cabuyao river water quality assessment report 2011

Cabuyao River Water Quality Assessment Report

Environmental Laboratory and Research Division Laguna Lake Development Authority

1

CABUYAO RIVER

WATER QUALITY ASSESSMENT REPORT

2011

Prepared by:

IRENEO G. BONGCO – Sr. Science Research Specialist

Reviewed by:

JOCELYN G. STA. ANA – OIC, Environmental Laboratory and Research Division

ADELINA C. SANTOS-BORJA – OIC, Resource Management and Development

Department

For more Information, please contact:

Environmental Laboratory and Research Division (ELRD)

Laguna Lake Development Authority

Park and Shop Bldg.

Km. 24, Brgy. San Juan, Taytay, Rizal

Tel. No. 286-61-43



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CABUYAO RIVER WATER QUALITY ASSESSMENT REPORT

Introduction:

Cabuyao is a first class urbanized city in the province of Laguna, Philippines. It is located

at the western portion of Laguna and about 43 kilometers southeast of Metro Manila. It is

bordered by the Laguna de Bay, the country's largest lake, to the north (N), Calamba City

to the east (E) with Barangays Uwisan (NE), Banlic & San Cristobal (E) and Mapagong

& Canlubang (SE), some portion of Silang, Cavite (Brgy. Puting Kahoy) to the south (S)

and by the Santa Rosa City to the west (W) with the Barangays Malitlit (SW), Dita (W)

and Caingin (NW) respectively. Based on the 2007 Census, the city has a total population

of 205,376.

The City of Cabuyao within the Sta. Rosa and San Cristobal

Micro-watersheds of Laguna de Bay

Cabuyao City was formerly the "Richest Municipality of the Philippines" and it is the

fastest growing municipality in Laguna with large number of migrant workers in the

town's industrial estates (http://www.cityofcabuyao.gov.ph/profile.php).

.

The rivers of Cabuyao are Cabuyao River between the boundary of Santa Rosa City and

Cabuyao, Niugan-Sala River along the boundary of Barangays Niugan and Sala, Tiway-

Tiway River, and San Cristobal River between the boundary of Calamba City and

Cabuyao. The municipality is politically subdivided into eighteen (18) barangays in

which six (6) of them are situated along the lake, namely: Bigaa, Butong, Marinig,

http://wn.com/Laguna_province

http://wn.com/Philippines

http://wn.com/Laguna_%28province%29

http://wn.com/Metro_Manila

http://wn.com/Laguna_de_Bay

http://wn.com/Calamba_City

http://wn.com/Canlubang

http://wn.com/Silang,_Cavite

http://wn.com/Santa_Rosa_City

http://wn.com/Santa_Rosa_City

http://wn.com/Cabuyao

http://wn.com/Barangay_Niugan,_Cabuyao,_Laguna

http://wn.com/Barangay_Sala,_Cabuyao,_Laguna

http://wn.com/San_Cristobal_River

http://wn.com/Calamba_City

http://wn.com/Cabuyao

http://wn.com/barangay

http://wn.com/Barangay_Bigaa,_Cabuyao,_Laguna

http://wn.com/Barangay_Butong,_Cabuyao,_Laguna

http://wn.com/Barangay_Marinig,_Cabuyao,_Laguna



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Gulod, Baclaran and Mamatid. In 2004, the data from the Municipal Agriculture Office

showed that the municipality had a total of 940.56 hectares riceland (or 9.4056 in square

kilometers) while the total number of farmers for the same year was 468. The

ricefields/ricelands in Cabuyao are found in Barangay Bigaa, Butong, Marinig, Gulod,

Baclaran, Mamatid, San Isidro, Pulo, Banay-Banay, Niugan and Sala. For 2010, the

Land Use Map of City of Cabuyao is presented below:

In support of the River Rehabilitation Program of LLDA, the Environmental Laboratory

and Research Division (ELRD) staff conducted water quality sampling in Cabuyao River

on January 27, 2011, representing the dry season and July 19, 2011, representing the wet

season in order to determine the seasonal variations of the water quality levels in this

river in terms of the biological, chemical and bacteriological parameters. Cabuyao River

was among the six (6) major tributary rivers targeted by LLDA for the River

Rehabilitation Program in 2011 aside from San Pedro, Sta. Cruz, Tanay, Sapang Baho

and Morong-Teresa Rivers after the “Adopt A River Project” was launched by LLDA on

the same year.

