pan, n. comparison of water quality of the tonlé sap river and the mekong river

Candidate Number: 001222-010 By Nettra D. Pan Word count: 2,569

A Comparison of the Water Quality

of the Tonlé Sap River and the Mekong River

in Phnom Penh

IB Geography HL Internal Assessment International School of Phnom Penh #1222

December 19, 2007, Cambodia

By Nettra D. Pan

Candidate #001222-011

International School of Phnom Penh (ISPP) Candidate Name: PAN Nettra Danette Candidate Number: 001222-011

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Cover photograph, ‘Riverviews,’ courtesy of Christopher Barlow of the Mekong River Commission during his presentation on the Mekong River. Acknowledgements Christopher Barlow, from the Mekong River Commission, for an insightful presentation on the river. Jan Willem Rosenboom, from the World Bank, for his time, detailed advice and useful information. Janette Fawcett, for teaching Geography and genuinely caring about our class, continuing to offer expert assistance after her departure from Phnom Penh. Lilo Henke, for imparting upon me the knowledge she gained in the IB Geography Diploma Programme. Robin and Erik Wilensky, for their valuable criticisms and feedback. S.J. Vermette, Ph. D., from New York State University at Buffalo Aquanaut Program, for donating water quality testing equipment to the International School of Phnom Penh (ISPP) and for helping to set up this project in the International Baccalaureate Geography program at ISPP.


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A Comparison of the Water Quality of the Tonlé Sap River and the Mekong River in

Phnom Penh

IB Geography HL Internal Assessment

Nettra D. Pan Candidate #001222-011

Word count: 2,499


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Contents Introduction _______________________________________________________________________ 6

I. General Background _____________________________________________________________________6 II. Rationale for Study______________________________________________________________________8 III. Aims of the Investigation________________________________________________________________8 IV. Hypotheses ____________________________________________________________________________8 V. Theoretical Background ________________________________________________________________10

1. Dissolved Oxygen_________________________________________________________________________ 10 2. Fecal Coliform ___________________________________________________________________________ 10 3. pH ______________________________________________________________________________________ 11 4. Biological Oxygen Demand (BOD)___________________________________________________________ 11 5. Temperature Change ______________________________________________________________________ 12 6. Nutrients ________________________________________________________________________________ 13 8. Turbidity ________________________________________________________________________________ 14 9. Total Solids______________________________________________________________________________ 14 10. Hardness ______________________________________________________________________________ 15 11. Other Pollutants _______________________________________________________________________ 15

Methodology______________________________________________________________________ 16 I. General Method ________________________________________________________________________16 II. Location of Sample Sites ________________________________________________________________16 III. Data Collection Methods _______________________________________________________________17

1. Temperature _____________________________________________________________________________ 17 2. pH ______________________________________________________________________________________ 17 3. Turbidity ________________________________________________________________________________ 18 6. Nitrates _________________________________________________________________________________ 19

IV. Evaluation of Data Collection Methods___________________________________________________23

Results ___________________________________________________________________________ 24 I. Collected Data _________________________________________________________________________24 II. Presentation of Data ___________________________________________________________________25 III. Analysis and Evaluation of Data _________________________________________________________28 IV. Conclusion ___________________________________________________________________________32

Bibliography ______________________________________________________________________ 33 Figures and Diagrams _____________________________________________________________________34

Appendices _______________________________________________________________________ 36 Appendix 1: Tonlé Sap River’s Bi-Directional Unimodal Flow __________________________________36 Appendix 1.5: Tonlé Sap River’s River Volume _______________________________________________38 Appendix 2: Seasons of Cambodia___________________________________________________________38 Appendix 3: The Effects of Urbanization_____________________________________________________39 Appendix 4: Heat, as an Effect of Urbanization _______________________________________________39 Appendix 5: Hard & Soft Water Explained ___________________________________________________40 Appendix 6: Complete List of Possible River Water Contaminants ______________________________41 Appendix 6.5: Length of Cambodian Seasons _________________________________________________45


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Appendix 7: Information about WQI ________________________________________________________46 Appendix 7.5: Improving the Precision and Accuracy of Data Collection _________________________48 Appendix 8: Turbidity_____________________________________________________________________50 Appendix: 9: % DO Saturation______________________________________________________________51 Appendix 10: Hardness Concentration _______________________________________________________51 Appendix 11: Evaluation of WQI ___________________________________________________________52 Appendix 12: Raw Data____________________________________________________________________53 Appendix 13: Standard Deviation ___________________________________________________________55 Appendix 14: Temperature_________________________________________________________________55


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Introduction I. General Background Every great civilization has a body of water which acts as a protective barrier between regions, or a meeting point for commerce and transportation. It is a renewable source of food, whether directly from the animals living in it, or else, indirectly, from the fertile, silt-covered grounds washed ashore during floods. From this waterway, cultures develop, supporting a myriad of lifestyles.

In Cambodia, two rivers play these roles: the Tonlé Sap River and the Mekong River (Fig. 1.1.1). The lengths of these rivers are 160 km and 4880 km respectively. The Tonlé Sap River’s depth ranges from 1.0m to 4.0m, whereas the Mekong River’s depth ranges from 2.4m to 4.5m. The Mekong River flows southwards through Cambodia, from Laos, northeast of Cambodia, while the Tonlé Sap flows southwest from the Great Lake in the northwest of Cambodia, and back. In Phnom Penh, the Mekong River has a greater width than the Tonlé Sap River (Fig. 1.1.2).1

Image 1.1.1: the Tonlé Sap River (labeled ‘Sab’) and the Mekong River (labeled ‘Mekong’), in Cambodia

The largest river in the world to seasonally change the direction of its flow,2 the Tonlé Sap

holds great significance for Cambodians. For them, this river is the foundation of a country whose main 1 Tonlé Sap Database. http://www.sumernet.org/tonlesap/eng/news/news_detail.asp?id=59 11/02/07, Tracing the Mekong River. http://www.hawaii.edu/hga/gaw01/workshop/TracingMekongRiv.html 11/02/07 2 Appendix 1


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forms of livelihood rely on agriculture and fisheries. As the volume of the Tonlé Sap lake swells to nearly five times its original size (Fig. 1.1.3.), the region is flooded with 8-9 tons of sediment that birds, fish and crops feast on, which, in turn feeds most of Cambodia, helping the Great Lake yield crops at a rate of 230kg per hectare per year.3

Fig. 1.1.2: Google earth image of the Tonlé Sap River and the Mekong river at their confluence in Phnom Penh4.

Fig. 1.1.3: Satellite image of Cambodia. The Tonlé Sap Lake and River have clearly expanded in the wet season.

The lower Mekong River basin is significant to many other countries (Fig. 1.1.4). In particular,

it provides 80% of the animal protein consumed by its 55 million inhabitants.5

3 Did You Know? The Mekong River Commission. http://www.mrcmekong.org/MfS/html/did_you_know.html 11/02/07 4 The Source of Life. Powerpoint presentation by Dr. S.J. Vermette from New York State University at Buffalo’s Aquanaut Program. 5 WWF Report: World’s Top Ten Rivers at Risk. WWF. http://assets.panda.org/downloads/worldstop10riversatriskfinalmarch13_1.pdf Date accessed 11/02/06


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Fig. 1.1.4: the Mekong River Basin flows through China, Myanmar, Thailand, Laos, Cambodia and Vietnam

II. Rationale for Study

Due to its location in Less Economically Developed Countries (LEDCs), limited study has been conducted on the Tonlé Sap and the Mekong River. An evaluation of the water quality in this unique river system during various seasons6 would be fascinating and necessary since its location indicates possible far-reaching implications for Cambodia and Asia, as a whole.

III. Aims of the Investigation

1. To compare the water quality of the Tonlé Sap and Mekong River in Phnom Penh while controlling for differences between Cambodia’s wet and dry season.

