Jose Rizal Memorial state College – Main Campus, Dapitan City. Jose Rizal .....
Mean salinity on the other hand, was 28.12 ppt ±6.69, which was quite lower.
E-International Scientific Research Journal ISSN: 2094-1749 Volume: 2 Issue: 4, 2010
HYDROBIOLOGICAL ASSESSMENT OF LIBORAN RIVER, DAPITAN CITY S. Campiseño, E. Campiseño, M.R. Naguit & B. Flores
Jose Rizal Memorial state College – Main Campus, Dapitan City Jose Rizal Memorial state College – Main Campus, Dapitan City Jose Rizal Memorial state College – Katipunan Campus, Katipunan, ZDN Jose Rizal Memorial state College – Main Campus, Dapitan City
Abstract The water quality of Liboran River was examined to determine its present condition to serve as future reference or gauge of any effect brought about by climate change. Data on plankton composition, total coliform, phosphates, total suspended solids, as well as physicochemical parameters such as dissolved oxygen, pH, temperature and salinity were collected. Based on the results of the three surveys, the river does not qualify for a Class SA coastal water suitable for fishery production.
Keywords: coliform, Liboran River, phosphates, pH, DO
Introduction Rivers are lotic or running water environment that are usually habitats to an amazing diversity of species with abundant specialized niches (Brown, 1995). They are also sources of water for drinking, cleaning, bathing, washing clothes, preparing and cooking food, gardening and even for irrigating farmlands. Moreover, they serve as source of livelihood like fishing and in some areas, quarrying. Liboran River is partly enclosing the city proper of Dapitan City (Fig 1). It has two outlets to Dapitan Bay which completes the encirclement of the city proper: Bagting and Polo. The river has a length of 7.7 km and an area of 62.6 ha. Its depth varies from 1 m to 2.7 m. It also receives at least six tributaries. Its greatest contributor (65.53 m3/sec) is Dapitan River at the south end (SUAKCREM, 2000). The river banks are line with naturally growing and planted mangrove trees. Milkfish grow out ponds are found on either side of the river. Fish pens and talaba cultures are evident in the river itself. Human settlements are also found along the river bank, particularly in Tambak and to the north and southeast of Bagting Bridge. Like any other ecosystems, rivers are also threatened by the effects of climate change. A global analysis of the potential effect of climate change on river basins indicates that many rivers impacted by dams or extensive development will require significant management interventions to protect ecosystems and people. Hence, this study is helpful in understanding climate change impacts on river system specifically the effects brought about by droughts and 366
E-International Scientific Research Journal ISSN: 2094-1749 Volume: 2 Issue: 4, 2010 typhoons due to the El Niňo and La Niňa phenomena. The trend towards the “shallowing” process and the flooding of rivers due to climate variability can significantly alter the conditions of river systems in terms of biodiversity composition and physical condition. Extreme drought causes rivers to dry out and this would mean the extinction of some species that are not resistant or adaptable to the absence of water (Juranilla-Sanchez et al., 2007). Flash flooding after heavy rains or during typhoons causes the river to swell or overflow and destroys the river banks and the plants that grow there. Floods also erode the soil that subsequently contribute to the siltation process downstream.
Research Method and Design Seven stations were established as sampling sites along the Liboran River and were sampled in June 2006 and May 2010. Physico-chemical parameters such as pH, temperature, dissolved oxygen (DO), salinity, total suspended solids, phosphates and nitrates were measured, as well biological parameters such as total coliform, Escherichia coli and plankton composition.