http://wn.com/Barangay_Gulod,_Cabuyao,_Laguna

http://wn.com/Barangay_Baclaran,_Cabuyao,_Laguna

http://wn.com/Mamatid

http://wn.com/Barangay_Bigaa,_Cabuyao,_Laguna

http://wn.com/Barangay_Butong,_Cabuyao,_Laguna

http://wn.com/Barangay_Marinig,_Cabuyao,_Laguna

http://wn.com/Barangay_Gulod,_Cabuyao,_Laguna

http://wn.com/Barangay_Baclaran,_Cabuyao,_Laguna

http://wn.com/Mamatid

http://wn.com/Barangay_San_Isidro,_Cabuyao,_Laguna

http://wn.com/Barangay_Pulo,_Cabuyao,_Laguna

http://wn.com/Barangay_Banay-Banay,_Cabuyao,_Laguna

http://wn.com/Barangay_Niugan,_Cabuyao,_Laguna

http://wn.com/Barangay_Sala,_Cabuyao,_Laguna



4

Stn. 1 – Mouth of Cabuyao River at the boundary of Brgy. Bigaa, Cabuyao and Brgy. Caingin, Sta. Rosa. Stn. 2 – Cabuyao River at Sitio Bulihan, Brgy. Sala fronting Purefoods and Villa Susana Subdivision Stn. 3 – Cabuyao River at Brgy. Malitlit, near the entrance of ETON City Stn. 4 – Malitlit tributary located along SLEX near the outlet of ETON City and before confluence with Cabuyao River

3

2

1

4

Figure 1

Location of

Cabuyao River

Sampling

Stations



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Sampling Stations and Frequency of Sampling:

ELRD has established four (4) sampling stations at various sections of the Cabuyao River

and their locations are depicted in Figure 1. These are the same stations where monitoring

was done in 1997. Specifically, the sampling stations are: Station 1 – Mouth of Cabuyao

River at the boundary of Brgy. Bigaa, Cabuyao and Brgy.Caingin, Sta. Rosa; Station 2 –

Cabuyao River at Sitio Bulihan, Brgy. Sala fronting Purefoods and Villa Susana

Subdivision; Station 3 – Cabuyao River at Brgy. Malitlit, near the entrance of ETON

City; and Station 4 – Malitlit tributary located along SLEX near the outlet of ETON City

and before confluence with Cabuyao River.

Photo documentations of the two (2) samplings conducted are shown in Figures 2 to 5.

Figure 2. Photo of Station 1 in Cabuyao River Mouth at the Boundary of Brgy.

Bigaa, Cabuyao, Laguna and Barangay Caingin, Sta. Rosa, Laguna

Figure 3. Photo of Stn. 2 in Cabuyao River at Sitio Bulihan, Brgy. Sala (fronting

Purefoods and Villa Susana Subdivision

January sampling (dry season) July sampling (wet season)




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Figure 4. Photo of Stn. 3 of Cabuyao River at Brgy. Malitlit (near the entrance of

ETON City)

Figure 5. Photo of Stn. 4 Malitlit tributary (located along SLEX near the outlet of

ETON City and before the confluence with Cabuyao River)





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Field Observations and In-Situ Measurements:

Field observations for the two (2) sampling activities are presented in Tables 1a and 1b.

During the first sampling (dry season), the recorded water temperature was 24oC in all of

the four (4) stations, the weather was sunny, and the color of the water was greenish to

brownish. The presence of garbage was observed at the river mouth (Stn. 1) and in that

section of the river in Sitio Bulihan, Brgy. Sala (Stn. 2).

For the second sampling (wet season), it was also undertaken on a sunny weather. The

observed river flows in all four (4) stations remained the same as the first sampling but

the recorded water temperatures were higher at 27oC. The second sampling also showed

clearing of the water in Stns. 3 and 4 wherein small fish, shrimps and crabs were noted.

The water remained turbid (grayish) in Stns. 1 and 2. Clearing of the water hyacinth was

observed in Stn. 1 and this could be attributed to river flushing during the rainy season.

In Stn. 2, garbage was still present and there were soft shelled turtle and abundant fish fry

seen in the area.



8

Table 1a. Field Observations and in-Situ Measurements for the Cabuyao River Sampling on January 27, 2011 (Dry Season)

Sampling Team : Bileynnie Encarnacion, Jonathan Nicolas and Usman Mamadra (ELRD), Reena Buena (CDD) and

Wilson Amoranto (Driver)