2. To examine the effect of the wet and dry season on the water quality of the Tonlé Sap and Mekong River in Phnom Penh.

IV. Hypotheses

1. The water quality of the Tonlé Sap is expected to be lower than that of the Mekong. The Tonlé Sap River’s proximity to Cambodia’s primate city suggests that it would be likely to receive larger amounts of sewage than the Mekong, increasing the amount of fecal coliform (FC) and nitrates

6 Appendix 2


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and phosphates (nutrients) and lowering the dissolved oxygen (DO) concentration of the river. Runoff from the streets and factories of Phnom Penh are more likely to contain pH-changing contaminants, compared to runoff from less developed areas around the Mekong River in Phnom Penh. The increased amount of automobile traffic in the inner city may lead to increased air pollution and therefore, acid rain, and nitrate and ammonium deposition.7 Also, heat pollution due to Phnom Penh’s greater amounts of concrete could increase the Tonlé Sap’s temperature and reduce the maximum amounts of DO saturation.8 Phnom Penh’s urbanization influences heavily weighted factors affecting Tonlé Sap’s water quality (Table 1.4.1).

Table 1.4.1: Factors and weights contributing to the Water Quality Index, a standard created by the United States’ National Sanitation Foundation (NSF) to evaluate the water quality of temperate rivers.

However, urbanization’s effect on the Tonlé Sap River may be considered insignificant if the

Mekong River’s route through developed areas in Thailand is taken into account. Undeveloped sewerage systems closer to the Mekong River may also encourage more defecation into the river (increasing the amount of FC and nutrients and lowering the DO concentration of the Mekong River). Nevertheless, the Mekong River’s consistently large volume makes the concentration of waste products less significant in terms of water quality.9 The Tonlé Sap River, on the other hand, only enjoys this diluting effect in May, during flow reversal, and even then, the Tonlé Sap experiences a surplus of suspended solids (SS) that are beneficial for soil fertility, yet, poor for water quality.

2. The water quality of both rivers is expected to be lower in the dry season than in the wet season.

In addition to turbidity, the concentration of solids, FC, and nutrients are expected to increase as the volume of both rivers decrease. This season’s increase in temperature is also likely to contribute to lower DO saturation and higher biological oxygen demand (BOD).

7 Appendix 3 8 Appendix 4 9 Appendix 1.5


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V. Theoretical Background To best compare the water quality of the Tonlé Sap and Mekong River, it is important to understand the factors affecting water quality.

1. Dissolved Oxygen Most river organisms require high levels of dissolved oxygen to survive. Low DO concentration indicates a decay of organic material (such as sewage or vegetation) by microbial action or chemical processes.

Q-value

Dissolved Oxygen Saturation (%)

Fig. 1.5.1: This weighing curve chart for (DO) Saturation demonstrates a positive correlation for dissolved oxygen concentration and water quality.

2. Fecal Coliform

Fecal Coliform Test Results

Fig. 1.5.2: This table shows a negative correlation between the number of FC colonies and water quality.


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3. pH pH Test Results

Fig. 1.5.3: pH Test Results indicates that a neutral pH will yield the greatest water quality, since most organisms are unable to survive outside a neutral environment.

4. Biological Oxygen Demand 5-Day BOD Test Results

Fig. 1.5.4: This chart demonstrates the negative correlation between water quality and BOD. The more oxygen is used up by organisms in the water after five days, the lower the WQI.


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5. Temperature Change

Warm climates sometime kill fish in ponds because the high temperatures reduce the oxygen concentration of the water. Temperature determines the maximum DO concentration in the water and influences the rate of chemical and biological reactions, thus determining which organisms can survive in the water.

Temperature (Water Quality Index Calculator) Based On Temperature Change from a Reference Site

Fig. 1.5.5: This chart demonstrates that the smaller the change in temperature, the better the WQI.


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6. Nutrients

High levels of phosphates in water are associated with an excess of sewage, fertilizers, detergent or decaying plants. Nutrients from fertilizer leaked into rivers may cause excess algae or moss to grow on the surface of the water or turn the water green, thus preventing much-needed sunlight from reaching the aquatic organisms. The absence of sunlight creates a decrease in the production of oxygen by plants through photosynthesis, which can then lead to decaying organisms and an even lesser water quality.

Total Phosphates

Fig. 1.5.6.1: Phosphate Results demonstrate a negative correlation between water quality and total phosphates.

High levels of nitrates in water are associated with an excess of sewage, fertilizers, detergent or decaying plants, as explained in Fig. 1.5.6.3.

Nitrates

Fig. 1.5.6.2: Nitrate results demonstrate a negative correlation between water quality and nitrates.

Fig. 1.5.6.3. A slide from Aquanaut’s Analytes, Dr. Vermette’s Presentation to the MRC.


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8. Turbidity Turbidity Results

. Fig. 1.5.8: Turbidity Results indicate a negative correlation between water quality and turbidity.

9. Total Solids Total Solids Test Result

Fig. 1.5.9: Total Solids Test Results indicate a negative correlation between water quality and turbidity.


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10. Hardness Both hard and soft water are helpful depending on the need.10

11. Other Pollutants Other waste products which may be detrimental to organisms and infrastructure, include: microorganisms and inorganic chemicals, such as, metals, hydrocarbons, disinfectants and their byproducts.11

10 Appendix 5 11 Appendix 6


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Methodology I. General Method

To best evaluate the water quality of the Tonlé Sap and Mekong River as many factors must be compared as possible. Due to limited resources, I will only collect and calculate data for the following: DO, FC, pH, BOD, temperature, nutrients, turbidity, and total solids. Later, values from both rivers will be compared and used to calculate their Water Quality Index (WQI)12 according to the NSF standard. Although this standard has not been specifically designed for tropical rivers,13 it allows a general comparison of water quality.

So that the differences in season do not affect the accuracy of our comparisons, four samples will be used. Two samples will be taken from the dry season and two samples will be taken from the wet season. To accurately portray each season, samples will be taken in the middle of each season.14

II. Location of Sample Sites To fairly compare these two rivers, samples will be taken from Site 2 on the Tonlé Sap River and Site 4 on the Mekong River, since both sites lead up the confluence. Site 1 will be compared with Site 4 because of their varying distance from Phnom Penh center and may inaccurately represent the effects of urbanization on each river. Sites 3 and 5 will not allow a clear comparison between the rivers in question since they contain samples of both rivers.

12 Appendix 7 13 Appendix 11 14 Appendix 6.5

SITE 1SITE 1

SITE 5SITE 5

SITE 4SITE 4

SITE 3SITE 3

SITE 2SITE 2

SITE 1SITE 1

SITE 5SITE 5

SITE 4SITE 4

SITE 3SITE 3

SITE 2SITE 2

Fig. 2.2.1: Satellite photograph of the five possible testing sites students were limited to in this investigation

Table 2.2.1: GPS Coordinates of river sites.

Site River GPS Coordinates (m)15

2 Tonlé Sap 491400 1281957 4 Mekong 495820 1277387


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III. Data Collection Methods Tests for DO, FC, pH, BOD, temperature, nutrients, turbidity and total solids were done in the following ways because of the portability, availability and low cost of the equipment required for each measurement.

1. Temperature

Fig. 2.3.1

2. pH

Fig. 2.3.2: Annotated image demonstrating colorimetric testing method.

15 Value refers to UTM coordinate system, based on the WGS84 ellipsoid in zone 48P.


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3. Turbidity16

Fig. 2.3.3

4. Dissolved Oxygen Saturation17

Fig. 2.3.4.1

Fig. 2.3.4.2: Colorimetric method requires using Comparator Ampoules.

16 Appendix 8 17Appendix: 9


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5. Biological Oxygen Demand

Fig. 2.3.5

6. Nitrates

Fig. 2.3.6

7. Total Phosphates

Fig. 2.3.7


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8. Fecal Coliform18

Fig. 2.3.8

9. Total Solids Total solids are the sum of dissolved solids (DS) and SS.

Dissolved Solids

18 This tests for Escherichia coli, a type of FC. Because 80 to 95% of FC found in feces are E-coli, the absence of E. Coli indicates few FC.