Determination of Dissolved Oxygen (DO), pH, Salinity and Temperature. In situ measurements of dissolved oxygen, pH, temperature and salinity were conducted a portable DO meter, pH meter, thermometer and refractometer, respectively in three replications. Phosphates (PO4-P mg/L) Analysis. Water samples in three replicates (350 ml each) were taken from the three sampling sites and were placed in a glass bottle. (Sampling bottles were soaked with muriatic acid and washed with a phosphate free detergent before use). Samples were then placed in a styropore box with ice and were brought to Silliman University Marine Laboratory for analysis. Stocks solutions of Sulphuric Acid, Ascorbic Acid, and Mixed Reagent were first prepared. Sulphuric Acid was prepared through adding 125 ml concentrated H2SO4 to water and was diluted to 500 ml, stored in a plastic bottle. Ascorbic Acid on the other hand, was prepared through dissolving 5.0g ascorbic acid in an amber glass bottle with 25 ml water, and added with 25 ml sulphuric acid solution and stored in the refrigerator. Mixed Reagent was prepared through dissolving 6.25 g (NH4) 6Mo7024.4H2O in 62.5 ml water. Then 0.25g potassium antimony tartrate (with or without 1/2H2O) was dissolved in 10.0 ml water. The molybdate solution was then added to 175 ml of dilute sulphuric acid with the tartrate, and was stored in a glass bottle. Then the following were added to a test tube or scintillation vial: 10 ml filtered sample, 0.2 ml ascorbic acid reagent, and 0.2 ml mixed reagent. Absorbance at 880 nm was measured between 5 and 30 minutes. The concentration of PO4-P in mg/L is given by the formula of Spotte as quoted by Argente (2009): C s Vs As Cu = Vu As
Where: Cu = the concentration of the unknown in mg PO4-P/L Cs = the concentration of the standard in mg PO4-P /L Au = the absorbance of the unknown As = the absorbance of standard 367
E-International Scientific Research Journal ISSN: 2094-1749 Volume: 2 Issue: 4, 2010 Vu = volume of the unknown pipetted in liters Vs = volume of the standard pipetted in liters Total Suspended Solids (TSS). One liter water samples in three replications were collected in each of the sampling station. In the laboratory, water samples were filtered using an Improvised Filtration Apparatus and pre-weighed Whatman GFC 47 mm filters. The filters were pre-stabilized to constant dry weight, labeled and weighed before filtration. After filtration, each filter with residue was air-dried for 24 hours, oven dried at 100 0C to constant dry weight, and weighed again. Total Suspended Solids (TSS mg/L) were calculated using the formula below (Argente 2009): TSS = (W f+r – Wf) / Vw Where Wf is the pre-stabilized weight of the filter in milligrams (mg), W f+r is the stabilized weight of the filter and residue in milligrams (mg), and Vw is the volume of the water in liter (L).
Nitrate Analysis Coliform Bacteria Contamination. Water samples (100 mL each) were collected using sterile sampling bottle and processed using membrane filtration method for coliform analysis. Coliform was cultured in endobroth medium at 35 C for 24 – 48 hours. The resulting colonies were counted indicated by the characteristic green-gold metallic sheen for Escherichia coli and light to dark pink color for Salmonella. The most probable number (MPN) of colonies per 100 ml of seawater was determined using the formula: No. of colonies MPN/100 mL = --------------------------------------------x 100 Volume of water sample in mL An ocular inspection was also conducted to determine the number of households without toilets.
Plankton Composition. Replicated vertical tows were done in each sampling site. A standard plankton net with 80 um mesh size was suspended at 1 m below the surface of the water column between 10:00 am and 2:00 pm. Samples were preserved in 4% buffered formalin with Rose Bengal stain. Counting and identification of species were done under a compound microscope. Population densities were calculated using the following formula (Newell & Newell, 1963):
No. of organism in 1 m sample x total volume of sample D = ---------------------------------------------------------------------------------Total volume of water sampled
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E-International Scientific Research Journal ISSN: 2094-1749 Volume: 2 Issue: 4, 2010 Species diversity was determined using the Shannon index of diversity and species richness.
Results Coliform Contamination. Water samples from all seven stations in both samplings were positive for total coliform (Table 1). In 2006, Stations 5 (Banonong) and 2 (Linabo) had the highest counts of Salmonella sp, with counts of 7.75 colonies x 103 100 ml-1 (±0.250) and 7.1667 colonies x 103 100 ml-1 (± 0.347 ), respectively. The former station recorded even higher count (TNTC, too numerous to count) in the 2010 sampling, along with station 4 (Ambogoc). Linabo recorded the second highest followed by Cawa-cawa and Polo. Esherichia coli colonies were also too numerous to count in both stations on the same sampling period. In the 2006 sampling, the fecal coliform was highest in Ambogoc( 2.0 colonies x 103 100 ml-1 ± 0.304) followed by Linabo (1.917 colonies x 103 100 ml-1 ± 0.344). These values were smaller compared to the counts obtained in November 1999 (Table 1) except for the TNTC readings for Salmonella sp. in Ambogoc and Banonong during the last sampling. Salmonella counts during the 2010 sampling was significantly higher compared to the 2006 sampling but was comparable to the 1999 sampling of SUAKCREM [F(2,17)= 4.156, p=0.034].