Sampling Stations

1 2 3 4

Time 11:35 AM 11:00 AM 10:30 AM 10:00 AM

GPS Reading (UTM) P0298091 P0296580 P0294604 P0294528

1581312 1578360 1577168 1578583

Air Temperature (oC) 25 26 27 27

Water Temperature

(oC) 24 24 24 24

Weather sunny sunny sunny sunny

Color of the Water brownish (turbid) greenish brown greenish greenish brown

Other observations: water slightly flowing,

thick growth of water

hyacinth and presence of

garbage noted, with low

river banks

water moderately

flowing, with sandy

bottom, illegal settlers

noticed along river

banks, presence of

garbage also noted

water fast flowing,

damming of the water

noted for irrigation

purposes, river banks

high with cogon grasses

and other vegetation,

with muddy river bed

water fast flowing,

presence of river bed

with boulders, head-

sized stones and pebbles,

both sides of the river

are high and with cogon

grass and trees

Stn. 1 - Mouth of Cabuyao River at the boundary of Brgy. Bigaa, Cabuyao and Brgy.Caingin, Sta. Rosa

Stn. 2 - Cabuyao River at Sitio Bulihan, Brgy. Sala fronting Purefoods Villa Susana Subdivision

Stn. 3 - Cabuyao River at Brgy. Malitlit, near the entrance of ETON City.

Stn. 4 - Malitlit tributary located along SLEX near the outlet of ETON City and before confluence with Cabuyao River



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Table 1b. Field Observations and in-Situ Measurements for the Cabuyao River Sampling on July 19, 2011 (Wet Season)

Sampling Team : Bileynnie Encarnacion, Jonathan Nicolas and Reynaldo Zulueta (Driver)

Sampling Stations

1 2 3 4

Time 11:40 AM 11:00 AM 10:20 AM 09:50 AM

GPS Reading (UTM) P0298091 P0296580 P0294604 P0294528

1581312 1578360 1577168 1578583

Air Temperature (oC) 26 28 26 28

Water Temperature

(oC) 27 27 27 27

Weather sunny sunny sunny sunny

Color of the Water grayish (turbid) grayish clear clear

Other observations: water slightly flowing,

absence of water

hyacinth in the area only

patches near the mouth.

water moderately

flowing, garbage on both

sides of the river banks,

presence of soft-shelled

turtle, abundant fish fry

on the side of the river.

water fast flowing,

presence of small fish

and shrimp, river banks

high with cogon grasses

and other vegetation,

with sandy river bed.

water fast flowing,

presence of river bed

with boulders, head-

sized stones and pebbles,

both sides of the river

are high and with cogon

grass and trees. Small

fish, shrimp and crab

present.

Stn. 1 - Mouth of Cabuyao River at the boundary of Brgy. Bigaa, Cabuyao and Brgy.Caingin, Sta. Rosa

Stn. 2 - Cabuyao River at Sitio Bulihan, Brgy. Sala fronting Purefoods Villa Susana Subdivision

Stn. 3 - Cabuyao River at Brgy. Malitlit, near the entrance of ETON City.

Stn. 4 - Malitlit tributary located along SLEX near the outlet of ETON City and before confluence with Cabuyao River



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Table 2. Results of the Physico-Chemical Analysis of Water Samples from Cabuyao River:

Sampling Dates: January 27, 2011 (Dry Season) and July 19, 2011 (Wet Season)

PARAMETERS

STATIONS DENR Class C

Water Quality

Criteria Stn. 1 Stn. 2 Stn. 3 Stn. 4

Dry Wet Dry Wet Dry Wet Dry Wet

pH, units 7 7.4 7 7.6 7.3 7.9 7.6 7.5 6.5-8.5

Total Suspended Solids, mg/L 4 6 7 9 122 6 26 5 <30 (increase)

Total Dissolved Solids, mg/L 242 486 244 371 290 284 291 340 1000

Total Solids, mg.L 246 492 251 380 412 290 317 345 *

Chemical Oxygen Demand,

mg/L

45 14 45 42 37 <4 25 30 *

Biochemical Oxygen

Demand, mg/L

14 8 35 33 5 <2 4 2 10

Dissolved Oxygen, mg/L 1.1 0.4 4.5 2.1 7.8 7.6 7.3 6.6 5 (minimum)

