Editing Manila Bay (section)

=== Pollution ===
With the presence of ports, sea-based sources of pollution around the bay are from ships and motorized boats. Twelve oil spills were recorded in 1995, but it was in 1999 where the highest total volume of oil spill occurred in the Manila South Harbor and Limay, Bataan.<ref name="Jacinto et al (A)" /> Increased presence of oil and grease in the waters are attributed to maritime activities at the harbors, together with the presence of oil terminals and the discharges from industries.<ref name="PEMSEA" /> These factors directly impacted the health of Manila Bay's waters.

Aside from oil spills, trace metals such as [[copper]], [[cadmium]] and [[zinc]] at the surface of the water<ref name="velas">Velasquez I., Jacinto, G.S., and Valera, F.S., (2002). The speciation of dissolved copper, cadmium and zinc in Manila Bay, Philippines. Marine Pollution Bulletin 45, pp 210-217</ref> were found at the bay coming from sea-based and land-based (e.g., domestic sewage, industrial effluents, runoff, combustion emissions, and mining operations)<ref name="Jacinto et al (A)" /> sources.

In 1996, concentrations of 16 commonly used [[pesticide]]s in surface sediment<ref name="Jacinto et al (A)" /> was found including dichloro-diphenyl-trichloroethane ([[DDT]]). [[Polycyclic aromatic hydrocarbon]]s (PAH) found in Manila Bay sediments have been influenced by human activities. PAH come principally from petrogenic sources (e.g., oil discharges from ships, refineries and industries) and pyrolytic sources (from combustion sources).<ref name="santi">Santiago, E.C., (1997). The levels and distribution of polycyclic aromatic hydrocarbons (PAH) contamination in bottom sediment in Manila Bay. Science Diliman 9, pp 16-28</ref>

Pesticide residues from rice paddy water draining into irrigation canals, which later on empty into river systems and eventually flowing into the surrounding lakes reaches the waters of Manila Bay.<ref name="carvalho">Carvalho, F.P., Villeneuve, J.P., Cattini, C., Tolosa, I., Bajet, C.M. and Calingacion, M.N. (2009). Organic Contaminants in the Marine Environment of Manila Bay, Philippines. Arch Environ Contam Toxicol. 57:348-358</ref> Compounds from these pesticide residues find themselves in food items with metamidophos, [[endosulfan]], [[chlorpyrifos]] and [[diazinon]] among the common contaminants.<ref name="carvalho" /> While chronic toxic effects on inhabitants of the bay are not found, impairment of marine [[biota (ecology)|biota]]<ref name="carvalho" /> were more evident.

In 1997, [[polychlorinated biphenyl]] congeners, compounds common in transformers, [[hydraulic fluid]]s, paint additives and pesticides were determined in sediments and oysters sampled from Manila Bay.<ref name="ville">Villeneuve, J.P., Cattini, C., Bajet, C.M., Navarro-Calingacion, M. and Carvalho, F.P. (2010). PCBs in sediments and oysters of Manila Bay, the Philippines. International Journal of Environmental Health Research. 20(4): pp 259-269</ref> The increase in the nutrient concentration and presence of [[nitrate]], [[ammonia]] and [[phosphate]] in the bay, from the 1980s, through to the 1990s and beyond are not only attributed to agricultural runoff and river discharges but also on fertilizers from fishponds.<ref name="Jacinto et al (B)" />

On July 25, 2024, the oil tanker MT ''Terra Nova'', carrying around {{convert|1.5|e6L|sp=us}} of industrial fuel, capsized in Manila Bay during [[Typhoon Gaemi]], causing an oil spill with a length of {{convert|4|km|sp=us}}.<ref>{{cite web |last1=Guinto |first1=Joel |title=Race to contain oil spill after ships capsize as typhoon hits Taiwan and Philippines |url=https://www.bbc.co.uk/news/live/ce98pq4e3d1t |website=BBC News |access-date=25 July 2024 |language=en |date=25 July 2024}}</ref>