Plastic river: Following the waste that’s choking the Chao Phraya

From the heart of Thailand to Bangkok and the sea, one of the country’s most important rivers is inundated with plastic

The rivers that feed the Chao Phraya are born from mountain streams in northern Thailand, flowing hundreds of kilometres south to the sea. By the time it travels through Bangkok and empties into the Gulf of Thailand, the Chao Phraya is carrying huge quantities of plastic waste – an estimated 4,000 tonnes each year. The plastic clogs the river along its course, drastically impacting communities and the waterway’s ecology.

China Dialogue’s sister site The Third Pole travelled from the Chao Phraya’s beginnings to the sea to explore what’s happening to one of Southeast Asia’s most important rivers.

The upper reaches

rows of agricultural fields on the bank of winding river
The Chao Phraya’s upper reaches are relatively rural, its banks lined with villages and paddy fields (Image: Mailee Osten-Tan / The Third Pole)
catfish peeking out of shallow murky water
The river is home to 190 native fish species, including several types of catfish. But the Chao Phraya giant catfish is now thought to be extinct here, surviving only in the Mekong. (Image: Mailee Osten-Tan / The Third Pole)
plastic waste among low plants near river bank
The Chao Phraya’s plastic problem is clear to see even in these upper reaches. One of the main causes is single-use plastics such as water bottles and plastic bags. (Image: Mailee Osten-Tan / The Third Pole)

The Chao Phraya starts at the confluence of the Ping and Nan rivers, which meet in Nakhon Sawan province in the heart of Thailand. Although the river’s waters have already travelled half of the country’s length by this point, it is still relatively clean, flanked by villages and farms.

The surrounding land is ideal for growing rice thanks to the river’s annual floods, which come with the monsoon from May to October and provide an ample supply of water and nutrients. In 2012, around 45% of land in the Chao Phraya river basin was used for rice farming. Fruit orchards are also common.

But plastics already make an appearance up here. The farms themselves are one indirect source – the material is used extensively in agriculture across Thailand.

rows of seedlings planted in sacks under a closed greenhouse
At Riche organic farm in Chai Nat province, vegetables are grown in plastic sacks inside greenhouses made from plastic sheeting (Image: Mailee Osten-Tan / The Third Pole)
mango enclosed in plastic bag growing on tree
In a nearby mango orchard, plastic bags are tied around the fruit to protect them from pests. Once the fruit is harvested, the bags are usually thrown away. (Image: Mailee Osten-Tan / The Third Pole)
old plastic containers near paddy field
Old plastic containers, which may have once held pesticides, are left next to a paddy field (Image: Mailee Osten-Tan / The Third Pole)

Floods bring plastic to ancient capital

The floods that bring water and nutrients to crops along the Chao Phraya also draw plastic into the river.

South of Nakhon Sawan, the Chao Phraya flows through the ancient city of Ayutthaya, which was the capital of Thailand until 1767. Built at the point where two other rivers join the Chao Phraya, the city is crisscrossed with canals, and traditional ways of life here are closely connected to the water. Seasonal flooding is expected, with homes along the waterways built on stilts to accommodate the higher water levels. But climate change and a range of other factors is intensifying rainfall, and severe flooding is a growing problem in the city.

Ratimaporn Pakorn is a 23-year-old boat driver in Ayutthaya. Her home was flooded in 2021 after unusually heavy rainfall. “The area floods nearly every year, but the extent of it varies. Last year, the water came all the way up to my calves,” she recalls.

woman at wheel of boat on water
Ratimaporn Pakorn drives her family’s boat on the Chao Phraya at Ayutthaya. Behind her a tug pulls a barge loaded with sand. Sand is extracted at numerous points along the river, which could be reducing the watershed’s capacity to absorb floodwaters. (Image: Mailee Osten-Tan / The Third Pole)
old tyres in front of house at edge of river
Many of the houses that line Ayutthaya’s waterways are built on stilts to accommodate regular flooding. This household appears to have shored up its defences using old tyres. (Image: Mailee Osten-Tan / The Third Pole)
plastic caught in fallen branched hanging over murky water
Last year’s floods picked up agricultural plastics from the fields around the city, as well as plastic bags, bottles and other urban waste. When the water receded, plastics were left stuck high up in tree branches. (Image: Mailee Osten-Tan / The Third Pole)

As a UNESCO World Heritage Site, the ancient capital attracts tourists from around the globe, many of whom take boat tours to view its famous temples. Ratimaporn relies on these tourists to make a living.