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Fig. 2.3.9.1

Suspended Solids

Fig. 2.3.9.2: Annotated photo detailed how MITYVAC filtration equipment was used.

Fig. 2.3.9.3


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10. Water Quality Index19

The NSF website provides a WQI calculator which

employs the tables presented in IV.

Theoretical Knowledge to indicate a water

quality index (WQI) for each of the 9

factors and combine them to create one

value ranging from 1-100 specifying the

sample’s water quality.

Fig. 2.3.11: Water Quality Index Calculator

19 Appendix 7


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IV. Evaluation of Data Collection Methods The methods used boasted several advantages: they were straightforward enough for secondary students to carry out; the fact that they were donated eliminated most costs involved; aside from small battery-operated instruments, no electricity was necessary and the equipments’ portability was high. However, several aspects of the data collection methods may have lead to inaccuracies, especially due to their interrelated nature.20

Many of the methods21 were colorimetric and therefore, influenced by operator characteristics, such as eyesight.22 The test for temperature and DS was electronic, so there was a smaller margin for human error.23 Finally, the WQI was devised in a temperate climate and intended for temperate rivers, not tropical rivers.24

20 Appendix 7.5 21 DO, pH, BOD, total phosphates, nitrates, turbidity and FC. 22 Appendix 8 and 9 23 The human factor may still have affected our results, though, since measuring temperature depended on the way water was retrieved for the test. Students were instructed to collect water 2-3 inches below the river surface but people may have lowered the container deeper or shallower into the water than each other, changing the effect of the sun on the water sample’s temperature. 24 Appendix 11: Evaluation of WQI


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Results

I. Collected Data

Table 3.1.1: All data calculated from the Tonlé Sap River and Mekong River25

Test Site 2 Site 4 pH 7.25 7.50Temperature (°C) 28.9 28.7Nitrates (ppm) 0.1 0.1Total Phosphates (ppm) 0.1 0.1Biological Oxygen Demand (ppm) 2.50 1.75Dissolved Oxygen (%) 50.975 58.185Total Solids (ppm) 122.50 174.25Turbidity (NTU) 37.0 45.5FC (# of E. coli colonies/100mL) 887.5 837.5Water Quality Index (Q-Value) 68.75 70.0

Table 3.1.2: Factors affecting water quality26

Tonlé Sap River Mekong River Water Quality Index Sample 1 Sample 2 Average Sample 1 Sample 2 AverageWet Season Samples 68.00 70.00 69.00 69.00 66.00 67.50Dry Season Samples 73.00 64.00 68.50 77.00 68.00 72.50Average 70.50 67.00 68.75 73.00 67.00 70.00

Table 3.1.3: Water Quality Index of the Tonlé Sap River and Mekong River27

25 Each season’s data averaged from two samples, taken each season from each river. 26 Each site’s data averaged from four samples taken from each site (two from each season). 27 Appendix 12

Tonlé Sap River Mekong River

Test Dry Season

Wet Season

Dry Season

Wet Season

Secchi (in) 15.750 9.860 33.465 4.935 pH 7.0 7.5 7.0 7.0 Temperature (°C) 28.85 28.95 28.75 28.50 Nitrate (ppm) 0.1 0.1 0.1 0.1 Phosphate (ppm) 0.1 0.1 0.1 0.1 Dissolved Oxygen (ppm) 5.5 6.0 6.5 6.0 Dissolved Oxygen in 5 day (ppm) 3.5 3.0 4.5 3.0 Biological Oxygen Demand (ppm) 2 3 2 3 Dissolved Oxygen (%) 69.5 77.0 82.0 75.0 Dissolved Solids (ppm) 60 60 125 65 Suspended Solids (ppm) 20 105 8.5 190 Total Solids (ppm) 80.0 165.0 133.5 255.0 Turbidity (NTU) 19 55 10 66 E. coli (# of colonies/100mL) 725 1050 350 1425 Water Quality Index (Q-Value) 68.5 69.0 72.5 67.5


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II. Presentation of Data

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III. Analysis and Evaluation of Data The first hypothesis is correct: the Mekong River does have a higher water quality than the Tonlé Sap River when controlling for wet and dry season (Fig. 3.2.1). The rivers are on a border line between medium and good high water quality, with the Mekong River more often corresponding to a good WQI (Table 3.1.3 and 3.3.1).

Table 3.3.1

Possible explanations for this may include the sewage dispatched by the large boating community on the Tonlé Sap Lake (Fig. 3.3.1), where the largest incident of inland fishing in the world takes place.28 This is likely to affect the WQI of the Tonlé Sap River, especially in the dry season, where the volume is lowest, increasing the concentration of waste. Table 3.1.1 shows an SS value for the Tonlé Sap River which more than doubles the Mekong River’s SS value.

Fig. 3.3.1: Overhead image of the fishing community on the Tonlé Sap Lake, a source of the Tonlé Sap River. 28 WWF Report: World’s Top Ten Rivers at Risk. WWF. http://assets.panda.org/downloads/worldstop10riversatriskfinalmarch13_1.pdf Date accessed 11/02/06


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Because of Tonlé Sap River’s proximity to Cambodia’s primate city, it would also be affected by

the city’s commercial enterprises (Fig 3.3.2).

Fig. 3.3.2: Images of a boat transporting sand (left) and gasoline (right).

However, a closer look at Tables 3.1.1 and 3.1.3 and Figures 3.2.3 and 3.2.4 shows that the

Tonlé Sap River’s lesser WQI only occurs during the dry season. In the wet season, the Tonlé Sap River’s water quality is greater than the Mekong River’s. This was unexpected due to the undeveloped nature of the area around the Mekong River in Phnom Penh and also because of the Mekong River’s expected capacity to dilute waste products (due to a large volume which would only increase in the wet season). However, the Mekong River’s high turbidity and sediment values (Fig. 3.3.3) nearly double the Tonlé Sap River’s amounts in the wet season (Table 3.1.1).

Fig. 3.3.3: Sediment containing filter paper from a wet season SS test, placed on an image of Fig. 1.1.2.

A possible explanation includes increased logging. In Cambodia, the annual deforestation rate

has risen by 74.7% between 2000 and 2005.29 This is more likely to be carried out near the Mekong River, in the outer city, where more vegetation is available.30 Also, the increased rain in the Mekong River during the flood season, thought to be able to dilute waste products, has instead, increased the

29 Cambodia. http://rainforests.mongabay.com/deforestation/2000/Cambodia.htm Date Accessed: 11/07/07 30 Vegetation inhibits soil erosion. Tree roots to hold the soil together preventing rainwater from sweeping silt into rivers.


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river’s velocity, eroding the loose, undeveloped banks of the Mekong River significantly more than the Tonlé Sap River’s banks, which are much shorter.

Fig. 3.3.4: A fishing boat by the Tonlé Sap’s cemented banks in Phnom Penh.

Increased amounts of DS in the Mekong River from the dry season to the wet season can be

attributed to the increased surface flow in the presence of rain which washes more minerals into the river. The Mekong River’s higher DS values than the Tonlé Sap River’s can be explained by residue left behind by traffic, since higher water levels greatly ease transportation between countries in the Mekong River’s lower basin (Fig. 3.3.5).

Fig. 3.3.5: A fishing boat traveling on the Mekong River during the flood season.

The second hypothesis is only partly true. Mostly due to a sharp decrease in DO, the Tonlé Sap

River’s WQI is higher in the wet season than in the dry season (despite sharp increases in turbidity and E. coli). Conversely, the WQI of the Mekong River decreases, mostly because of increased turbidity. Velocity, caused by an increase in river volume, prevents solids from to settling on the riverbed, augmenting turbidity. Also, the wet season caused an unprecedented rise in FC which was overlooked when determining the hypothesis. Logically, higher water levels increase accessibility of the river, allowing more organisms to defecate in it. Added to this, increased humidity provides more resources and breeding grounds to FC.


