PARTIDO STATE UNIVERSITY
Goa, Camarines Sur
PHYSICO-CHEMICAL ASSESSMENT OF LAKE BAAO IN BAAO, CAMARINES SUR,
PHILIPPINES
By:
JOEL C. GONOWON
IAN CHRISTOPHER D. PALAYAR
ISABEL L. PARRO
Professor:
MARIA WENDY M. SOLOMO, EdD
October 2022
INTRODUCTION
Baao is located on the map of the Philippines with coordinates 123o 17' to 123o 26' east
longitude
13o
and
25'
to
13o
30'
north
latitude.
To the north it is bordered by the autonomous cities of Pili and Ocampo; the east borders the town
of Iriga and the municipality of Sagnay; and to the northwest it borders the municipality of Bula.
Baao is about 480 km south of Metro Manila; 30 km. South of Naga City; 7.5 km. from Iriga city
and
70
km.
north
of
the
town
of
Legaspi.
For planning purposes, Baao has a total area of 14,304 hectares, of which 2,748.45 hectares are in
dispute with Bula City and Iriga City. Of which 50% or a total of 7,152 ha is located along
mountainous
terrain
with
an
average
slope
of
3.18%.
Of the total, 7,152 hectares of highland, or about 4,014 hectares, have a slope of more than 18
percent. A subtotal of 4,291 ha or 30% of the total land area is mostly flat land, about 1,430 ha or
10% is built up area, and the remaining 105 is water bodies including lakes and wetlands
(Municipality
of
Baao
Official,
2020,
Geophysical
Profile,
Website).
Baao lake is in a low-lying area in the Rinconada district, and it is prone to flooding during
the rainy season. All the small rivers that flow in the different barangays in Baao, Camaranies Sur
and, nearby municipalities go to the lake that’s why it is called the catch basin. The lake is also
surrounded by rice fields, near the residential area, and the dumping area of Partido Rice Mill
where they dumped tons of black rice ashes. The lake swells to 2,000 ha during the rainy season
but recedes to 400-600 ha, towards the municipality of Bula during the dry season. Hence it is
treated as Lake Baao-Bula (Palma, 2013). Therefore, lakes are susceptible to water pollution and
bacterial contamination by waste from the sources. Baao Lake still oozes majestic and calm waters
and thrives with an amazing biodiversity of aquatic life. However, over the years, the lake has not
been spared from various human activities associated with increasing demands on the lake's
resources. Water for domestic and agricultural use, as well as for contact recreation, boating,
washing, bathing, or swimming, and fishing. Domestic consumption and subsistence, and various
lake-related uses. The Baao - Bula people rely on Lake Baao for such purposes. We also catch fish
from the lake and sell them to nearby barangays and communities. This little-known lake serves
as a revenue-generating inland waterway through the great plains of the Rinconada part of
Camarines Sur. Baao Lake provides a reservoir that receives food sources, irrigation needs,
laundry, and discarded agricultural and household sector waste. It used to be a fishing spot for the
villagers, but it has been neglected for a long time. Research indicates that Baao Lake was last
classified by DENR Region V in 2006 as 'Class B', Recreational Water Class I. Lakes can also be
developed for aquaculture purposes and are suitable for breeding and growing fish. A water quality
analysis of Lake Bao should be conducted for residents to know the status of the lake. As a result,
residents can gain knowledge about how human, industrial, and agricultural activities affect the
water quality of the lake. Human activities in landscapes have affected water quality in progressive
and destructive ways. Given the growing demand and use of freshwater resources and growing
interest in ecosystem conservation, the results presented in this study highlight the importance of
stakeholder involvement in resource management and the importance of physico-chemical It
emphasizes the value of research aimed at providing a comprehensive understanding to gain the
necessary resources. features of tropical lake environments.
Furthermore, published data on the physicochemical properties of Lake Baao water are
very limited. Unfortunately, due to its importance to the community, few people came to study the
lake. Overall management of lakes requires basic scientific information about water quality. Direct
residents' knowledge, perceptions and attitudes regarding lake use and conditions are also assessed.
Baao Lake needs further research for better management. The people living near Lake Baao, LGU
of Baao, Camarines Sur, and future researchers who wish to study further Baao Lake would benefit
from this present research. Hence, this study was conducted to assess Baao Lake’s water quality
and evaluate policies to determine appropriate lake management initiatives. Several
physicochemical parameters have been evaluated and may help inform residents about potential
uses of the lake and local government agencies for future policy implementation.
OBJECTIVES OF THE STUDY
This study aims to assess the physico-chemical quality of Baao Lake.