Plankton Community. The plankton community in Liboran River were categorized into diatoms dinoflagellates and zooplankton (Fig. 3). As shown, the latter comprised 50% and 46% of the total community in 2006 and 2010, respectively. The diatoms made up the 29% in both sampling periods while the dinoflagellates comprised the 21% (2006) and 25% (2010). Species composition and estimated population densities of plankton in Liboran River are presented in Tables 2 and 3. In 2006, the diatoms were composed of fifty-seven species with five dominant genera: Coscinodiscus, Navicula, Gyrosigma, Chaetoceros and Amphiprora. The blue-green alga, Oscillatoria was also abundant Table 2. A total of fourteen species of dinoflagellates were identified belonging to 11 genera. Three of these genera, Dinophysis, Ceratium and Peridinium are known to cause red tides. The first two genera dominated the dinoflagellate community. Dinophysis has also toxin-producing species. Zooplankton was made up of 21 species typically dominated by crustaceans particularly, the copepods. In 2010, there were only 44 species of diatoms, 14 dinoflagellates and 11 zooplankton species identified. With regard to the diversity of the plankton community, richness and Shannon diversity indices were 2.54 ±0.340 and 1.12 ±0.069, respectively in 2010 and 2.84 ±0.34 and 1.20 ± 0.10 in 2006.
Table 1. Comparison of mean total coliform, Escherichia coli and Salmonella typhymurium counts (colonies 100 ml-1)with the study conducted by SUAKCREM in 1999.
Stations
This study 2010 2006 Colonies 100-1 colonies 100 ml-1 Salmonella E. coli Salmonella E.coli sp. sp
SUAKCREM, 1999 Colonies 100-1 Salmonella E. coli sp
369
E-International Scientific Research Journal ISSN: 2094-1749 Volume: 2 Issue: 4, 2010 1 Bagting
4 Ambogoc
13000 ±57.98 29100 ±77.78 12800 ±181.02 TNTC
700 ±9.19 4700 ±45.96 1400 ±10.6 TNTC
5 Banonong
TNTC
TNTC
6 Maria Uray
18900 ±95.46 22000 ±17.68
670 ±22.63 970 ±137.2
26200 ±77.07
440 ±62.22
2 Linabo 3 Tambak
7 Polo 8 Cawa-cawa
6917 +0.250 7167 +0.347 3833 +0.441 6417 +0.599 7750 +0.250 917 +0.250 1917 +0.008
1417 +0.250 1917 +0.344 833 +0.167 2000 +0.304 1000 +0.000 83 +0.083 250 +0.160
33000
12700
37500
10300
22500
0
33000
2200
30000
2100
Physico-chemical Parameters. In 2006, phosphate concentrations ranged from 0.1250.205 mg /L while in 2010, it ranged 0.04-0.13 mg /L (Figure 4). Total suspended solids were from 0.02-0.04 mg/L in 2006 and from 0.04-0.249 mg/L in 2010, both, primarily composed of sediments. These values were lower compared to the values obtained from other similar studies conducted in Bais Bay in Negros Oriental (22.75 – 76.74 mg/L) (Dawa, 2007) and Lingayen Gulf (5.8 – 71.6 mg/L) (San Diego & Ranches, 2003). Other hydrological parameters measured are presented in Table 3. As revealed, the mean dissolved oxygen of Liboran River in the latest survey was comparable to the readings obtained in 2006 (4.63 mg/L ±0.919 and 4.76 mg/L ±0.37, respectively) [t(12)=0.364, p=0.722]. Mean salinity on the other hand, was 28.12 ppt ±6.69, which was quite lower compared to the 2006 reading, 32.62 ppt ±2.20 but not significant [t (12)=1.42, p=0.180]. In addition, pH levels were almost the same in both sampling periods (2006=7.92 ±0.053; 2010= 7.8 ±0.215) [t(12)=1.42, p=0.180]. Lastly, the average water temperature was significantly lower (30.75 °C ±0.92) in 2010 than in 2006 (31.77 °C ±0.204) [t(12)=2.8, p=0.014].
