HEAVY-METAL CONCENTRATIONS IN SEDIMENTS FROM MANILA BAY, PHILIPPINES AND INFLOWING RIVERS

Concentrations of Fe, Mn, Zn, Cu, Pb, Ni, Cd and Co were determined in surface and core sediments collected from Manila Bay and in surface s ediments from inflowing rivers. Core profiles revealed highly fluctuat ing and enriched Pb, Cd, Zn and Cu concentrations on the surface, sugg estive of recent inputs coming from anthropogenic sources. Concentrati ons of Pb, Zn and to a lesser extent Cu and Cd were higher in riverine sediments as compared with marine sediments, which may be attributed to the proximity of these riverine sites to pollutant sources. Compari son of metal concentration levels obtained with other areas in the wor ld revealed elevated values for Pb and Cd, indicating a considerable a mount of pollution in the area. Continuous monitoring and further stud ies of the area are recommended to ascertain long-term effects that ma y have not yet been reached.