Oil/Grease, mg/L 0.5 <1 0.5 <1 7.8 <1 7.3 <1 2

Ammonia, mg/L NH3-N 3.1 2.307 0.924 2.088 0.029 0.069 0.053 0.055 *

Nitrate, mg/L NO3-N 0.001 <0.002 0.647 0.046 1.739 0.846 0.463 0.544 10

Inorganic Phosphate, mg/L 0.714 0.601 0.602 0.610 0.579 0.785 0.369 0.514 0.4

Total Phosphate, mg/L 0.999 0.904 0.912 0.97 0.922 0.889 0.595 2.47 *

Total Nitrogen, mg/L 6.4 5.5 3.7 5.2 2.9 1.7 2 0.9 *

Chloride, mg/L 74 48 22 22 15 19 22 22 350

Alkalinity, mg CaCO3/L 308 304 212 244 188 172 204 208 *

Calcium Hardness, mg

CaCO3/L

132 88 88 80 80 64 92 88 *

Total Hardness,mg CaCO3/L 212 220 148 172 140 124 156 168 *

Turbidity, NTU 5 6 3 9 20 4 20 3 *

Conductivity, uS/cm 830 720 457 512 396 381 429 457 *

*Note: No set DENR Class C Water Quality Criteria



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WATER QUALITY ASSESSMENT

1. Physico-Chemical Parameters:

The results of the physico-chemical analyses of the collected water samples for

the two (2) sampling dates are summarized in Table 2. The analytical results were

compared to the DENR Water Quality Criteria for Class C Waters as specified in

DENR Administrative Order (DAO) No. 34 and below are the findings:

a) pH

This parameter is a measure of the level of the hydrogen ion concentration. As

observed, measured pH in all of the four (4) stations in Cabuyao River which

ranged from 7.0 to 7.9 for the dry and wet season were found within the

acceptable range of 6.5 to 8.5 for Class C waters.



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b) Solids - Total Suspended Solids (TSS) and Total Dissolved Solids (TDS)

The presence of high amounts of solids will affect water clarity as it will

impede light to pass through the water body.

In Stns. 3 and 4, the TSS levels decreased from 122 to 6 mg/l and from 26 to 5

mg/l, respectively. This could possibly be explained by the comparatively

higher volume of water flow in these two (2) sampling stations during the

second sampling (wet season). Thus, dilution of the water resulted to low TSS

levels.

For TDS, Stn 4 obtained the highest concentration at 291 mg/l in January and

while in Stn. 1 at 486 mg/l in July. Nevertheless, measured TDS

concentrations in all stations were found within the Class B criterion of 1000

mg/l.

Total Suspended Solids

Cabuyao River

0

20

40

60

80

100

120

140

Stn. 1 Stn. 2 Stn.3 Stn. 4

mg

/L

Dry

Wet



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c) Biochemical Oxygen Demand (BOD)

This parameter is a measure of the approximate amount of oxygen needed by

the microorganisms for the aerobic decomposition of organic matter. For the

first sampling, results of the analysis for BOD showed that measured

concentrations in Stns. 1 and 2 at 14 and 35 mg/l, respectively, exceeded the 10

mg/l criterion for Class C. Comparison of the BOD levels obtained during the

two (2) sampling dates indicated that in Stn. 1, it improved to 8 mg/l in the

second sampling from 14 mg/l in the first sampling but in Stn. 2, Class C

criterion remained exceeded at 33 mg/l from 35 mg/l because of the presence

of garbage in the area. For both Stns. 3 and 4, measured BOD concentrations

for the two (2) sampling dates were low and conformed to the Class C

criterion. The adequate supply of oxygen due to the moderate flow of the

water in Stn. 3 and the fast flow of the water in Stn. 4 as well as the presence of

cogon grasses along the river banks in these two (2) stations during the water

quality samplings done in January and July could possibly be the reasons for

the low BOD levels.



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d) Dissolved Oxygen (DO)

Dissolved oxygen is required by aquatic organisms for their metabolism and is

needed for the oxidation and removal of organic wastes in water. In polluted

waters, large amount of available dissolved oxygen is consumed by aerobic

bacteria, thus, depriving aquatic organisms of the dissolved oxygen they need

to breathe and live. In both Stns. 3 and 4, the dissolved oxygen concentrations

measured in January and July which ranged from 6.6 to 7.8 mg/l conformed to

the water quality criterion for Class C set at a minimum of 5 mg/l. However,

this criterion was not met in Stns. 1 and 2 as measured DO concentrations

appeared to be low for the two (2) sampling dates ranging from 0.4 to 4.5 mg/l.

The observed low DO might be due to the high organic loading at the river

mouth and the garbage undergoing decomposition in Stn. 2.



15

e) Oil and Grease

Oil may injure aquatic organisms by direct contact, by poisoning with various

soluble toxic substances that may be leached from it or by emulsions which

may cause clogging of the gills of the fish. Under DAO 34, the oil and grease

concentration of 2 mg/l is the set criterion for Class C waters. During the first

sampling in January, the results of oil and grease analysis showed that

measured concentrations in Stns. 1 and 2 both at 0.5 mg/l were within the

criterion while in Stns. 3 and 4 at 7.8 mg/l and 7.3 mg/l., respectively, failed

the criterion. However, recorded oil and grease concentrations in all of the

four (4) stations for the July sampling ranging from <1 to 0.5 mg/l passed the

Class C criterion.

f) Nitrate (NO3-)

Nitrate is the most highly oxidized form of nitrogen. It is an important plant

nutrient that in some cases, acts as growth-limiting nutrient. The DENR Class

C water quality criterion for nitrate was set at 10 mg/l while for ammonia, there

is no water quality criterion. Based on the analytical results, very low levels of

nitrates as compared to the 10 mg/l Class C criterion were recorded in all four

(4) stations for the two (2) sampling dates wherein the concentrations only

ranged from <0.002 to 1.739 mg/l.