Figure 3 . Plankton distribution at Liboran River in two samplings using vertical tow. 370
E-International Scientific Research Journal ISSN: 2094-1749 Volume: 2 Issue: 4, 2010 Discussion There was a decrease in the total coliform in 2006 from 31,746 colonies/100 mL in 1999 to 6,059 colonies/100 mL. The decrease could be attributed to the removal of abandoned oyster culture structures, fish traps and other obstructions within the river which increased the flow of water in and out of the river. An alarming increase was observed in the recent survey. Ambogoc and Banonong consistently have higher total coliform counts in all three suveys. Both total and fecal coliform counts exceed the standard limit for Class SA coastal and marine waters but were below for class SB (DENR standard No. 34 s. 1999). In the recent survey, it was observed that the river’s opening has been reduced at the portion where a bridge was being constructed. The bridge’s design requires the filling up both sides of the river bank with soil and shorter and stouter concrete support structures that even the smallest banca cannot pass through it. It should be noted that the movement of water in the river is tidal. The only means for the inner portions of the river to flush out and receive fresh supply of water is tidal currents. The plankton community is fairly the same in terms of diversity, although there was a decrease in the zooplankton and dinoflagellates composition by 4 %. The phosphate values obtained in both samplings (2006= 0.17 mg/L ±0.025; 2010= 0.08 mg/L ±0.045) were way above the ASEAN phosphate concentration criteria values for coastal (0.015 mg/L) and estuarine (0.045 mg/L) waters. These high values is probably caused by water from adjacent fishponds (fertilizer and fishmeal) as well as from rice fields that empty into the different creek tributaries of Liboran River and local residents (soap used for washing and bathing).
Table 2. Species composition of plankton in Liboran River. 1
2
3
2010 4 5
6
7
8
1
2
√
√
√
√
√
√
√
√
3
2006 4 5
6
7
√
√
√
√
√ √ √
√
Species Phytoplankton Diatom Achnanthes Acterionellopsis Actinocyclus Actinoptychus Amphipleura pellucida Amphiprora hyperborean Amphora Amphora ovalis Asterionella sp√ Asterionella japonica Bacillaria Biddulphia Caloneis siloula var inflata Campylodiscus Centropages hamatus Chaetoceros Chlorobotrys Closteriopsis
√ √ √
√ √
√
√ √
√
√
√ √
√ √
√ √ √
√
√
√
√
√
√
√
√
√
√
√
√
√
√
√
√
√ √
√
√
√
√
√
√ √ √
√ √
√
√
√
√
√ √
371
E-International Scientific Research Journal ISSN: 2094-1749 Volume: 2 Issue: 4, 2010 Closterium Closterium acutum Cocconeis Coscinodiscus Cosmarium Cylindrotheca C. closterrium Cymatopleura Cymbella Diatoma Diatoma vulgare Dictyostelium Diplosalis Eunotia Entomoneis Epithemia Fragilaria Giardia flacida Guinardia Guinardia Gyrosigma Halosphaera Hyalodiscus Hyalotheca Lauderia borealis
√ √
√ √
√ √
√
√ √
√ √
√ √
√
√
√ √
√ √
√
√
√
√ √
√
√
√
√ √ √
√
√ √
√ √ √ √
√ √ √ √
√
√
√ √ √ √
√ √
√ √ √
√
√
√
√
√ √ √
√
√ √ √
√
√
√
√
√ √ √
√
√
√
√
√ √
√
√
√
√
√ √
√
√
√
√
2010 Leptocylindricus minimus Melosira M. dubia M. nummuloides Merismopedia Navicula N. circumsecta Nitzschia N. seriata Odontella Paralia sulcata Parasterope muelleri Pinnularia Pleurosigma Pseudonitzschia Pseudocalanus elongatus Rhizosolenia R. fragilissima Rufusiela Skeletonema Skeletonema costatum Stauronesi Surirella Synedra S. ulna var contracta Tabellaria fenestrate Temora longicornis Thalassionema Thalassiothrix Terspsinoe musica Tetrastum Ulothrix Dinoflagellates
