Home > Spotlight

UP marine scientists explain why dumping dolomite can’t solve Manila Bay problems

A view of the “white sand” project in Manila Bay as it temporarily opens to public on September 19, 2020. George Calvelo, ABS-CBN News

MANILA — Marine scientists from the University of the Philippines (UP) Diliman on Wednesday said there are no shortcuts to address the environmental problems in Manila Bay, and dumping dolomite does not offer a solution.

"There are no short-cuts to a cleaner environment. The use of crushed Dolomite sand will not help solve the environmental problems in Manila Bay," the UP Marine Science Institute (UP MSI) said in a statement.

"At most, it is a beautification effort that is costly and temporary. The task of cleaning and restoring Manila Bay may be daunting but it needs to be done for future generations of Filipinos to benefit from its many uses," it said.

The institute explained the implications of dumping dolomite, the environmental problems in Manila Bay that should be addressed, and the solutions that need to be executed. 

‘Implications of using crushed dolomite in Manila Bay’

It said the "addition of Dolomites crushed to 2-5 mm diameter cannot serve to anchor the loss of beach sand, nor serve as replacement for eroded sediments."

"Dolomite sand grains will erode given the hydrodynamic conditions in coastal Metro Manila during storms. Even with the breakwater off the baywalk area, elevated seas and larger waves during storms can penetrate and pound the Baywalk area."

"Hence, continuously replacing the sand will be expensive and will not contribute to improving water quality in the Bay," the institute said.

Considering the rising sea levels and the country's weather, "the Dolomite sand will wash away into the Bay with subsequent intense and heavy rainfall events and wave action especially during storms."

The dolomite addition will not help solve as well the potential acidification happening in Manila Bay.

Lastly, the institute also stated that "the finer particles of Dolomite are more problematic as with other rock materials that are pulverized."

"Dust inhalation may 'cause discomfort in the chest, shortness of breath, and coughing. Prolonged inhalation may cause chronic health effects',” it said.

"Grain size of particles should be monitored to make sure these are not the size which may cause health problems," the institute said.

Environmental problems in Manila Bay

The institute said authorities should address "poor water quality" and the "threat of erosion" in Manila Bay under the government's rehabilitation program.

"The lack of wastewater treatment plants surrounding the watershed of Manila Bay, and the loss of natural clean-up from wetland, mangrove, and seagrass ecosystem services, are not able to filter and remove pollutants that drain from urban and residential areas. These include wastewaters that are discharged by homes or establishments or channeled into storm drains," it noted.

"Some components in wastewaters are emerging pollutants detected in Manila Bay, which include personal care and pharmaceutical products, endocrine disrupting substances (e.g. hormones, pesticides), fecal steroids, and plastic components in micro- and nano- sizes," it added.

The threat of erosion is worsened by additional reclaimed areas found south of the baywalk, the institute said.

What should be done?

The UP MSI said that the rehabilitation of Manila Bay is an "arduous task" and effort should be exerted by both residents, people using the area, and the government.

"This will entail infrastructure infusion for wastewater treatment plants, transfer of informal settlers especially those living in the dangerous riverbanks and coastal areas, “operationally clean” effluent discharge, decreased sedimentation from the watershed, and zero garbage inputs," it said..

"These are achieved with government interventions, social and community behavioral change, and legislations and policy guidelines implemented."

"In addition, we need to review closely the parameters that are tested for water quality monitoring in DAO-2016-08. This is timely as the guidelines are due for review every few years. The range of allowable values, component measured, protocols for how and where water samples were collected are some of the major items to review," the institute said. 

It said that monitoring the area for emerging organic pollutants and massive reforestation should also be done.