Trash in Manila Bay declined in 2024: How to sustain it?

MANILA, Philippines — Cleaning up Manila Bay is not as simple as picking up trash.

For Johnny Ching, assistant vice chancellor for research at De La Salle University-Dasmariñas (DLSU-D), this “dynamic” problem of marine litter requires research- and evidence-based solutions.

“We’ve had this experience before with tree-planting activities. We thought the solution to deforestation is to plant more trees, but due to the lack of evidence, of reason, most of what was planted turned out to be invasive species,” Ching said. “Instead of solving the problem, we just added to it.”

In 2024, DLSU-D conducted its Marine Litter Monitoring Survey Report in partnership with the environmental group EcoWaste Coalition and funded by the Korea International Cooperation Agency-Philippines and the Korea Marine Environment Management Corp.

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The report examined the counts and weights of different types of litter across 10 project sites around Manila Bay and discovered that waste in those areas has “significantly” decreased.

“An average of 46 pieces of marine litter per meter coastline of Manila Bay were counted in 2023 to 2024,” which is a 36-percent decline compared to DLSU-D’s previous survey.

On the other hand, “in terms of weight, the collected marine litter per meter coastline in Manila Bay for 2023 to 2024 weighed an average of 1,780 grams (1.78 kilograms),” showing a reduction of 42 percent.

However, Ching pointed out that researchers have yet to establish a “trend” in their monitoring.

“[I]n 2023, the amount of litter rose, but in 2024, it went down. We don’t know in 2025 if it will continue to go down or it might go up again. That is why it is important to continue conducting monitoring surveys,” he said.

Mandamus ruling

Efforts to rehabilitate Manila Bay began as early as 2008 when the Supreme Court issued a mandamus ruling directing 13 government agencies, including the Department of Environment and Natural Resources, to clean up, rehabilitate, and preserve Manila Bay.

In 2019, former Environment Secretary Roy Cimatu launched the “Battle for Manila Bay” to clean up designated esteros and waterways as well as reduce the waters’ fecal coliform level.

“Manila Bay is connected to seven major rivers draining 26 catchment basins. According to studies, this is where the pollution in Manila Bay comes from,” said Ching.

The most common type of waste in Manila Bay is plastics. According to the DLSU report, “nine [out of] 10 pieces of collected marine litter are plastics.” Additionally, “plastics shared 66 percent of the total weight of all collected marine litter.”

“Plastics still represent a significant portion of marine debris, accounting for 91 percent of the total collected waste, with hard and film plastics being the most prevalent forms,” added the EcoWaste Coalition.

In total, there were almost 8 million pieces of plastic collected within 190 kilometers of coastline in Manila Bay, weighing more than 225,000 kg.

“Most of the film plastics were single-use food sachets and plastic bags. This only shows the popularity of single-use plastics such as sachets, food wrappers, grocery bags, thin-filmed bags (plastic “labo”), diapers, and disposable caps,” the report said.

Among the areas surveyed for the report were five barangays in Cavite: Silangan I in Rosario, Timalan Conception in Naic, San Rafael IV in Noveleta, and Capipisa and Julugan in Tanza.

For the National Capital Region (NCR), researchers monitored the Las Piñas-Parañaque Wetland Park in Parañaque City and the Tanza Marine Tree Park in Navotas City.

In Bataan, the survey sites were Barangay Cabcaben and Agwawan Beach in Barangay Sisiman in Mariveles, as well as Barangay Bantan in Orion.

Highest count

Out of all these survey sites, the areas in NCR logged the most amount of waste. Navotas City had the highest count of litter at 92 pieces per meter of coastline, while Parañaque had the heaviest amount of waste collected at 4,500 g (4.5 kg) of litter per meter of coastline.

Still, Ching reiterated that marine litter is a “dynamic” problem, saying that “we cannot determine where [the trash comes from] or who is to blame.”

“The important thing is we are aware that each one of us has a responsibility, and each one of us can do something [to clean up Manila Bay],” he said.

With the decline in marine litter, Aileen Lucero, national coordinator of EcoWaste, said that “these findings demonstrate the progress we’ve made, but they also highlight the urgent need for stricter waste management practices.”

Among the recommendations in the report were the implementation of information and education campaigns on solid waste management at every coastal barangay.

“Households as well as beach resort owners and locals must be knowledgeable on different classifications of waste, aware of its negative impacts, and practice proper waste segregation and minimization,” the report said.

It also called for the adoption of standardized cleanup methods as well as the development of a comprehensive marine litter management plan for Manila Bay.

“We have made remarkable progress, but we can’t stop here. It is crucial that everyone—from government agencies to local communities—joins forces to implement the solutions outlined in this report,” Lucero said.

(2025/01/30-04:40)