Nitrate Cabuyao River

00.10.20.30.40.50.60.70.80.9

11.11.21.31.41.51.61.71.81.9


mg

/L

Dry

Wet



16

g) Inorganic Phosphate (IPO4-3

)

Phosphorus is found in natural waters and in wastewaters chiefly as

phosphates. Phosphorus is also an important plant nutrient and a primary

element in the metabolic reactions of both plants and animals. In events where

phosphate is a growth-limiting nutrient, the discharge of raw or treated

wastewater, agricultural drainage or industrial wastes with large quantity of

phosphorus into the body of water may enhance the growth of algae in

nuisance density, thus, may cause bloom or cultural eutrophication. For the

January sampling, Stn. 4 was the only station whose measured inorganic

phosphate concentration at 0.369 mg/l passed the 0.4 mg/l Class C criterion.

For the other three (3) stations, the inorganic phosphate levels were notably

higher than the Class C criterion at 0.7139 mg/l in Stn. 1, 0.6017 mg/l in Stn. 2,

and 0.5793 mg/l in Stn. 3. The analytical results for the July sampling revealed

that all of the four (4) sampling stations yielded inorganic phosphate levels

higher than the Class C criterion. Possible main sources of phosphorus are

from leaching of soil and from domestic wastes or sewage effluents.



17

h) Chloride

Chloride is present nearly in all waters, but most are in combination with

sodium as sodium chloride (NaCl) or common salt and to a lesser extent with

calcium and magnesium. Intrusion of saline water during Pasig river backflow

which usually occurs during summer months increases the chloride level of the

lake. The assessment of the Cabuyao River’s water quality in terms of chloride

showed that measured concentrations in all four (4) stations for the two (2)

sampling periods which ranged from 15 to 74 mg/l, were very much within the

350 mg/l criterion for Class C Waters.

i) Ammonia

Among the chemical parameters analyzed without the set DENR criteria,

ammonia concentrations appeared to be within alarming levels. According to

the Environmental Studies Board (1973) of U.S. Environmental Protection

Agency (EPA), a level of 0.02 mg/l un-ionized ammonia (NH3) should not be

exceeded for the protection of aquatic life. However, high concentrations of

ammonia in Stns. 1 to 4 were recorded ranging from 0.0289 to 3.099 in

January, 2011 and from 0.055 to 2.307 in July, 2011. High ammonia

concentrations could have emanated from the decomposition of nitrogenous

organic materials at various sections of the river.



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2. Biological Parameters:

a) Phytoplankton or Microscopic Algae

Based on the results of quantitative and qualitative analysis of phytoplankton

samples collected in Cabuyao River last January, 2011, the percentage

contributions of polluted water algae appeared to be significantly higher than

the percentage contribution of clean water algae in all four (4) sampling

stations, thus, all of them are assessed as polluted (see Table 3A).

In Table 3B, it can be seen that the most dominant algae identified in Stns. 1

to 4 was a polluted water species, specifically, Nitzschia sp. from Division

Bacillariophyta (diatom). In July, 2011, all of the four (4) sampling stations

remained polluted wherein the polluted algae were predominated again by

Nitzschia sp.

The results of the qualitative and quantitative analyses of algae are shown in

Table 3B while for the benthic fauna analysis, are in Table 3D.

Table 3. Results of Biological Analyses of Water Samples

3A. Summary of Water Quality Assessment in Cabuyao River Based on

Phytoplankton/Algal Population

Table 3A.1

Date of Sampling - January 27, 2011 (Dry Season)

Stations Location

Counts (organism/sq.m.) % Contribution Water

Quality

Assessment CWA PWA OTHERS TOTAL

%

CWA

%

PWA

%

OTHERS

1

Mouth of

Cabuyao

River 12209 45505 360712 418426 2.9 10.9 86.2 Polluted

2 Sitio Bulihan,

Brgy. Sala 5777 168353 10728 184858 3.1 91.1 5.8 Polluted

3

Brgy. Malitlit

(near ETON City

entrance) 16505 166703 1651 184859 8.9 90.2 0.9 Polluted

4 Malitlit

Tributary (along SLEX) 7177 169357 828848 1005382 0.7 16.8 82.4 Polluted



19

Table 3A.2

Date of Sampling – July 19, 2011 (Wet Season)