“It’s dirty,” says Ratimaporn, noting that plastic can be seen floating in the river, where it often clogs her propellers. She worries that this will impact tourists’ perceptions of the city.

person in small boat on river
For those involved in tourism in Ayutthaya, the pollution of the city’s many waterways is a blight. “The tourists really do look at the plastic debris along the river. It’s dirty for them,” says boat driver Ratimaporn. (Image: Mailee Osten-Tan / The Third Pole)
plastic sandbags embedded in mud at river's edge
Plastic sandbags left along the banks of the Chao Phraya following last year’s floods. Weathered by the elements, sandbags like these disintegrate into microplastics, which are a threat to aquatic life. (Image: Mailee Osten-Tan / The Third Pole)
plastic waste caught in water hyacinth
Water hyacinth is an invasive species on the Chao Phraya and can cause problems, blocking routes and reducing oxygen in the water. It also traps plastic waste, causing unsightly garbage floats. (Image: Mailee Osten-Tan / The Third Pole)

Plastic-clogged canals

As the Chao Phraya snakes through densely populated central Thailand and on to the country’s modern-day capital, Bangkok, it’s often treated as a catch-all waste disposal unit.

Much like Ayutthaya, Bangkok grew from a settlement built on canals that borrowed the waters of the Chao Phraya to form convenient transport routes. These canals, known as khlongs in Thai, remain a significant feature in today’s megacity, which has over a thousand, lined with settlements and home to over 23,500 mainly low-income households. Many are choked with plastic.

Sira Leepipattanawit is a community leader who grew up on the Bangkok Yai canal.

Video: Mailee Osten-Tan / The Third Pole

Many of the communities along Bangkok’s canals are hard to reach by road, making it difficult to access municipal services. Throwing waste directly into the water is an old habit. Although this is now officially illegal, and people could be fined, Sira explains that it’s almost impossible to identify the culprits. Houses are often situated directly above the water, and residents “can easily open their window and plop their trash bag into the water when no one’s looking – at night, for example”, he says.

This used to just be an easy way to deal with household waste. But in the old days, this waste was organic. Today, everyday items come wrapped in plastic – not just in Bangkok, but all over Thailand.

person shredding jackfruit placed on banana leaves
At a street market in Uthai Thani province just south of where the Chao Phraya River starts, a seller uses banana leaves – the traditional material used to package food in Thailand – to display her jackfruit (Image: Mailee Osten-Tan / The Third Pole)
monk on river boat accepting parcel from man on dock
Nearby, a riverside resident offers alms to a monk. Even this traditional practice now comes with single-use plastic bags. (Image: Mailee Osten-Tan / The Third Pole)
stall in covered market
This stall in a covered market in Ayutthaya sells single-use plastic cups and food boxes in bulk (Image: Mailee Osten-Tan / The Third Pole)
food being scooped into plastic bag
Takeaway street food, which many Thais eat daily, is now nearly always served in plastic (Image: Mailee Osten-Tan / The Third Pole)
overflowing outdoor bin
Once used, the plastic bags and food boxes are discarded, causing a huge waste-management problem (Image: Mailee Osten-Tan / The Third Pole)

On a Monday afternoon on the Bangkok Yai canal, tourists cruise around on long-tail boats while children swim among old flip-flops and polystyrene fragments. Still, the water here is at least relatively clean. On the other side of the city, at the Lat Phrao canal, the scene is different. The water has a tar-like consistency and a putrid stench envelops the whole area.

“It’s from the wastewater and all the junk,” explains Samnieng Bonlu, a 66-year-old resident who has lived on the Lat Phrao for most of his life. Notoriously polluted, the canal was built to help drain rainwater away from the city into the Chao Phraya. Over its 31-kilometre length, the canal is home to over 7,000 low-income households.

man standing in front of piles of waste
Long-time Lat Phrao resident Samnieng Bonlu has seen his canal become increasingly polluted over the years. “Before, people would just use banana leaves and metal bento boxes… But now it’s all plastic.” (Image: Mailee Osten-Tan / The Third Pole)
houses on polluted canal
Residents use the canal as a convenient rubbish dump. Unless it’s removed, this waste either sinks to the bottom of the canal, or flows out into the Chao Phraya. (Image: Mailee Osten-Tan / The Third Pole)

Samnieng recalls that the area used to be mainly paddy fields, but as the urban population sprawled, it turned into a popular area for rural migrants to gain a foothold in Bangkok. 