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However, when analyzing the data in its entirety, the overall differences between each season and each river’s WQI are too small to be considered significant.31 Not all contaminants have been measured in this investigation32 and the interrelated nature of these rivers makes it difficult to accurately compare each river (Fig. 3.3.6).33

Fig. 3.3.6: Origin of Tonlé Sap Lake’s Water

Though possible for these two rivers to maintain similar WQI values throughout the year, it is

important to revisit the limitations of the methods of study.34 Firstly, the WQI was not designed to evaluate tropical rivers and therefore, could be inaccurate.35 Secondly, this investigation’s calculated WQI is based only on eight factors, not nine.36 Thirdly, some inaccuracies may be attributed to human error and natural, annual variations of the river. Finally, Table 3.3.2 indicates the uncertainty values of the equipment and methods employed in this investigation.

31 The sole average WQI change exceeding two units is the change from the Mekong River in the wet season to the dry season. See Appendix 12 & 13. 32 Appendix 6 33 The water quality of the Tonlé Sap River water contains great amounts of Mekong River water due to flow reversal. 34 See Methodology: IV. Evaluation of Data Collection Methods. 35 Appendix 11 36 Appendix 14

Test Uncertainty (± units) Secchi (cm) 1pH 1Hardness (ppm) 18Temperature (°C) 1Nitrate (ppm) 0.1Phosphate (ppm) 0.1Dissolved Oxygen (ppm) 1Biological Oxygen Demand (ppm) 1Dissolved Oxygen (%) 1Dissolved Solids (ppm) 1Suspended Solids (ppm) 4Total Solids (ppm) 5Turbidity (NTU) 10E. coli (# of colonies/100mL) 1Water Quality Index (Q-value) 1

Table 3.3.2: Uncertainty values of factors measured.


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With these inaccuracies in mind, this investigation does not prove nor disprove its hypotheses. The data shows generally constant levels of pH, hardness, temperature and nutrients and a good-to-excellent water quality. The rivers in question do not contain hazardous levels or fertilizers, decomposing organic matter or minerals, demonstrating that urbanization is actually a minor influence on the Tonlé Sap and Mekong River. Any fluctuations between each river’s WQI are attributed to seasonal variations in DO, total solids and FC.

IV. Conclusion The Tonlé Sap and Mekong River were studied in order to evaluate their water quality while controlling for the changes in wet and dry season, as well as to determine the effect of the wet and dry season on their water quality. This was done by testing two hypotheses: 1) the Mekong River would yield a higher water quality than the Tonlé Sap River throughout the year and, 2) the wet season would yield a higher water quality than the dry season for both rivers.

Data collected demonstrated that both hypotheses were only partly true. Because of the detrimental effect the wet season has on the Mekong River (affecting DO, SS and FC), the Mekong River actually only yields higher water quality than the Tonlé Sap during the dry season. Future investigations should focus specifically on DO, SS, and FC, as this investigation indicates these as the deciding factors in influencing water quality in Cambodia.

It will also be important to continue studying WQI in Cambodia over time to appreciate emerging trends and set up a WQI standard for tropical rivers. The uniqueness of the reversal phenomenon in this area also warrants more study since there are no other rivers to compare these rivers to.37

The Mekong River Commission names agriculture, population pressure, economic development and fishery as the main stressors on WQI in Cambodia. In addition to measuring the effects of these things, it would be interesting to modify the hypotheses to compare the effects of deforestation, dams or sewerage systems on the WQI of these and other Cambodian rivers and their seasonal variations.

37 Smaller examples of river flow reversal exist but data available to the public is limited.


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Bibliography - About Floods in the Mekong Basin. The Mekong River Commission.

http://www.mrcmekong.org/flood_report/2006/about-foods.htm Date accessed November 3, 2007.

- Aquanaut’s Analytes. Vermette, S. J. Power Point Presentation to the MRC. - Cambodia. http://rainforests.mongabay.com/deforestation/2000/Cambodia.htm Date Accessed:

11/07/07 - Coliscan Tests. http://www.nscollegeprep.cps.k12.il.us/depts/science/avites/AP%20Water-

coliform_tests.htm Date accessed: November 2, 2007 - Did You Know? The Mekong River Commission.

http://www.mrcmekong.org/MfS/html/did_you_know.html 11/02/07 - Foote K. E., and Molch, K. E. Effects of Urbanization on Environment: An Overview

http://www.colorado.edu/geography/virtdept/stylesheets/samples/machine_space/html/body.html November 2, 2007

- Geography of Cambodia. http://www.tourismindochina.com/geography-cambodia.htm Date accessed: 11/02/07

- Hard vs. Soft Water Explained. http://www.freedrinkingwater.com/water-education/quality-water-hard.htm Date Accessed: November 2, 2007

- How exactly does dissolved oxygen affect water quality? http://www.freedrinkingwater.com/water_quality/quality1/1-how-dissolved-oxygen-affects-water-quality.htm Date Accessed: November 2, 2007

- http://www.ifredi.org/Documents/BS/Built%20Structures%20synthesis.pdf Date Accessed: 11/02/07

- Ikeazota, S. I. & Jeje L.K. Effects of Urbanization on Channel Morphology: The Case of Ekulu River in Enugu, South Eastern Nigeria http://www.blackwell-synergy.com/doi/abs/10.1111/1467-9493.00117?cookieSet=1&journalCode=sjtg Date accessed: November 3, 2007

- Mekong River Watershed. http://en.wikipedia.org/wiki/Image:Mekong_River_watershed.png Date accessed: November 2, 2007

- MRC, World Fish Center. Influence of Built Structures on Tonle Sap Fisheries. - MRC (2007) Diagnostic study of water quality in the Lower Mekong Basin. MRC Technical Paper

No. 15, Mekong River Commission, Vientiane. 57pp. - Office of Council of Ministers. Inland Waterways. http://www.ocm.gov.kh/c_inf3.htm Date

accessed: 11/02/07 - Overview of Contaminants & Their Potential Health Effects.

http://www.freedrinkingwater.com/water-education/water-contaminants-health-effects.htm Date accessed: November 2, 2007

- Rosenboom, Jan-Willem (2004) Not Just Red or Green: An analysis of arsenic data from 15 upazillas in Bangladesh. Arsenic Policy Support Unit, Dhaka.

- Seasons of Cambodia. http://www.travelfish.org/cambodia-weather.php Date accessed: November 2, 2007

- Structural Analysis of Deforestation in Cambodia. http://www.iges.or.jp/en/fc/phase1/ir99/4-13-ruth.pdf Date accessed: 11/02/07

- Structural Analysis of Deforestation in Cambodia. http://www.iges.or.jp/en/fc/phase1/ir99/4-13-ruth.pdf Date accessed: 11/02/07

- The Source of Life. Powerpoint presentation by Dr. S.J. Vermette from New York State University at Buffalo’s Aquanaut Program.

- Tonlé Sap Database. http://www.sumernet.org/tonlesap/eng/news/news_detail.asp?id=59 11/02/07, Tracing the Mekong River. http://www.hawaii.edu/hga/gaw01/workshop/TracingMekongRiv.html 11/02/07


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- Tracing the Mekong River. http://www.hawaii.edu/hga/gaw01/workshop/TracingMekongRiv.html 11/02/07

- Turbidity. Australian Government. http://www.waterwatch.org.au/publications/module4/turbidity.html Date accessed : November 3, 2007

- Vietnam plans Mekong mega dam in Laos http://www.straitstimes.com/Latest%2BNews/Asia/STIStory_190092.html Dec 25, 2007

- Water Quality Index: Iowa. The Iowa Department of Natural Resources. http://wqm.igsb.uiowa.edu/wqi/wqi.asp 11/02/07

- Water, the Source of Life. PowerPoint presentation by Dr. S.J. Vermette from New York State University at Buffalo’s Aquanaut Program.

