Evaluation of surfeace warter quality in west lake hanoi

MINISTRY OF AGRICULTURE AND RURAL DEVELOPMENT VIETNAM FORESTRY UNIVERSITY STUDENT THESIS EVALUATION OF SURFACE WATER QUALITY IN WEST LAKE, HANOI Major: Natural Resources Management

MINISTRY OF AGRICULTURE AND RURAL DEVELOPMENT

VIETNAM FORESTRY UNIVERSITY

STUDENT THESIS

EVALUATION OF SURFACE WATER

QUALITY IN WEST LAKE, HANOI

Major: Natural Resources Management (Advanced Curriculum)

Code: D850101

Advanced Education Program

Developed in Collaboration with Colorado State University, USA

Student: Nguyen Ngoc Son

Class: 55 Advanced Curriculum

Supervisor: Phi Thi Hai Ninh

Student ID:1053091309 Course: 2010 - 2014

Hanoi, October 2014

ABSTRACT

West Lake is currently facing serious water pollution due to a rapid urbanization and population growth, but the levels of pollution are not the same at different points across the lake This research aims to asses the quality of surface water of West Lake, identify causes of the issues and to propose appropriate solutions to protect and recover West Lake‟s water quality The research was conducted by applying the following principal methods: literature review, field surveys, sampling and laboratory analysis and desk analysis The findings

demonstrate that the water quality is relatively good at the middle of the lake (Point P2, Table 5.6) whereas the water quality is worsen when getting near the lakeside since it is contaminated by the sewage from the city (Point S2, Table 5.6) It is proved by the data of Table 5.6 that the quality of water at point P2 satisfied almost least requirements (except

Phostphate) while the quality of water at point S2 did not qualified several requirements (Those are BOD5, COD, Phostphat, Ammoniac, Coliform) To protect the lake, this research

proposes to build new wastewater treatment plants and new drainage systems around the lake, and then inhibit any business activities that are currently running on the lake These solutions are expected to be applied not only to West Lake but also applicable to other water bodies within mega cities in Vietnam

ACKNOWLEDGEMENTS

I would firstly like to gratefully thank my advisor, Ms Phi Thi Hai Ninh for her guidance, support and assistance during I carried out my research I would like to be thankful to Ms Le Kim Ngan, a staff at Institute of Environmental Technology, Vietnam Academy of Science and Technology, for assisting in the laboratory I would also like to sincerely thank Prof Lee MacDonald for his invaluable and enthusiastic instructions, recommendations during his course and during the time I conducted my graduate dissertation After all, I would highly

appreciate teachers and staff in the Advanced Curriculum Program for providing me

knowledge, skills and supports over last 5 years Finally, I sincerely thank my parents and my sister for their unconditional love, encouragement and support during I studied at Vietnam Forestry University

TABLE OF CONTENTS

II LITERATURE REVIEW

1 National technical regulation on surface water quality 3

2 Water quality of West Lake in recent years 4

3 West Lake‟s water quality changes over the last 5 years 6

V RESULTS AND DISCUSSION

1 Water Pollution Distribution and current activities around West Lake 18

2 Characteristics of West Lake‟s water throughout study period 21

LIST OF TABLES AND FIGURES

Table 2.3: Levels of West Lake‟s water

quality at each parameter and location

(2010-2014)

Table 4.1: Water quality parameters

Table 4.2: Measuring method for each water

Table 5.5: Characteristics of West Lake‟s

water for the whole period

Table 5.6: Comparison of West Lake‟s

Figure 2.1: TSS of West Lake (2010-2014)

Figure 2.2: TDS of West Lake (2010-2014) Figure 2.3: Turbidity of West Lake (2010-2014)

Figure 2.4: pH of West Lake (2010-2014) Figure 2.5: DO of West Lake (2010-2014) Figure 2.6: BOD5 of West Lake (2010-2014)

Figure 2.7: COD of West Lake (2010-2014) Figure 2.8: Nitrate of West Lake (2010-2014) Figure 2.9: Phosphate of West Lake (2010-2014)

Figure 2.10: Ammoniac of West Lake 2014)

Figure 2.11: Coliform of West Lake 2014)

(2010-Figure 4.1: the location of West Lake in Hanoi (Source: Google Maps, 2014)

Figure 4.2: Sampling locations Figure 5.1: Distribution and Levels of Water Pollution in West Lake, Hanoi

