Re-assessment of the water quality of Ormoc Bay

Authors / Editors: J.V. Juario, J.R. Silapan Galapate, Ritchelita P.


ABSTRACT

The water quality of Ormoc Bay was monitored from May 2001 to May 2002 and evaluated in terms of pH, temperature, salinity, transparency , dissolved oxygen (DO), biological oxygen demand (BOD), ammonium-nitrogen (NH4-N), nitrate-nitrogen (NO3-N), and phosphate-phosphorus (PO4-P), cadmium (Cd), chromium (Cr), lead (Pb), copper (Cu), mercury (Hg), arsenic (As), organochlorines, and Escherichia coli. Seven offshore sampling stations were chosen for water quality assessment and additional five nearshore stations were selected for E. coli determination. Six fish and four mollusk samples were collected for heavy metals analysis. Observed pH, temperature, salinity, transparency, and DO levels throughout the study period were generally within the acceptable levels for class SA waters. Escherichia coli was not detected and BOD values were very low indicating no massive intrusion of human, animal, or other organic wastes to the Bay. The nutrient levels of the bay were within safe levels. No detectable amount of organochlorine was found in the samples.
Arsenic and mercury were not detected throughout the study period. However, Cd, Cr, Cu, and Pb exceeded the levels set by DENR for Class SA waters. Cadmium, Cr, Cu, and Pb were also found in the fish and mollusk samples. Based on the acceptable daily intake recommended by the US Environmental Protection Agency and the World Health Organization for Cd, Cr, Cu, and Pb, daily intake of about 140 g of edible portion of fish or 40 g of the mollusk collected from the Bay would not give chronic adverse effects on human health. This is however not conclusive. The basis of the estimates is limited to only six fish and four mollusk samples. Additional data is needed to establish reliable estimates. The values obtained in the 2001-2002 study exhibited a general increase compared to the 1992-1993 figures reported by IMFO and BFAR in 1993. Most of the parameters determined were however within the acceptable levels set by the DENR. The overall quality of Ormoc Bay is still considered suitable for fishery and coastal resources.


Published by: UPV Journal of Natural Sciences 9 (2) , 2004 | Page Nos: 177-302
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Type of Publication: Journal Article