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  • The Mekong River is an important Southeast Asian waterway. Its basin is home to an estimated 65 million people.  All are now confronted by the problems of plastic waste and microplastic contamination.
  • Waste in the Mekong is largely due to poor waste management by riverine communities. Although it includes plastic materials from China, this material may well have been discarded locally. Chinese products are popular in Laos and Myanmar.  There are also an abundance of discarded containers from Thailand and neighbouring Myanmar.
  • Microplastic contamination can now be found along the entire length of the river.  Reaching the Mekong Delta, it enters the ocean.  Bordering countries are increasingly aware of the problem.


Amidst a global plastic waste crisis that is polluting our planet’s oceans, there is a widespread perception that superpowers such as China are exacerbating the problem by producing massive amounts of consumer products that are either made from, or packaged in, plastic.

Given the number of major Chinese rivers that flow into the ocean, it is also easy to assume that a high volume of plastic waste from the country is causing marine pollution.

This in-depth report examines the matter by exploring various aspects of the waste problem along the Mekong River, a 4,000 km waterway that originates in China and passes through 5 South East Asian countries: Myanmar, Laos, Thailand, Cambodia and Vietnam.

Plastic Problems in the ‘Mekong River’

Plastic waste in the Mekong at Chiang Saen, Chiang Rai, in Sep 2022 | Source: The Glocal

‘The Mekong River’ is one of the world’s large rivers with a length of 4,909 km.  It passes through 6 countries including China, Myanmar, Laos, Thailand, Cambodia and Vietnam. Its basin covers a total of 759,000 square kilometres. It is estimated that the Mekong River Basin has a population of 65 million.  Right now, people living in the region are facing problems from plastic waste. 

The United Nations Environmental Programme’s (UNEP) CounterMEASURE Project, the first comprehensive study of plastic waste in the Mekong River, found microplastic contamination in water samples taken from 30 out of 33 survey locations.

The level of contamination was higher in the river’s lower reaches.  In samples collected near Phnom Penh, Cambodia, microplastic contamination was as high as 2.13 pieces/m3. Contamination was higher still at Can Tho, Vietnam, on the river delta.

In Thailand, the river’s deteriorating water quality has been frequently discussed, sometimes in response to developments.  In August 2015 a kilometer-long waste patch was found floating near the Chiang Khong and Chiang Saen Districts in Chiang Rai.  A dark red mud-like substance mixed with the debris caused nearby fish to die in large numbers.  Another event occurred in August of 2022 when a 15-meter waste patch killed fish reared in floating baskets and clogged a water pump raft belonging to villagers near Chiang Khan, Loei.

According to CounterMEASURE, Thailand’s stretch of the river also has microplastic contamination, mostly polypropylene (PP), which comes from food containers.  Moreover, it gets worse as one moves downstream.  Survey samples from Chiang Rai contain about 0.23 piece/m3.  Samples from Ubon Ratchathani are higher at about 0.38 piece/m3.  
The issue is not just water quality.  Recent studies of microplastic ingestion by local freshwater fish in the Chi River by Pattira Kasamesiri and Wipavee Thaimuangphol published in the International Journal of GEOMATE in Mar 2020 show how microplastic pollution contaminates our food chain as well.


River waste collected during a tourism sector research project

A participative plastic waste reduction programme, conducted as a part of a Mekong River tourism sector research project, collected samples from 5 locations in the Chiang Saen and Chiang Khong Districts in Chiang Rai.  In this upper reach of the river, they found polyethylene (PE), high density polyethylene (HDPE), low density polyethylene (LDPE), polypropylene (PP), polystyrene (PS), polyvinylchloride (PVC) and polyethylene terephthalate (PET), microplastics derived from deteriorating plastic bottles, plastic lids, bags, foam and other containers floating in the Mekong River.


Survey points and examples of microplastics in the Mekong Source: Pirika

The findings are in line with microplastic contamination data obtained by Pirika Inc, an environmental services company which surveyed water quality at six sites along the river.

Plastic waste in the Mekong near Chiang Saen, Chiang Rai in Sep 2022.  Source: The Glocal


During field research near Chiang Saen, Chiang Rai in Sep 2022, the Glocal found garbage patches of various sizes clustered around pontoons and piers.   Most of the waste was plastic - bottles, bags, and other items.

Local waste management of critical importance

Assistant Professor Panate Manomaivibool, PhD, from the research group, Circular Economy for Waste-Free Thailand (CEWT), Mae Fa Luang University | Source: The Glocal

To better understand plastic waste pollution in the Mekong, the Glocal interviewed Assistant Professor Panate Manomaivibool, PhD.   Prof. Panate is with the Circular Economy for Waste-Free Thailand (CEWT) research group at Mae Fa Luang University.  He is also the research head for a Mekong River participative plastic waste reduction programme.  Part of a tourism sector research project, the programme is supported by the National Research Council of Thailand (NRCT).

