Cabuyao River Water Quality Assessment Report 2011

Cabuyao River Water Quality Assessment Report

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

Environmental Laboratory and Research Division 1 Laguna Lake Development Authority Cabuyao River Water Quality Assessment Report

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,

Environmental Laboratory and Research Division 2 Laguna Lake Development Authority Cabuyao River Water Quality Assessment Report

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.

Environmental Laboratory and Research Division 3 Laguna Lake Development Authority Cabuyao River Water Quality Assessment Report

Figure 1 1

Location of Cabuyao River Sampling

Stations 2 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

Environmental Laboratory and Research Division 4 Laguna Lake Development Authority Cabuyao River Water Quality Assessment Report

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

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

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)

Environmental Laboratory and Research Division 5 Laguna Lake Development Authority Cabuyao River Water Quality Assessment Report

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

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

Figure 5. Photo of Stn. 4 Malitlit tributary (located along SLEX near the outlet of ETON City and before the confluence with Cabuyao River)

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

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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.

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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, water moderately water fast flowing, water fast flowing, thick growth of water flowing, with sandy damming of the water presence of river bed hyacinth and presence of bottom, illegal settlers noted for irrigation with boulders, head- garbage noted, with low noticed along river purposes, river banks sized stones and pebbles, river banks banks, presence of high with cogon grasses both sides of the river garbage also noted and other vegetation, are high and with cogon with muddy river bed 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, water moderately water fast flowing, water fast flowing, absence of water flowing, garbage on both presence of small fish presence of river bed hyacinth in the area only sides of the river banks, and shrimp, river banks with boulders, head- patches near the mouth. presence of soft-shelled high with cogon grasses sized stones and pebbles, turtle, abundant fish fry and other vegetation, both sides of the river on the side of the river. with sandy river bed. are high and with cogon grass and trees. Small fish, shrimp and crab present.

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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)

STATIONS DENR Class C Water Quality PARAMETERS Stn. 1 Stn. 2 Stn. 3 Stn. 4 Criteria 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, 45 14 45 42 37 <4 25 30 * mg/L Biochemical Oxygen 14 8 35 33 5 <2 4 2 10 Demand, mg/L 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 132 88 88 80 80 64 92 88 * CaCO3/L 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

Environmental Laboratory and Research Division 10 Laguna Lake Development Authority Cabuyao River Water Quality Assessment Report

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.

Environmental Laboratory and Research Division 11 Laguna Lake Development Authority Cabuyao River Water Quality Assessment Report

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.

Total Suspended Solids Cabuyao River

140 120 Dry 100 Wet 80

mg/L 60 40 20 0 Stn. 1 Stn. 2 Stn.3 Stn. 4

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.

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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.

Environmental Laboratory and Research Division 13 Laguna Lake Development Authority Cabuyao River Water Quality Assessment Report

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.

Environmental Laboratory and Research Division 14 Laguna Lake Development Authority Cabuyao River Water Quality Assessment Report

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

1.9 Dry 1.8 1.7 Wet 1.6 1.5 1.4 1.3 1.2 1.1 1

mg/L 0.9 0.8 0.7 0.6 0.5 0.4 0.3 0.2 0.1 0 Stn. 1 Stn. 2 Stn.3 Stn. 4 Environmental Laboratory and Research Division 15 Laguna Lake Development Authority Cabuyao River Water Quality Assessment Report

-3 g) Inorganic Phosphate (IPO4 )

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.

Environmental Laboratory and Research Division 16 Laguna Lake Development Authority Cabuyao River Water Quality Assessment Report

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.

Environmental Laboratory and Research Division 17 Laguna Lake Development Authority Cabuyao River Water Quality Assessment Report

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) Counts (organism/sq.m.) % Contribution Water Stations Location % % % Quality CWA PWA OTHERS TOTAL CWA PWA OTHERS Assessment Mouth of 1 Cabuyao River 12209 45505 360712 418426 2.9 10.9 86.2 Polluted Sitio Bulihan, 2 Brgy. Sala 5777 168353 10728 184858 3.1 91.1 5.8 Polluted Brgy. Malitlit (near ETON 3 City entrance) 16505 166703 1651 184859 8.9 90.2 0.9 Polluted Malitlit 4 Tributary (along SLEX) 7177 169357 828848 1005382 0.7 16.8 82.4 Polluted

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Table 3A.2 Date of Sampling – July 19, 2011 (Wet Season)