Figure 5.2: Seasonal change of TSS and TDS Figure 5.3: Seasonal change of pH

water quality with Vietnamese Surface

Water Standard at different locations

Table 5.7: Seasonal variation of West

Lake‟s water quality

Figure 5.4: Seasonal change of Nitrate, Phosphate, Ammoniac

Figure 5.5: Seasonal change of Coliform Figure 5.6: Seasonal change of BOD5, COD and DO

LIST OF ABBREVIATION

TSS: Total suspended solid

TDS: Total dissolved solid

DO: Dissolved oxygen

BOD5: Biological oxygen demand

COD: Chemical oxygen demand

I INTRODUCTION

West Lake is the largest freshwater lake and also one of the most important lake in Hanoi Located in the north of Hanoi, West Lake is holding a great role in terms of historical culture values and economic and social significance However, West Lake recently has been facing serious water pollution that consequently causes other environmental issues and loss of biodiversity

The area of West Lake is also being gradually narrowed down due to the urbanization and

encroachment According to the results investigated by West Lake Exploitation Company, the

shore length of the lake has been reducing from 19km in 1997 to 17km in 2014 In 2002, the local people found that some snails lost their coiled shells that never happened before; the size

of few snail species were found to be 2/3 smaller than the same ones in other places (Vinh, 2010) The lake had 36 species of fish, 106 species of phytoplankton (Mai, 2005) but a similar

investigation taken place from 2007 to 2011 showed that the number of phytoplankton had a

significant decrease, it now remains 70 species (Thủy, 2012) In addition, in 2012, the number

of fish was recorded to increase to 48 species mainly due to natural immigration and aquaculture activities It is hard to find any benthic organisms within a distance of 20m from

sewers (Thủy, 2012) In every summer, there is always a big number of fish dead and floating

on the surface water That causes a bad smell and inconvenience for the local people The main reason of dead fish in this lake is mainly caused by water pollution

According to the statistical data from People’s Committee of Tay Ho District, the

estimated population of the entire Tay Ho District is about 97,000 and one third of them are living closely around the lake A large portion of Hanoi citizens tightly depend on this lake due to its big value of aquaculture and ecotourism In contrast, their activities are significantly contributing to water pollution Most of pollutants come from the sewers of the local residents

(domestic wastewater is directly discharged into the lake water without any treatment) The pollutants also come from surrounding restaurants, food production and agricultural activities

An estimation of 10.000 m3 domestic wastewater is discharged into the lake everyday (Vinh,

2011) Among around 22 sewers around the lake, the largest sewers include: „Cay Si‟ sewer in

Thanh Nien Street, „Tau Bay‟ sewer near Ly Tu Trong Flower Garden, „Muong Do‟ sewer in

Thuy Khue Ward and „Trich Sai‟ sewer in Trich Sai village (Mai, 2005)

In addition, pesticides and fertilizers are the other sources of water pollution The agricultural area is 26.24 ha The purposes of agricultural lands are mainly to grow vegetables, ornamental plants (Peach, Kumquat…) and flowers in Nhat Tan Ward, Quang An Ward and Nghi Tam Street Pesticides and fertilizers have been using popularly in these areas to protect plants from harmful pests and stimulate plant growth Consequently, fertilisers and pesticides

runoff water has seriously contaminated the lake water (Thủy, 2012)

Due to these West Lake‟ environmental issues, it is critically important to propose efficient solutions to control pollution and recover water quality of the lake This research has been carried out to provide better undertanding in relation to causes of West Lake‟s water issue, and then suggest effective measurments to deal with the issue

II LITERATURE REVIEW

1 National technical regulation on surface water quality

This standard is applied to evaluate and control the quality of surface water It is also the base to serve protection and promote suitable water usages

Table 2.1: QCVN 08: 2008/BTNMT National technical regulation on surface water quality

Source: Directorate for Standards, Metrology and Quality, 2008

The standard classifies surface water quality in 4 levels which correspond to different purposes of water use:

- A1 can be used for domestic water supply and can also be used for other purposes mentioned in the classification of A2, B1 and B2

- A2 can be used for aquaculture and conservation of aquatic animals and plants It can

be used as domestic water supply but must be applied appropriate treatment technologies before using It can also be used for the purposes of class B1 and B2

- B1 can be used for irrigation and other purpose of class B2

- B2 can be used for traffic waterway and other purposes with low water quality requirement

2 Water quality of West Lake in recent years

Table 2.2 displays the water quality levels of West Lake from 2010 to 2014 at 2 points: one is at the middle of the lake (P2, Figure 4.2) and one is near Thanh Nien Street and Tran Quoc Pagoda (S5, Figure 4.2)