“I’ve seen a change in the way of life, with more housing along the river as people move in, and with people using more plastic,” says Samnieng.

Clean-up attempts

Samnieng now works with the TerraCycle Global Foundation, a project of the recycling company TerraCycle that aims to capture plastic waste along rivers and canals before it flows into the ocean. The foundation’s Lat Phrao clean-up project started in July 2020.

people scooping waste trapped on surface of water onto boat
In 2020, TerraCycle installed two metal cages on the Lat Phrao canal to catch waste before it reaches the Chao Phraya. Once caught, it’s easier for the team to manually scoop the waste from the water. (Image: Mailee Osten-Tan / The Third Pole)
severely litered water clogged with waste
Over the past two years, the team have collected about a tonne of waste every day. “What stands out for me is that the amount of trash has not decreased,” says Samnieng. “This goes to show that people’s mindsets remain the same.” (Image: Mailee Osten-Tan / The Third Pole)
people in boat collecting waste from man on balcony of canal house
TerraCycle’s presence on the canal is, however, raising awareness. Many canalside residents now collect recyclable waste for the team to pick up instead of throwing it into the water. (Image: Mailee Osten-Tan / The Third Pole)
man sitting on boat carrying baskets of plastic waste
Once collected, the waste is taken back to TerraCycle’s base for drying and sorting. As much plastic as possible is extracted to be recycled into reusable pellets. (Image: Mailee Osten-Tan / The Third Pole)

Mangroves and marine life

Mangroves grow along the last stretch of the Chao Phraya, perfectly adapted to the brackish water where the river meets the sea. At the mouth of the Chao Phraya, the muddy mangrove forests of Samut Prakan province are covered in plastic, a testament to how much waste the river is carrying.

plastic bags caught in mangrove trees
As the tide recedes at the mouth of the Chao Phraya, residents wade into the muddy water in search of shrimp. Plastic bags can be seen caught in the mangroves around them. (Image: Mailee Osten-Tan / The Third Pole)
plastic waste among mangrove roots
The tangled roots and mud of the mangrove forests in Samut Prakan trap large amounts of plastic waste carried by the river. By this stage, a lot of the waste has already been broken down into microplastics. (Image: Mailee Osten-Tan / The Third Pole)
people pouring clear liquid onto pile of burning matter
The poor provision of waste-management services in many areas means that local people often get rid of their trash by burning it, releasing toxic fumes that are harmful to health (Image: Mailee Osten-Tan / The Third Pole)
monkey among branches
A monkey watches the humans invading its forest. The mangroves of Samut Prakan are full of monkeys, who enjoy a dip when the tide is high. These coastal ecosystems are rich in biodiversity and an important carbon store. (Image: Mailee Osten-Tan / The Third Pole)

What waste does not get caught by the twisted roots of the mangroves is funneled out into the Gulf of Thailand.

Rivers are an important contributor to plastic waste in the world’s oceans, says Suchana Chavanich, a professor with the Department of Marine Science at Chulalongkorn University in Bangkok. “We estimate about one to two million tonnes of the plastic waste ending up in the ocean is from rivers,” she says. The situation is particularly bad in Asia, which is home to the world’s “top 20 polluting rivers”.

This is having a major impact on marine life, with animals not only becoming entangled in debris, but also mistaking items like plastic bags for food. 

In 2018, a pilot whale was found dead in southern Thailand after it swallowed 80 plastic bags, leaving it unable to eat.

Suchana explains that animals like sharks and sea turtles are “top predators that control the marine ecosystem. If their population declines, and they die because of plastic waste consumption, it impacts the health of the ecosystem.”

Video: Mailee Osten-Tan / The Third Pole

The big problem with microplastics

By the time the Chao Phraya reaches the sea, a lot of the plastic waste it’s carrying is too small to see, having been broken down into microplastics (defined as pieces smaller than five millimetres).