Stations Location

Counts (organism/sq.m.) % Contribution Water

Quality

Assessment CWA PWA OTHERS TOTAL

%

CWA

%

PWA

%

OTHERS

1 Mouth of

Cabuyao

River 9302 46509 22091 77902 11.9 59.7 28.4 Polluted

2 Sitio Bulihan,

Brgy. Sala 17941 205270 2871 226082 7.9 90.8 1.3 Polluted

3

Brgy. Malitlit

(near ETON

City

entrance) 0 36168 4305 40473 0 89.4 10.6 Polluted

4 Malitlit

Tributary (along SLEX) 9867 162361 211697 383925 2.6 42.3 55.1 Polluted

Notes:

CWA - Clean Water Algae

PWA - Polluted Water Algae

Others - Algae not classified as CWA or PWA

3B. Qualitative and Quantitative Analysis of Phytoplankton or Algae

Table 3B.1.


Phytoplankton/Algae

Identified (counts per

square meter)

Sampling Stations

Stn. 1 Stn. 2 Stn. 3 Stn. 4

Clean Water Indicator

Division Bacillariophyta

Navicula sp. 12209 5777 16505 6459

Pinnularia sp. 718

Sub Total 12209 5777 16505 7177

Polluted Water Indicator

Division Cyanophyta

Oscillatoria sp. 825 2476 1435


Gomphonema sp. 1110 1435

Nitzschia sp. 44395 167528 164227 166487

Sub Total 45505 168353 166703 169357



20

Phytoplankton/Algae

Identified (counts per

square meter)

Sampling Stations


Others

Division Cyanophyta

Anabaenopsis sp. 2220 274130

Division Chlorophyta

Actinastrum sp. 3330 5741

Coelastrum sp. 8879 5741

Cosmarium sp. 2870

Closterium sp. 718

Crucigenia sp. 204218 9903 80373

Oocystis sp. 4440 2870

Pediastrum sp. 5023

Scenedesmus sp. 116537 442770

Selenastrum sp. 3330


Amphora sp. 1435

Rhopalodia sp.

Stauroneis sp. 825 718

Stephanodiscus sp. 13318 6459

Synedra sp. 2220 1651

Division Pyrrophyta

Glenodinium sp. 2220

Sub Total 360712 10728 1651 828848

TOTAL 418426 184858 184859 1005382



21

Table 3B.2.


Phytoplankton/Algae

Identified (counts

per square meter)

Sampling Stations


Clean Water

Indicator


Cladophora sp 718

Navicula sp. 3488 718 9867

Pinnularia sp. 5814 17223

Sub Total 9302 17941 0 9867

Polluted Water

Indicator

Division Cyanophyta

Lyngbya sp. 2153

Oscillatoria sp. 1163 156072 2691


Spirogyra sp 3488

Division

Bacillariophyta

Gomphonema sp. 3488 718 11661

Nitzschia sp. 38370 48480 36168 148009

Sub Total 46509 205270 36168 162361



22

Phytoplankton/Algae

Identified (counts

per square meter)

Sampling Stations


Others


Closterium sp. 718

Cosmarium sp. 1794

Golenkinia sp. 897

Division

Bacillariophyta

Amphora sp. 2325 1722 2691

Cymbella ap 861

Melosira sp. 17441 204521

Stauroneis sp. 1722

Stephanodiscus sp. 2325 718 1794

Division Pyrrophyta

Glenodinium sp. 1435

Sub Total 22091 2871 4305 211697

TOTAL 77902 226082 40473 383925

b) Benthic Fauna

Table 3C shows the water quality assessments based on the identified benthic

fauna population. Stns. 1 and 4 were moderately polluted while Stns. 2 and 3

were polluted during the January sampling. The moderately polluted benthic

fauna indicators in Stns. 1 and 3 are from Families Thiaridae (Tarebia

granifera, Tiara scabra and Melanoides tuberculatus), Planorbidae (Gyralus

sp.), Stenothyridae (Stenothyra Formosa), Conidae and Corbiculidae

(Corbicula manilensis) while in Stns. 2 and 4, the polluted water indicators

are from Families Chironomidae (chironomid larvae and pupae),

Ceratopogonidae (ceratopogonid larvae), Psychodidae (Psychoda pupae) and

Tubificidae as well as from Class Hirudinea. For the July sampling, obtained

water quality assessments for benthic fauna were moderately polluted for Stn.

