97% of plastic trash on Singapore’s beaches originate from offshore sources: NEA study

SINGAPORE – Heaps of plastic trash on Singapore’s beaches are a common sight during the country’s two main monsoon seasons. Most of the debris originates from offshore sources, according to a new study.

A key finding was that 97 per cent of the plastic waste on Singapore’s recreational beaches came from sea-based sources, such as ships, or were transported across boundaries by marine currents.

The study was published on the National Environment Agency’s (NEA) website on Jan 13.

Commissioned by NEA in 2021, it was aimed at better understanding the possible sources of plastic waste on Singapore’s shores and how the waste ended up there.

The study was led by NEA, which worked closely with other agencies including national water agency PUB, National Parks Board, the Maritime and Port Authority of Singapore and Singapore Food Agency.

Consultants from two organisations, DHI Water and Environment and SGS Testing and Control Services, were also involved.

NEA told The Straits Times that the study involved sampling various inland and coastal waters and recreational beaches monthly over a one-year period.

Information collected on the plastic debris, such as its size, as well as other factors like rainfall and surface wind speed, enabled researchers to model the amount of marine plastics on Singapore’s beaches.

“The modelling found that only about 3 per cent of the macro- and micro- plastics found on our beaches were from inland waterways, while 97 per cent were from marine-based sources,” said NEA.

The study used international classification standards to define macroplastics as being larger-sized plastic particles with diameters greater than 5mm, and microplastics as smaller fragments with diameters less than 5mm.

From the samples collected at the mouths of rivers, researchers found that over 90 per cent of the samples presented no trace of microplastics.

“This makes it more likely that plastics found on Singapore’s beaches came from sea-based sources,” said NEA.

The study also found that the amount of marine litter and how it ended up on Singapore’s beaches were heavily influenced by the weather, such as the winds and marine currents.

For example, during the north-east monsoon season between November and March, winds blow mainly from the north. During this period, higher volumes of trash were washed up on Singapore’s northern shores, in areas such as Sembawang Park Beach, Coney Island and Pasir Ris Beach.

From April to September, when the south-west monsoon brings winds blowing from the south, a greater quantity of debris was found along Singapore’s southern shores, such as at East Coast Park Beach and the beaches of Sentosa.

The study also found that the level of macroplastics deposited at Singapore’s northern recreational beaches during the north-east monsoon was three times that of the debris deposited on the southern recreational beaches during the south-west monsoon. “This is likely due to the larger and more open marine waters in the south of Singapore that enable better dispersal of plastic debris,” NEA said.

The Singapore Strait, the body of water south of Singapore, is more expansive than the narrow Johor Strait to the nation’s north.

The study also showed that bigger pieces of plastic debris tend to be dispersed much farther from release sites, compared with smaller plastic fragments, because of their larger exposed surface areas that allow surface winds to carry them over long distances.

On microplastics, the study found that plastic particles smaller than 5mm in diameter mostly came from larger post-consumer plastic products, like food containers or takeaway cups.

Such products refer to materials that are discarded by consumers, instead of being generated during the manufacturing process.

Researchers found that plastic polymer polypropylene was the top plastic product identified, making up 61 per cent to 79 per cent of microplastics across all sampled sites. Polypropylene is found in everyday consumer products, including plastic food containers, cups, bottle caps, disposable bags and soap bottles.

The release of the findings of the latest study comes after countries in November 2024 failed to reach an agreement on a global treaty to end plastic pollution.

NEA said the findings of the latest study, as well as earlier research which found that most marine litter along Singapore’s coastlines comprised plastic debris, had provided useful insights on the level of plastics in Singapore’s inland and coastal areas.

“This has improved our understanding of the effectiveness of the approach and strategies Singapore has adopted in tackling the issue,” its spokeswoman said.

In 2022,

Singapore launched a national action strategy for marine litter,

which guides national efforts to address the problem. This includes efforts to minimise plastic waste from land-based sources through proper waste management, strict anti-littering laws and a firm enforcement regime.

To further nudge businesses to be conscious of the waste they generate, companies that use large quantities of plastics in their packaging are currently mandated to report to NEA their packaging data and plans on reusing, reducing and recycling packaging.

The disposable carrier bag charge at supermarkets was also implemented in 2023 to reduce the consumption of plastic bags.

A beverage container return scheme, in which customers get a 10 cent refund when they return plastic and metal containers of pre-packaged beverages to vending machines, is also slated to be introduced in April 2026.

Mr Yasser Amin, chief officer of Stridy, a non-profit organisation that organises clean-ups, said the findings of the study reflected what his volunteers were seeing on the ground.

He said: “From the brands and languages that we often see on packaging along the shores of East Coast Park Beach, it is apparent they are mostly Indonesian and not items we can find in Singapore’s stores.”

He added that the findings of this study reinforce that additional focus should be given to those whose jobs are to clean Singapore’s coasts.

“We saw emergency manpower additions during the major oil spill recently, so I am sure resources could be put in place to support our cleaner-workers during the monsoon periods when trash loads on beaches increase.”

He added: “Our workers, who are at the brunt of increased trash loads, could be given extra support during these times, be it in terms of manpower additions, increased compensation or additional welfare.”