Table 2.2: Water quality of West Lake from 2010 to 2014

Table 2.2 presents that the levels of BOD, COD, NH4+, NO3-, PO43- of the inshore point

(S5) are approximately 2 times higher than those in the middle of the lake (S2) In terms of Coliform, there are significant differences between 2 points S5 and P2 In 2010, 2011 and

2012, the difference is about 4 times In 2013 and 2014 the difference decreases to 2 times Based on the monitored water parameters, the lake water was separated into different

classification of A1, A2, B1 and B2 (Table 2.1) There are some indicators that were not

qualified by the standard and they are marked as X Turbidity and Total suspended solid are not standardized

Table 2.3: Levels of West Lake’s water quality at each parameter and location (2010-2014)

According to the table (Table 2.3), pH has been gradually becoming neutralized from

2012 TTS was also better at the middle of the lake over the last 2 years DO, BOD, COD did not have any significant change but they had a slightly improvement on the lakeside in 2013 The concentration of Ammoniac (NH4+) did not match any standard during the whole period

but it was notably enhanced in 2013 and 2014 The amount of Phosphates (PO43-) has been

significantly declined, but it is still too high over the standard The amount of Nitrate (NO3-)

almost satisfied standard A2 throughout this period The Total Coliform was improved as well from 2010 to 2014 when the point of the lakeside (S5) started to fulfill standard B2

3 West Lake’s water quality changes over the last 5 years

Based on Table 2.2, the trend of individual water qualiy parameter in West Lake from

2010 to 2014 are shown from Figure 2.1 to Figure 2.11

Figure 2.1: TSS of West Lake (2010-2014) Figure 2.2: TDS of West Lake (2010-2014)

Figure 2.3: Turbidity of West Lake (2010-2014) Figure 2.4: pH of West Lake (2010-2014)

of S5 A2 Criterion for TSS B1 Criterion for TSS

0 50 100 150 200 250

0 2 4 6 8 10

Figure 2.5: DO of West Lake (2010-2014) Figure 2.6: BOD 5 of West Lake (2010-2014)

Figure 2.7: COD of West Lake (2010-2014) Figure 2.8: Nitrate of West Lake (2010-2014)

Figure 2.9: Phosphate of West Lake (2010-2014) Figure 2.10: Ammoniac of West Lake (2010-2014)

Figure 2.11: Coliform of West Lake (2010-2014)

5 10 15 20 25 30

of S5 B1 Criterion for COD B2 Criterion

1 2 3 4 5 6

Nitrate (mg/L) of S5

A2 Criterion for Nitrate

Phosphate

0 0.5 1 1.5 2 2.5 3 3.5 4

of P2 Coliform (MPN/100ml)

of S5 A2 Criterion for Coliform B2 Criterion for Coliform

Most of these figures demonstrate that the values of 11 water quality parameters are fluctuated such as TSS, Turbidity, DO, COD and Nitrate In detail, TSS of P2 and S5 rose and fell throughout the last five years and it corresponded to the change of Turbidity The same trend occurs at DO, COD and Nitrate but they still qualified some requirements pH was fairly stable and still in the safe range BOD5 has a slightly improvement and itpersistently satisfied

standard B2 over the study period Some parameters had remarkable improvement like Phosphate, Ammoniac and Coliform However, the concentration of Phosphate was still too high during the last five years and it continuously exceeded the least standard In general, the

water qualities of both points (P2 and S5) were relatively less changed and mostly met

national surface water standards

4 Water quality parameters

Each parameter indicates the water pollution level in a different way

a Temperature

Water temperature affects the growth and reproduction of living aquatic organisms Some animals and plants may grow faster at warmer temperatures but it may influence sensitively some other animals and plants when it reaches closer to their upper temperature limit Water temperature has a tremendous impact on water density Differences in water temperature and density cause stratification For fisheries managers, the spatial distribution of fish within a lake

is often adversely affected by thermal stratification and in some cases may indirectly cause large die-offs of recreationally important fish

b Total suspended solid

Total Suspended Solids (TSS) is the total volume of suspended particles in water which will not pass through a filter Suspended solids absorb heat from sunlight, which increases water temperature and subsequently decreases levels of dissolved oxygen (warmer water holds

less oxygen than cooler water) Photosynthesis also decreases, since less light penetrates the water In addition, under low pH condition, toxic substances such as heavy metal may stick on the surface of suspended particles that will increase level of pollution of the lake

