Fish in Indonesia are eating plastic from used nappies, passing the toxic fibres up the food chain to humans, a new study into the country's rampant waste problem warns.

A staggering 80 per cent of fish examined by scientists were found to have ingested tiny plastic fibres from disposable diapers, including two species eaten by locals.

Half a metric ton of nappies are dumped into the River Brantas – the longest river in Indonesia's East Java province – every year, researchers found.

They said used diapers quickly break down in the sun into microscopic pieces that are easily swallowed by fish and later transferred to humans.

Even those who don't eat fish are at risk from the pollution, with experts warning diapers dumped in the Brantas 'contaminate' drinking water with plastic, putting the health of an additional 3 million people in Surabaya at risk.

Four of Indonesia's rivers, including the Brantas, are ranked among the 20 most polluted in the world, with the country dumping 200,000 tonnes of plastic into the world's oceans every year.

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Fish in Indonesia are eating plastic from used nappies. A staggering 80 per cent of fish examined were found to have ingested plastic from disposable diapers. Pictured is a microscopic image of one fish's stomach, with diaper fibres highlighted

Experts at environmental group Ecological Observation and Wetlands Conservation (Ecoton), examined waste collected at a single Brantas sluice gate.

The sliding gates are used to control water flow, and are often clogged by large pieces of floating debris.

Following 30 clean-ups at the sluice gate over the course of 12 months, researchers estimated how much waste is dumped into the river Brantas each year.

Researchers also caught members of 21 species of fish at the sluice gate and examined the contents of their stomach.

Plastic fibers from disposable diapers were found in the stomachs of several types of fish, including those known locally as rengkik, nila, keting, bader putih and jendil.

Andreas Agus, a researcher at the group, said residents at the nearby city of Surabaya commonly ate keting and rengking fish.

Four of Indonesia's rivers are ranked among the 20 most polluted in the world, with the country dumping an estimated 200,000 tonnes of plastic into the world's oceans every year. Pictured is a scavenger paddling through the River Sentiong in the country's capital, Jakarta

His team found plastic fibers in 80 per cent of the fish they examined.

Ecoton executive Prigi Arisandi said: 'When disposable diapers are immersed in water and exposed to sunshine, over time they break down into smaller pieces.

'The fish swallow the pieces, which can be transferred from the stomach to the meat. When people eat the fish, the plastic will be transferred to their bodies.'

Other solid wastes had 'contaminated' the water with plastic, Ecoton said, putting the health of 3 million tap water customers in Surabaya at risk.

The group urged the officials to protect Indonesia's rivers from solid waste, particularly disposable diapers.

HOW SEVERE IS INDONESIA'S PLASTIC WASTE PROBLEM? Four of Indonesia's rivers rank among the 20 most polluted in the world. Plastic waste in Indonesia's Ciliwung River This means the country is the second-largest contributor to marine plastic pollution after China. An estimated 200,000 tonnes of plastic flows into the world's oceans from Indonesia's rivers every year, mainly from Java and Sumatra. As well as ocean pollution levels, the country's plastic problem also affects its residents. Microplastic produced by the break-down of larger pieces of waste are ingested by fish, and later passed up the food chain to humans. Trash Free Seas Alliance (TFSA), a United States NGO, revealed in December 2017 that microplastics had been found in 28 per cent of fish in Indonesia's markets. Advertisement

Ecoton also called on the public to switch to reusable cloth diapers to cut waste.

'Consumers must change their behaviour, the more comfortable a product makes us, the more threatening it is to our lives,' Mr Agus said.

An East Java authority spokesperson said local mayors had been asked to establish more waste storage facilities and instruct residents not to dump waste into rivers.

Trash Free Seas Alliance (TFSA), a United States NGO, revealed in December that micro plastics had been found in 28 per cent of fish in Indonesia's markets.

The micro-plastics come from plastic waste that enters rivers and ends up in the sea.

Half a metric ton of nappies are dumped into the River Brantas - the longest river in Indonesia's East Java province - every year