Research has found that microplastics harm the health of mangrove ecosystems by hindering gas exchange and releasing harmful chemicals. They are also entering aquatic food chains, not to mention our own bodies. “Scientists have found that we can [consume] microplastics through the food that we eat, the water that we drink, and the air that we breathe,” says Suchana.

people carrying plastic basket
This fish farm in Ang Thong province, opposite Thailand’s only viscose factory, raises red tilapia. Aquaculture is common on the Chao Phraya, and another source of plastic pollution both big and small. Exposed to the elements, the plastic nets and floats used on the farms slowly disintegrate, releasing microplastics into the water. (Image: Mailee Osten-Tan / The Third Pole)
clothes hanging over water from balcony of riverside house
Many people living along the Chao Phraya use the river’s waters to wash their clothes. The washing of synthetic fibres such as polyester and nylon releases microfibres, a pervasive type of microplastic that escapes even when wastewater is treated. (Image: Mailee Osten-Tan / The Third Pole)
fresh prawns on banana leaf
Freshly caught giant river prawns for sale at a market in Uthai Thani province. Grilled on a bed of charcoal, these prawns are a popular dish associated with the Chao Phraya. A recent study on farmed specimens of the species found significant amounts of microplastics in their guts. (Image: Mailee Osten-Tan / The Third Pole)
threads on filter paper in small glass container held by gloved hands
Suchana Chavanich explains that microplastics are usually much smaller than these fragments. Inadvertently consumed by animals, they are entering the food chain – some are excreted, but some accumulate in tissue. The impact of this contamination is yet to be fully understood. (Image: Mailee Osten-Tan / The Third Pole)

Microplastics have even been found in human blood. The impact on humans is still a relatively new area of research that requires time to establish causal links. But already, studies are showing that the consumption of seafood that contains microplastics can have implications for our health.

Roadmaps to preventing plastic pollution?

In 2019, the Thai Ministry of Natural Resources and Environment released the Roadmap on Plastic Waste Management (2018-2030). The plan outlines targets for various agencies to reduce plastic waste, including a proposed ban on four types of single-use plastic by 2022: lightweight plastic bags, polystyrene food containers, plastic cups and plastic straws. However, the Covid-19 pandemic interfered with the achievement of these targets and reportedly triggered a rise in plastic use.

person reaching into basket of waste
A staff member at TerraCycle’s base in Bangkok sorts through waste collected from the Lat Phrao canal to pick out recyclable plastics. Removing waste before it reaches the sea can reduce some of the Chao Phraya’s impact on marine plastic pollution. (Image: Mailee Osten-Tan / The Third Pole)
baskets of waste on ground
Once sorted, the recyclable waste is press packed and sent to a recycling facility where it is turned into plastic pellets that can be used to make items such as chairs and bottles. Recycling plastic reduces its quality, and so can only be repeated a few times without adding virgin plastic. (Image: Mailee Osten-Tan / The Third Pole)
Waste being tossed into incinerator
Waste that cannot be recycled is incinerated on site, keeping it from being sent to landfill. Despite TerraCycle’s valiant efforts, solving Thailand’s plastic problem will require more than just proper waste management. Reducing use has to come first. (Image: Mailee Osten-Tan / The Third Pole)

In 2021, the Department of Marine and Coastal Resources announced a collaboration with non-profit The Ocean Cleanup to tackle riverine plastic pollution in the Chao Phraya. The project includes deploying a vessel known as the Interceptor to collect plastic debris, as well as monitoring the flow of plastic waste through bottle-tagging and placing cameras on bridges along the river.

“[Through this research], we can gain an accurate measure of how much [plastic] waste is passing through the river,” says Suchana. “Hopefully this data will be very useful for further management in this area.”

Though the Thai government and non-government organisations are trying to better manage plastic waste in the rivers and oceans, Suchana stresses that the best solution is to prevent plastic from getting into waterways in the first place.

child on river holding up plastic bottle
Children play in the waters of the Bangkok Yai canal. Community leader Sira Leepipattanawit works with young people to raise awareness of plastic waste and help clean up the city’s waterways. For him, children bring hope that the future will be different. “No one wants to grow up to be part of a social problem,” he says. (Image: Mailee Osten-Tan / The Third Pole)

“When plastic waste goes from the river into the ocean… it takes [up to] 500 to 600 years to decompose. So you can see that once it gets there, it will stay there almost forever,” Suchana says.

For Sira Leepipattanawit from the Bangkok Yai canal, “This is a problem for humanity, not just waterside communities. It is a problem for all lives that starts with us humans.”

This article is a collaboration between The Third Pole and the China Environment Forum’s Turning the Tide on Plastic Waste in Asia initiative. It is also available on the Wilson Center’s New Security Beat blog

(Cover illustration: Neutron T. / The Third Pole)