c Total dissolved solid

Total dissolved solids (TDS) is a measure of the total amount of all inorganic and organic substances – including minerals, salts, metals, cations or anions – that are dispersed within a volume of water By definition, the solids must be small enough to be filtered through a sieve measuring 2 micrometers TDS is not considered a primary pollutant, high TDS levels typically indicate the hardness of water and may lead to scale buildup in pipes, valves, and filters reduced efficiency of water filters, hot water heaters, and adding to system maintenance costs

d Turbidity

Turbidity is an expression of the amount of light that is scattered by material in the water when a light is shined through the water sample Materials that increase turbidity include micro-organisms, plankton, algae and mostly suspended particles (TSS) A high level of TSS resulted in a high turbidity of the water body In lakes, rivers, high turbidity levels can reduce the amount of light reaching lower depths, which can inhibit growth of submerged aquatic plants and consequently affect species which are dependent on them, such as fish and shellfish High turbidity levels can also affect the ability of fish gills to absorb dissolved oxygen In addition, the affects of Turbidity to a water body are the same as the affects of TSS

to that

e pH

pH is the measurement of alkalinity and acidity levels of water Excessively high and low pHs can be detrimental for the use of water High pH causes a bitter taste, water pipes and

water-using appliances become encrusted with deposits, and it depresses the effectiveness of the disinfection of chlorine, thereby causing the need for additional chlorine when pH is high Low-pH water may corrode or dissolve metals and other substances that harm to aquatic organisms

f Dissolved oxygen (DO)

In aquatic environments, oxygen saturation is a relative measure of the amount of oxygen (O2) dissolved in the water Supersaturation can sometimes harm organisms and cause decompression sickness However, insufficient oxygen (environmental hypoxia) that often caused by the decomposition of organic matters and/or nutrient pollution may occur in bodies

of water such as ponds and rivers, tending to suppress the presence of aerobic organisms such

as fish Deoxygenation increases the population of anaerobic organisms such as some Obligate anaerobes, Aerotolerant organisms and Facultative anaerobes that cause deaths of fish and other adverse events

g Biological oxygen demand (BOD5)

Biochemical Oxygen Demand (BOD) refers to the amount of oxygen that would be consumed if all the organic matters in one liter of water were oxidized by bacteria and protozoa When BOD levels are high, dissolved oxygen (DO) levels decrease because the oxygen that is available in the water is consumed by the bacteria Due to lack of available dissolved oxygen in the water, fish and other aquatic organisms may be affected

h Chemical oxygen demand (COD)

Chemical oxygen demand (COD) is an indicator to measure the amount of organic compounds that cannot be oxidized biologically in a sample of water Higher chemical oxygen demand always refers to higher level of pollution in the test sample

i Nitrate (NO3-)

Nitrate is a polyatomic ion with the molecular formula NO3− Infants below six months who drink water containing nitrate exceeding the maximum contaminant level (MCL) could become seriously ill and if untreated they may die Symptoms include shortness of breath and blue baby syndrome In nature, the excess amount of nitrates in water can create conditions that make it difficult for aquatic insects or fish to survive

j Phosphate (PO 4 3- )

Phosphate (PO43−) is an inorganic compound or a salt of phosphoric acid Phosphorus is one of the key elements necessary for growth of plants and animals in aquatic ecosystems Phosphates are not toxic to people or animals unless they are present in very high levels The high concentration of phosphate also can cause eutrophication

k Ammoniac (NH 4 + )

Ammonia is toxic to fish and aquatic organisms, even in very low concentrations When levels reach 0.06 mg/L, fish can suffer gill damage When levels reach 0.2 mg/L, sensitive fish like trout and salmon begin to die As levels of 2.0 mg/L, ammonia-tolerant fish like carp begin to die, too Ammonia levels greater than approximately 0.1 mg/L usually indicate polluted water The danger ammonia poses for fish depends on the water‟s temperature and

pH, along with the dissolved oxygen and carbon dioxide levels The higher the pH and the warmer the temperature is, the more toxic the ammonia could be Ammonia is also more toxic

to fish and aquatic life when water contains little dissolved oxygen and carbon dioxide

l Coliform bacteria

Coliforms themselves are not normally causes of serious illness, but their presence is used to indicate that other pathogenic organisms of fecal origin may be present Such pathogens include bacteria, viruses, or protozoa and many multicellular parasites