Specifically, this study aims to:
1.
Analyze the level of variation in the physico-chemical quantities in the different sampling
sites of the lake system in terms of the following parameters:
a.
surface water temperature
b.
pH
c.
dissolved oxygen (DO)
d.
turbidity
e.
alkalinity
f.
Total Dissolved Solids
2. Compare the physico-chemical parameters of Baao Lake with the standard parameters of
a lake based on Water Quality Guidelines of the DENR.
3. Determine the factors (e.g. human activities) that affect the current status of Baao Lake
MATERIALS AND METHODS
Study Site
The study area was Baao Lake which is located 13°28’8’’ N and 123o18'36’’ E off the southern
part of Baao, Camarines Sur, Philippines. It is located at an elevation of 8 meters above sea level.
Three sampling sites were established along Baao Lake. The site was characteristically located
near rice paddies. Human activities are also evident in the sampling sites like quarrying, boating
and fishing.
Collection of water for physico-chemical analysis
In the lake, there were three potential collection locations. Starting from the mouth, body (middle),
and tail, representative samples of lake water were collected. As a reference point, floating bamboo
rafts were placed at each sampling site. The 1.5 L of water that was collected from each site was
stored in polyethylene (PE) bottles for chemical analysis in the laboratory. Before collecting
samples, each bottle was sterilized with warm water and rinsed with distilled water. Water samples
should be taken between the hours of 9:00 and 4:00 p.m., according to the DENR's Water Quality
Guidelines (2016).On September 23, 2022, from 10:30 to 11:00 a.m., one grab sample was used
to collect lake water samples for analysis.Fig.1 to 3 depict the locations from each station where
water samples were taken. Samples of water for: Each sampling site's temperature, pH, dissolved
oxygen, salinity, turbidity, and total dissolved solids were measured in triplicate. The samples were
transported to the Bureau of Fisheries and Aquatic Resources Laboratory-Bula for analysis in a
sealed, insulated, and properly labeled cooler box. During sampling times, field observations were
also carried out.
Figure 1. Site where water samples were taken in Station 1-Mouth
Figure 2 Site where water samples were taken in Station 2-Body(middle)
Figure 3. Site where water samples were taken in Station 3-Tail
Figure 4. Anthropogenic activities along the shore of Baao, Lake: A. bulldozer and backhoe pushing
massive rocks alongside of the shore; B. Fishing; C. Boating; D. Farming
A.
B.
C.
D.
Physico-chemical Analysis
In the Bureau of Fisheries and Aquatic Resources Laboratory-Bula, the pH, dissolved oxygen,
salinity, turbidity, and Total dissolved solids content of the water samples were evaluated. In order
to ensure the accuracy of the results, samples were brought in within an hour of being collected.
The DENR Water Quality Guidelines' standard methods for examining water were used in all
physicochemical analyses. In place of mercury-in-glass thermometers, alcohol thermometers were
used to measure the temperature of the water in degrees Celsius. In addition, pH, dissolved oxygen,
salinity, turbidity, and total dissolved solids were the ex-situ measurements; pH measured with an
Atago Digital Ph meter; the Palintest Turbidity Meter to measure turbidity; while using the YSI
Professional Water Quality Multiparameter to measure the total dissolved solids, salinity, and
dissolved oxygen, respectively. The obtained values of the various physicochemical parameters
were compared to the DENR's permissible limits to determine the water's quality (2016).
RESULTS
Samples were collected in three stations in triplicates. The description of each station is presented
in Table 1.
