Kiwis might think by recycling they are doing a good thing for the environment - but a new study suggests New Zealand's plastic waste could be "poisoning" Indonesian villages.
Indonesia has become New Zealand's top dumping ground for plastic recycling, with exports there doubling between 2017 and 2018, from just under 6000 tonnes to over 12,000.
The jump came after China - previously the top recipient - imposed a ban on waste imports to the mainland at the start of 2017.
Overall plastic waste imports to Indonesia have doubled since then, with the majority coming from Australia, Canada, Ireland, Italy, the United Kingdom, the United States and New Zealand.
While Kiwis might believe they are helping the environment by sorting their plastic, due to the sheer amounts and contamination - dirty plastic or plastic mixed with paper - much of it could not be recycled properly.
Prigi Arisandi, of local environmental organisation Ecoton, said consequently a lot of it ended up being stockpiled or used as fuel in tofu boilers.
In his village of Bangun, plastic waste was ending up polluting the Brantas River, and was burned to reduce the sheer volume of trash clogging streets and piling up around houses.
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In another village, Tropodo, plastic waste was used as a cheap fuel in local tofu factories. Arisandi said plastic was about 70 per cent cheaper than alternatives like wood.
While it was difficult to pinpoint exactly where the plastic originated, Arisandi had evidence of shipments arriving from New Zealand and had found New Zealand plastic waste in his village.
In September, Indonesia sent hundreds of containers of contaminated plastic back to where they came from, including five to New Zealand.
Now a study by environmental groups the International Pollutants Elimination Network (IPEN), Arnika, and Ecoton and the Nexus3 Foundation based in Indonesia has found dangerously high levels of toxins entering the food chain near those international junkyards.
Researchers collected free-range chicken eggs - the best indicators of toxins entering the food chain - at sites in the villages of Bangun and Tropodo to test for organic pollutants.
Near a tofu factory, tests found eating one egg would exceed the European Food Safety Authority (EFSA) tolerable daily intake for chlorinated dioxins 70 times over.
Researchers said this was the second-highest level of dioxins in eggs ever measured in Asia - behind only an area of Vietnam contaminated by Agent Orange, considered one of the most dioxin-contaminated locations on Earth.
Dioxin exposure was linked to a variety of serious illnesses in humans, including cardiovascular disease, cancer, diabetes, and endometriosis.
"These stark findings illustrate the dangers of plastics for human health and should move policymakers to ban plastic waste combustion, address environmental contamination, and rigorously control imports," said Lee Bell, an adviser to the IPEN and a co-author of the report.
"It is a new colonisation"
Plastic scrap entered these areas through recycling imports, including paper scrap shipments.
Researchers found over the past three years plastic scrap bundled inside the paper stocks had skyrocketed from below 10 per cent to 60 to 70 per cent, indicating that paper scrap was being used to conceal plastic waste dumping.
According to the International Pollutants Elimination Network, paper waste exported from New Zealand to East Java jumped from 6736 tonnes in 2014 to 18,943 tonnes by 2018 - a 281 per cent increase.
Customs NZ was unable to provide its own paper recycling data to the Herald on deadline.
Along with New Zealand, the report listed Australia, Canada, Ireland, Italy, the UK and the US as the main contributors.
"Our communities that are being choked by plastic are being poisoned by it, too," Arisandi said.
"Plastic waste dumping needs to end everywhere. Otherwise we will see the same polluting nations find ways to dump their plastic waste on poor communities in other countries."
He said he'd written to the New Zealand Government in May this year to address the issue, but received no response.
"It is a new colonisation."
Greenpeace New Zealand campaigner Jessica Desmond said it was "deeply disturbing" to see New Zealand playing a part in the toxification of food in Indonesia.
"The Government must do more than just divert waste from landfill, it must dramatically reduce our use of disposable plastics such as Coke bottles."
A spokeswoman for the Ministry for the Environment said there was a legitimate plastic waste import industry in Indonesia, as long as the materials were of a high standard.
New Zealand companies needed to obtain permits from countries to export plastic for recycling, and it was up to them to follow local laws and regulations.
"It would be disappointing if this were not the case."
Exports of plastic waste must meet the domestic regulations of the importing country, and the requirements of the Basel Convention - an international treaty on hazardous and other waste products.
The spokeswoman said none of the containers of contaminated waste returned from Indonesia had yet arrived in New Zealand.
They had also not yet received information about the volume nor level of contamination of the plastic.
In May, New Zealand and more than 180 countries agreed to better regulate the global trade in plastic waste earlier, amending the Basel Convention to require exporters of contaminated or hard-to-recycle plastic waste to gain consent from receiving countries before shipping.
The aim was to incentivise trade in high-quality, clean, sorted materials that could be recycled, reducing the chance of recyclables sent off shore ending up as badly managed waste polluting the environment.
The amendment would come into force on January 1, 2021.
Indonesia's Ministry of Environment and Forestry had not responded to the Herald by deadline.
A spokeswoman told Australia's ABC that burning of plastic was banned, and that the Government "will not tolerate imported waste".
New Zealand's plastic recycling exports
According to Customs data, New Zealand exported over 12,000 tonnes to Indonesia in 2018, and over 8300 tonnes from January 1 to September this year. The second highest recipient was Malaysia, receiving 7400 tonnes last year and 7700 tonnes to September.
Since 2014 the total amount of plastic waste exported from New Zealand has been decreasing, from 45,253 tonnes in 2014 to a high of 48,813 tonnes in 2016 - just before China closed its doors - down to 31,616 tonnes last year.
To September this year 23,098 tonnes had been exported.
After China banned imports of plastic waste, large amounts were stockpiled across New Zealand , prompting the Government to initiate a range of domestic recycling measures.