Using bottles to track the movement of litter

Reducing litter through education

The NSW Premier made it a personal Premier’s Priority to engage in ‘Keeping our Environment Clean’, with a target to reduce the volume of litter by 40% from 2013-14 to 2020. NSW achieved a 43% reduction in litter volume, compared to 19% nationally.

This project let the bottles tell the story of:

  • why litter is an important environmental issue
  • why people should put their rubbish in the bin
  • how litter travels once it reaches waterways
  • how litter can linger in precious mangroves, harbours and rivers.

Watch here to see what happened.

Launch locations and results

The bottle launch locations were selected in consultation with Office of Environment and Heritage coastal scientists.

Canada Bay, Sydney
The bottles bounced around the Bay for 2 weeks before travelling across the harbour to Balls Head Reserve, Milsons Point and Neutral Bay, with some even reaching the Northern Beaches.

Wagga Wagga
Released at Wilks Park in Wagga Wagga, these bottles travelled out of the township and along Murrumbidgee River, with 2 ending up in areas adjacent to farmland.

Vaucluse, Sydney
Bottles released in Vaucluse and Rose Bay tracked around the bays before crossing the harbour, with 1 bottle washing up near Taronga Zoo. Two others settled in Manly, where 1 was picked up by clean-up services and taken to the tip in Terry Hills. Another bottle was pushed by storms out of the harbour and travelled over 45 km before ending up in Cronulla.

Bottles launched at William Park Reserve proved that if you leave your litter here, it will stay. These bottles remained close by, becoming trapped in the mangroves on the riverbanks.

Cooks River, Sydney
Bottles released in Cooks River went up and down the river with the tides. Some travelled as far as Canterbury, while others got stuck in mangroves. One bottle made its way into Botany Bay before heading towards Georges River in the south.

Central Coast and Newcastle
On the Central Coast, the bottles were released in Erina Creek and Empire Bay. In Empire Bay, the bottles bobbed around the waterway. One bottle swiftly headed into Broken Bay. It travelled out to Palm Beach before doing a u-turn to head north and wash up on Soldiers Beach near Norah Head where a local lifeguard found it.

The bottle released in Erina Creek stayed near where it was released.

In Newcastle, the bottle bobbed around the banks of Throsby Creek before making its way to Styx Creek.

Parramatta, Sydney
In Parramatta, the bottles showed that mangroves, which support a delicate ecosystem, are also a magnet for rubbish with several bottles becoming trapped in the vegetation along the riverbank. Two bottles travelled from the ferry terminal to Putney before ending up in the bay at Rhodes.

Bottles travelled downstream along Hawkesbury River, past Pitt Town. One bottle travelled as far as Wisemans Ferry. Other bottles reached Leets Vale, Cumberland Reach and Cattai National Park.

Why the bottles were released

The CSIRO found that around 75% of marine debris in Sydney Harbour, on its surrounding beaches and in rivers, is plastic and comes from local sources.. (Commonwealth of Australia: Threat of marine plastic pollution in Australia - An inquiry into the threat of marine plastic pollution in Australia and Australian waters:

Cockle Bay and Darling Harbour were the worst locations in the Sydney maritime area with 2,456 pieces of rubbish per 1,000 square metres being recorded. That statistic did not include litter below the water’s surface.

Tracking the bottles’ movement

The bottles were tracked daily through their GPS systems and updates were shared on the Facebook page so everyone could see what was happening to each bottle.

Ensuring the bottles did not harm wildlife or become litter

  • The size and shape of each plastic bottle was considered to ensure it would not harm wildlife.
  • Each bottle was fitted with a GPS tracker to ensure the EPA always knew its location (within 2 metres), and so it could be collected.
  • The GPS trackers provided updates on their location approximately every 2 hours.
  • GEO fences (virtual barriers) were established to trigger an alert if the bottles travelled outside a specified area. This ensured the EPA was alerted before the bottles reached areas that made them difficult to retrieve.