EMB, MGB find no toxic chemicals in dolomite sand from Manila Bay

Published October 1, 2020, 10:10 AM

by Ellalyn De Vera-Ruiz

The Department of Environment and Natural Resources (DENR) has not found toxic chemicals on the dolomite sand from the Manila Bay beach nourishment project, based on the test results released by its Environmental Management Bureau (EMB) and Mines and Geosciences Bureau (MGB).


EMB and MGB released on Wednesday evening the test results of the analyses conducted on the dolomite sand samples taken from the beach nourishment project on Sept. 18 to determine if they contain heavy metals that are harmful to health and marine life.

Both bureaus conducted testing on the presence of iron, nickel, lead, and mercury; grain size analysis; acidity/alkalinity (pH) and specific metals using the Toxicity Characteristic Leaching Procedure (TCLP); and x-ray diffraction analysis.

The metals analyzed also include arsenic, barium, cadmium, chromium, lead, mercury and selenium.

According to EMB OIC Director William P. Cuñado, the results of the analysis were compared to the limits set in DENR Administrative Order No. 2013-22, or the Revised Procedures and Standards for the Management of Hazardous Wastes (Revising DAO 2004-36).

Basing from the results of the TCLP, the EMB and MGB cited that none of the values obtained from the sample leachate exceeded the limits stated in the DENR AO 2013-22, “hence the sample is not classified as hazardous.”

“It does not contain mobile forms of the mentioned metal constituents that may leach into the environment under conditions similar to that in a landfill,” they pointed out.

“Moreover, the pH value is also less than the set limit for pH in the provisions of the same AO to be classified as hazardous,” they said.

In a statement issued last Wednesday, the University of the Philippines-Marine Science Institute (UP-MSI) noted that acid rain close to cities, such as in Metro Manila and groundwater seeping across the beach will slowly dissolve these dolomite granules and dissociate them into ions including carbonates.

“Carbonates are important in maintaining the alkalinity (or basicity) of the seas or raising the pH level to balance the effects of ocean acidification,” it said.

However, ocean acidification occurs on a much larger scale, such that augmentation in the carbonate ion budget from dolomite addition is not a solution to the potential acidification happening in Manila Bay, it pointed out.

Likewise, the UP-MSI pointed out that the addition of white sand invites more contact of people with a chemically uncharacterized material. “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.”

“Grain size of particles should be monitored to make sure these are not the size which may cause health problems,” it added.

The UP-MSI pointed out that “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. 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.