- WELCOME TO PROJECT CHILDREN. http://www.projectchildrenni.com/states.htm 11/02/07

- Why Temperature is Important. http://www.water-research.net/Watershed/temperature.htm Date accessed: November 2, 2007

- WWF Report: World’s Top Ten Rivers at Risk. WWF. http://assets.panda.org/downloads/worldstop10riversatriskfinalmarch13_1.pdf Date accessed 11/02/06

- www.ocm.gov.kh Date Accessed: November 11, 2007

Figures and Diagrams - Fig. 1.1.1: Map/Still: Cambodia’ Encyclopædia Britannica.

http://cache.eb.com/eb/image?id=4052&rendTypeId=4 Date accessed: November 2007. - Fig. 1.1.2: Satellite image taken from Google Earth, April 4, 2005. - Fig. 1.1.3 has been taken from:

http://earthobservatory.nasa.gov/Newsroom/NewImages/images.php3?img_id=15294 Date accessed: 11/02/07

- Fig. 1.1.4: http://www.mrcmekong.org/img/flood_report/2006/map1.gif 11/02/07 - Fig.1.4.1: taken from Calculating NSF Water Quality Index. http://www.water-

research.net/watrqualindex/index.htm Date Accessed: November 2, 2007 - Fig.1.5.1: taken from Calculating NSF Water Quality Index. http://www.water-

research.net/watrqualindex/index.htm Date Accessed: November 2, 2007 - Fig. 1.5.2: taken from Calculating NSF Water Quality Index. http://www.water-



research.net/watrqualindex/index.htm Date Accessed: November 2, 2007 - Fig. 1.5.5: taken from Why Temperature Is Important

http://www.nsf.org/consumer/just_for_kids/wqi.asp Date Accessed: November 2, 2007 - Fig. 1.5.6.1: taken from Calculating NSF Water Quality Index. http://www.water-

research.net/watrqualindex/index.htm Date Accessed: November 2, 2007 - Fig. 1.5.6.2: taken from Calculating NSF Water Quality Index. http://www.water-

research.net/watrqualindex/index.htm Date Accessed: November 2, 2007 - Fig. 1.5.6.3: Aquanaut’s Analytes. Vermette, S. J. Power Point Presentation to the MRC. - Fig. 1.5.8: taken from Calculating NSF Water Quality Index. http://www.water-


research.net/watrqualindex/index.htm Date Accessed: November 2, 2007


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- Fig.2.2.1: Source unknown. - Fig. 2.3.1-2.3.9.2: Images taken by teacher and friends during field work, annotations by Pan, N. - Fig. 2.3.9.3: Water, the Source of Life. PowerPoint presentation by Dr. S.J. Vermette from New

York State University at Buffalo’s Aquanaut Program. - Fig. 2.3.11: taken from Calculating NSF Water Quality Index. http://www.water-

research.net/watrqualindex/index.htm Date Accessed: November 2, 2007 - Table 3.1.1-3.1.3: Results of Experiment carried out by IB Geography class, ISPP, ‘06-‘07 - Fig. 3.2.1-3.1.3: Graphs by Pan, N. - Table 3.3.1: taken from Calculating NSF Water Quality Index. http://www.water-

research.net/watrqualindex/index.htm Date Accessed: November 2, 2007 - Table 3.3.2: Source: Pan, N. - Fig. 3.3.1: Source unknown. - Fig. 3.3.2: Water, the Source of Life. PowerPoint presentation by Dr. S.J. Vermette from New

York State University at Buffalo’s Aquanaut Program. - Fig. 3.3.3: Photo credit: Pan, N. - Fig. 3.3.4: Photo credit: Pan, N. - Fig. 3.3.5: Photo credit: Pan, N. - Fig. 3.3.6: ‘Origin of Tonlé Sap Lake’s Water’ taken from Influence of Built Structures on Tonle Sap

Fisheries. http://www.ifredi.org/Documents/BS/Built%20Structures%20synthesis.pdf Date accessed: 01/10/2007


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Appendices

Appendix 1: Tonlé Sap River’s Bi-Directional Unimodal Flow From mid-October the Tonlé Sap flows seaward, feeding the Mekong River at its confluence in Phnom Penh. However, as the wet season (also referred to as the monsoon season) continues and more rainwater and melted ice (from the Himalayas) flows into the Mekong River, the Mekong can no longer accept any water from the Tonlé Sap Lake and actually flows upslope into the lake, forcing the Tonlé Sap to reverse its flow around late May.

Source: MRC Overview of the Hydrology of the Mekong Basin, November 2005:53

Tan Chau & Chau Doc = rivers on the Cambodia-Vietnam border also with a unimodal shape.

Source: Diagnostic study of water quality in the Lower Mekong Basin., November 2007:12

Mean monthly discharge at selected locations showing the main tributaries in each reach. Arrows indicate from upstream to downstream. The period of record is 1960-2000 (MRC, 2004)


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This example of bi-directional flow is unique in the world; a drawback in this investigation for the results gathered in this study cannot be compared to another instance in the world. There are other smaller scale examples, but limited data is available on those streams.


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Appendix 1.5: Tonlé Sap River’s River Volume River Volume

Due to the unimodal flow of tributaries in the Lower Mekong River Basin and variations in season, the volume of the respective rivers is difficult to quantify. Also, there is limited information about this unique occurrence and the Tonlé Sap River and the Mekong River are greatly interrelated. This interrelatedness means that during the dry season, the Tonlé Sap River feeds the Mekong River and in the wet season the Mekong River feeds the Tonlé Sap River, making it difficult to determine the respective volume of each river.

Appendix 2: Seasons of Cambodia Dry season – runs from November to April on the back of the northeast monsoon. Months between November to January are cooler and humid while between February to April months are hot and dusty. November is the coolest month, April the hottest. Wet season - runs from May to October courtesy of the southwest monsoon. Wet season brings some 75% of Cambodia's annual rainfall. Months between July and September are the wettest months. Source: Seasons of Cambodia. http://www.travelfish.org/cambodia-weather.php Date accessed: November 2, 2007


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Appendix 3: The Effects of Urbanization Dangers of Urbanization Urban areas have the potential to pollute water in many ways. Runoff from streets carries oil, rubber, heavy metals, and other contaminants from automobiles. Untreated or poorly treated sewage can be low in dissolved oxygen and high in pollutants such as fecal coliform bacteria, nitrates, phosphorus, chemicals, and other bacteria. Treated sewage can still be high in nitrates. Groundwater and surface water can be contaminated from many sources such as garbage dumps, toxic waste and chemical storage and use areas, leaking fuel storage tanks, and intentional dumping of hazardous substances. Air pollution can lead to acid rain, nitrate deposition, and ammonium deposition, which can alter the water chemistry of lakes. Source: Dangers of Urbanization. http://www.livinglakes.org/issues/pollution.html Date accessed: November 2, 2007 In urban areas, there is less interception from plants, which directs rainwater directly to the ground level where the soil is either compacter or covered in tarmac or concrete, creating an impermeable surface, that allows large volumes of rapid surface flow. This running water dissolves minerals found on the surface of cities and transports them to rivers and sewerage systems.

