Philippine Journal of Science
149 (S1): 183-195, Special Issue on Nuclear S&T
ISSN 0031 – 7683
Date Received: 18 Jun 2019

 

Environmental Assessment of Metal Pollution
in Manila Bay Surface Sediments

 

Ryan U. Olivares1,2*, Efren J. Sta Maria1, and Elvira Z. Sombrito1

 

1Department of Science and Technology–Philippine Nuclear Research Institute
(DOST-PNRI) Commonwealth Ave., Diliman, Quezon City 1101 Philippines

2Department of Environment Systems, Graduate School of Frontier Sciences
University of Tokyo, Kashiwa 277-8583 Japan

 

*Corresponding author: ruolivares@pnri.dost.gov.ph

 

[Download]
Olivares R et al. 2020. Environmental Assessment of Metal Pollution
in Manila Bay Surface Sediments. Philipp J Sci 149(S1): 183–195.
https://doi.org/10.56899/149.S1.21

 

ABSTRACT

The impact of human activities on the sediments of Manila Bay was evaluated through elemental analysis to determine the trace metal element concentration and calculate the corresponding metal enrichment factor (EF). The samples were analyzed using the X-ray tube-excited XRF (X-ray fluorescence) with Ag secondary target to quantify elements Mn to Pb, while the Fe target was used to quantify elements Na to Cr. The radioisotope-excited XRF with 241Am was used for Cd and Hg. The normalized EF has been calculated against baseline values to estimate the environmental impacts of human activity on the bay. In an attempt to provide a better understanding of sediment movement and reworking in the bay, spatial distribution of metals was correlated with the obtained 210Pb radioactivity levels in Manila Bay sediments. Overall, heavy metal and other trace elements are low in Manila Bay sediments, mostly ranging from deficient or minimal to moderate enrichment except for some stations where enrichment of Mn and Cu is significant. Nevertheless, there is a need to estimate the enrichment levels in marine sediments to effectively understand the risk and impact of heavy metals to support management and decision making for the rehabilitation, protection, and maintenance of a healthy ecosystem along the bay.