Prof. Panate began by explaining the CounterMEASURE study that was conducted by the UNEP with funding from the Japanese government.  It established 6 measurement points along the river at: Chiang Rai; Ubon Ratchathani; Vientiane; Tonlé Sap in Cambodia; Phnom Penh; and Can Tho at the river mouth in Vietnam). The cleanest location was in the upper reach of the river at Chiang Rai.  It had the lowest amount of waste, in part because of local waste management efforts.
According to Prof. Panate, Thailand’s waste management system is the best of all 6 riparian countries and its usage of river resources is also comparatively light.  Acknowledging that Chiang Rai and Ubon Ratchathani are not small cities, he pointed out that Vientiane and Phnom Penh are major population centres which necessarily made greater use of river resources.  As for the people of Tonlé Sap, he noted that they are largely water-based: living on rafts with no waste management system there is only one place for the waste to go - the river.

The survey also indicated that at least some of the waste found in Chiang Rai, Vientiane and Ubon Ratchathani originated in other countries whereas the waste in Phnom Penh, Tonle Sap and Can Tho was almost entirely domestic.

Prof. Panate believes that local management is of critical importance in addressing the problem.  He added that in Thailand, management was currently much better than that found in Myanmar and Laos.

“Even in larger cities like Lao’s Vientiane or Myanmar’s Tachileik, there’s a collection system but no decent post-collection disposal system. Sometimes they throw waste right into the river. That’s why the waste we find near Lao cities or Myanmar cities is often in black garbage bags.  In Thailand, it’s mostly smaller pieces thrown into the river by thoughtless people. As for Laos and Myanmar … we’re not sure if people throw the garbage bags into the river themselves or garbage collectors do.”

Asked whether the river carried Chinese waste into the region, Prof. Panate  replied that it depends upon what one meant by “waste from China” - waste that floated here from there or waste resulting from Chinese products imported into the region. Noting that without a tracking system, there is no way to ascertain the origins of river-borne waste, he further explained that labels indicating that products were made in China were also of no help as people in Myanmar, Laos and Thailand commonly consume Chinese products.

Acknowledging that Chinese waste might float into the Golden Triangle, he said that the plastic waste … most often found are plastic bottles from Myanmar. An indication of inadequate local management, their waste now contributes to trans-border pollution.
Thailand’s does too.  Data from one research project found lots of plastic waste with Thai labels in the Golden Triangle region, where Thai products are also commonly consumed.

‘Microplastic’ a small but worrisome type of international trash

Examples of microplastics found in the Mekong River Source: Pirika

Prof. Panate explained that in addition macroplastics, waste we can see with our naked eyes, there is the far more disturbing issue of microplastic contamination in the Mekong as it enters our food chain through fish in the river. Indeed, microplastic contamination ultimately spreads into the ocean.

“As for macroplastic, the Mekong River has dams in various points, so the chances of large pieces of garbage reaching Can Tho in Vietnam and entering the sea are small. But there is a good chance that microplastics will pass barriers and borders. [This type of pollution] enters the food chain; it turns up inside fishes. This is the real issue, but it’s more difficult to see.”

Riverine microplastic contamination is now found around the world. According to a Pirika researcher, this extends to countries known for strict environmental regulation like Japan.  In a survey of 100 waterways around the country, only two were found to be free of microplastics.  Both were high in the mountains.

“With respect to microplastics, even countries with adequate waste management have contamination issues. Sometimes it comes from types of waste we don’t normally consider like synthetic turfs. Some countries use a lot of fake grass.  After a time it gets worn down.  Where does it disappear to? Into the water. 

The problem is growing.  In 2017, the International Union for Conservation of Nature (IUCN) released a report on microplastics in streams, rivers, seas, and oceans. The study indicated an increase in microplastics of 0.8 – 2.5 million tonnes/year, 98% of which came from households and construction. The UNEP found that in New York alone, microplastics in local water resources were increasing by as much as 19 tonnes/year.

In a recent publication, Thailand’s National Bureau of Agricultural Commodity and Food Standards noted that microplastics in natural water sources may be the start of long-term ecosystem problems. One study found that microplastics sucked into mussels, filter-feeders, remained in the animal’s tissue for up to 48 days. Worse, the microplastics caused tissue damage. Another study found that microplastic decomposition produced toxins harmful to sea animals, such as PAHs, PCBs and PBDEs.  These substances can be passed through the food chain, eventually reaching humans. Mussels at a farm surveyed in Germany had up to 0.36 pieces/gram of microplastic contamination per consumable part of each mussel.  The result?  Eating 250 grams of mussel meat could result in over 90 bits of microplastic entering your body.  Given annual per capita consumption figures, this could amount to a total of 11,000 pieces per year.
Were this not bad enough, microplastics also hide unexpected dangers, acting as a medium for the transfer and accumulation of poisons such as DDT and other chemicals.  Due to their water holding capacity, microplastics absorb contaminated substances which they later spread to various water sources. 

Reducing plastic waste before it reaches the water
In an essay published in Scientific American in 2018, Christian Schmidt, a hydrogeologist at Helmholtz Center for Environmental Research in Leipzig, Germany, observed that rivers not only carry trash over long distances but also connect nearly all land surfaces with the oceans.  Because of this, rivers are fast becoming a major battleground in the fight against sea pollution.