Appendix 4: Heat, as an Effect of Urbanization Effects of Urbanization on Environment: An Overview Cities are made of concrete, asphalt, brick, stone, and steel. These materials absorb and reflect energy differently than vegetation and soil. They absorb more radiant energy and radiate this energy back into the atmosphere at different times through the day. The result is that cities are warmer than the surrounding countryside, sometimes considerably. Furthermore, cities remain warm well into the night when the countryside has already cooled. Source: Foote K. E., and Molch, K. E. Effects of Urbanization on Environment: An Overview http://www.colorado.edu/geography/virtdept/stylesheets/samples/machine_space/html/body.html November 2, 2007


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Appendix 5: Hard & Soft Water Explained Hard water contains dissolved minerals which can corrode pipes and infrastructure. Rain water is an example of softer water, containing less of these minerals and more sodium ion. Both hard and soft water can be useful. HARD vs. SOFT WATER EXPLAINED -Hard water is water that contains an appreciative quantity of dissolved minerals (like calcium and magnesium) -Soft water is treated water in which the only ion is sodium. As rainwater falls, it is naturally soft. However, as water makes its way through the ground and into our waterways, it picks up minerals like chalk, lime and mostly calcium and magnesium. Since hard water contains essential minerals, it is sometimes the preferred drinking water, not only because of the health benefits, but also the flavor. On the other hand, soft water tastes salty and is sometimes not suitable for drinking. So why, then, do we soften our water? When it boils down, the major difference between hard and soft water can best be seen while doing household chores. Hard water is to blame for dingy looking clothes, dishes with spots and residue and bathtubs with lots of film and soap scum. Even hair washed in hard water may feel sticky and look dull. Hard water can take a toll on household appliances as well, using up more energy. The elements of hard water are to blame for all of these negative factors, as soap is less effective due to its reaction to the magnesium and calcium. The lather is not as rich and bubbly. Chore-doers will love using soft water, as tasks can actually be performed more efficiently with it. Soap will lather better and items will be left cleaner. Glasses will sparkle and hair will look healthy. The shower curtain will be scum-free. Clothes and skin are left softer. In addition to time, this can also save money, as less soap and detergents will be used. Since appliances have to work less hard, soft water can also prolong the life of washing machines, dishwaters and water heaters. Energy bills are noticeably lower when in households with water softeners. In a time of rising energy costs, this is something to think about. Soft water is not, however, suggested for those with heart or circulatory problems, or others who may be on a low sodium diet. In the softening process, as minerals are removed, sodium content increases. Research shows that cardiovascular disease has the lowest risk in areas where water has the most mineral content. Source: Hard vs. Soft Water Explained. http://www.freedrinkingwater.com/water-education/quality-water-hard.htm Date Accessed: November 2, 2007

Image taken from Aquanaut’s Analytes, Dr. Vermette’s Presentation to the MRC.


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Appendix 6: Complete List of Possible River Water Contaminants Overview of Contaminants & Their Potential Health Effects. Microorganisms

Contaminant Potential Health Effects from Ingestion of Water

Sources of Contaminant in Drinking Water

Cryptosporidium Gastrointestinal illness (e.g., diarrhea, vomiting, cramps)

Human and fecal animal waste

Giardia lamblia Gastrointestinal illness (e.g., diarrhea, vomiting, cramps)

Human and animal fecal waste

Heterotrophic plate count

HPC has no health effects; it is an analytic method used to measure the variety of bacteria that are common in water. The lower the concentration of bacteria in drinking water, the better maintained the water system is.

HPC measures a range of bacteria that are naturally present in the environment

Legionella Legionnaire's Disease, a type of pneumonia

Found naturally in water; multiplies in heating systems

Total Coliforms (including fecal coliform and E. Coli)

Not a health threat in itself; it is used to indicate whether other potentially harmful bacteria may be present5

Coliforms are naturally present in the environment; as well as feces; fecal coliforms and E. coli only come from human and animal fecal waste.

Turbidity Turbidity is a measure of the cloudiness of water. It is used to indicate water quality and filtration effectiveness (e.g., whether disease-causing organisms are present). Higher turbidity levels are often associated with higher levels of disease-causing microorganisms such as viruses, parasites and some bacteria. These organisms can cause symptoms such as nausea, cramps, diarrhea, and associated headaches.

Soil runoff

Viruses (enteric) Gastrointestinal illness (e.g., diarrhea, vomiting, cramps)

Human and animal fecal waste

Disinfection Byproducts



Bromate Increased risk of cancer Byproduct of drinking water disinfection

Chlorite Anemia; infants & young children: nervous system effects

Byproduct of drinking water disinfection

Haloacetic acids (HAA5)

Increased risk of cancer Byproduct of drinking water disinfection

Total Trihalomethanes (TTHMs)

Liver, kidney or central nervous system problems; increased risk of cancer

Byproduct of drinking water disinfection


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Disinfectants



Chloramines (as Cl2)

Eye/nose irritation; stomach discomfort, anemia

Water additive used to control microbes

Chlorine (as Cl2) Eye/nose irritation; stomach discomfort


Chlorine dioxide (as ClO2)

Anemia; infants & young children: nervous system effects


Inorganic Chemicals



Antimony Increase in blood cholesterol; decrease in blood sugar

Discharge from petroleum refineries; fire retardants; ceramics; electronics; solder

Arsenic Skin damage or problems with circulatory systems, and may have increased risk of getting cancer

Erosion of natural deposits; runoff from orchards, runoff from glass & electronicsproduction wastes

Asbestos (fiber >10 micrometers)

Increased risk of developing benign intestinal polyps

Decay of asbestos cement in water mains; erosion of natural deposits

Barium Increase in blood pressure Discharge of drilling wastes; discharge from metal refineries; erosion of natural deposits

Beryllium Intestinal lesions Discharge from metal refineries and coal-burning factories; discharge from electrical, aerospace, and defense industries

Cadmium Kidney damage Corrosion of galvanized pipes; erosion of natural deposits; discharge from metal refineries; runoff from waste batteries and paints

Chromium (total) Allergic dermatitis Discharge from steel and pulp mills; erosion of natural deposits

Copper Short term exposure: Gastrointestinal distress Long term exposure: Liver or kidney damage People with Wilson's Disease should consult their personal doctor if the amount of copper in their water exceeds the action level

Corrosion of household plumbing systems; erosion of natural deposits

Cyanide (as free cyanide)

Nerve damage or thyroid problems

Discharge from steel/metal factories; discharge from plastic and fertilizer factories

Fluoride Bone disease (pain and tenderness of the bones);

Water additive which promotes strong teeth; erosion of natural


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Children may get mottled teeth deposits; discharge from fertilizer and aluminum factories

Lead Infants and children: Delays in physical or mental development; children could show slight deficits in attention span and learning abilities Adults: Kidney problems; high blood pressure

Corrosion of household plumbing systems; erosion of natural deposits

Mercury (inorganic)

Kidney damage Erosion of natural deposits; discharge from refineries and factories; runoff from landfills and croplands

Nitrate (measured as Nitrogen)

Infants below the age of six months who drink water containing nitrate in excess of the MCL could become seriously ill and, if untreated, may die. Symptoms include shortness of breath and blue-baby syndrome.

Runoff from fertilizer use; leaching from septic tanks, sewage; erosion of natural deposits

Nitrite (measured as Nitrogen)

Infants below the age of six months who drink water containing nitrite in excess of the MCL could become seriously ill and, if untreated, may die. Symptoms include shortness of breath and blue-baby syndrome.

Runoff from fertilizer use; leaching from septic tanks, sewage; erosion of natural deposits

Selenium Hair or fingernail loss; numbness in fingers or toes; circulatory problems

Discharge from petroleum refineries; erosion of natural deposits; discharge from mines

Thallium Hair loss; changes in blood; kidney, intestine, or liver problems

Leaching from ore-processing sites; discharge from electronics, glass, and drug factories

Radionuclides

Contaminant MCL or TT1 (mg/L)2

Potential Health Effects from Ingestion of Water


Alpha particles 15 picocuries per Liter (pCi/L)

Increased risk of cancer Erosion of natural deposits of certain minerals that are radioactive and may emit a form of radiation known as alpha radiation

Beta particles and photon emitters

4 millirems per year

Increased risk of cancer Decay of natural and man-made deposits of certain minerals that are radioactive and may emit forms of radiation known as photons and beta radiation

Radium 226 and Radium 228 (combined)

5 pCi/L Increased risk of cancer Erosion of natural deposits


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Uranium 30 ug/L as of 12/08/03

Increased risk of cancer, kidney toxicity

Erosion of natural deposits

Source: Overview of Contaminants & Their Potential Health Effects. http://www.freedrinkingwater.com/water-education/water-contaminants-health-effects.htm Date accessed: November 2, 2007


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Appendix 6.5: Length of Cambodian Seasons Ideally, the tests in this investigation would be carried out several times a month, every month for several years, but instead, the above was carried out only one time every month, and only while school was in session. This led to an absence of samples for the wet season (June and July) and no samples in the beginning of the dry season (November), which affected which samples I chose to compare in my investigation.38 The uneven number of samples from the wet and dry season would have made a comparison between, for example, an average of the Tonlé Sap’s wet season measurements and an average of the Tonlé Sap’s dry season measurements inaccurate, as explained by Fig. 3.4.1.

