposable cups, lids, straws etc (38%)
• Tyre dust (14%)
• Fugitive waste from manufacturing and recycling facilities (10%)
• Maritime waste (5%)
• Plastic bags (4%)
• Cigarette butts (3%)
• Microbeads – washing detergents and scrubs (2%)

Forum delegates heard it was too early to know the biological impacts of microplastics and PFAS on ecosystems in the Wet Tropics and around the world.

PFAS specialist Dr Karl Bowles said concerns had been raised since the early 2000s about PFAS, or poly-fluoroalkyl substances, which are a group of synthetic chemicals used in industrial and household products for their flame-retardant and water-resistant properties.

Dr Bowles said research had revealed their potential to bioaccumulate in human and animals and in the Wet Tropics their movement after floods posed a potential threat to the Great Barrier Reef.

Like microplastics, PFAS never fully break down, but become a permanent part of our ecosystems and food chains.

The Wet Tropics’ first Emerging Issues in Waterways Health Forum also heard from Special Envoy for the Great Barrier Reef, MP Warren Entsch, who opened the event, Dr Christoph Braun on PFAS, Prof. Steve Turton and Prof. Jonathan Nott on climate change and Dr Brendan Ebner and Travis Sydes on aquatic biosecurity.

Professor Turton said the Wet Tropics Report Card, released by Wet Tropics Waterways each year, assessed runoff of nutrients, pesticides and sediments.

“These emerging issues (microplastics, PFAS) don’t get picked up yet and may need to be monitored as part of future report cards,’’ he said.

“We must be vigilant about emerging issues that could affect our waterways flowing into the Great Barrier Reef lagoon.  These are global issues and we are only just realising their potential threats to our ecosystems. We don’t yet know how these things will affect our rivers, estuaries and coral reefs.

“This forum will start examining how these issues might affect our biodiversity. The Wet Tropics is a good place to start doing this because we are a global biodiversity hotspot, with significant natural assets that are the backbone of our regional economy. Any threats to our biodiversity and natural environment are a problem that we need to manage.”

The Emerging Issues on Waterway Health Forum was sponsored by LSC Recycling and Rehab, Cairns Regional Council, Canegrowers, CQUniversity and RPS Group.