“Better waste collection and management practices in the most polluted regions would help stem the tide,” Schmidt wrote, “but raising public awareness is also crucial.”

Taking stock of the huge number of rivers that flow into the ocean, the editorial team at Our World in Data in 2021 points out that focusing on just a few big rivers to stop plastic pollution is not enough. They recommend a global approach to manage and reduce waste so that it does not leak into the natural environment.

Many countries have started to push forward policies to solve plastic waste issues at their source. In January 2021, the European Union (EU) prohibited the export of unseparated plastic waste and non-recyclable plastic to non-OECD countries. The policy aims to place the burden of clean up on those who created the mess. It also encourages people everywhere to treat and reuse plastic waste.
The prohibition followed an earlier July 2019 EU directive to reduce single-use plastics.  It specifically targeted products that frequently turned up as trash on European beaches. The list included cotton buds, plastic plates, straws and stirrers, balloons and sticks for balloons, food containers, cups for beverages, beverage containers, cigarette butts, plastic bags, packets and wrappers, wet wipes and sanitary items.

Similar measures are being adopted elsewhere. In late 2017, China prohibited the import of plastic waste.  In early 2021, it also prohibited the use of single-use plastic straws and bags. Australia is looking to optimise recovery and recycling of packaging while Canada is promoting sustainable packaging in a bid to eliminate plastic waste by 2023.  Meanwhile in India, regulations have been imposed to promote the use of recyclable materials and raise awareness about separating garbage.
The danger posed by microplastics to the ecosystem has caused many countries to draft regulations to reduce and stop their use. The USA, Canada, New Zealand, Australia and the EU have all taken steps to limit their production and use. This includes constraints on the import and retailing of cosmetics and health products containing ‘micro-beads’ - a microplastic that does not readily breakdown.  Related industries have been obliged to find replacement materials like polylactic acid, which does decompose.

In Thailand, local government agencies and companies play a critical role in reducing plastic waste. Communities along the Mekong River are aware of the issue and have started to properly manage waste.  The Tha Sadet community in Nong Khai Province serves as a good example.  The focus of a waste management case study in 2019 (see Thawatchai Phengphinit et al, ‘Mekong River Community waste management model, case study: Tha Sadet community, Nong Khai Province’, Suan Dusit University, 2019), Tha Sadet was found to have a total of 1,148 households and 275 shops which collectively produced an average of 5-8 tonnes of waste per day. In the past, household waste was left unseparated, there were no public garbage bins for tourists, and public littering was common. 

To improve waste management, the community began with households - the primary waste source. Together, community members agreed that all households would separate their garbage into saleable and non-saleable waste. Studies indicate that separation alone can reduce the amount of waste by as much as 60%. It also provided municipal workers with increased income. The cooperation of waste makers and collectors reduced the cost for waste collection.

Tha Sadet shops were also required to have rubbish containers for customers and visitors. As these were small, parking lots also had to have 2 larger garbage bins - one for dry waste and one for wet.  With support coordinated by the Tha Sadet municipal committee, the community now has an effective waste management system.

Another case study comes from the ‘participative plastic waste reduction in the Mekong River tourism sector research project’ mentioned earlier.  Its immediate aim was to make tourist attractions in Chiang Rai cleaner.  It also hoped to serve as a model for neighbouring countries pursuing sustainable tourism development on behalf of businesses, tourists, local communities and the environment.

Carried out in collaboration with the local government and local tourism businesses, the project involved the installation of plastic waste collection equipment on the Thai bank of the Mekong.  Local staff and fishermen were trained in its use and random samplings of large-sized plastic waste were conducted each month.  To improve public awareness, seminars were organised to discuss plastic waste issues and the tourism industry.

A number of activities were also organised to reduce the volume of waste produced by tourism-related business.  These included: collecting plastic use data; analysing plastic waste; discussing  strategies for reducing plastic waste and related costs and building customer satisfaction. Businesses in the tourism sector such as Anantara Golden Triangle Elephant Camp & Resort cooperated by sending personnel as volunteers to collect waste from the riverbanks.  They also provided space to install waste tracking equipment.

Despite improvements, Prof. Panate notes that river waste problems remain an ongoing issue for tourist attractions. Encouraging tourist-related businesses to reduce waste and use environmentally friendly products is hindered by the fact most are small-sized enterprises which lack access to available solutions.

“The view from the tourism sector is that they have to do business first. It is not easy to encourage them to reduce the use of plastic just because it may end up in the water.  Replacement materials are hard to find and the price is not attractive.  The government wants to solve the problem by having shops change materials and stop using some items.

But what can small-sized businesses like coffee shops do when we ask them to cooperate? … It’s difficult for small stores to order products themselves. The public sector doesn’t promote environment-friendly products that fit the needs of small businesses. It’s like when we encouraged people to stop using plastic bags.  Only the larger businesses, about 30%, participated.  The remaining 60-70% are all smaller firms. Everyone tried but then COVID-19 came, and their efforts ended.  The measures we have adopted so far don’t work for their businesses,” Prof. Panate said.

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