Manila Bay rehabilitation

FAST FACTS: What is dolomite sand, and how will it affect Manila Bay?

Michelle Abad

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FAST FACTS: What is dolomite sand, and how will it affect Manila Bay?

Workers prepare white sand to patch the beach along Manila Bay on Thursday, September 3, 2020 as part of the rehabilitation plan and in preparation for International Coastal Cleanup Day on September 19. Photo by Inoue Jaena/Rappler

(UPDATED) Dolomite, which is mainly used in construction, poses risks to humans and aquatic life in and around Manila Bay

The Department of Environment and Natural Resources (DENR) is under fire following the dumping of artificial white sand along the Manila Baywalk. The government defends its decision, saying the beautification of the bay will “signify cleanliness.”

The white sand is made from dolomite rock mined and exported from Cebu. Later reports revealed that Cebu province did not greenlight the extraction, but it was the DENR’s Mines and Geosciences Bureau that did.

But what exactly is dolomite, the material at the center of the controversy? We know it’s the material from which the sand is made, but other questions about its possible adverse effects on Manila Bay persist. Here’s basic information you should know.

Used in construction

Dolomite, also known as calcium magnesium carbonate, is a non-metallic material used in manufacturing bricks, mortar, cement, concrete, plastics, paving materials, and other construction materials.

The rock originates in warm, shallow, marine environments and is believed to form when limestone is modified by magnesium-rich groundwater, according to geologist Hobart King. It has low solubility, which makes it resistant to acid content of rain and soil.

Hazards to people

There are a number of hazards dolomite can pose to handlers, according to a 2012 safety data report by Texas distributor and builder Lehigh Hanson Inc. Dolomite contains varying levels of crystalline silica, which can cause damage to lungs or even cancer when it is breathed in. The material can also cause irritation to the skin and eyes.

The Department of Health also attested to dolomite’s health risks, especially the adverse reactions in humans when inhaled. Health Undersecretary Maria Rosario Vergeire said that when ingested, dolomite can cause pain in the stomach and result in diarrhea.

Hazards to Manila Bay

Manila Bay has already been beset by long-standing environmental problems, such as pollution and resource exploitation.

The DENR claimed that the crushed dolomite will not disrupt the bay’s ecosystem.

DENR Undersecretary Benny Antiporda said in a report, “Kami sa DENR pinag-aralan natin ‘yan. In the first place ‘yung mga ginamit d’yan, especially ‘yung sand, ‘yung dolomite boulders na ‘yan it contains calcium carbonate and if you will look sa corals, calcium carbonate din. So it will not disrupt the coastal ecosystem.”

(We at the DENR studied that. In the first place, the sand we used, the dolomite boulders contain calcium carbonate and if you will look at the corals, they’re calcium carbonate as well. So it will not disrupt the coastal ecosystem.)

However, environmental group Oceana Philippines warned that since the sand does not naturally occur at the bay, the government could be destroying both the natural ecosystem of Manila Bay as well as the source of the synthetic sand.

Marine scientist Diovanie de Jesus said the dolomite could cause hazards to creatures in and around the water. Sediments in the water could make it turbid, or opaque. The polluted water can also make it “stressful” for the bodies of sardines, mackerel, anchovies, and other fish.

Lehigh Hanson had the same finding – allowing the sand into water can increase total suspended particulate (TSP) levels, which can be harmful to aquatic life.

The sand from the baywalk area could also transfer to other areas of the bay where there are mangrove trees, beaches, and mudflats. De Jesus said if the dolomite polluted these – where shellfish, crabs, and fish nurseries thrive – they would become less habitable. Worms live here, too, which serve as food for birds.


Oceans researcher and Greenpeace campaigner Sonny Batungbacal highlighted the importance of conducting and disclosing to the public the environmental impact assessment of the project, which is required under environmental laws.

“It’s very concerning there are these types of activities knowing fully well we have environmental assessment processes,” Batungbacal said in a mix of English and Filipino during a phone interview .

“There needs to be a baseline and impacts if this pushes through… This way we can have science-based decision making,” he added.

Groups have slammed the DENR project, saying it focused on aesthetic improvement over existing environmental concerns that Manila Bay already faces. Others raised concerns over the government’s priority projects amid the coronavirus pandemic.

Public policy think tank Infrawatch PH said the situation presents a writ of kalikasan case in the Supreme Court – a legal remedy protecting the constitutional right to a healthful ecology. –

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Michelle Abad

Michelle Abad is a multimedia reporter at Rappler. She covers the rights of women and children, migrant Filipinos, and labor.