1, polluted for Stn. 2 and clean for both Stns. 3 and 4. The moderately

polluted algae in Stn. 1 belong to Families Thiaridae (Thiara riqueti, Thiara

scabra and Semisulcospira libertine) and Planorbidae (Hippeutis umbicalis).

The polluted algae in Stn. 2 are from Family Chironomidae (chironomid

larvae and chironomid pupae). The clean water species of benthic fauna found

in Stns. 3 and 4 are from Families Gerridae (water strider), Baetidae (Baetis

sp.), Caenidae (Caenis sp.), Hydropsychidae (Hydropsyche sp.),

Hydrophilidae (Hydrochus sp.), Potamidae (freshwater crab) and Crustacea

(freshwater shrimp).



23

3C. Summary of Water Quality Assessment in Cabuyao River Based on Benthic

Fauna Population

Table 3C.1


Station

Counts (individuals per square meter) % Contribution Water

Quality

Assessment CWI MPWI PWI Others Total %CWI %MPWI %PWI %Others

Stn. 1 95 334 95 571 1095 8.7 30.5 8.7 52.1 Moderately

Polluted

Stn. 2 0 55 555 33 643 0 8.6 86.3 5.1 Polluted

Stn. 3 110 33 166 11 320 34.4 10.3 51.9 3.4 Polluted

Stn. 4 166 233 67 0 466 35.6 50 14.4 0 Moderately

Polluted

Table 3C.2


Station

Counts (individual per square meter) % Contribution Water

Quality

Assessment CWI MPWI PWI Others Total %CWI %MPWI %PWI %Others

Stn. 1 0 192 95 - 287 0 66.9 33.1 - Moderately

Polluted

Stn. 2 11 11 578 - 600 1.8 1.8 96.3 - Polluted

Stn. 3 111 33 22 - 166 66.9 19.9 13.3 - Clean

Stn. 4 132 0 11 - 143 92.3 0 7.7 - Clean

Notes:

Stn. 1 - Cabuyao River mouth

Stn. 2 - Cabuyao River in Sitio Bulihan, Brgy. Sala

Stn.. 3 - Cabuyao River in Brgy. Malitlit (near ETON City)

Stn. 4 - Malitlit tributary (along SLEX) CWI - Clean Water Indicator

MPWI - Moderately Polluted Water Indicator

PWI - Polluted Water Indicator

Others - Organisms not classified as either CWI, MPWI or PWI



24

3D. Qualitative and Quantitative of Benthic Fauna

Table 3D.1 Date of Sampling - January 27, 2011 (Dry Season)

Organisms (individual

per square meter)

Sampling Stations



(CWI)

Class Arachnida

Hydracarina

Hydracnellae 95

Order Ephemeroptera

Family Baetidae

Baetis sp. 33

Family Caenidae

Caenis sp. 33

Order Trichoptera

Family

Hydropsychidae

Hydropsyche 44 22

Family

Helicopsychidae 144

TOTAL CWI 95 0 110 166

Moderately Polluted

Indicator (MPWI)

Class Gastropoda

Family Thiaridae 56

Tarebia granifera 48 22 33

Thiara scabra 95 11 44

Melanoides tuberculatus

11 22

Family Planorbidae

Gyralus sp. 95

Family Stenothyridae

Stenothyra formosa 48 11

Family Viviparidae

Viviparus viviparus 11

Bellamya angularis 67

Family Conidae 11

Class Pelecypoda

Family Corbiculidae

Corbicula manilensis 48



25

Organisms Sampling Stations


Class Insecta

Order Odonata

Sub-order Zygoptera 22

Family Viviparidae

Viviparus viviparus

Bellamya angularis

TOTAL MPWI 334 55 33 233

Polluted Water

Indicator (PWI)

Class Gastropoda

Family Physidae

Physa gyrina 95

Class Insecta

Order Diptera

Family Chironomidae

chironomid larva 322 111 56

chironomid pupa 233 11

Family

Ceratopogonidae

ceratopogonid larva 11

Family Psychodidae

Psychoda (pupa) 11

Class Oligochaeta

Family Tubificidae 22

Class Hirudinea 11

TOTAL PWI 95 555 166 67

Others

Class Crustacea

Order Ostracoda

Family Cyprididae

Cypricercus

cypricercus 571 11

Class Insecta

Unidentified insecta 22 11

TOTAL OTHERS 571 33 11 0



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Table 3D.2 Date of Sampling - July 19, 2011 (Wet Season)


per square meter)

Sampling Stations



(CWI)