Table 1: The exact location and description of the three collection sites in Baao Lake, Baao,
Camarines Sur, Philippines
Sampling Sites
Station 1
GPS Coordinates
13.459440,123.319318
Mouth
Description
(Located a
few
distance away from the shore;
within water hyacinth; littoral
zone)
Station 2
13.466118,123.322665
Body (middle); Located in the
limnetic area
Station 3
13.471293,123.311765
Tail ; Far from the shore
Table 2: Physico-chemical assessment of the three sampling sites in Baao Lake, Baao, Camarines
Sur, Philippines
Parameter
(unit)
Water
Temperature
Mouth
Body (Middle)
Tail
T1
T2
T3
T1
T2
T3
T1
T2
T3
34
34
34
32
32
32
32
32
32
Dissolved
4.25
4.29
4.27
4.62
4.63
4.63
6.57
6.57
6.57
Salinity (ppt)
0.04
0.04
0.04
0.04
0.04
0.04
0.04
0.04
0.04
pH
6.5
6.5
6.5
6.6
6.5
6.6
6.5
6.5
6.5
Turbidity
41.6
41.6
41.6
29.2
29.3
29.3
38.9
38.8
38.6
53.30
53.27
53.32
56.53
56.59
56.61
62.4
62.4
62.5
oxygen(mg/L)
(NTU)
Total
Dissolved
Solids (mg/L)
Table 3: Physico-chemical assessment of the three sampling sites in Baao Lake, Baao, Camarines
Sur, Philippines
Parameter
(unit)
Mouth
Body (Middle)
Tail
Average
Remarks
WT
AVERAGE
34
AVERAGE
32
AVERAGE
32
32.67
Normal
DO (mg/L)
4.27
4.63
6.57
5.16
Low to Normal
Salinity
0.04
0.04
0.04
0.04
Freshwater
pH
6.5
6.6
6.5
6.53
Normal
Turbidity
41.6
29.3
38.8
36.57
High
(ppt)
(NTU)
TDS
53.30
56.58
62.4
57.43
Freshwater
(mg/L)
Remarks: WT – Water Temperature DO – Dissolved Oxygen Demand TDS – Total Dissolved
Solids
Table 4. shows the mean values of each physico-chemical parameters for each station in Baao
Lake, Baao Camarines Sur on September 23, 2022 compared to the standard set by DENR for
surface waters.
Parameter
Station 1-
DENR
Station 2-
Mouth
limit Class
Body(middle) limit Class
C
WT
34
DO (mg/L) 4.27
Station 3-
DENR
Tail
limit Class
C
C
25-31
32
25-31
32
25-31
5
4.63
5
6.57
5
(Minimum)
Salinity
DENR
(Minimum)
(Minimum)
0.04
-
0.04
-
0.04
-
pH
6.5
6.5-9.0
6.6
6.5-9.0
6.5
6.5-9.0
Turbidity
41.6
-
29.3
-
38.8
-
53.30
-
56.58
-
62.4
-
(ppt)
(NTU)
TDS
(mg/L)
DISCUSSION
Physico-chemical Analysis of Water
Using a thermometer, the temperature is measured in degrees Celsius (Centigrade).Tables
1-4 present the outcomes of physicochemical examinations of Baao Lake's water. Since most
aquatic organisms' body temperatures are the same as those of the water around them, they are
affected by temperature fluctuations. Because they are adapted to live in a limited temperature
range, the majority of aquatic organisms die when the temperature drops too low or too high.
Temperature has an impact on aquatic organisms' metabolism, growth and respiration,
reproduction and emergence, rate of photosynthesis in aquatic plants, and rate of physiological
processes. The lake water sample taken from the mouth had the highest temperature (34°C), while
the body and tail had the lowest temperature (32°C). The lake water at station 1 (mouth)
probably had a higher temperature because it was shallower than the other sampling sites. Solar
radiation was likely to warm the shallow lake water in the littoral zone. The metabolic activities
of aquatic organisms are sped up by this rise in water temperature. However, the river water
temperatures at the two sampling sites were within the DENR's permissible range of 25 to 31
degrees Celsius. This further suggests that the fish in Lake Baao were able to tolerate the water
temperature, which was slightly
above the ideal range for freshwater. Chemical and biological reactions, the solubility of gases and
minerals, and the toxicity of water contaminants are all influenced by temperature. Temperatures
can raise the toxicity of pollutants. The presence of rice paddies that allow agricultural runoff, a
water pump for irrigation, and some human activities observed at each sampling site indicated that
contamination of the water in Baao Lake was likely. Massive quarrying, boating, fishing, and
farming were the most common activities observed in the river. The lake system's activities all
posed a threat to the safety and quality of the water. Weather, the removal of vegetation on
streambanks that provides shade, urban storm water, and agricultural runoff are some of the factors
that alter temperature. The water's temperature can rise through thermal pollution. Thermal
pollution is when a body of water is heated up by adding water that is relatively warm to it. Storm
water that runs from warm urban surfaces or agricultural runoff can cause thermal pollution.
Station 1's mouth is 34°C, Station 2's body is 32°C, and Station 3's tail is just slightly above the
DENR Standards normal range. While larger temperature swings are more likely to have a negative
impact on aquatic organisms, smaller temperature swings are better for maintaining healthy aquatic
systems.
As the water warms, the amount of dissolved oxygen decreases. Aquatic organisms'
metabolic rates, photosynthesis rates, and DO levels will all be affected by extreme temperatures.