√ √
2006
√ √
√
√
√
√
√
√
√
√
√
√
√ √ √ √
√
√
√
√
√
√
√
√ √ √
√ √
√ √
√
√
√
√
√
√
√
√ √
√ √ √ √ √
√
√
√ √
√
√
√ √
√ √
√
√ √
√ √
√
√ √
√
√
√
√
√
√ √
√ √
√
√
√
√
√
√ √ √
√
√
√
√ √ √
√
√ √
√ √
√ √
√ √
√ √
√
√
√
√
√ √ √
√ √ √ √
√ √
√
√ √
√ √
√
√
√
√ √ √
√
√
372
E-International Scientific Research Journal ISSN: 2094-1749 Volume: 2 Issue: 4, 2010 Alexandrium fundyense Alexandrium tamarense Ceratium furca Ceratium fusus Ceratim tripos Ceratulina pelagi Cochlodinium Coolia Cosmarium Cossmarium pyramidatum var. convexum Cosmarium prarr Diploneis puella Dinophysis Gymnodenium Gonyaulax Fibrosa japonica Klebsormidium Lithodesmium intricatum Noctiluca Peridium Protocentrum P. mexicanum P. micans P. reticulum Protoceratium reticulatum Zooplankton Tintinid Rotifera Foraminefera Orbulina Globigerina Nauplii Calanoid Cyclopoid Harpaticoid Daphnia Amphipoda Zoea larva (crab) Nematode Polychaete larvae Gastropod larvae Bivalve larvae Chaetognath
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√
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√ √ √ √ √ √ √ √
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√ √ √ √ √ √ √
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√ √ √
√ √
√ √
√ √ √ √
√ √ √ √
√ √ √ √
√ √ √ √
√ √ √ √
√ √ √ √
√ √ √ √
√ √ √ √ √
√ √ √ √ √
√
√
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√
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For dissolved oxygen (DO), values were about 0.24-0.27 mg/L below the tolerable limit (5 mg/L) but slightly higher to the marine water quality criteria for the ASEAN region (4 mg/L). Readings were quite low when compared to the previous study conducted by SUAKCREM (2000). DO readings were generally high during high tides when influx of fresh seawater gets into the inner portion of the river. Moreover, there was a significant decrease in the temperature between the two surveys (2006 = 31.77 °C ±0.204; 2010 = 30.75 °C ±0.92) [t(13)= 2.83, p=0.014]. Trends in annual mean temperature anomalies for the globe revealed a relatively rapid and steady warming through the early 1940s, followed by another period of relatively stable temperatures through the mid-1970s. 373
E-International Scientific Research Journal ISSN: 2094-1749 Volume: 2 Issue: 4, 2010 From this point onward, another rapid rise similar to that in the earlier part of the century is observed. The year 2009 was the sixth warmest in the global record (0.43°C above the 1961-1990 reference period mean), exceeded by 1998, 2005, 2003, 2002, and 2004. The period 2001-2009 (0.43°C above 1961-90 mean) is 0.19°C warmer than the 1991-2000 decade (0.24°C above 1961-90 mean).
Station Bagting Linabo Tambak Ambogoc Banonong Maria Uray Polo Cawa-cawa
Shannon index 2010 2006 1.04 1.18 1.10 1.33 1.13 1.19 1.00 1.05 1.14 1.15 1.17 1.33 1.22 1.17 1.12
Richness 2010 2006 2.40 3.15 2.88 2.86 3.09 2.91 1.52 2.17 2.45 2.80 3.03 3.22 2.70 2.83 2.22
The 1990s were the warmest complete decade in the series. The warmest year of the entire series has been 1998, with a temperature of 0.55°C above the 1961-90 mean. Fourteen of the fifteen warmest years in the series have now occurred in the past fourteen years (19952009).