Counts (organism/sq.m.) % Contribution Water Stations Location % % % Quality CWA PWA OTHERS TOTAL CWA PWA OTHERS Assessment Mouth of 1 Cabuyao River 9302 46509 22091 77902 11.9 59.7 28.4 Polluted Sitio Bulihan, 2 Brgy. Sala 17941 205270 2871 226082 7.9 90.8 1.3 Polluted Brgy. Malitlit (near ETON 3 City entrance) 0 36168 4305 40473 0 89.4 10.6 Polluted Malitlit 4 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. Date of Sampling - January 27, 2011 (Dry Season)

Phytoplankton/Algae Sampling Stations Identified (counts per square meter) 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

Division Bacillariophyta Gomphonema sp. 1110 1435 Nitzschia sp. 44395 167528 164227 166487

Sub Total 45505 168353 166703 169357

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Phytoplankton/Algae Sampling Stations Identified (counts per square meter) Stn. 1 Stn. 2 Stn. 3 Stn. 4 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

Division Bacillariophyta 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

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Table 3B.2. Date of Sampling – July 19, 2011 (Wet Season)

Phytoplankton/Algae Sampling Stations Identified (counts Stn. 1 Stn. 2 Stn. 3 Stn. 4 per square meter) Clean Water Indicator

Division Bacillariophyta 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

Division Chlorophyta Spirogyra sp 3488

Division Bacillariophyta Gomphonema sp. 3488 718 11661 Nitzschia sp. 38370 48480 36168 148009

Sub Total 46509 205270 36168 162361

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Phytoplankton/Algae Sampling Stations Identified (counts per square meter) Stn. 1 Stn. 2 Stn. 3 Stn. 4 Others

Division Chlorophyta 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).

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

Table 3C.1 Date of Sampling - January 27, 2011 (Dry Season) Counts (individuals per square meter) % Contribution Water Station Quality CWI MPWI PWI Others Total %CWI %MPWI %PWI %Others Assessment Moderately Stn. 1 95 334 95 571 1095 8.7 30.5 8.7 52.1 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

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

Table 3C.2 Date of Sampling – July 19, 2011 (Wet Season) Counts (individual per square meter) % Contribution Water Station Quality CWI MPWI PWI Others Total %CWI %MPWI %PWI %Others Assessment Moderately Stn. 1 0 192 95 - 287 0 66.9 33.1 - 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

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3D. Qualitative and Quantitative of Benthic Fauna

Table 3D.1 Date of Sampling - January 27, 2011 (Dry Season) Organisms (individual Sampling Stations per square meter) Stn. 1 Stn. 2 Stn. 3 Stn. 4 Clean Water Indicator (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 11 tuberculatus 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 Environmental Laboratory and Research Division 24 Laguna Lake Development Authority Cabuyao River Water Quality Assessment Report

Sampling Stations Organisms Stn. 1 Stn. 2 Stn. 3 Stn. 4 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 571 11 cypricercus

Class Insecta Unidentified insecta 22 11

TOTAL OTHERS 571 33 11 0

Environmental Laboratory and Research Division 25 Laguna Lake Development Authority Cabuyao River Water Quality Assessment Report

Table 3D.2 Date of Sampling - July 19, 2011 (Wet Season) Organisms (individual Sampling Stations per square meter) Stn. 1 Stn. 2 Stn. 3 Stn. 4 Clean Water Indicator (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 48 libertina Family Planorbidae Hippeutis 48 umbicalis

TOTAL MPWI 192 11 33 0

Environmental Laboratory and Research Division 26 Laguna Lake Development Authority Cabuyao River Water Quality Assessment Report

Sampling Stations Organisms (individual per square meter) Stn. 1 Stn. 2 Stn. 3 Stn. 4 Polluted Water

Indicator (PWI)

Class Gastropoda Family Physidae Physa gyrina 95

Class Insecta Order Diptera Family 378 22 Chironomidae 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

Environmental Laboratory and Research Division 27 Laguna Lake Development Authority Cabuyao River Water Quality Assessment Report

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)

Stn. 1 Stn. 2 Stn. 3 Stn. 4 Parameters Dry Wet Dry Wet Dry Wet Dry Wet Total Coliform >160000 1600000 160000 >1600000 >160000 54000 90000 1300 (MPN/100 ml) Fecal Coliform >160000 920000 160000 1600000 >160000 54000 90000 330 (MPN/100 ml) Detection of Present Present Present Present Present Present Present Present Escherichia coli

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

1800000 1600000 Dry 1400000 Wet 1200000 1000000 800000

MPN/100ml 600000 400000 200000 0 Stn. 1 Stn. 2 Stn.3 Stn. 4

Environmental Laboratory and Research Division 28 Laguna Lake Development Authority Cabuyao River Water Quality Assessment Report

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

Environmental Laboratory and Research Division 29 Laguna Lake Development Authority