The concentration of oxygen gas molecules (O2) in water is called dissolved oxygen, and it is
measured in milligrams per liter (mg/L) or parts per million (ppm). The majority of the oxygen
that is dissolved in water is produced by diffusion of air at the interface between air and water. A
secondary source is provided by aquatic plants and algae. Animals and plants cannot directly
utilize the oxygen that is a component of the water molecule (H2O), as their respiration is
dependent on dissolved oxygen. Like a lake system, still water. have a lower concentration of
dissolved oxygen than running water's constant mixing. The temperature of the water, the season,
the time of day, the depth, the rate of flow, and the altitude are just a few of the many factors that
affect the level of dissolved oxygen in the water. At higher temperatures and altitudes, there will
be less oxygen dissolved in the water. Because photosynthesis has stopped, dissolved oxygen
levels rise during the day and fall at night. However, oxygen-consuming processes like respiration,
oxidation, and respiration continue until just before dawn. Human factors that affect dissolved
oxygen in a lake are the addition of oxygen-consuming organic wastes like sewage, nutrients,
raising the water temperature, and chemicals. Water depth (altitude), temperature, salinity, and
anthropogenic activities all play a role in the DO values that vary between sampling sites. These
activities may have contributed to thermal pollution, which led to an increase in water temperature
and a decrease in river water DO values. However, the DO values of the river water sample at the
station 3 (tail) sampling site were within the DENR's acceptable limit of 5 mg/L (2016).This
suggests that the tail sampling point's water quality was safe for aquatic organism propagation in
general. The majority of locations had DO concentrations that were critically low (4.27-6.57)
ppm;5.15 ppm on average. All stations' mean dissolved oxygen levels, as determined by in-situ
and laboratory analyses of water samples, are within low to normal ranges. Due to the high rate of
organic matter decomposition, sampling stations within water hyacinth or the littoral zone that are
a short distance from the shore typically have very low DO (4.25-4.27 ppm). Another common
feature of hypereutrophic lakes is low DO. Algae and aquatic plants primarily produce the oxygen
in the water as a byproduct of their photosynthetic activity. Baao Lake is generally good for many
aquatic animals, with the exception of cold-water fish, with a mean dissolved oxygen level of 5.16
mg/L. Based on the standards established by DENR Administrative Order No., this result also falls
well within the normal range.2016-08. Dissolved oxygen (DO) is a measure of aquatic life's
likelihood of survival. The river water samples from station 3 (tail) had the highest dissolved
oxygen level (6.57 mg/L), which was significantly higher than the lowest value (4.27 mg/L) from
station 1 (mouth).
A solution's pH is measured on a logarithmic scale from 1 to 14, with 1 being extremely
acidic, 7 being neutral, and 14 being extremely basic. A wide variety of freshwater aquatic
organisms prefer a pH range between 6.5 and 9.0, and the majority of aquatic plants and animals
are sensitive to changes in pH. One of the primary indicators used to evaluate the quality of
surface water is the pH set by DENR. bacterial activity, water turbulence, chemicals entering the
water body, sewage overflows, algal blooms; The average pH of the river water samples collected
at the mouth, body, and tail were comparable to normal, and impacts from land pollution,
accidental spills, acid rain, minerals dissolved in the water, airborne aerosols and dust,
photosynthesis, respiration, and decomposition of biotic fauna also affect the pH of the water.
The varied topographical location of each sampling point and the various types of anthropogenic
activities on each site probably contributed to the slight observed variation in the average pH
values of the water samples from each sampling site. The DENR set a tolerable limit of 6.5 to 9.0
for the pH of the river water at the various sampling sites. Despite this, the values were within this
range. This suggests that the pH of Baao Lake was within the range that aquatic organisms need
to grow and survive in order to thrive. The pH of the lake's water was normal (6.5-6.6);a mean of
6.53, which remained suitable for fish. The pH levels at stations 1 (6.5), 2 (6.6), and 3 (6.5) are
slightly below the normal range. The majority of aquatic organisms can die if the pH of the water
changes even slightly because they are adapted to a very specific pH level. Water pH is critical to
aquatic organisms' optimal growth and survival. As a result, the pH of the water is crucial to the
pH values between 6.5 and 9
that are ideal for supporting a diverse aquatic ecosystem and are necessary for the survival of the
majority of aquatic plants and animals. In most cases, a pH range of 6.5 to 9 is acceptable. When
pH levels fall below 5 or rise above 9, a lot of species have trouble staying alive. With a mean pH
of 6.53, the water in Baao Lake is in good to excellent condition for supporting the lake's aquatic
ecosystem and falls within the DENR standards' normal range.