Order Hemiptera

Family Gerridae

Water strider 11

Order Ephemeroptera

Family Baetidae

Baetis sp. 67 22

Family Caenidae

Caenis sp. 33

Order Trichoptera

Family

Hydropsychidae

Hydropsyche 44 44

Order Coleoptera

Family Hydrophilidae

Hydrochus sp. 11

Family Potamidae

Freshwater crab 11

Family Crustacea

Freshwater shrimp 11

TOTAL CWI 0 11 111 132

Moderately Polluted

Indicator (MPWI)

Class Gastropoda

Family Thiaridae

Thiara riqueti 48

Thiara scabra 48 11

Thiara sp. 11 22

Semisulcospira

libertina 48

Family Planorbidae

Hippeutis

umbicalis 48

TOTAL MPWI 192 11 33 0



27


per square meter)

Sampling Stations


Polluted Water

Indicator (PWI)

Class Gastropoda

Family Physidae

Physa gyrina 95

Class Insecta

Order Diptera

Family Chironomidae

378 22

chironomid larva 200 11

chironomid pupa

TOTAL PWI 95 578 22 11

Others

Class Crustacea

Order Ostracoda

Family Cyprididae

Cypricercus

cypricercus

TOTAL OTHERS 0 0 0 0



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4. Bacteriological Parameters:

The results of the bacteriological analyses of the water samples are indicated in

Table 4.

Based on the total coliform concentrations in all of four (4) stations in Cabuyao

River last January 2011, all of them significantly exceeded the DENR Class C

water quality criterion of 5000 MPN/100 ml for total coliforms. The total

coliform levels in Stns. 1 and 2 considerably increased in July to 1,600,000 and

>1,600,000 MPN/100ml, respectively, which further exceeded the Class C DENR

criterion. In Stn. 3, the total coliform concentration at 54 MPN/100 ml remained

higher than the 5,000 MPN/100 ml criterion but in Stn. 4, low total coliform level

was noted at 1,300 MPN/100 ml. For both the dry and wet seasons sampling, all

stations were found contaminated with Escherichia coli, a bacterium that can

cause diseases such as diarrhea and urinary tract infections. For fecal coliforms,

DENR has no set criterion for Class C Waters. However, the data on fecal

coliforms showed high levels in all of the four (4) stations in January. For July,

the fecal coliforms remained high in Stns. 1, 2 and 3 while obtained concentration

in Stn. 4 reduced considerably from 90,000 MPN/100 ml in January to only 330

MPN/100ml.

Table 4. Results of Bacteriological Analyses of Water Samples

Sampling Dates: January 27, 2011 (Dry Season) and July 19, 2011 (Wet Season)

Parameters Stn. 1 Stn. 2 Stn. 3 Stn. 4

Dry Wet Dry Wet Dry Wet Dry Wet Total Coliform (MPN/100 ml)

>160000 1600000 160000 >1600000 >160000 54000 90000 1300

Fecal Coliform

(MPN/100 ml) >160000 920000 160000 1600000 >160000 54000 90000 330

Detection of

Escherichia coli Present Present Present Present Present Present Present Present

Note: DENR Class C Water Quality Criterion for total coliforms is 5,000 MPN/100 ml.

There is no set criterion for fecal coliforms.

Total Coliform

Cabuyao River

0

200000

400000

600000

800000

1000000

1200000

1400000

1600000

1800000


MP

N/1

00m

l

Dry

Wet



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Conclusion and Recommendations:

From the above findings, it is very evident that Cabuyao River is polluted to some extent

based on BOD, dissolved oxygen (DO), oil and grease and inorganic phosphate levels.

The observed high inorganic phosphate and ammonia levels in the four (4) river stations

in January and July indicate high organic loadings. The polluted condition of the river

both in the dry and wet seasons was also reflected on the assessments using algae as

water quality indicators. However, in spite of the observed varying levels of pollution in

Cabuyao River, low total coliform level relative to the DENR Class C criterion was noted

in July in Stn. 4 and the benthic fauna population was dominated by clean water species

in Stns 3 and 4 during the same period. The natural purification due to dilution by rain

during the wet season could somehow be the reason for the improved water quality

condition in Stn. 4 in July in terms of total coliform counts and the dominant benthic

fauna identified.

Overall, Cabuyao River is recommended for clean-up/rehabilitation. In order for the

improvement of the river’s water quality to be sustainable, it is strongly recommended

that this activity be initiated by LLDA and its implementation must have full support

from the Local Government of Cabuyao. The community must also be actively involved

because of their big role in the rehabilitation activity. Through the community

participation component, the government can run on the ground activities and workshops

for the public and involve them in decision-making processes. The participation of the

private/industrial sector, river council and environmental army is equally very vital. In

addition, saturation drives should be done to track down and control the pollution source

cabuyao river water quality assessment report 2011

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