Fig. 3.4.1: Hydrograph depicting the dry season and the wet season (labeled here as the flood season).39 Graph based on mean annual hydrograph recorded at Kratie, Cambodia, a province northeast of Phnom, also on the Mekong River. This demonstrates that the dry season is longer than the wet season, so two months of the wet season missing from the records would indeed misrepresent the two rivers being studied.

Even without missing samples, it is important that the same number of samples from each

season be compared for each river and vice versa. Also, the more samples tested the more accurate our results will be, since an average of three measurements in a single season would best represent that season. However, the maximum number of results from a single season which can be tested is 3 – August, September and October – in July; school was not in session so we could not take measurements. Therefore, it would make sense for me to choose three months from the dry season as well. However, because October is part of Transition Season 2, I did not want the period of flow reversal to influence the river’s water quality readings. Though not expressed on this graph, many other sources including the Office of Council of Ministers in Cambodia40 state that October is when the Tonlé Sap begins changing directions. Therefore, I have decided to choose two samples near the middle of each season for each river,41 which I have averaged and compared.

38 Please see Introduction: II. Aims of the Investigation 39 About Floods in the Mekong Basin. The Mekong River Commission. http://www.mrcmekong.org/flood_report/2006/about-foods.htm Date accessed November 3, 2007. 40 www.ocm.gov.kh Date Accessed: November 11, 2007 41 Please see Methodology: I. General Method


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Appendix 7: Information about WQI Water Quality Index: Iowa In 1970, the National Sanitation Foundation developed the Water Quality Index (WQI), a standardized method for comparing the water quality of various water bodies. In Iowa, the WQI is calculated by using eight common water quality parameters (dissolved oxygen, fecal coliform bacteria, pH, 5-day BOD, total phosphorus, nitrate-nitrogen, turbidity, and total dissolved solids). Values range from 0 – 100 and streams are classified as poor (0-25), fair (25-50), medium (50-70), good (70-90), or excellent (90-100). Source: Water Quality Index: Iowa. The Iowa Department of Natural Resources. http://wqm.igsb.uiowa.edu/wqi/wqi.asp Date accessed: November 2, 2007 The following website, maintained by Wilkes University’s Center for Environmental Quality, Environmental Engineering and Earth Sciences, was used to calculate the NSF Water Quality Indexes in this investigation.

Screen shot of: http://www.water-research.net/watrqualindex/index.htm

This WQI standard has been used to indicate the general water quality of a river and not the water quality recommended for a specific activity e.g. drinking, swimming, cooking, etc. For example, this standard has not taken into account the concentration of sodium chloride as well – which is necessary for some forms of aquaculture. The following table shows the values the Mekong River Commission uses to determine water quality based on several factors. When viewed in contrast with V. Theoretical Background, this table demonstrates the minor differences present in each organization’s parameters of measuring water quality.


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Diagnostic study of water quality in the Lower Mekong Basin. 2007: 17


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Appendix 7.5: Improving the Precision and Accuracy of Data Collection Precision and accuracy In all experimental measurements, there is a degree of uncertainty or error. When reporting data, the degree of uncertainty can be measured by considering the precision and accuracy of the analysis. The precision simply means the reproducibility of the analysis: If the same sample is analyzed multiple times, how much will the results vary? Accuracy, on the other hand, refers to how close the measurement is to the true value. Analytical precision can be assessed by making repeat measurements and calculating the ratio of the standard deviation to the average. This is called the coefficient of variation, and as a rule of thumb should be less than 10% for laboratory measurements. Precision will depend primarily upon the instrument and method, but also on the operator and quality control procedures. The picture below illustrates these concepts:

Source: Rosenboom, Jan-Willem (2004) Not Just Red or Green: An analysis of arsenic data from 15 upazillas in Bangladesh. Arsenic Policy Support Unit, Dhaka. Precision of the measurements carried out for the river water analysis cannot be assessed, since only one single measurement was performed on each monthly because of lack of resources. Therefore, to improve accuracy and precision, we must eliminate issues of quality control. This could be done through using standard procedures, training operators, taking multiple samples and comparing data collected with existing scientific literature. With the limited method that we have, we were all taught a standard method by a qualified chemist, who stressed to us the importance of following the standard procedures outlined in III. Data Collection Methods. In regards to multiple samples, as mentioned in Appendix 6.5, and the conclusion, although we would ideally want to compare as many samples of each season and for as long as possible (a decade or more), this was not possible during the two years of our project. Also mentioned in the body of the essay, it is extremely difficult to find data to compare the results of this investigation to because of the unique hydrological system found in Cambodia. Another way to improve quality and precision is by following the Standard Methods for the Examination of Water and Wastewater’s official website standardmethods.org, put together by the American Public Health Association, the American Water Works Association and the Water Environment Federation, which provides extensive guidelines on how to best evaluate water quality.

Not precise, not accurate Accurate, not precise Precise, not accurate Accurate and precise


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It indicates that when using colorimetric methods, the use of an instrument called a photometer would eliminate the dependency the results have on the operator, to reduce bias and increase accuracy and precision. Since so many of our experiments use colorimetric methods, the use of a photometer would have greatly increased the precision and accuracy of our results. The increased accuracy would be especially useful for measuring nutrients. In this investigation, it has always been difficult to distinguish between 0.1 ppm or <0.1 ppm. Electronic instruments would make the process more convenient for pH, as well. Since this measurement is affected by temperature, it would be doubly useful to have an instrument that could take this into account too. However, as shown by the figure below, these types of instruments are expensive, and therefore explain why we have used the equipment donated to us by the New York State University through the Buffalo Aquanaut Program.

Waterproof pH and Temperature Thermometer A superb digital dip-and-read meter, automatic 2 point self calibrating feature, Full microprocessor circuit with automatic compensation resolution 0.1 and temperature meter can be set to f or c scale Batteries, Instructions, & 2 buffer calibration solutions are included free. Replaceable pH probe. Temperature can be set to either F or C scale. Batteries, 2 buffer solutions and instructions are included.

Code Product Price Order DPHM Waterproof pH and Temperature Thermometer £79.00 Source: http://www.absolute-koi.com/water_testing/hanna.html Date accessed: 11/02/07


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Appendix 8: Turbidity

Once secchi depth is measured (see right), turbidity can be calculated using a scale (see above). By connecting the value of the site’s secchi depth (on the top scale) with the turbidity in nephelometric turbidity units (NTUs) (on the bottom scale), we can determine what the turbidity measurement is. This diagram is a visual representation of the positive correlation between secchi depth and turbidity. It also demonstrates that the values calculated for turbidity saturation may not be very accurate since the subjective personal judgment must be used to estimate which value corresponds to which, since there are not enough marks between each unit. This is especially difficult because of its logarithmic increments. Varied lighting at each site may have further contributed to the inaccuracy of these tests. Turbidity indicates water quality by measuring the cloudiness of water. Higher turbidity may indicate low filtration effectiveness because of the high prevalence of disease-causing microorganisms such as viruses, parasites and bacteria or may be due to suspended solids and algae. Pathogens can cause nausea, cramps, diarrhea and headaches, while water cloudiness can block sunlight, leading to less oxygen produced by plants through photosynthesis, decaying plants and a lesser water quality. Suspended solids also absorb heat, making temperature rise faster in turbid water, thus lowering the DO concentration. They can also harm aquatic organisms in the water, such as fish.43

42 Image taken from: Turbidity. Australian Government. http://www.waterwatch.org.au/publications/module4/turbidity.html Date accessed : November 3, 2007 43 Turbidity. Australian Government. http://www.waterwatch.org.au/publications/module4/turbidity.html Date accessed : November 3, 2007

42


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Appendix: 9: % DO Saturation

