The state of water resources in the Philippines - Greenpeace

The EMB report on monitoring of DO levels shows that approximately 47 percent
of 127 water bodies are found to have good water quality and could be tapped as
sources for water supply.
Forty percent recorded fair water quality, which means that the water bodies
partially comply with the designated water quality criteria but do not support its
intended beneficial use in 50 to 97.99 percent of sampling instances.
Thirteen percent, however, showed poor water quality. These include the four
rivers in NCR – San Juan River, Parañaque River, Navotas-Malabon-Tullahan-
Tenejeros River, and Pasig River; Guadalupe River in Region VII; Meycauayan
and Bocaue Rivers in Region III; and Calapan River in Region IV-B.
Data in the PEM 2004 issue states, however, that as of 2004, 15 rivers
nationwide have dissolved-oxygen at or below zero, indicating that they are
“dead” during the dry months. In addition, Environment Secretary Angelo Reyes
also mentioned in a published news article early this year (2007) that as many as
50 of the 421 rivers in the country can be considered "biologically dead"
(Gaylican, C, PDI, 2007).
Biochemical oxygen demand (BOD)
Biochemical oxygen demand, or BOD, measures the amount of oxygen
consumed by microorganisms in decomposing organic matter in stream water.
BOD parameter measures the organic strength of wastes in water; the greater
the BOD, the greater the degree of organic pollution.
BOD also directly affects the amount of dissolved oxygen in rivers and streams.
The greater the BOD, the more rapidly oxygen is depleted in the stream. This
means less oxygen is available to higher forms of aquatic life. The consequences
of high BOD are similar as those for low dissolved oxygen: aquatic organisms
become stressed, suffocate, and die.
National standards for BOD vary from 1 to 15 mg/L based on beneficial water
usage and classification.
For this parameter, 47 percent of the 107 water bodies with at least four sampling
events were found to show good water quality, 41 percent have fair water quality,
while the remaining 12 percent have poor water quality with the highest BOD
recorded at the downstream section of Bulua Creek in Region X. According to
the report, this indicates high organic discharges from manufacturing facilities,
runoff from livestock production, and discharges from households.
The EMB Report further mentions that there are three rivers that recorded zero
percent compliance of all samples with the BOD criterion.
GREENPEACE | The state of water in the Philippines 15