In most cases, turbidity is above the class limit. In each of the three stations, the level of
turbidity is always higher than normal. Meanwhile, total dissolved solids (TDS) (53.30-62.4 ppm)
and salinity (0.04) The average of 57.43 was still within the fish's growth tolerance. Baao Lake
falls into the Department of Environment and Natural Resources' (DENR) Class C, which is
meant for boating and the propagation and growth of fish and other aquatic resources. According
to the DENR Revised Water Usage and Quality Criteria, Class C waters are suitable as Fishery
Water for the propagation and growth of fish and other aquatic resources, Recreational Water
Class II (boating, etc.), and Class C waters should have a DO of at least 5 ppm, a pH range of 6.50
to 9.00, and a temperature range of 25 to 31 0C.and Industrial Water Supply Class I (for posttreatment manufacturing processes).The Department of Environment and Natural Resources'
(DENR) 2016 Water Quality Guidelines (WQG) and General Effluent Standards (GES) serve as
the foundation for interpreting the findings of in-situ and laboratory analyses.2016-08, focusing
on the class of each station. This suggests that the water pollution in Baao Lake was not too bad
and was within the acceptable range. Additionally, this suggests that the water quality of Baao
lake in station 3 (tail) is satisfactory and suitable for aquaculture.
Numerous human effects can result from pollution, particularly when lake water is used for
human activities. The presence of rice paddies on the site contributes to agricultural runoff that
carries excess fertilizers and indicates a certain level of river pollution. The presence of
impurities in minerals and salts like calcium, magnesium, sodium, potassium, manganese, and so
on. Contributes to what are commonly referred to as total dissolved solids (TDS).The river water
samples from Station 3 (tail) and Station 2 (56.58 mg/L) had significantly higher average TDS
values than those from Station 1 (mouth) (53.30 mg/L).The intensive sand and gravel quarrying
that increased the availability of some dissolved solids from inorganic materials like rocks
containing calcium carbonate and other minerals coming from agricultural run-off may have
contributed to the significantly higher TDS of the lake water at Station 3 (tail) and Station 2
(body).Although the river water TDS from each sampling site varied significantly, they were all
within the US EPA's acceptable limit of 500 mg/L. This further suggests that the water in Baao
Lake was safe for aquatic organisms to move around in and that there was little water pollution.
Was probably caused by the various pollution point sources from fertilizer runoff. This suggests
that Baao Lake could support aquaculture and was extremely tolerable.
The weather has an effect on salinity, especially near the water's surface. Salty water is
produced when water evaporates during dry seasons, and when it rains, the salty water is diluted
by the fresh water. Parts per thousand (ppt) refers to the number of units (parts) of salts per
thousand units of water, and salinity is measured as a ratio of salts to water. The three main types
of salinity are as follows: fresh water (0-0.5 ppt), brackish water (0.5-30 ppt) and salt water (full
seawater, greater than 30 ppt) are the three types of water. The results show that the fresh water at
stations 1 (mouth),2 (body), and 3 (tail) has a salinity of 0.04 parts per trillion.
Most of the physico-chemical parameters of Baao Lake were within the normal limits set
by the DENR (2016) standard. Nonetheless, it is not suitable to use the water for human
consumption given its classification set by the DENR-EMB. Based on the physicochemical
parameters assessed in this study, the quality of the water in the Baao Lake could be classified as
Class C surface water based on the freshwater classification of DENR (2016). The quality of the
water in Baao Lake especially in the Station 1 mouth should be maintained, improved, and
preserved since there are evidences of eutrophication with the abundance of aquatic plants in the
area such as water hyacinth. Periodic monitoring of the physicochemical characteristics of the
water in the Baao Lake for better quality assessment should be done. The data collected should aid
as the baseline information in the environmental impact assessment and other water quality
monitoring purposes. The government of Baao must build real watershed communities
surrounding the lake and establish management policies through efforts of the local government
of Baao and its residents. If organic pollution from agricultural, storm and urban runoff, dumped
solid wastes continue, further deterioration of the lake will happen in the future. Subsequently the
findings of this study do not give the over-all representation of the present state of Baao Lake
considering that other factors were not taken into account, a more comprehensive study of the
river is recommended. Actions should be taken to find out the over-all state of the Baao Lake so
that appropriate watermanagement policies can be formulated.
ACKNOWLEDGEMENT
The researchers would like to extend their profound gratitude and the Bureau of Fisheries and
Aquatic Resources Laboratory- Bula headed by Ma’am Fhel-Ann Dalaodao for the extended
support to make this study possible; to Dr. Wendy Solomo for the guidance and mentoring and
most especially to the Almighty Father who made all these things possible.
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APPENDIX