By using a straight line to connect the value of the site’s temperature (on the top scale) with the DO in parts per million (on the bottom scale), we can determine what the percentage of DO saturation is by recording where the straight line intersects with the scale for % saturation (on the middle diagonal scale). This diagram is a visual representation of temperatures effect on water’s maximum ability to absorb oxygen (DO Saturation). It also demonstrates that the values calculated for DO saturation may not be very accurate since the subjective personal judgment must be used to estimate where lines intersect, if there are not enough marks between each unit. Also, if water temperature exceeds 30 centigrade, an estimated extension of the top scale must be created, which is especially difficult because of its logarithmic increments

Appendix 10: Hardness Concentration 1 drop = 18 ppm

2 drop = 36 ppm 3 drop = 54 ppm 4 drop = 72 ppm 5 drop = 90 ppm

6 drop = 107 ppm 7 drop = 125 ppm 8 drop = 143 ppm 9 drop = 161 ppm 10 drop = 179 ppm

11 drop = 197 ppm 12 drop = 215 ppm 13 drop = 233 ppm 14 drop = 251 ppm 15 drop = 269 ppm


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Appendix 11: Evaluation of WQI WQI is not designed for tropical climates, therefore it is important to understand its limitations when applying NSF’s water quality standard to tropical rivers which tend to contain have a higher temperature, sediment load (and thus SS, BOD, FC and nutrients) and slower speed. The following graphs show that streams in Iowa, a place with a temperate climate, have seasonal trends.

Seasonal WQI trends of rivers in Iowa44

The same streams with nearly 69% good WQI and some medium WQI, flips over to over less

than 30% good WQI in the summertime. This change may be an indicator of the increase in animal or human use of the streams for transportation or leisure during this season, or else, it could indicate that it is the temperature change which greatly affected the WQI. Summertime in Iowa is on average 26.745 near the average temperature of sites tested in this investigation: 28.76.

This data suggests that it is possible that in tropical rivers, its high temperature may lower the WQI of what may be in fact a ‘good’ quality river. So for tropical rivers perhaps temperature should have less weight.

It could also be argued that given the conditions of an LEDC, such as Cambodia where river water is used for drinking without treatment, that the weight for FC should be much higher. So a WQI that would indicate good quality in Cambodia, may in fact, if used for the same purposes in temperate climates, be of excellent quality, since water in MEDCs is generally treated further before usage.

Finally, the WQI has been designed to give a general overview of water quality, assigning weights to the different factors in order of most harm or benefit to humans. It should not be viewed as the ultimate indicator of water quality since water is used for a variety of different purposes, e.g. drinking, cooking, bathing, fish raising, agricultural irrigation, recreation (such as fishing, sailing, swimming), or industrial use. The following table compares the World Health Organization’s guidelines for drinking water with Cambodia’s actual average drinking water quality.

Indicator Unit WHO guidelines Cambodia standard Colour Pt/Co 15 5 pH value Unit 6.5 – 8.5 6.5 - 8.5 Suspended solids Mg/L 1 - Turbidity NTU 5 5 Total dissolved solids Mg/L 1000 800 Dissolved oxygen Mg/L <10 - Total coliform Cfu/100ml 0 0 Fecal coliform Cfu/100ml 0 0 N-Ammonia (NH3-N) Mg/L 0.05-0.50 -

Source: Phnom Penh Water Supply Authority, 2006

This table indicates that much processing is done after retrieving water from a source, so the value of the WQI of rivers on its own is less significant than if compared with other standards. It is useful in comparing tropical rivers against other tropical rivers, but should not be considered as the ultimate water quality standard, nor should tropical rivers’ WQI be compared with temperate rivers since they are different, and appropriately, should have different standards. 44 Water Quality Index: Iowa. The Iowa Department of Natural Resources. http://wqm.igsb.uiowa.edu/wqi/wqi.asp 11/02/07 45 WELCOME TO PROJECT CHILDREN. http://www.projectchildrenni.com/states.htm 11/02/07


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Appendix 12: Raw Data Information was collected from the 5 sites, every month from August to May. From the dry season’s set of data, I decided to use the following, since they were not prone to be affected by the reversal of the river flow: Sample 1: January 13, 2007

Test Site 2 Tonlé Sap

Site 4 Mekong River

Secchi (cm) 30 70 pH 7 7 Hardness (ppm) 36 54 Temperature (°C) 27.2 26.8 Nitrate (ppm) < 0.1 < 0.1 Phosphate (ppm) 0.1 < 0.1 Dissolved Oxygen (ppm) 6 7 Dissolved Oxygen in 5 days (ppm) 4 5 Biological Oxygen Demand (ppm) 2 2 Dissolved Oxygen (%) 73 85 Dissolved Solids (ppm) 60 120 Suspended Solids (ppm) 30 12 Total Solids (ppm) 90 132 Turbidity (NTU) 22 11 E. coli (colonies/100 ml) 1050 500 Water Quality Index (WQI) 73 77

Sample 2: February 17, 2007

Test Units Site 2

Tonlé SapSite 4

Mekong Secchi inches 19.69 39.37 pH pH 7 7 Hardness ppm 54 54 Temp °C 30.5 30.7 Nitrate ppm <0.1 <0.1 Phosphate ppm <0.1 <0.1 Dissolved Oxygen ppm 5 6 DO (5 days) ppm 3 4 BOD ppm 2 2 DO % 66 79 Dissolved Solids ppm 60 130 Suspended Solids ppm 10 5 Total Solids ppm 70 135 Turbidity NTU 17 8 E. Coli /100ml 400 200 Water Quality Index WQI 64 68


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For the wet season, I decided to use the following, for the same reasons: Sample 1: August 26, 2007

Test Site 2 Tonlé Sap

Site 4 Mekong River

Secchi (cm) 2.2 2.2 pH 8 7 Hardness (ppm) 72 36 Temperature (°C) 29 28.4 Nitrate (ppm) < 0.1 < 0.1 Phosphate (ppm) 0.2 < 0.1 Dissolved Oxygen (ppm) 7 7 Dissolved Oxygen in 5 day (ppm) 3 3 Biological Oxygen Demand (ppm) 4 4 Dissolved Oxygen (%) 90 88 Dissolved Solids (ppm) 60 60 Suspended Solids (ppm) 200 200 Total Solids (ppm) 260 260 Turbidity (NTU) 90 90 E. coli (colonies/100mL) 1000 750 Water Quality Index 68 69

Sample 2: September 30, 2007

Test Units Site 2

Tonlé SapSite 4

Mekong Secchi inches 17.72 7.87 pH pH 7 7 Hardness ppm 36 36 Temp °C 28.9 28.6 Nitrate ppm <0.1 0.1 Phosphate ppm <0.1 0.1 Dissolved Oxygen ppm 5 5 DO (5 days) ppm 3 3 BOD ppm 2 2 DO % 64 63 Dissolved Solids ppm 60 70 Suspended Solids ppm 10 180 Total Solids ppm 70 250 Turbidity NTU 20 42 E. coli /100ml 1100 2100 Water Quality Index WQI 70 66


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Appendix 13: Standard Deviation

Tonlé Sap River Mekong River Water Quality Index Standard Deviation Standard Deviation Wet Season Samples 1.0 1.5 Dry Season Samples 4.5 4.5 Average 1.3 3.0

Standard Deviation

Calculating the standard deviation (SD) of the results do not indicate whether or not the results are reliable because although the SD values suggest that the average differences between each measurement can be attributed to chance, repeated measurements at each site within each month were not taken, so these variations can also be attributed to the seasonal changes occurring in the time between when Samples 1 and Samples 2 were taken.

Appendix 14: Temperature It wasn’t possible to calculate temperature change (the difference of one site’s temperature to the temperature of a site further upstream on the same river), for Site 4 on the Mekong (because we did not measure a site upstream from Site 4) so this calculation was not done for the Tonlé Sap’s Site. Although calculations for DO directly involved the temperature measurements, the calculated WQI does not take into account temperature change.


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Two fishing boats on the Mekong River in Phnom Penh during the rainy season.

2007 © Nettra Pan