Table 3. Diversity Indices of plankton at Liboran River in two samplings.
2006
2010
374
E-International Scientific Research Journal ISSN: 2094-1749 Volume: 2 Issue: 4, 2010 Figure 4. Mean phosphate concentration (mg PO4/L + SE) of the different stations established in Liboran River.
Figure 5. Mean total suspended solids (TSS) (mg/L) of the different stations. Relating the trends in the number of total coliform and plankton composition between 2006 and 2010 to temperature, Pearson product moment analysis revealed no significant correlation, hence, the trends could not be related to climate change. The high coliform count in Liboran River could only be attributed to the reduction of the water movement in the river. Mitigating measures should be done at this point for Liboran River to be suitable for Talaba culture and other aquaculture activities. Based on the results of the three surveys, the river does not qualify for a Class SA coastal water suitable for fishery production.
Table 4. The average values of the physico-chemical parameters in Liboran River. DO Station Bagting
Temperature
2006 2010 (mg/L)
Salinity
2006 (°C)
2010
2006 (ppt)
pH 2010
2006
2010
4.7
4.65
31.6
30.9
34.8
30
8.0
7.95
0.1
0.49
0.2
1.7
0.4
0.00
0.0
0.21
4.6
4.95
31.9
30.6
35.0
35
8.0
7.9
0.0
1.48
0.2
0.1
0.0
8.49
0.0
0.28
TAMBAK
4.7
5
31.7
30.3
34.0
29.5
8.0
7.85
SD +
0.0
0.28
0.1
1.0
0.0
7.78
0.0
0.21
AMBOGOC
5.6
3
32.0
32.7
30.8
16
7.9
7.4
0.0
0.00
0.0
0.1
0.4
0.00
0.0
0.00
4.4
4
31.7
31.2
30.0
25
7.9
7.65
0.0
0.42
0.0
0.2
0.0
7.07
0.0
0.07
4.7
4.15
32.1
30.9
31.3
22
7.9
7.65
0.1
0.78
0.1
1.6
0.4
2.83
0.0
0.21
SD + Linabo SD +
SD + BANONONG SD + MA. URAY SD +
375
E-International Scientific Research Journal ISSN: 2094-1749 Volume: 2 Issue: 4, 2010 POLO
4.8
6.05
31.6
29.6
32.5
35
8.0
8.05
SD +
0.1
2.19
0.0
0.8
0.0
0.00
0.0
0.07
Cawa-cawa SD +
5.25
30.0
32.5
7.95
0.78
1.4
3.54
0.21
References Alcala, E. and J. Maypa. 2000. preliminary water quality assessment of Liboran River, Dapitan City. In: A.C. Alcala, A report on Liboran River, Dapitan City submitted to Mayor Cedrick O. Ruiz, Dapitan City. Chandran, A. and A.A.M.Hatta. 2001. Survival of Escherichia coli in a tropical estuary. Journal of Environmental Sciences, Mahatma Ghandi University, Kerala, India 41-45 pp. DENR. 1990. Department of Environmental and Natural Resources Administrative Order No. 34 Series 1990. 78-80. English, S.C., wilkinsn and V. Baker (eds.). 1994. Survey manual for Tropical Marine Resources. Australian institute of Marine Science, Townsville Grasshoff, K., M. Ehrhardt and K. Kremling. 1983. methods of seawater Analysis. Weinheim: Verlag Chemie, pp.125-131. Johnston, R.1976.Marine Pollution. Department of Agriculture and Fisheries for Scotland, marine Lab, Aburdeen Scotland.Lodon: Academic Press inc. London Ltd. 13-33 pp. McPherson, C.A., P.M. Chapman, G.A.Vigers and K.S. Ong.1999. ASEAN Marine Water Quality Criteria: Contextual Framework, Principles, Methodology and Criteria for 18 Parameters. ASEAN marine Environmental Quality Criteria –working group (AMEQC-WG), ASEAN-Canada Cooperative Programme onMarine Science-Phase II). EVS Environment consultants, North Vancouver and Departmentof Fisheries, Malaysia. Pp. 568
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