A Preliminary Study of the Sources of Organic Pollutants in the Iloilo River, Philippines

Abstract

The Iloilo River in the Philippines is an estuarine ecosystem where urbanization has increased throughout the years and caused deterioration in the water quality of the river. The present study is an attempt to determine the major sources of pollution in the river using a variety of geochemical markers associated with various contaminants in the sediment. Samples were collected from six sampling stations established along the 10-km long stretch of the lower Iloilo River. Commercial establishments, institutions, and informal settlers abound in the central portion of the river. Sewage pollution from human and animal waste is a major source of organic contaminants that has greatly reduced the water quality of the river. Three major compound groups were examined, namely polycyclic aromatic hydrocarbons, branched and cyclic saturate hydrocarbons, and a variety of sterols. The polycyclic aromatic hydrocarbons clearly indicated the presence of significant input from transportation sources; the branched and cyclic hydrocarbons indicated the presence of degraded crude oil residues in the sediments, probably derived from imported Middle East crude; and finally the presence of coprostanol and other sterols indicated the presence of waste sewage and fecal material in the sediments.

Keywords:

• Philippines
• Iloilo River
• pollution
• biomarkers
• sterols
• oil
• sewage
• soot
• PAHs
• sediments

Notes

^a A First sampling period.

^b B Second sampling period.

^a A First sampling period.

^b B Second sampling Period.

^c Petrogenic vs pyrogenic boundary limits using PAH ratios (Budzinski et al., 1997; Yunker et al., 2002).

^a A First sampling period.

^b B Second sampling period.

^a A First sampling period.

^b B Second sampling period.